Mission report in Mozambique: Rapid Epidemiological Mapping of Onchocerciasis

WORLD TIEALTH ORGANIZATION ' AFRICAN PROGRAMME FOR ONCHOCERCIASIS CONTROL (wHo/APOC) RAPID EPIDEMIOLOGICAL MAPPTNG OF ONCI{OCERCIASIS (REMO) MOZAMBTQUE MISSION REPORT BY Dr. Peter Enyong (WHO Temporary Advisor). Team Leader Tropical Medicine Research Station, P.O. Box 618, Kumba Cameroon. Tel. (237) 77 7s 41 01, E-mail : enyongap@yahoo.com Mr. Hilary Adie (WHO Temporary Advisor) Team Member Onchocerciasis Control Unit c/o College of Health Technology Ministry of Health Calabar, Nigeria Tel: (234) 80 57422164,80 3706371I E-mail : enternity2 00Zng@yahoo.com Mr. Mathias Esum (WHO Temporary Advisor) Team Member Department of Plant and Animal Sciences Faculty of Science University of Buea, Buea, Cameroon. Tel: (237) 77 68 34 7t E-mail : mathias_mesum@yahoo. fr 0 5 t{0v. 2007 Table of Content 1.0 Summary . . 2.0Infroduction 3.0 Materials and Methods 3.1 Description of Study Area.. 3.2 REMO Methodology 4.0 Results....... 5.0 Discussion 6.0 Recommendation 7.0 Constraints 8.0 Acknowledgements 9.0 References 10.0 Appendices l0.l List of National Team Members 10.2 Time table of REMO Activities... 10.3 Tables...... .4 3 .6 6 7 8 8 l0 l0 10 .12 ...11 ......12 t2 ......13 2 1.0 SummarT : Human Onchocerciasis exists in Malawi and Tanzania" neighbouring countries to Mozambique. It is therefore, quite legitimate for the health authorities of this country to be worried about the probable presence of this disease, especially in the Northem Provinces. Unfortunately, no baseline data had existed before 2001 when the first REMO study was carried out. The present study which is taking place six years later was to re-evaluate the situation of this disease in relation to the findings of 2001, when the disease was found to be hypo-endemic. This study was restricted to the four Norttrem Provinces because the results of the 2001REMO exercise demonstrated that these were the Provinces in which some cases of onchocerciasis were found. Also, the ecology, topography and probably climate of these Proviric'es could be very suitable for the breeding of the Simulium vector and consequently the imptantation of the disease if it does not actually exist. The continuous movement of people between these Provinces and the neighbouring Onchocerciasis endemic countries of Malawi and Tanzaniaalso led to the focusing of this study in the north of Mozambique. After the training of the future participants in the REMO exercise, 114 villages were selected following standard procedures (30 from Zarrrbezia,25 from Tete, 30 from cabo Delgado and,29 from Niassa). In all, 97(85.1%) villages were visited and consenting adult males (including some women) present in the village at the time of the exercise, were examined for Onchocerca volvulus nodules. l7 villages were either inaccessible, or had moved to other positions far from the location on the map. In cases where the name of the village had changed, the new name was used but the old name was kept for reference. The results show that all the four Provinces had cases of nodule carriers with the highest number coming from Tete Province (19), followed by Cabo Delgado Province (18), Niassa (15) and 7-ambezia(9). The distribution of the villages by Onchocercal nodule rate is as follows: 40 villages were positive for O. volvulus nodules, while 38 had a nodule rate of I -g%and only 2hada nodule rate varying between 10 and l9o/uNo village has a nodule rate up to, or higher than2D%o. In the four Provinces, a total of 3780 persons were examined during the entire exercise. Of this number, 6l(I.6%) had visible or palpable nodules which were characteristic of O. volvuhzs. From our experience in other countries, there was only one case of skin disease and one case of visual impairement which could be linked to Onchocerciasis. There was no blindness due to this disease. It can be concluded that although onchocerciasis exists in Mozambique it is hypo-endemic. The Atlas GIS presentation of the villages on a map of Mozambique will better reveal the spread of the disease in the Provinces concemed. 3 1.0 Introduction: Human Onchocerciasis is still a serious public health problem in much of Africa within the tropics (Prost, 1986) especially among the farming population (Nwoke et al1999). The main clinical manifestations of this disease include subcutaneous nodules, skin lesions (skin atrophy or thickening, depigrnentations: leopard skin, sawda) which are associated with excessive itching. The most debilitating effects are linked to the eye and range from mild reversible ocular lesions of the anterior chamber to severe irreversible and ultimately btinding posterior chamber lesions (Duke, 1990). Globally, Onchocerciasis affects 17.7 million people world wide and about 17.5 million in Africa. It is estimated that 122.9 million are at risk of infection from the disease globally and about 96Yo of these are in sub-Saharan Africa (WHO, 1995a). The control of Onchocerciasis has been limited to vector control by larviciding of breeding sites of Simulium damnosum s./. because of the non availability of a suitable macio or microfilaricide. The discovery of Ivermectin (Mectizan) and its registration by Merck &Co as an effective and safe microfilaricide suitable for large scale treafrnent of Onchocerciasis (Lindley, 1980), revolutionised the control of this disease. The decision by Merck & Co Inc. to donate the drug for the control of Onchocerciasