Implementing Taenia solium control programmes in countries: monitoring and evaluation framework

iImplementing Taenia solium control programmes in countries: monitoring and evaluation framework Implementing Taenia solium control programmes in countries Monitoring and evaluation framework

Implementing Taenia solium control programmes in countries Monitoring and evaluation framework Implementing Taenia solium control programmes in countries: monitoring and evaluation framework ISBN 978-92-4-010085-5 (electronic version) ISBN 978-92-4-010086-2 (print version) © World Health Organization 2024 Some rights reserved. This work is available under the Creative Commons Attribution-NonCommercial- ShareAlike 3.0 IGO licence (CC BY-NC-SA 3.0 IGO; https://creativecommons.org/licenses/by-nc-sa/3.0/igo). Under the terms of this licence, you may copy, redistribute and adapt the work for non-commercial purposes, provided the work is appropriately cited, as indicated below. In any use of this work, there should be no suggestion that WHO endorses any specific organization, products or services. The use of the WHO logo is not permitted. If you adapt the work, then you must license your work under the same or equivalent Creative Commons licence. 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In no event shall WHO be liable for damages arising from its use. iii Contents Acknowledgements .................................................................................................................................. v Glossary ...................................................................................................................................................... vi 1. Introduction ............................................................................................................................................ 1 1.1 Objectives of this document .....................................................................................................................1 1.2 For whom is this document intended? ................................................................................................1 1.3 Importance of monitoring and evaluation ..........................................................................................2 2. Background ............................................................................................................................................ 3 2.1 Public health interventions to control T. solium taeniasis and cysticercosis .........................4 2.2 Mapping tool ..................................................................................................................................................5 2.3 Diagnostic tools and suggested thresholds ......................................................................................5 3. Indicators for evaluating progress in T. solium control ............................................................... 7 3.1 Global indicators ...........................................................................................................................................8 3.1.1 Number of countries endemic for T. solium ..............................................................................8 3.1.2 Number of endemic countries that have completed mapping in high-risk areas .....................................................................................................................................8 3.1.3 Number of countries with intensified control in hyperendemic areas ..........................8 3.2 Country-level epidemiological indicators ..........................................................................................8 3.2.1 Number of neurocysticercosis cases reported .......................................................................8 3.3 Country-level control indicators ............................................................................................................9 3.3.1 Number of people at risk of T. solium ........................................................................................9 3.3.2 Percentage of people at risk of T. solium living in a control area ..................................9 3.3.3 Number of areas at risk ..................................................................................................................9 3.3.4 Coverage of preventive chemotherapy for taeniasis ..........................................................9 4. Epidemiological considerations ....................................................................................................... 11 4.1 Broad areas .....................................................................................................................................................11 4.2 Focal areas .....................................................................................................................................................11 5. T. solium survey characteristics ........................................................................................................ 12 5.1 Survey goal ......................................................................................................................................................12 5.2 Operational indicators ...............................................................................................................................12 5.3 Survey area .....................................................................................................................................................12 5.4 Diagnostic tests ............................................................................................................................................13 5.4.1 Considerations for human diagnostics ......................................................................................13 5.4.2 Considerations for pig diagnostics ............................................................................................14 5.5 Age group .......................................................................................................................................................14 5.6 Sample size ....................................................................................................................................................14 5.7 Sampling strategies ....................................................................................................................................15 5.7.1 Selection of the survey area ...........................................................................................................15 5.7.2 Selection of villages .........................................................................................................................15 5.7.3 Number of samples per village ....................................................................................................16 5.7.4 Timing ....................................................................................................................................................16 5.8 Target thresholds .........................................................................................................................................16 5.9 Frequency .......................................................................................................................................................16 5.10 Summary of survey characteristics .....................................................................................................18 6. Special considerations ........................................................................................................................ 20 6.1 Sampling in humans or pigs .....................................................................................................................20 6.2 Specificity of tests, local infections and selection of individuals .............................................20 6.3 Use of other diagnostic tools..................................................................................................................20 6.4 Surveillance integration with other diseases, especially in relation to Kato–Katz.............20 7. Conclusion .............................................................................................................................................. 22 References .................................................................................................................................................. 23 Annex 1. Methods and contributors ...................................................................................................... 25 Annex 2. Steps for conducting T. solium surveys: translating theory into practice ................. 28 Annex 3. Tongue palpation for diagnosis of porcine cysticercosis .............................................. 38 Annex 4. Lot quality assurance sampling and calculation details ................................................ 41 iv Acknowledgements The World Health Organization (WHO) is grateful to the many individuals who contributed to the development of this document. Members of the drafting group Bernadette Abela (WHO Global Neglected Tropical Diseases Programme, Geneva, Switzerland [WHO/NTD]), Vicente Y. Belizario Jr. (University of the Philippines, Manila, Philippines), Meritxell Donadeu (University of Melbourne, Melbourne, Australia), Katherine Gass (Task Force for Global Health, Decatur, United States of America), Patrick J. Lammie (Task Force for Global Health, Decatur, United States of America), Ana Luciañez (WHO Regional Office for the Americas, Washington, United States of America), Harena Rasamoelina (Indian Ocean Commission, Moka, Mauritius), Anne Straily (United States Centers for Disease Control and Prevention, Atlanta, United States of America), Paul Torgerson (University of Zurich, Zurich, Switzerland), Aya Yajima (WHO Regional Office for South-East Asia, New Delhi, India). WHO also gratefully acknowledges the experts and programme managers who participated in the regional workshops. Special thanks are due to Katie Gass (Task Force for Global Health, Decatur, United States of America) for technical support; to Katrin Bote (WHO Regional Office for South-East Asia, New Delhi, India), Marshall Lightowlers (University of Melbourne, Melbourne, Australia) and Pauline Mwinzi (WHO Regional Office for Africa, Brazzaville, Congo) for peer review; to Meritxell Donadeu (University of Melbourne, Melbourne, Australia) for writing this document and guiding the regional meetings; and to Bernadette Abela (WHO/NTD) for leading the process. The preparation of this document was financially supported by WHO. v Glossary The definitions given below apply to the terms used in this document. They may have different meanings in other contexts. broad survey Type of survey used when there are more than 20 villages or communities in a survey area. control Reduction of disease incidence, prevalence, morbidity and/or mortality to a locally acceptable level as a result of deliberate efforts; continued interventions are required to maintain the reduction. Control may or may not be related to global targets set by WHO. effectiveness Degree to which an intervention is successful in producing the desired public health result. efficiency A measurable level of peak performance by which waste is minimized by using the least amount of inputs and harnessing synergies to attain the highest output and desired impact of neglected tropical disease programmes. endemic areas (for Taenia solium) Areas in which the full life cycle of Taenia solium is present. In practical terms, this means areas with autochthonous cases of T. solium taeniasis in humans or porcine cysticercosis in local pigs. evaluation Periodic, rigorous and independent assessment of information about programme activities, processes and outcomes to make judgements about programme effectiveness and inform decisions about future programme development. focal survey Type of survey used when there are 20 villages or less in a survey area. hyperendemic areas (for Taenia solium) Areas in which the infection with Taenia solium is a public health problem. The current suggestion is that hyperendemic areas are those in which the key risk factors are present (roaming pigs and deficient sanitation) and ≥ 0.5% T. solium taeniasis in humans or ≥ 2% porcine cysticercosis in pigs has been detected. implementation unit Area or administrative unit for which a public health intervention is applied. indicator Quantitative or qualitative variable that provides a simple and reliable basis for assessing achievement, change or performance towards objectives; means of measuring what actually happens against what has been planned in terms of quantity, quality and timeliness. intensified control (of Taenia solium) Implementation of at least one core “rapid impact” intervention (i.e. treatment of humans for taeniasis or interventions in pigs (vaccination plus anthelminthic treatment). vi Kato–Katz technique Diagnostic method based on the microscopic examination of human stools for the detection of parasite’s eggs. Also known as cellophane faecal thick smear. mass drug administration Distribution of medicines to the entire eligible population of a given administrative setting (for instance, state, region, province, district, subdistrict or village). monitoring Regular collection, analysis and use of data on programme implementation (weekly, monthly, quarterly or annually) to measure progress towards programme/project objectives through tracking activities conducted, resources deployed and outputs generated; programme outcomes and impacts may also be included. One Health Integrated, unifying approach that aims to sustainably balance and optimize the health of people, animals and ecosystems. It recognizes that the health of humans, domestic and wild animals, plants, and the wider environment (including ecosystems) are closely linked and interdependent. preventive chemotherapy Large-scale use of medicines, either alone or in combination, in public health interventions. Mass drug administration is one form of preventive chemotherapy; other forms could be limited to specific population groups such as school-aged children and women of childbearing age. public health control programme (for Taenia solium) A programme whose aim is to break the transmission cycle of the parasite in endemic areas leading to control and prevention of taeniasis/cysticercosis. sensitivity The effectiveness of a diagnostic or screening test to identify individuals with the disease. It is the proportion of true positives identified by the test as positive. specificity The effectiveness of a diagnostic or screening test to identify non-diseased individuals. It is the proportion of true negatives identified by the test as negative. surveillance Ongoing systematic collection, collation, analysis, interpretation and prompt dissemination of data for use in planning, implementation, monitoring and evaluation of public health programmes. survey area The area for which a public health decision regarding the presence of Taenia solium is desired; it should correspond to the area or administrative unit for which a public health intervention could be implemented. The survey area can include several communities or villages. vii viii Implementing Taenia solium control programmes in countries: monitoring and evaluation framework © Cysticercosis Group Madagascar 11. Introduction This document aims to provide best practice on monitoring and evaluation of Taenia solium, as part of the World Health Organization’s (WHO) effort to develop M&E guidance across the neglected tropical diseases (NTDs). T. solium has been included in WHO’s list of NTDs since 2010 (1) and is featured in the NTD road map 2021–2030 (2). T. solium control programmes are relatively new compared with other NTD programmes and, as a result, the information available is limited. This monitoring and evaluation framework is based on the best information and evidence available at this time, as well as on experience from other disease control programmes. It will be updated as learning evolves and new diagnostic tools become available. Infection with the parasite T. solium causes two diseases in humans: taeniasis (infection with the adult parasite) and cysticercosis (infection with the larval stage of the parasite). Progress to control these diseases in endemic countries has been slow as resources are scarce, and adequate diagnostics, control tools and knowledge are lacking. Recently, however, new tools and guidance have become available, including the donation of taenicidal medicines (praziquantel and niclosamide), the publication of the Pan American Health Organization/WHO Guideline for preventive chemotherapy for the control of Taenia solium taeniasis (3) and WHO Guidelines on management of Taenia solium neurocysticercosis (4), the commercial availability of the TSOL18 pig vaccine (and its inclusion in the terrestrial manual of the World Organisation for Animal Health (5)) and the use of the vaccine in conjunction with oxfendazole in pigs, as well as results from an increasing number of field studies evaluating control interventions. This document responds to the request of several countries that are ready to begin implementing T. solium control programmes in order to provide guidance on diagnostic tools for use in public health programmes (6), on opportunities for integration and on monitoring and evaluation. The methods used to develop this monitoring and evaluation framework and the list of contributors are provided in Annex 1. 1.1 Objectives of this document The main objective of this document is to provide practical operational best practice on monitoring and evaluation to countries implementing T. solium public health control programmes in order to reduce the disease burden caused by the parasite. It is based on existing diagnostic methods. The specific objectives are: to suggest indicators to monitor progress globally and nationally; and to provide details on surveys for confirming endemicity (mapping) or for monitoring and evaluation of a T. solium public health programme. 1.2 For whom is this document intended? This framework is intended for managers of national T. solium control programmes; programme staff working at national and sub-national levels; development and technical agencies; nongovernmental organizations; and other organizations involved in supporting activities to control T. solium. Implementing Taenia solium control programmes in countries: monitoring and evaluation framework 1.3 Importance of monitoring and evaluation Monitoring of implementation is a critical component of programme management. The regular collection, processing, analysis and use of data on programme implementation (weekly, monthly, quarterly or annually) allows measurement of progress towards programme/project objectives. Monitoring implies not only gathering and reporting data but using those data to assist programme managers at national and subnational levels in assessing the status of the programme, reviewing progress against targets and making programmatic adjustments as necessary to achieve programme objectives. Monitoring also allows detection of unforeseen outcomes and actions for correction, so they can be promptly rectified, and the programme can get back on track. Programmatic evaluation is the periodic, rigorous and independent assessment of information about programme activities, processes and outcomes to enable judgements to be made about programme effectiveness and inform decisions about future programme development and expansion. 2 32. Background Taeniasis and cysticercosis caused by infection with T. solium affect vulnerable populations, mainly in Latin America, sub-Saharan Africa and Asia, where pigs roam free and poor sanitation allows pigs access to human faeces (Fig. 1) (7). Fig. 1. Global endemicity of Taenia solium, 2022 Source: WHO Taenia solium endemicity map – 2022 (7). The transmission cycle of the parasite involves humans and pigs (Fig. 2). Humans develop taeniasis infection with the adult tapeworm (see 1 in Fig. 2) when they ingest contaminated raw or undercooked pork (5 in Fig. 2). The tapeworms reach maturity over a 2–3 month period (8) and taeniasis may be asymptomatic. Pigs develop porcine cysticercosis, the infection with the larval stages of the parasite, when they ingest items contaminated with the tapeworm eggs released into the environment by a T. solium tapeworm carrier (2 and 3b in Fig. 2). Pigs usually show no clinical signs of infection, but heavily infected pigs can harbour larval cysts in their tongues, and in some settings, this can decrease their value. The most important disease caused by T. solium is human cysticercosis, especially neurocysticercosis. Human cysticercosis results from ingestion of the parasite eggs, and infection with the larval stages of the parasite (3a in Fig. 2), which causes cysts in the muscles, skin, eyes and the central nervous system. Neurocysticercosis refers to the development of T. solium cysts in the human central nervous system, which may cause focal epilepsy, epileptic seizures, hydrocephalus, chronic headaches, focal deficits and symptoms associated with increased intracranial hypertension; it can be fatal. Neurocysticercosis is one of the leading preventable causes of epilepsy worldwide, where it is estimated to contribute up to 30% of epilepsy cases in endemic countries (9); in specific communities it can be up to 70%. 4Implementing Taenia solium control programmes in countries: monitoring and evaluation framework Fig. 2. T. solium life cycle Source: Adapted from How to prevent the pork tapeworm? A neglected parasitic infection caused by Taenia solium (10). 2.1 Public health interventions to control T. solium taeniasis and cysticercosis A One Health approach should be used to sustain and more efficiently control T. solium integrating all relevant sectors and disciplines across the human–animal–environment interface, including public health and animal health. According to the report of the WHO Expert Consultation on foodborne trematode infections and taeniasis/cysticercosis (Vientiane, Lao People’s Democratic Republic, 12–16 October 2009) (11), the best options for sustainable prevention and control are: Core “rapid impact” interventions: treatment of human taeniasis and mass treatment and vaccination of pigs; Supporting measures: community health education and improved sanitation to end open defecation; Measures requiring more fundamental societal changes: improved pig husbandry to avoid free-roaming pigs and improved meat inspection, control and handling of pork. 5Fig. 3. Mapping steps (this document provides information to aid with step 4) 2.3 Diagnostic tools and suggested thresholds When planning a survey, it is important to know which diagnostic tools are available and understand their characteristics. A WHO expert meeting was convened in 2022 to discuss the use of existing diagnostic tools in T. solium control programmes (6). The experts concluded that a limited number of diagnostic tools are currently available for public health programmes, namely stool microscopy for taeniasis in humans, and tongue palpation and enhanced meat inspection for cysticercosis in pigs. These tools all have important limitations regarding sensitivity, so an adequate sample size should be used. This framework takes into account those limitations. The experts also concluded that given the low sensitivity of the available tests considered, even a weak signal should warrant a public health response, either in terms of treatment or further investigation. Therefore, the suggested prevalence threshold to start a programme is ≥ 0.5% T. solium taeniasis in humans or ≥ 2% porcine cysticercosis in pigs (Fig. 4). Once implemented, T. solium control programmes should be monitored and evaluated (section 1.3). WHO has produced two new resources that can be used as starting points to assist countries in monitoring and evaluating their T. solium control programmes: (i) a mapping tool and (ii) a report on existing diagnostic tools for use in T. solium public health programmes. 2.2 Mapping tool WHO has developed a mapping tool (12) to help identify areas endemic for T. solium (areas with the presence (or likely presence) of the full life cycle of T. solium). The tool has three companion elements: a mapping protocol, a risk classification tool and a mapping tool video. The mapping protocol describes four steps (Fig. 3) and provides details on the first three steps. The last step is to confirm endemicity; in many cases, surveys of humans and or pigs will be needed. This monitoring and evaluation framework complements the mapping tool by providing more details on the surveys required to confirm endemicity (step 4). 1 2 3 4 Collect the information Organize the information Classify areas by risk Confirm endemicity 2. Background P ig s: t o ng ue p al p at io n (T P ) in p ig s > 4 m o nt hs o f ag e o r m ea t in sp ec ti o n (M I) . I n lo ca lly b o rn a nd r ea re d p ig s* H um an s: M ic ro sc o p y (o r co p ro A g ) in a s ur ve y p ow er ed t o d et ec t a lo w p re va le nc e o f in fe ct io n, us in g p ur p o si ve s am p lin g E it he r o p ti o n ca n b e us ed , t he y ar e no t m ut ua lly e xc lu si ve . C o nfi rm T . s ol iu m N o c ap ac it y to co nfi rm T . s ol iu m P re va le nc e TP o r M I ≥ 2 % P re va le nc e TP ≥ 1 % - < 2% P re va le nc e: T P < 1 % , M I < 2% R e- ev al ua te in 1 2 m o nt hs ** * * In fe ct ed m ea t sh o ul d n o t en te r th e m ea t ch ai n an d s ho ul d f o llo w lo ca l l eg is la ti o n. T o ng ue p o si ti ve p ig s sh o ul d b e tr ea te d w it h ox fe nd az o le . I f p ig s ar e no t lo ca lly b o rn a nd r ea re d , f ur th er in ve st ig at io ns a re n ee d ed . ** If b o th k ey r is k fa ct o rs a re n o t p re se nt ( ro am in g p ig s + d efi ci en t sa ni ta ti o n) , t he n ac ti ve t ra ns m is si o n cy cl e is n o t o cc ur ri ng . I nf ec ti o n m ig ht b e sp o ra d ic o r im p o rt ed . ** * R ep ea ti ng a t 6 — 12 m o nt hs in te rv al w ill r ep re se nt a n ew c o ho rt o f p ig s. A r ep ea t p o si ti ve fi nd in g a t si m ila r le ve ls , i nd ic at es lo w t ra ns m is si o n an d a p ub lic h ea lt h p ro g ra m m e sh o ul d b e co ns id er ed . O R Su sp ic io n o f d is ea se s ca us ed b y T. s ol iu m B o th k ey r is k fa ct o rs p re se nt (r o am in g p ig s + d efi ci en t sa ni ta ti o n) ST A R TI N G P O IN T O P TI O N 1 O P TI O N 2 T. s ol iu m c o nfi rm ed ≥ 0 .5 % s am p le s T. s ol iu m c o nfi rm ed < 0 .5 % s am p le s Tr ea t in d iv id ua ls C he ck p ig s A N D p re se nc e of b ot h ke y ri sk fa ct or s* * A N D p re se nc e o f b o th ke y ri sk f ac to rs ** B o th k ey r is k fa ct o rs ar e N O T p re se nt ** St ar t a p ub lic h ea lt h p ro g ra m m e C o nd uc t m ea t in sp ec ti o n C he ck h um an d at a R ep ea t m o ni to ri ng 6 m o nt hs ** * C he ck h um an d at a R ep ea t m o ni to ri ng 1 2 m o nt hs ** * St ar t a p ub lic h ea lt h p ro g ra m m e Fi g . 4 . S ug g es te d fl ow t o t ri g g er a T . s ol iu m p ub lic h ea lt h in te rv en ti o n in a re as w he re t he re a re s us p ic io ns o f d is ea se s ca us ed b y T. s ol iu m o r b o th k ey r is k fa ct o rs a re p re se nt S o ur ce –T ae ni a so liu m – u se o f ex is ti ng d ia g no st ic t o o ls in p ub lic h ea lt h p ro g ra m m es : r ep o rt o f a vi rt ua l m ee ti ng o f ex p er ts , 1 7 M ay 2 0 22 ( 6 ). 6 73. Indicators for evaluating progress in T. solium control Indicators are useful measures for tracking progress and evaluating the efficiency of T. solium control programmes. They can be used to measure the inputs, implementation, outputs, outcomes and impact of a programme. The indicators in Fig. 5 are suggested for monitoring progress towards control of T. solium. Some indicators are for use at global level (and are monitored by WHO); other indicators are for use at country level. The country-level indicators are classified as epidemiological indicators when they describe the general burden of the disease, whereas control indicators refer to a control programme. Some of the country-level indicators can be aggregated for use at global level. While not all of the country-level indicators are readily available or easy to measure, programmes and endemic countries are encouraged to put systems in place to measure them. Endemic countries should consider the suggested indicators, but contemplate adding more as appropriate and useful to their local circumstances and as technically feasible to measure. The definitions for areas of T. solium endemicity are provided in Box 1. Source: Adapted from WHO Taenia solium endemicity map – 2022 (7). Box 1. Endemicity status in relation to T. solium An endemic area is an area in which the full life cycle of T. solium is present. In practical terms, this means areas with autochthonous cases of T. solium taeniasis in humans or porcine cysticercosis in local pigs. Within endemic areas, there may be hyperendemic areas, in which the infection is a public health problem. The current suggestion is that hyperendemic areas are those in which the key risk factors are present (roaming pigs and deficient sanitation) and ≥ 0.5% T. solium taeniasis in humans or ≥ 2% porcine cysticercosis in pigs has been detected. A suspected endemic area is an area in which the full life cycle of the parasite is suspected but not confirmed as present. It can be identified based on suspicion or historical evidence of the presence of some of the diseases caused by T. solium, and the presence of the key risk factors (roaming pigs and deficient sanitation). In these cases, a mapping survey as described in this framework is suggested. A non-endemic area is an area in which the full life cycle of the parasite is not present; however, it is possible that imported cases of cysticercosis or taeniasis may be detected. 8Implementing Taenia solium control programmes in countries: monitoring and evaluation framework * Intensified control is the implementation of at least one core “rapid impact” intervention; that is, implementing the treatment of human taeniasis or implementing intervention in pigs (vaccination plus anthelminthic treatment). The indicator should include countries that are implementing intensified control in at least two identified endemic areas and not necessarily in all of them. This should be reviewed and adjusted as the T. solium control programmes mature. ** If aggregated, these indicators can also be used at global level. *** Areas are to be defined by each country as appropriate to their epidemiological situation. 3.1 Global indicators (for the period assessed) 3.1.1 Number of countries endemic for T. solium The number of countries endemic for T. solium is the number of countries in which the full life cycle of the parasite is present. 3.1.2 Number of endemic countries that have completed mapping in high-risk areas The number of countries that have completed mapping (ideally following the WHO mapping protocol (12)) and have confirmed autochthonous cases of T. solium taeniasis or porcine cysticercosis as described in this document. 3.1.3 Number of countries with intensified control in hyperendemic areas Intensified control is the implementation of at least one core “rapid impact” intervention, as defined by the WHO expert meeting in 2009 (11) (that is, implementing treatment for human taeniasis or intervention in pigs (vaccination plus anthelminthic treatment)). This indicator includes the number of countries implementing intensified control in at least two identified endemic areas, not necessarily in all of them. It should be reviewed and adjusted as T. solium control programmes mature. 3.2 Country-level epidemiological indicators (for the period assessed) 3.2.1 Number of neurocysticercosis cases reported In many countries, neurocysticercosis is not a notifiable disease; as a result, information is very limited. Nevertheless, neurocysticercosis is the main disease caused by T. solium and the reason why control programmes are implemented; it is therefore imperative to monitor the disease and encourage countries to make it notifiable. The number of cases reported is a long-term indicator, as the period of incubation of clinical neurocysticercosis can be as long as 20 years. The effects of a control programme will therefore not be evident in the short term given the currently available, practical diagnostics. Fig. 5. Global and country-level indicators to evaluate progress on the control of T. solium GLOBAL indicators Number of countries endemic for T. solium Number of endemic countries that have completed mapping (and confirmation of endemicity if necessary) in high-risk areas Number of countries with intensified control in hyperendemic areas for T. solium* Number of neurocysticercosis cases reported (disaggregated by age)** COUNTRY-LEVEL epidemiological indicators Number of people at risk of T. solium** Percentage of people at risk of T. solium living in a control area (with control interventions in humans, pigs or both) Number of areas at risk*** Coverage of preventive chemotherapy for taeniasis (over people who need it)** COUNTRY-LEVEL control indicators 9The case definitions for neurocysticercosis are provided in Box 2. Source: Adapted from Del Brutto, 2012 (13); Del Brutto et al., 2017 (14); and Garcia et al., 2020 (15). Box 2. Case definitions of neurocysticercosis A suspected case is a person living in an area endemic for T. solium with neurological symptoms compatible with neurocysticercosis. A probable case is a person living in an area endemic for T. solium with positive serology and clinical signs compatible with neurocysticercosis.* A confirmed case is a case of neurocysticercosis confirmed by imaging (computed tomography scan or magnetic resonance image). *In areas with high seroprevalence, unless an antigen detection test is used, positive serology has limited value as the presence of antibodies may only indicate past exposure to the parasite. 3.3 Country-level control indicators (for the period assessed) 3.3.1 Number of people at risk of T. solium The number of people at risk of T. solium is the number of people living in endemic areas. If endemicity has not been confirmed, this number can also include those living in high-risk areas in which both key risk factors are present (roaming pigs and deficient sanitation). 3.3.2 Percentage of people at risk of T. solium living in a control area A control area is an area implementing intensified control (that is, interventions in humans (preventive chemotherapy) or interventions in pigs (vaccination and treatment). Forthe purpose of the indicator, there is no need to implement control measures in humans and pigs; only one of them is sufficient. The formula used to calculate this indicator is the following: 3.3.3 Number of areas at risk The number of areas at risk is the number of areas endemic for T. solium. An area can be defined by each country based on the local epidemiological situation. If endemicity has not been confirmed, it can also include high-risk areas. This indicator can be monitored over time within a country to record the impact of interventions. In the future and as the control programmes progress, it can be replaced by the number of areas that have successfully controlled the disease. 3.3.4 Coverage of preventive chemotherapy for taeniasis Coverage should be monitored after each round of preventive chemotherapy to indicate how the programme is performing. Monitoring of coverage assesses how many people received preventive chemotherapy over the population who should have received the intervention. The formula used is as follow. × 100( )Number of people at risk of T. solium living in a control area Number of people at risk of T. solium × 100( )Number of individuals that received preventive chemotherapy for taeniasis Number of individuals in the target population 3. Indicators for evaluating progress in T. solium control 10 Implementing Taenia solium control programmes in countries: monitoring and evaluation framework The most recent population data should be used to estimate the target population. Guidance on implementing preventive chemotherapy for taeniasis, including how to estimate the target population, is provided in the PAHO/WHO Guideline for preventive chemotherapy for the control of T. solium taeniasis (3). Other WHO publications provide guidance on monitoring and measuring coverage for preventive chemotherapy: Monitoring drug coverage for preventive chemotherapy (16) Preventive chemotherapy: tools for improving the quality of reported data and information. A field manual for implementation (17) Preventive chemotherapy for neglected infectious diseases – Manual for the design and use of record sheets (18) Tools for monitoring the coverage of integrated public health interventions – Vaccination and deworming of soil-transmitted helminthiasis (19) 11 4. Epidemiological considerations Taeniasis and cysticercosis are focal diseases, as the presence of roaming pigs and deficient sanitation are necessary conditions for the full transmission cycle of the causative parasite. These conditions can be limited to certain communities or areas due to cultural or geographical circumstances, and thus areas can vary from involving only a small community to involving a very large area, such as an entire district. For pragmatic reasons, this framework considers the following epidemiological situations or categories. 4.1 Broad areas Broad areas are those in which the full T. solium transmission cycle occurs in large areas. This happens where pigs are commonly reared in local communities, such as in many rural places in Africa (e.g. areas in Madagascar or Uganda). 4.2 Focal areas Focal areas are those in which the full T. solium transmission cycle occurs in small, specific communities (e.g. areas where pigs are kept by specific indigenous or ethnic communities such as indigenous populations in Latin America, or the Dalit families in Nepal). For the purposes of this framework, a focal area is one in which there are 20 villages or less in the survey area. While these two situations are not discrete categories, and may include a continuum of situations and settings in between, programme managers can determine the most appropriate option based on the local situation and knowledge. 5. T. solium survey characteristics This framework proposes two types of surveys for T. solium: surveys to confirm endemic areas (mapping) and determine the need for a public health intervention; and surveys to monitor and evaluate public health interventions (control programmes). Some characteristics are identical for both types of survey but may differ for others. In this case, the differences are clearly marked. The characteristics for each type of survey are summarized in section 5.10. Practical steps for implementing a survey are provided with examples in Annex 2. 5.1 Survey goal The goal of the survey will differ for each type of survey. The lack of adequate diagnostics poses some limitations to monitoring public health interventions (6). 5.2 Operational indicators Operational indicators refer to the variables to be measured. 5.3 Survey area The survey area is the area for which a public health decision on the presence of T. solium is desired. The survey areas are the same for mapping and monitoring surveys. Characteristic 1. Confirm endemic areas (mapping) 2. Monitor public health interventions Survey goal Confirm active transmission of T. solium (when there is not enough recent data to confirm endemicity and a survey is needed). • Ideally: Identify the level of active transmission of T. solium. • Until better diagnostics are available: Confirm active transmission of T. solium. Characteristic 1. Confirm endemic areas (mapping) 2. Monitor public health interventions Operational indicator Presence of T. solium in the selected high-risk areas. • Ideally: Prevalence of T. solium in the control areas. • Until better diagnostics are available: Presence of T. solium in the control areas. Characteristic 1. Confirm endemic areas (mapping) 2. Monitor public health interventions Survey area For both types of surveys, the survey areas are high-risk areas or communities, in which both key risk factors are present (roaming pigs and deficient sanitation). 13 In very large areas or very densely populated areas, it may be necessary to define several survey areas. The survey area may be as small as a village or community. The maximum population size of a survey area should correspond to the reasonable treatment or implementation unit for the area (presumably a district or smaller); for example, 200 000–300 000 people in rural areas (excluding urban areas with no risk factors). 5.4 Diagnostic tests Both mapping and monitoring surveys are based on the available diagnostic tests as described in the WHO meeting of experts in 2022 (6). More information on Kato–Katz is contained in WHO’s Bench aids for the diagnosis of internal parasites (20) and on pig tongue palpation in Annex 3. Characteristic 1. Confirm endemic areas (mapping) 2. Monitor public health interventions Diagnostic tests Options for both type of surveys: Humans: Kato–Katz stool microscopy (two slides from the same specimen) followed by species confirmation (by molecular or parasitological methods). Other taeniasis tests such as coproantigen tests can be used if available but must be followed by species confirmation. OR Pigs: Tongue inspection, enhanced meat inspection after slaughter to detect larval cysts. It is not necessary to conduct surveys in both humans and pigs unless there is a valid reason to do so. Depending on the local circumstances and experience, one option may be preferred over the other. 5.4.1 Considerations for human diagnostics When using microscopy (such as the Kato–Katz technique), the species of Taenia must be confirmed because T. solium eggs are indistinguishable from those of other Taenia species such as T. saginata or T. asiatica, which do not cause a serious public health problem. Taenia species can be confirmed using molecular methods or by direct parasitological examination (identifying the positive person, medicating, and collecting the proglottids and the scolex where available). To confirm the Taenia species by molecular methods, samples can be stored in ethanol (collect about 2–5 g of faeces into at least double the volume of ethanol 95%). Samples can be kept at room temperature in dark storage for up to 5–6 days before storing them in ethanol. This provides an option to do the Kato–Katz first and only store the positive samples in ethanol. If Kato–Katz is done after day 6, or if the samples cannot be stored appropriately, then all samples should be stored in ethanol after collection. Taenia eggs are relatively small (30–35 μm) compared with those of other intestinal helminths (20). It is therefore essential that technicians who are not used to evaluating samples for Taenia eggs receive specific training before conducting the examinations and have access to a reference laboratory to confirm positive findings. 5. T. solium survey Characteristics 14 Implementing Taenia solium control programmes in countries: monitoring and evaluation framework The Kato–Katz technique is generally considered to have low sensitivity (the proportion of true positives identified as positive) for diagnosis of taeniasis (although the evidence to support this view is weak). This has been considered when calculating the necessary sample size. It is recommended to prepare two Kato–Katz slides from each faecal sample. The inclusion/exclusion criteria should include the history of travel or migration, as people may have acquired the tapeworm from other areas. The tapeworms are expected to live 2–3 years (21), so people who have lived in the area for more than 3 years are very likely to have acquired the parasite locally. Preferably, only local people should be included in the survey (this may not be applicable, for example, if evaluating a refugee camp). Consider the ethical implications of a positive diagnostic. Taeniasis-positive people should be offered treatment because any person with T. solium poses a risk to others and themselves for transmitting neurocysticercosis and maintaining the transmission cycle. Treatment can be preventive chemotherapy or individual treatment, depending on the overall results, local strategies and timings (for example, if preventive chemotherapy is to be conducted many months later, individual treatment should be considered). 5.4.2 Considerations for pig diagnostics Pigs should be at least 4 months of age to allow time for them to get infected and for cysts to develop. The pigs should have been roaming free for at least some pointin their lives, which excludes all commercially reared pigs (reared their entire life under hygienic conditions). It is important to ensure they are local pigs. In some areas it may be common practice to buy piglets from other areas to fatten them up, so it may not be possible to ascertain where they acquired the infection. In such cases, testing should be restricted to locally born and reared pigs. Specificity (proportion of true negatives identified as negatives) of the tongue inspection is influenced by the presence of viable cysts, the number of cysts and the experience of the person conducting it (for more details, see Annex 3). Identification of at least one viable cyst or several non-viable cysts can be considered as indicative of porcine cysticercosis. However, the presence of only 1 or 2 non-viable lesions in the tongue should be considered doubtful as it is very difficult or impossible to differentiate between a non-viable cyst and a lesion caused by some other source (e.g. traumatic injury or presence of a foreign body). Caution should be exercised when only a few non-viable cysts are observed. 5.5 Age group Characteristic 1. Confirm endemic areas (mapping) 2. Monitor public health interventions Age group For both types of surveys: • Humans: All ages from 5 years and above. • Pigs: From 4 months of age. 5.6 Sample size Experience with other neglected tropical diseases programmes suggests that Lot Quality Assurance Sampling (LQAS) is the most appropriate method for conducting both types of surveys (mapping and monitoring public health interventions) (22, 23); more details are provided in Annex 4. This may change in the future as new diagnostics, knowledge and evidence emerge. 15 Characteristic 1. Confirm endemic areas (mapping) 2. Monitor public health interventions Sampling strategies • Area selection: Purposive selection of the survey area based on risk, followed by random sampling (of humans or pigs) within the area. • Village selection: In focal areas, all villages should be selected. In broad areas, 20 villages need to be randomly selected. • Number of samples per village: The number of samples per village (for human or pig surveys) should be proportional, if possible, to the number of pigs. Survey timing: Not relevant unless there has been a recent event that could affect or interfere with the results. Survey timing: Assessment to be done before the next round of intervention (for example before the next round of mass drug administration) and not too soon after the previous intervention, to give enough time for new infections to occur and be detectable. 5.7.1 Selection of the survey area The survey area is the geographical expanse within which the LQAS survey is applied. It should correspond to the implementation unit (the area or administrative unit for which a public health intervention could be applied). It is appropriate to purposefully select the survey area, based on known key risk factors. However, within the survey area, it is important that the sampling subjects (pigs or humans) be selected randomly. If the number of observed positives is less than or equal to the critical cut-off (as detailed in the LQAS tables in Annexes 2 and 4), then the survey area can be classified as below the threshold, and therefore a public health intervention is not needed. 5.7 Sampling strategies The sampling strategies are based on purposive selection of the survey area for both types of survey. 5.7.2 Selection of villages When the surveys are conducted in focal areas (20 villages or less, as per definition in section 4), all villages should be selected for sampling. When sampling large areas (for example a province) in which roaming pigs are not uniformly distributed, the first step is to list all the areas where roaming pigs are present as well as the estimated number of roaming pigs, if that information is easily accessible. The sampling frame is restricted to those areas in which roaming pigs are present, and 20 villages should be randomly selected from this sampling frame (see section 5.1 for the maximum population size of a survey area). Detailed instructions on systematic random sampling of villages are provided in Annex 2, Box A2.1. Sampling should be restricted to the at-risk areas; that is, the areas with the presence of both key risk factors (roaming pigs and deficient sanitation) as they are a necessary condition for the presence of the full parasite cycle. 5. T. solium survey Characteristics 16 Implementing Taenia solium control programmes in countries: monitoring and evaluation framework 5.7.3 Number of samples per village Ideally, if the number of pigs per village is known (excluding commercial pigs), then the number of samples (for human or pig surveys) should be proportional to the number of pigs. That is because pigs are a necessary condition for transmission, and the number of pigs increases the likelihood of transmission. The number of samples should not be proportional to the human population, as there is a risk of taking a larger number of samples from larger towns where risk factors such as sanitation may not be present at the same level as in small villages. For more details on the calculations and examples, see Annex 2, Box A2.2. 5.7.4 Timing The timing of a mapping survey is not relevant unless there has been a recent event that could interfere with the results. For example, if in recent months there has been mass drug administration in children with praziquantel for schistosomiasis, or if the pig population has suffered a recent outbreak of disease with high mortality and the pigs present are recently acquired and arrived in the area, enough time should be provided after the event for infections to be acquired and detected in humans (10 months after the event) or in locally-born pigs (i.e. > 4 months of age). When a survey is undertaken to monitor a control programme, it should be done at least 10 months after the last intervention to give enough time for new infections to occur and be detectable. If, for example, mass drug administration is planned annually, the survey should be conducted just before the next round of treatment. 5.8 Target thresholds Until further evidence and better diagnostics are available, the thresholds for triggering a public health intervention are those suggested by the WHO meeting of experts in 2022 (6): ≥ 0.5% T. solium taeniasis in humans or ≥ 2% cysticercosis in pigs (see section 2.2 and Fig. 4). 5.9 Frequency Characteristic 1. Confirm endemic areas (mapping) 2. Monitor public health interventions Frequency Mapping should be done when active transmission of T. solium is unknown or suspected, and there are reasons to believe it could be present. • Monitoring surveys can be conducted every 2 or 3 years depending on the type and coverage of the interventions.* • The surveys should be conducted at least 10–12 months after interventions stop. • See Fig. 5 for details. * As the efficacy of the interventions in humans, pigs or combinations is expected to be different, the type of intervention implemented and the coverage achieved could help in selecting an appropriate survey frequency. For example, a One Health intervention including human treatment and pig vaccination and treatment is expected to be more effective than only human treatment; and if the coverage in humans and animals is high, a 2-year period could be considered. If only humans were treated, or if coverage was low, then a 3-year period or even longer could be considered. The frequency will also be influenced by the funding available. 17 Monitoring should be done at least 10 months after the last intervention, and before the next round of control measures are implemented; it can also be done in people, pigs or both. Fig. 6 shows the suggested flow for monitoring and evaluating a T. solium public health intervention. Given the current limitations with the diagnostics available, it is suggested that if the survey is below the threshold after implementing a control programme, the existence of risk factors should be considered. This is only a suggested flow, which should be updated as new evidence and new diagnostics are developed. * When implementing One Health interventions, surveys can be conducted at shorter intervals than those for interventions in humans only. Mapping: baseline above threshold Survey (every 2 or 3 years) depending on type of interventions and coverage* Risk factors present Control interventions Results below threshold Results above threshold Control interventions for at least another year Survey Results below threshold Risk factors absent ∙ Stop intervention ∙ Monitor at least twice every 2 years ∙ Stop intervention ∙ Monitor at least twice every 2 years Results above threshold Fig. 6. Suggested flow for monitoring and evaluation of a T. solium public health intervention based on the limitations of existing diagnostics 5. T. solium survey Characteristics 18 Implementing Taenia solium control programmes in countries: monitoring and evaluation framework 5.10 Summary of survey characteristics Characteristic 1. Confirm endemic areas (mapping) 2. Monitor public health interventions 1. Survey goal Confirm active transmission of T. solium (when there is not enough recent data to confirm endemicity and a survey is needed). • Ideally: Identify the level of active transmission of T. solium. • Until better diagnostics are available: Confirm active transmission of T. solium. 2. Operational indicator Presence of T. solium in the selected high-risk areas. • Ideally: Prevalence of T. solium in the control areas. • Until better diagnostics are available: Presence of T. solium in the control areas. 3. Survey areas For both: High-risk areas or communities, in which both key risk factors are present (roaming pigs and deficient sanitation). 4. Diagnostic tests For both: Humans: Kato–Katz stool microscopy (two slides from same specimen) followed by species confirmation by molecular or parasitological methods. Other taeniasis tests such as coproantigen tests can be used if available but must be followed by species confirmation OR Pigs*: Tongue inspection, enhanced meat inspection after slaughter to detect larval cysts. 5. Age group For both: Humans: All ages from 5 years of age, Pigs*: From 4 months of age. 6. Sample size The aim is to identify the presence of disease. Sampling as per Lot Quality Assurance Sampling tables (see Tables A2.1 and A2.2 in Annex 2) Until better diagnostics are available, the aim is to identify the presence of autochthonous cases of disease as per mapping surveys. 7. Sampling strategy Area selection: Purposive selection of the survey area based on risk, followed by random sampling (of humans or pigs) within the area. • Village selection: In focal areas, all villages should be selected. In broad areas, 20 villages need to be randomly selected. • Number of samples per village: The number of samples per village (for human or pig surveys) should be proportional, if possible, to the number of pigs. Survey timing: Not relevant unless there has been a recent event that could affect or interfere with the results. Survey timing: Assessment to be done before the next round of intervention (for example before the next round of mass drug administration) and not too soon after the previous intervention, to give enough time for new infections to occur and be detectable. 19 Characteristic 1. Confirm endemic areas (mapping) 2. Monitor public health interventions 8. Target threshold Until there is more evidence or better diagnostics are available, the thresholds suggested by the WHO meeting of experts in 2022 (6) should be considered as ≥ 0.5% T. solium taeniasis in humans or ≥ 2% porcine cysticercosis in pigs. 9. Frequency Mapping should be done when active transmission of T. solium is unknown or suspected, and there are reasons to believe it could be present. • Monitoring surveys can be conducted every 2 or 3 years depending on the type and coverage of the interventions. • The surveys should be conducted at least 10–12 months after the interventions stop. • See Fig. 5 for details. *Pigs should be local backyard pigs, that have roamed free at some point during their lives. They should not be commercial pigs reared under hygienic conditions all their lives. 5. T. solium survey Characteristics 6. Special considerations 6.1 Sampling in humans or pigs There is no need to conduct surveys on humans and pigs unless there is a specific reason to do so (for example, an inconclusive result). The human and pig surveys are intended to measure the same thing: the potential for ongoing transmission of T. solium. Sampling humans may be preferred if the country has experience with Kato–Katz or if the survey can be done in conjunction with other programmes that use Kato–Katz, such as those for schistosomiasis or soil-transmitted helminthiases. Sampling pigs may be an easier option in areas with experience in handling pigs and conducting tongue palpation. Due to the higher threshold in pigs (compared with that for taeniasis), pigs require a smaller sample size. Additionally, demonstrating the disease in pigs will also encourage taking a more effective One Health approach including interventions in pigs. 6.2 Specificity of tests, local infections and selection of individuals Given the low critical cut-off, meaning a small number of positive results will trigger an intervention as per Tables A2.1 and A2.2 in Annex 2), it is critical that the tests have high specificity (see diagnostic considerations in section 5.4). 6.3 Use of other diagnostic tools This framework is based on the available tools for diagnosis of taeniasis and porcine cysticercosis for public health programmes as discussed in the report of the WHO expert meeting in 2022 (6); that is, the Kato–Katz for humans and tongue palpation for pigs. The use of different tests must consider the proper validation of those tests and the sample size and sample strategy based on the characteristics of those tests. To properly validate a new test, a field validation should be conducted independently using the appropriate controls. For example, to validate a pig test, negative controls should be used, with pigs from endemic areas that have been diagnosed as negative based on carcass dissection, and not commercial pigs that have not been exposed to the same antigenic challenges from the environment and its associated infections. 6.4 Surveillance integration with other diseases, especially in relation to Kato–Katz To maximize efficiencies in controlling parasitic infections, it makes sense to integrate parasitic assessments. Surveys based on Kato–Katz are also used for other diseases such as schistosomiasis, soil-transmitted helminthiases and some foodborne trematodiases. Integrating Kato–Katz assessments is useful where these diseases are co-endemic acrossan entire subdistrict or district; in areas where T. solium is highly focal, integration may not be appropriate. The survey design and strategy for other parasites usually requires a smaller sample size and is focused on sampling school-aged children at schools. To meet the needs of the T. solium approach it would be necessary for those programmes to conduct sampling at the community level (not only in school-aged children) and to augment the sampling by adding in adults at each of the survey sites. If free-roaming pigs are not present in each of the sites, it may be necessary to add additional villages to ensure that areas at greatest risk for T. solium are well-represented (Box 3). 21 Box 3. Considerations for integrating the Kato–Katz survey for taeniasis with that for schistosomiasis or soil-transmitted helminthiases programmes 1. Number of samples: It is likely that the number of samples required for other parasitic surveys is smaller than the number of samples required for a taeniasis survey. Therefore, additional samples may need to be collected for the taeniasis survey. 2. Number of slides per sample: Some programmes may examine only one slideper faecal sample. For taeniasis it is suggested that two slides are made from each sample. 3. Training for technicians: T. solium eggs are smaller than those of many other parasites such as Schistosoma and technicians may not be used to identifying them. Additional training or refresher courses should be conducted before doing the survey. Access to a reference laboratory may be necessary to confirm positive results. 4. Target population: Taeniasis surveys target everyone from 5 years of age. Some other programmes may target only school-aged children so additional samples representing the whole community will be required for the taeniasis survey. 5. Purposive sampling: It is imperative for taeniasis to only collect samples from communities in which both risk factors are present (roaming pigs and deficient sanitation). When designing a combined survey, the requirements for all programmes need to be considered while trying to maximise the synergies. For example: • If a smaller number of samples are required for schistosomiasis or soil-transmitted helminthiases surveys which target children, the additional samples required for taeniasis should be collected from the adult population so the taeniasis survey combines adults and children. • If other parasitic surveys target schools in areas where there are no roaming pigs and therefore are not eligible for the taeniasis survey, the taeniasis programme will need to collect additional samples to compensate for those samples collected from areas that are not eligible for a taeniasis survey. 6. Special considerations 7. Conclusion Taenia solium control programmes are relatively new and the information available is limited. Operational research is needed to validate the sample size estimation, the sampling strategy and the survey design, as suggested in this framework. The framework makes compelling arguments for new or improved diagnostics. The options for monitoring and evaluation are limited by current diagnostics as changes in prevalence are difficult to detect using existing tools with very low sensitivity and/or specificity. Operational research is needed to better understand the sensitivity and field performance of some of the current tests, for example the sensitivity of microscopy tests in increasing the number of slides per sample, taking samples on consecutive days, or comparing different parasitological tests in settings with different levels of endemicity. This framework will be revised and updated as new information becomes available. 22 23 References 1. Working to overcome the global impact of neglected tropical diseases: first WHO report on neglected tropical diseases. Geneva: World Health Organization; 2010 (https://iris.who.int/handle/10665/44440). 2. Ending the neglected to attain the Sustainable Development Goals: a road map for neglected tropical diseases 2021-2030. Geneva: World Health Organization; 2020 (https://iris.who.int/ handle/10665/338565). 3. Guideline for preventive chemotherapy for the control of Taenia solium taeniasis. Washington (DC): Pan American Health Organization; 2021 (https://iris.paho.org/handle/10665.2/54800). 4. WHO guidelines on management of Taenia solium neurocysticercosis Geneva: World Health Organization; 2021 (https://iris.who.int/handle/10665/344802). 5. Cysticercosis (including infection with Taenia solium). In: WOAH Terrestrial Manual 2021 [Chapter 3.10.3]. Paris: World Organization for Animal Health (https://www.woah.org/fileadmin/Home/eng/Health_ standards/tahm/3.10.03_CYSTICERCOSIS.pdf, accessed 9 July 2024). 6. Taenia solium – use of existing diagnostic tools in public health programmes: report of a virtual meeting of experts, 17 May 2022. Geneva: World health Organization; 2022 (https://iris.who.int/ handle/10665/364042). 7. Donadeu M, Bote K, Gasimov E, Kim SH, Lin Z, Lucianez A, et al. WHO Taenia solium endemicity map – 2022 update. Weekly Epidemiol Rec. 2022;97(17):169–72 (https://iris.who.int/handle/10665/353612). 8. Ito A, Saito M, Donadeu M, Lightowlers MW. Kozen Yoshino’s experimental infections with Taenia solium tapeworms: An experiment never to be repeated. Acta Trop. 2020;205:105378. 9. Ndimubanzi PC, Carabin H, Budke CM, Nguyen H, Qian YJ, Rainwater E, et al. A systematic reviewof the frequency of neurocyticercosis with a focus on people with epilepsy. PLoS Negl Trop Dis. 2010;4(11):e870. 10. How to prevent the pork tapeworm? A neglected parasitic infection caused by Taenia solium. World Health Organization, World Organisation for Animal Health, Food and Agriculture Organization of the United Nations; 2022 (https://iris.who.int/handle/10665/360863). 11. Report of the WHO expert consultation on foodborne trematode infections and taeniasis/cysticercosis. Vientiane, Lao People’s Democratic Republic 12–16 October 2009. Geneva: World Health Organization; 2011 (https://iris.who.int/handle/10665/75209). 12. Mapping protocol for Taenia solium: identification of endemic and high-risk areas. Geneva: World Health Organization; 2023 (https://iris.who.int/handle/10665/372868). 13. Del Brutto OH. Neurocysticercosis: a review. ScientificWorldJournal. 2012; 2012:159821. 14. Del Brutto OH, Nash TE, White AC, Jr., Rajshekhar V, Wilkins PP, Singh G, et al. Revised diagnostic criteria for neurocysticercosis. J Neurol Sci. 2017;372:202–10. 15. Garcia HH, Gonzalez AE, Gilman RH. Taenia solium cysticercosis and its impact in neurological disease. Clin Microbiol Rev. 2020;33(3). 16. Monitoring drug coverage for preventive chemotherapy. Geneva: World Health Organization; 2010 (https://iris.who.int/handle/10665/44400). 17. Preventive chemotherapy: tools for improving the quality of reported data and information. A field manual for implementation. Geneva: World Health Organization; 2019 (https://iris.who.int/ handle/10665/329376). 24 Implementing Taenia solium control programmes in countries: monitoring and evaluation framework 18. Preventive chemotherapy for neglected infectious diseases – Manual for the design and use of record sheets. Washington (DC): Pan American Health Organization; 2017 (https://iris.paho.org/ handle/10665.2/34495). 19. Tools for monitoring the coverage of integrated public health interventions – Vaccination and deworming of soil-transmitted helminthiasis. Washington (DC): Pan American Health Organization; 2017 (https://iris.paho.org/handle/10665.2/34510). 20. Bench aids for the diagnosis of intestinal parasites, second edition. Geneva: World Health Organization; 2019 (https://iris.who.int/handle/10665/324883). 21. Lightowlers MW. Eradication of Taenia solium cysticercosis: a role for vaccination of pigs. Int J Parasitol. 2010;40(10):1183–92. 22. Lemeshow S, Taber S. Lot quality assurance sampling: single- and double-sampling plans. World Health Stat Q. 1991;44(3):115–32. 23. Robertson SE, Anker M, Roisin AJ, Macklai N, Engstrom K, LaForce FM. The lot quality technique: a global review of applications in the assessment of health services and disease surveillance. World Health Stat Q. 1997;50(3-4):199–209. 25 Annex 1. Methods and contributors This monitoring and evaluation framework was developed through a global consultative process involving experts from all regions of the World Health Organization (WHO) in which Taenia solium is endemic to ensure its suitability in these regions. 1. The framework was prepared by a drafting group convened through virtual meetings and discussions held during November and December 2022. The members of the drafting group are listed below. a. The discussions included the definitions presented in Box 1 and Box 2 of the framework, which were adapted from the sources specified therein and were accepted by consensus. b. After the first meeting, Dr Katherine Gass prepared the tables to estimate the sample size, using the lot quality assurance sampling (LQAS) methodology, which is used by other neglected tropical diseases programmes. The calculations and tables were presented, discussed and accepted by consensus during the second meeting. More details are provided in Annex 4. 2. The draft framework was presented and discussed at three regional virtual workshops at which participants provided opinions and feedback; after each meeting they were given 2 weeks to provide any additional feedback. The regional workshops were conducted on the following dates: Region of the Americas: 26 January 2023 African Region: 24 May 2023 South-East Asia and Western Pacific regions: 20 September 2023 3. The participants at each workshop are listed below. The regional WHO focal points and at least two members of the drafting group participated in each workshop. 4. Feedback from each regional workshop was included in the draft and discussed at the next regional workshop, after which the draft framework was updated. 5. The draft framework was validated after discussion with the representatives of Costa Rica and Namibia. Both countries were developing their T. solium mapping strategy, and their questions and needs helped to refine the framework. 6. Once the framework was updated after the regional workshops and country feedback, then reviewed by the drafting group for its final approval. Additional information: the basis for the suggested diagnostic tools and algorithms presented in Fig. 4 of the framework is the report of the meeting of experts on the use of existing T. solium diagnostic tools in public health programmes (1). Currently, there is inadequate evidence available to support the development of formal WHO guidelines, therefore the process was as follows: the experts were requested to provide information on the following tests from peer-reviewed publications, or unpublished data to serve as a landscape analysis: For taeniasis: Kato-Katz and other microscopy tests, copro-PCR, copro-antigen, serology (different formats). For human cysticercosis: Serology (different formats). For porcine cysticercosis: Tongue inspection, serology (different formats), meat inspection. The attributes included were sample type, age group, sensitivity, specificity, usefulness for mapping, usefulness for monitoring, commercial availability and affordability in low- and middle-income countries. The experts provided the information based on their experience, including references for. The findings were consolidated, summarized and circulated before the meeting of experts. The replies were analysed by range (sensitivity and specificity) or frequency (usefulness for mapping or monitoring). During the meeting of experts, the findings were discussed, analysed and conclusions and suggestions were reached by consensus during the virtual meeting of experts in May 2022. 26 Implementing Taenia solium control programmes in countries: monitoring and evaluation framework Drafting group Bernadette Abela, WHO Global Neglected Tropical Diseases Programme, Geneva, Switzerland Vicente Y. Belizario Jr., University of the Philippines, Manila, Philippines Meritxell Donadeu, University of Melbourne, Melbourne, Australia; WHO consultant and member of the Strategic and Technical Advisory Group for Neglected Tropical Diseases’ Working Group on Monitoring, Evaluation and Research Katherine Gass, Task Force for Global Health, Decatur, United States of America Patrick J. Lammie, Task Force for Global Health, Decatur, United States of America; Chairman of the Diagnostic Technical Advisory Group for Neglected Tropical Diseases Ana Luciañez, WHO Regional Office for the Americas/Pan American Health Organization, Washington, United States of America Harena Rasamoelina, Indian Ocean Commission, Moka, Mauritius Anne Straily, Centers for Disease Control and Prevention, Atlanta, United States of America Paul Torgerson, University of Zurich, Zurich, Switzerland Aya Yajima, WHO Regional Office for South-East Asia All external experts, in accordance with WHO policy, submitted to WHO a declaration of interest disclosing potential conflicts of interest that might affect, or might reasonably be perceived to affect, their objectivity and independence in relation to the subject matter of the meetings. WHO reviewed each of the declarations and concluded that none could give rise to a potential or reasonably perceived conflict of interest related to the subjects discussed at the meeting or covered by the framework. Region of the Americas workshop: 26 January 2023 Colombia: Adriana Arévalo Jamaica (National Health Institute), Sofía Duque Beltrán (National Health Institute), Carlos Esteban Franco Muñoz (National Health Institute), Lydia Muñoz Galindo (National Health Institute), Mario Javier Olivera Rivero (National Health Institute), Marcela Pilar Rojas Díaz (Ministry of Health), Julián Trujillo Trujillo (Ministry of Health) Costa Rica: Ted Alpizar Calvo (Epidemiology Unit, Department of Health Surveillance), Roberto Castro Cordoba (Epidemiology Unit, Department of Health Surveillance), Warren Hidaldo Jara (National Services for Animal Health), Albin Padilla (Ministry of Health), Gabriela Perez Molina (National Services for Animal Health), Susana Ureña (National Services for Animal Health) Honduras: Roxana Castillo (National Services for Animal Health), Mauricio Días (National Services for Animal Health), Gabriela Marina Mejia (National Services for Animal Health), Reina Teresa Velásquez (Zoonosis Surveillance Unit, Ministry of Health) Mexico: Verónica Gutiérrez Cedillo (Zoonosis Department, Ministry of Health), Deyra Ortiz (Zoonosis Department, Ministry of Health), Peru: Jose Luis Bustamante Navarro (Ministry of Public Health), Luz Criollo Benavides (Ministry of Public Health), Olimpia Chuquista Alcarraz (Ministry of Public Health), Ricardo Gamboa Moran (Ministry of Public Health), William Quispe Paredes (Ministry of Public Health) WHO Regional Office for the Americas/Pan American Health Organization: Ana Luciañez, Maria Nazario Drafting group members: Katherine Gass, Meritxell Donadeu 27 African Region workshop: 24 May 2023 Angola: Elsa Mendes (Ministry of Health, NTD programme) Cameroon: Tchuem Tchuente (Centre for Schistosomiasis and Parasitology) Madagascar: Mihaja Rakotoarinoro (National Center for Applied Research on Rural Development (FOFIFA) Madagascar) United Republic of Tanzania: Safari Kinunghi (WHO Country Office United Republic of Tanzania) Zambia: Grace Mwape (Ministry of Health, NTD programme), Evans Kabemba Mwape (University of Zambia) WHO Regional Office for Africa: Pauline Mwinzi, Jorge Cano, Takafira Mduluza Drafting group members: Harena Rasamoelina, Katherine Gass, Meritxell Donadeu South-East Asia and Western Pacific regions: 20 September 2023 Cambodia: Virak Khieu (National Center for Parasitology, Entomology and Malaria Control) India: Kalamakar Laskhkare (WHO Country Office India), Vedantam Rakshekhar (The Christian Medical College, Vellore), Gagandeep Singh (Dayanand Medical College, Ludhiana) Indonesia: Naufal Azhari (WHO Country Office Indonesia), Kadek Swastika (Udayana University), Toni Wandra (Sari Mutiara Indonesia University) Lao People’s Democratic Republic: Thip Chanthapaseuth (WHO Country Office Lao People’s Democratic Republic) Nepal: Gaurav Devkota (Ministry of Health and Population), Samir Kumar Adhikari (Ministry of Health and Population) Philippines: Raffy Fornillos (University of the Philippines), Lydia Leonardo (University of the Philippines), WHO Regional Office for South-East Asia: Aya Yajima, Katrin Bote WHO Regional Office for the Western Pacific: Alexander Taruc Drafting group members: Vicente Y. Belizario Jr., Katherine Gass, Meritxell Donadeu Reference 1. Taenia solium - use of existing diagnostic tools in public health programmes: report of a virtual meeting of experts, 17 May 2022. Geneva: World Health Organization; 2022 (https://iris.who.int handle/10665/364042). Annex 1. Methods and contributors Annex 2. Steps for conducting T. solium surveys: translating theory into practice This Annex provides practical advice and examples for confirming Taenia solium endemicity or monitoring a public health intervention based on the survey characteristics described in section 5 of the framework. The theory and principles used are the same but are presented sequentially by steps, as shown in Fig. A2.1. Step 1 is based on the survey characteristic 5.3 (survey area); step 2 is based on survey characteristics 5.4 (diagnostics) and 5.5 (age); step 3 is based on survey characteristic 5.6 (sample size); and steps 4, 5 and 6 are based on survey characteristic 5.7 (sampling strategy). Fig. A2.1. Steps for confirming T. solium endemicity or monitoring a public health intervention 5.1 Ideally, the number of samples in each village should be proportional to the number of pigs (even if survey is done in humans). 5.2 If the number of pigs is not known, the same number of samples should be taken from each village. 6.1 Timing: when monitoring a public health intervention, the survey should be done at least 10 months after the last intervention. 6.2 Random sampling of the eligible population. 6.3 If on arrival, risk factors are not present, move to the next village. 6.4 Use of adequate data collection forms. 2.1 Decide if the survey will be conducted in humans, pigs or both. 2.2 Diagnostic considerations (section 5.4): • Humans: Kato-Katz (plus species confirmation). • Pigs: tongue palpation (Annex 3). 2.3 Inclusion and exclusion criteria: • Humans: aged ≥ 5 years. • Pigs: local roaming pigs, aged > 4 months. No commercial pigs. 3.1 Define the sample size as per the LQAS tables for each survey area, based on population census or estimations. 3.2 If the survey is in pigs, and the number of pigs is not known, assume the maximum number of pigs in the LQAS table. 1.1 Identify high-risk areas with both key risk factors (roaming pigs and deficient sanitation). 1.2 Identify the survey areas. In larger areas, or densely populated areas, there can be more than one survey area. One survey should be conducted in each survey area. 4.1 Purposive selection followed by random sampling. • Focal area: all villages. • Broad area: randomly select 20 villages. All selected villages should have the key risk factors. 6. Conduct the sampling 5. Determine the number of samples per village 3. Determine the sample size 2. Select the methodology 4. Select the villages 1. Define the survey areas 29 1. Define the survey areas The objective of this first step is to group the identified at-risk areas and define the survey areas. Is each at-risk area one survey area or do several contiguous at-risk areas form one survey area? For example, several neighbouring communities with the same risk factors could be considered the same survey area. The decision should be based on the contiguity of the areas and the presence of the same key risk factors. The mapping or monitoring survey will result in a decision regarding the prevalence of T. solium within the survey area. Consequently, it is important that the survey area corresponds to the area or administrative unit for which a public health intervention could be reasonably implemented. If there are doubts about the extent of a survey area, the presence of roaming pigs can be used as a decision factor. The survey area can be as small as a village or a community. The maximum population size should correspond to the reasonable treatment unit for the area (presumably a district or smaller); for example, 200 000–300 000 people in rural areas (excluding urban areas with no risk factors). The survey areas need to be clearly demarcated on a map so it is clear for all people involved in the survey. Furthermore, it is necessary to have an estimate of the target population size (either humans or pigs, depending on the survey). For human surveys, the target population size should be based on census estimates of the number of people aged 5 years and older living in the survey area. For pigs, it should be based on the number of local roaming pigs. This first step is very important as it will be used to decide the type of survey and the number of samples. 2. Select the methodology There are two methodological options: identification of T. solium in humans and identification of T. solium in pigs. Both methodologies can be used simultaneously, but there is no need to implement both unless there is a valid reason. For example, when the mapping is first implemented in a country with no previous experience, some countries may prefer to use both, to develop capacity and have a choice when mapping other areas in the future. Section 5.4 of the framework provides more details on diagnostics. 1. Identification of T. solium in humans: the methodology to be used is Kato–Katz, reading two slides per sample. Considerations: a. If the technicians have not received recent refresher training in identification of T. solium eggs using Kato–Katz (1), a refresher course should be conducted. Material showing the characteristics of T. solium eggs should be provided. b. Kato–Katz does not allow species differentiation, so a species confirmation technique must be identified and made available (it could include sending the positive samples to a specialised laboratory for confirmation). More details are provided in section 5.4.1. c. Target population: individuals aged 5 years and older (both children and adults) living in the survey area. The target population should be determined for each survey area using census data, projections or estimations. d. Additional data to be collected: age, gender, household GPS. Annex 2. Steps for conducting T. solium surveys: translating theory into practice 30 Implementing Taenia solium control programmes in countries: monitoring and evaluation framework 2. Identification of T. solium in pigs: the methodology to be used is tongue palpation. Considerations: a. Only pigs with viable cysts, or with more than 2 non-viable cysts, will be considered positives. Training will be required on confirmation of positives, pig handling and biosecurity (to avoid spreading pig diseases such as swine fever). If there is no or limited expertise, it is suggested that during training, some of the positive pigs with only non-viable cysts are purchased to conduct necropsy and confirm the diagnosis. b. Target population: backyard pigs aged over 4 months. It should only include pigs that may have had the opportunity to roam freely at any point during their lives. The target population size should be determined by census data or estimations. c. Exclusion criteria: commercial pigs. d. Additional data to be collected: approximate weight, GPS location. 3. Determine the sample size The sample size for each survey area should be based on the target population in that survey area. The sample size used to determine if the survey area has a human infection above a threshold of 0.5% is shown in Table A2.1 (based on Kato–Katz microscopy); the sample size used to determine if a survey area has a porcine infection above a threshold of 2% is shown in Table A2.2 (based on tongue palpation). If the number of observed positives is less than or equal to the critical cut-off, then the survey area can be classified as being below the threshold; a public health intervention is not needed. In order to trigger a public health intervention, the number of positives must be ABOVE the critical cut-off PLUS the presence of both key risk factors (roaming pigs and deficient sanitation). Table A2.1 Sample size to determine if a survey area has a human infection of T. solium taeniasis above a threshold of 0.5% (using Kato-Katz test) Refers to the total ELIGIBLE HUMAN population in the survey area (aged 5 years and older). ** To account for non-response, absenteeism or other causes of loss, it is important to increase the sample size by dividing it by (1 – non-response rate). For example, if a 30% non- response is expected and the sample size is 960, then the new target would be 1372 persons (960/0.7). If this is done, then it IS NOT necessary to seek a replacement person. Population size* Target sample size (n)** Critical cutoff*** <700 Census 0.005 x n 700—719 620 1 720—819 650 1 820—899 675 1 900—1 099 720 1 1 100—1 499 760 1 1 500—2 099 820 1 2 100—2 499 850 1 2 500—3 499 880 1 3 500—5 999 900 1 6 000—9 999 920 1 10 000—17 999 940 1 >18 000 960 1 31 Table A2.2 Sample size to determine if a survey area has porcine cysticercosis infection above a threshold of 2% using tongue inspection. * Refers to the total backyard PIG population in the survey area. ** Sampled pigs must be over 4 months of age and must have roamed free at least at some point in their lives. If the critical cut-off is reached before all the pigs are examined, the sampling can be stopped, unless we want to learn more about the geographical distribution of the disease. But the intervention should be conducted in all the area (true to the original intent). Population size* Target sample size (n)** Critical cutoff*** <200 Census 0.02 x n 200—219 165 1 220—259 170 1 260—279 185 1 280—449 190 1 450—599 200 1 600—12 999 220 1 >14 000 240 1 In practical terms, triggering a public health intervention in a survey with a target population exceeding 700 people in the survey area, means finding at least 2 positives, and in a porcine survey conducted in a survey area with over 200 pigs, finding at least 2 positive pigs. If the total population of pigs or humans is less than the minimum population shown in Tables A2.1 or A2.2, a census is required and should be interpreted based on whether the observed number of positives exceeds the threshold (2% or 0.5%). For example, if the target population in a human survey is 500 individuals (aged 5 years and older), because this is less than the minimum 700 in Table A2.1, all 500 people should be tested: the critical cut off will be 500 x 0.005 = 2.5. This means that if 3 people are found to be positive (and the key risk factors are present), then it triggers a public health intervention. The cut-off is higher because in this case all the population has been tested and there is no need to rely on statistics to tell us the likelihood that we are above or below the threshold. In the case of pigs, if there are estimated to be 150 backyard pigs in the survey area, because that is less than the minimum 200 shown in Table A2.2, all 150 pigs should be inspected: the critical cut off will be 150 x 0.02 = 3 pigs. That means that 3 pigs need to be positive (and key risk factors present) to trigger a public health intervention (because the target threshold is ≥ 2%). If the programme chooses to sample pigs but does not know how many pigs are in the survey area, the default should be to use the maximum sample size for pigs (240 pigs), recognizing that the detection of a small number of infected animals in a smaller sample can provide sufficient evidence of prevalence above the threshold for triggering an intervention. Non-response: In any human survey, there will be a certain number of individuals who do not provide a specimen due to refusal, absenteeism, or inability to provide a faecal sample. In household surveys, it is not uncommon for 10–30% of selected household and/or individuals to not provide a specimen. Survey teams should try to mitigate non-response rates through social mobilization (meeting with local leaders in advance of the survey to make them aware of the survey and sensitize the population to be home at the time of the survey team’s visit) and careful microplanning (making sure that the survey is conducted during a season year, day of-the-week and time-of-day when people are most likely to be at home). Despite these efforts, some non-response is unavoidable and thus needs to be accounted for in the survey to ensure that the target sample size is reached. To account for non-response, divide the target sample size by [1 - non-response rate]. For example, if a 30% non-response is expected and the sample size is 960, then the new adjusted target sample size is now 1372 persons (960/0.7). The survey team should use this adjusted target sample size when determining the number of people to sample per village. Annex 2. Steps for conducting T. solium surveys: translating theory into practice 32 Implementing Taenia solium control programmes in countries: monitoring and evaluation framework By using the adjusted target sample size, it is NOT necessary to seek a replacement person or household if the selected person/household is not available. Simply proceed to the next selected household. If, by using this methodology, the number of samples collected is much larger than the original target sample size (for example because the non-response rate was lower than expected), the programme may conserve resources and not test all the samples collected, but randomly select the original target size of samples (from Table A2.1) from among the samples collected. Alternatively, the programme may test all the samples; however, if the total number of samples tested exceeds the target sample size from Table A2.1 by more than 25%, the programme should seek the advice of a statistician to calculate the upper 1-sided 95% confidence interval. If this upper limit of the confidence interval exceeds the target threshold (0.5% in humans, 2% in pigs), then a public health intervention is necessary. 4. Select the type of survey and the villages or communities It is expected that the survey areas will comprise several villages or communities. If a survey area has 20 villages or less, it will be a focal survey. If there are more than 20 villages or communities in a survey area, a broad survey will be used. The village selection will depend on the number of villages or communities in the survey area: 1. Focal survey (<_ 20 villages): all villages will be included. 2. Broad survey (> 20 villages): 20 villages will be selected. To select them, follow the steps in Box A2.1. Box A2.1. Instructions for systematic random selection of villages in a survey area (for a human or pig survey) 1. Prepare the sampling frame: Obtain a list of all the at-risk villages in the survey area (e.g. district, province). If possible, it is preferable for this list to be in geographical order (e.g. starting from the northwest and ending in the southeast) or at the very least, according to sub-district. This is done to ensure greater geographic representation of the final selected sites. 2. Determine the sampling interval: Determine the village sampling interval by dividing the number of total villages by 20. For example, if there are 127 villages, the village sampling interval is 127 villages/20= 6.35 3. Choose the starting village: Pick a random number using two decimals, between 1 and the sampling interval. Round down to the nearest whole number and this will correspond to your starting village. For example, suppose 1.82 is chosen. In this case, the first village selected is the first village won the list. 4. Select the remaining villages: To select the remaining 19 villages, continuously add the sampling interval to the random number and then round down; that number corresponds to the next selected village from the list. Continuing with the example, the 2nd village will be 1.82 + 6.35 = 8.17 (village 8 on the list). The third village will be 1.82 + (6.35 x 2) = 14.52 (village 14 on the list). Remember to always round down, then continue until all 20 villages have been selected. 5. Determine if the village is at risk of transmission: Upon arrival to conduct the survey, the survey team should ask local leaders if there are any free roaming pigs in the village (they can also ask about open defecation, but sometimes the answers can be less reliable). If the presence of roaming pigs is confirmed, the village is eligible for inclusion in the survey and random sampling of humans/ pigs can commence. If a selected village does not have any free roaming pigs, the survey team should go to the nearest neighboring village, not previously selected for inclusion, as a replacement site until a village with free roaming pigs is found. 33 5. Determine the number of samples per village Once you have determined your sample size and identified villages for inclusion, the next step is to determine the number of samples needed per village. The method used to determine the number of samples needed per village, for a human or a pig survey, depends on whether the number of pigs in the area and the number of pigs per village (excluding commercial pigs) is known. That is because pigs are a necessary condition for transmission of the parasite, and the number of samples needed per village should be proportional to the number of pigs in each village. The number of samples should not be proportional to the human population, as there is a risk of taking a larger number of samples from larger towns where risk factors such as sanitation may not be present at the same level as in small villages. Box A2.2. Calculating the number of samples per village (example) 1. If the number of pigs in the area is not known: Take the total objective sample size and divide it by 20 (or the number of villages in the area if it is a focal distribution). If, for example, 960 Kato– Katz samples are needed for a human survey from 20 villages, 960/20 = 48 samples per village. If, for example, 220 samples are needed for a pig survey from five villages, 220/5 = 44 samples per village. 2. If the number of pigs in the area is known (preferred option): The number of samples per village should be calculated proportionally to the number of pigs. For example, if we have an area with 20 000 people and 900 pigs, we need to sample 960 humans or 220 pigs (as per Tables A2.1 and A2.2). If there are five villages in the area, with 50, 230, 326, 97 and 197 pigs respectively, the calculation of the number of samples per village will be as follows: • First calculate the percentage of pigs in each village. For example, for village 1 it is (50/900) x 100 = 5.6%. • Then use that percentage to determine the number of samples from each village. For village 1, it would be 960 x 5.6% = 53 samples if sampling humans, or 220 x 5.6% = 12 if sampling pigs. Instead of testing 960/5 = 192 samples per village, we take more samples from the villages where there are more pigs. Sample size calculation if sampling humans: # pigs % pigs Calculation # samples Village 1 50 5.6% 960 x 5.6% = Village 2 230 25.6% 960 x 25.6% = Village 3 326 36.2% 960 x 36.2% = Village 4 97 10.8% 960 x 10.8% = Village 5 197 21.9% 960 x 21.9% = TOTAL 900 960 Examples for calculating the number of samples per village are shown in Box A2.2. # samples per village 53 245 348 103 210 To facilitate steps 2–4, an Excel Tool has been created. After listing the at-risk villages, the Excel Tool selects 20 villages randomly. This Excel Tool is available from the WHO website (2). Annex 2. Steps for conducting T. solium surveys: translating theory into practice 34 Implementing Taenia solium control programmes in countries: monitoring and evaluation framework 6. Conduct the sampling Samples must ONLY be taken in areas where BOTH risk factors are present (roaming pigs and poor sanitation), as these are necessary conditions for the T. solium transmission cycle. If the risk factors are not present when arriving at a selected village, the next village should be selected. Although there is a PURPOSIVE selection of the survey area because the risk factors must be present, sampling must be RANDOM within the selected area. Considerations: 1. Timing When the surveys are used to monitor or evaluate a control intervention, the surveys should be conducted at least 10–12 months after the cessation of the interventions. 2. Sampling in humans The selection of the households depends on whether the households are numbered or not (see Box A2.3). The households should be randomly selected. Instead of testing 220/5 = 44 samples per village, we take more samples from the villages where there are more pigs. Sample size calculation if sampling pigs: # pigs % pigs Calculation # samples Village 1 50 5.6% 220 x 5.6% = Village 2 230 25.6% 220 x 25.6% = Village 3 326 36.2% 220 x 36.2% = Village 4 97 10.8% 220 x 10.8% = Village 5 197 21.9% 220 x 21.9% = # samples per village 12 56 80 24 48 TOTAL 900 220 35 Box A2.3. Randomly selecting households within a village If the households are numbered or there is a census: • If the households can be numbered or there is a census that can be used to create a list, use that list to select the households using systematic sampling (e.g. taking every nth household from the list to achieve the target sample size, accounting for non-response). If the households are not numbered or there is no census: • One method that could be used, is the “random walk approach”, but this method should ONLY be used if efforts to construct an ad hoc list of households fail (3): 1. Go to a central location within the community, such as a market, a church, a health facility or the junction between two roads. If possible, find a local guide who can accompany you, introduce you to the families, and help you find the households and the community boundaries. 2. Select a direction at random by spinning a bottle/pen/pencil. Walk in the direction that the bottle/pen/pencil is pointing and count every house in your path, starting from the centre of the village to the edge of the village. If possible, number each house with chalk as you go. 3. Draw a random number (e.g. using slips of paper from a hat) between 1 and the total number of households you counted in step 2. This number will represent your starting house. For example, if you count five households from the centre of the village to the edge of village and you randomly pick the number 4, then the fourth household that you counted becomes your starting household. 4. Within a selected house, randomly select up to two individuals (aged 5 years and older) to include in the survey. Collect demographic information, along with a stool sample from the selected individuals. 5. Proceed to the nearest neighbour household and again enrol up to two individuals in the survey. 6. Repeat this process until the target sample size for the village has been met. • Other methods of random selection, such as systematic sampling or segmentation, can also be used to determine which households to include in the survey. Systematic sampling may be preferred in rural areas with smaller populations, where it does not take too much effort to enumerate all the households in a village. Segmentation may be more efficient when there are some large communities (e.g. > 1000 households) in which enumerating all households requires significant effort. Programmes are encouraged to select a method of random household selection that is appropriate to the local situation, and for which there is local experience. Regardless of which method of random sampling is used, it is strongly recommended that the same method be applied across all villages in which households are not numbered within the survey area. Source: Training for mid-level managers (MLM). Module 7: the EPI coverage survey (3). Source: Training for mid-level managers (MLM). Mobile 7: the EPI coverage survey. Geneva: World Health Organization; 2008, republished 2020 1 2 3 4 5 6 7 8 9 10 No more than 2 participants should be sampled per household. It is important that all individuals who are part of the survey population living in the selected household are eligible to be selected into the survey. To do this, list the names of all individuals ages 5 years and older living in the household on a piece of paper, regardless of whether they are present at the time of the visit. Two persons from this list should be randomly selected by drawing names from a hat or using the random number table. If one of the selected individuals is not able to provide faeces by the time the survey team collects the faecal samples, he or she should not be replaced by another individual in the same household. A wide-mouth container will be given to the participants to collect a stool sample. The stool should be collected on the day of sampling or the day before. Participants and survey staff will be advised to maintain strict personal hygiene and wash their hands with water and soap after collecting the faeces, as there is potential to transmit disease. See Box A2.4 for more details. Annex 2. Steps for conducting T. solium surveys: translating theory into practice 36 Implementing Taenia solium control programmes in countries: monitoring and evaluation framework Box A2.4. Collecting stool samples in the field Preparation • Supplies needed: sterile stool collection kits, including 100 mL plastic collection containers with a spoon or spatula attached to the lid. The containers should be plastic to allow for recycling and should be large enough to allow the participant to easily introduce a small quantity (10 g) of stool, using a wooden stick; permanent-ink markers; soap and hand sanitizer; cleaning material and biohazard bags; cooler with ice packs for transportation (if applicable); and ethanol to conserve samples for PCR testing (see section 5.4). • Personal protective equipment: gloves and, if necessary, masks and protective eyewear. • Ensure participants have access to clean toilets, hand-washing and tissue paper. Collection process • The stool collection containers should be labelled as per participant register. • The containers should be distributed either on the day of collection or during the previous day. Each participant should receive one container for a stool specimen. • When stool containers are distributed, the amount of stool needed should be indicated (usually a few grams) by demonstrating how to put it into the container using the container’s spoon or spatula to transfer stool into the container without contaminating the outside. • If using a pit latrine/toilet, participants especially children may be guided to place stool besides the pit on a piece of newspaper, use the spatula to place a small amount in the cup and drop the rest into the pit. If using a flush toilet, the spatula is used to scoop a small amount into the cup, before flushing. Securely close the container. • Emphasize the need to wash hands with soap after finishing the stool collection. In some places, a bar of soap is given to each participant. • An ID number must be allocated to each participant and used to mark his or her sample containers and form. This practice also allows identification of the participant in the event that any special treatment or care is needed. • No fixative (such as formalin) should be added unless indicated otherwise. This is particularly relevant if also using the stools for soil-transmitted helminthiases, as fixatives may damage hookworm eggs and dilute the specimens, hampering the calculation of infection intensity. General considerations • The cultural appropriateness of this approach must be checked before the start of the survey. • Ethics and consent: ensure that all sample collections are conducted ethically, with informed consent from all participants. 37 If integrating the Kato–Katz survey for taeniasis with surveys for other diseases, please see section 6 (Special considerations) and Box 1 of this framework. The appropriate forms should be completed. Below is an example of a form that could be used.. Safety procedures • Follow biosafety guidelines to prevent exposure to potentially infectious agents. Team members are advised to wear latex gloves during the collection, preparation and reading of the microscopic slides of stool. Any material contaminated with stool should be cleaned with water and soap and then soaked in sodium hypochlorite solution (or other suitable disinfectant). The containers and slides can then be rinsed and dried for reuse or disposed of by incineration. Dispose of waste and decontaminate equipment according to local regulations. Source: adapted from Helminth control in school-age children: a guide for managers of control programmes (4) and protocols from the Expanded Special Project for Elimination of Neglected Tropical Diseases (5). STOOL SAMPLING FOR MICROSCOPY Date (dd/mm/yyyy) and time: ID: District: Community: Address: Name: Surname: Sex: M F Age: 3. Sampling in pigs It is preferable to select pigs from several households. If multiple households rear pigs, it is preferable to spread the sample out amongst the different households with pigs. Pigs should be randomly selected. Selected pigs must be local backyard pigs, at least 4 months of age, that have roamed free and are representative of the geographic area in which pigs are found in the village. Appropriate forms should be used to record the pig location, owner and other data considered of interest. References 1. Bench aids for the diagnosis of intestinal parasites, second edition. Geneva: World Health Organization; 2019 (https://iris.who.int/handle/10665/324883). 2. Excel tool on Taenia solium infection. In: WHO/Control of Neglected Tropical Diseases [website]. Geneva: World Health Organization; 2024 (https://apps.who.int/neglected_diseases/ntddata/forms/taenia/en/ WHO_VST_TSOL_v1.xlsm). 3. Training for mid-level managers (MLM). Module 7: the EPI coverage survey. Geneva: World Health Organization; 2020 (https://iris.who.int/handle/10665/337065). 4. Helminth control in school-age children: a guide for managers of control programmes, second edition. Geneva: World Health Organization; 2024 (https://iris.who.int/handle/10665/44671). 5. ESPEN: Expanded Special Project for Elimination of Neglected Tropical Diseases [website]. Brazzaville: World Health Organization Regional Office for Africa; 2024 (https://espen.afro.who.int). Annex 2. Steps for conducting T. solium surveys: translating theory into practice Annex 3. Tongue palpation for diagnosis of porcine cysticercosis Inspection and palpation of the pig’s tongue can be used to diagnose porcine cysticercosis. The sensitivity of the method varies depending on the burden of Taenia solium. For pigs with less than 100 cysts, the sensitivity is 2.7% (1); the average sensitivity according to the published data (2–5) is estimated at 27.6%. The specificity also varies depending on the experience of the person inspecting and palpating the pig’s tongue, and the type and number of cysts. When viable cysts, or multiple non-viable cysts are identified, it can be 100% specific. However, if only 1 or 2 non-viable cysts are identified, it can be nonspecific as it may be very difficult to differentiate these 1 or 2 non-viable lesions from scar tissues or other tongue lesions that may not be infrequent, depending on the environment in which the pig is roaming. Nevertheless, tongue inspection and palpation is a relatively simple and inexpensive method that can be used to identify pigs, especially those with a high burden of T. solium. Considerations for tongue inspection and palpation It should only be conducted by trained personnel. Hold the pig firmly using a pig snare or in lateral recumbency. Always use an adequate pig snare for larger animals (Fig. A3.1 and Fig. A3.2). Use a thick wall polyvinyl chloride (PVC) tube, or a similar object, placed parallel to the tongue to open the mouth and keep it open (ensure that the PVC tube is thick enough so the pig cannot break it). In some places, hard wooden sticks are used, but the main drawback is that they cannot be disinfected. Mouth openers could also be used. Hold the tongue with the help of a cotton cloth and extend it gently. Examine it visually and by palpation, especially on the ventral side and near the base of the tongue. A viable cyst measures about 3–15 mm and looks like a bladder full of liquid with a white dot in the middle (the scolex) (Fig. A3.3). A non-viable cyst can be in different stages of degeneration. In dead cysts, the fluid disappears, the scolex is not visible, and purulent material may be present and sometimes calcified; they generally look like grains of rice. Any pig with viable cysts or multiple non-viable cysts on the tongue is considered positive for T. solium cysticercosis. The presence of 1 or 2 non-viable cysts is considered as suspicious. In that case, if confirmation by necropsy is not an option, it is suggested to inspect more pigs in the area. Important: Keep in mind that wooden sticks and cloths will be covered in saliva and can be a vehicle for transmitting disease. Sticks and cloths should never be reused after examining a sick animal. 39 Arrows showing viable cysts in the pig’s tongue. Fig. A3.3. Identifying the cysts © Meritxell Donadeu Fig. A3.1. Inspecting the tongue Fig. A3.2. Palpating the tongue The pig is restrained with a pig snare, and a wooden stick is used to keep the mouth open and turn its head slightly to make it easier for the person conducting the inspection. © Meritxell Donadeu © Meritxell Donadeu A “tongue palpator” is used to examine the tongue while the pig is restrained on its side and a wooden stick is used to keep its mouth open. Annex 3. Tongue palpation for diagnosis of porcine cysticercosis 40 Implementing Taenia solium control programmes in countries: monitoring and evaluation framework References 1. Flecker RH, Pray IW, Santivanez SJ, Ayvar V, Gamboa R, Muro C, et al. Assessing ultrasonography as a diagnostic tool for porcine cysticercosis. PLoS Negl Trop Dis. 2017;11(1):e0005282. 2. Gonzalez AE, Cama V, Gilman RH, Tsang VC, Pilcher JB, Chavera A, et al. Prevalence and comparison of serologic assays, necropsy, and tongue examination for the diagnosis of porcine cysticercosis in Peru. Am J Trop Med Hyg. 1990;43(2):194–9. 3. Dorny P, Phiri IK, Vercruysse J, Gabriel S, Willingham AL 3rd, Brandt J, et al. A Bayesian approach for estimating values for prevalence and diagnostic test characteristics of porcine cysticercosis. Int J Parasitol. 2004;34(5):569–76. 4. Chembensofu M, Mwape KE, Van Damme I, Hobbs E, Phiri IK, Masuku M, et al. Re-visiting the detection of porcine cysticercosis based on full carcass dissections of naturally Taenia solium infected pigs. Parasit Vectors. 2017;10(1):572. 5. Chilundo AG, Johansen MV, Pondja A, Miambo R, Afonso S, Mukaratirwa S. Piloting the effectiveness of pig health education in combination with oxfendazole treatment on prevention and/or control of porcine cysticercosis, gastrointestinal parasites, African swine fever and ectoparasites in Angonia District, Mozambique. Trop Anim Health Prod. 2018;50(3):589–601. Annex 4. Lot quality assurance sampling and calculation details Lot quality assurance sampling (LQAS) is considered a relatively rapid and inexpensive approach to data collection in lieu of traditional surveys. It allows for small sample sizes and more frequent sampling than standard probability surveys. In the LQAS application, a pre-defined area is sampled. If that sample comes up with an indicator deemed as performing acceptably, then that indicator as a whole is deemed acceptable. If not, then the indicator is not performing acceptably. It gives an indication of whether or not a programme is meeting its objectives and targets. For the calculations in this document, we have considered two types of error (Table A4.1): a type 1 error occurs when the likelihood that the survey, conducted in an area with true prevalence above the threshold, does not exceed the critical cutoff. It is the accepted risk for undertreatment, and 5% has been used as it is the same value used by other neglected tropical diseases communities. a type 2 error occurs when the likelihood that the survey, conducted in an area with true prevalence equal to half the threshold (e.g. 1% for porcine surveys), detects positive individuals exceeding the critical cutoff. In other words, it is the accepted risk of overtreatment. In this case, due to the low sensitivity of the diagnostic tests, a high value is accepted (70%). This can be reviewed once more evidence is available. Human survey Pig survey Diagnostic Microscopy (Kato–Katz, 2 slides per sample) Tongue palpation Threshold 0.5% 2.0% Max. Type 1 error 5% 5% Max. Type 2 error 70% 70% Table A4.1. Assumptions used to develop LQAS Tables A2.1 and A2.2 (Annex 2) to determine if a survey area has a human infection of T. solium taeniasis above a threshold of 0.5%, or a porcine cysticercosis infection above a threshold of 2% 41

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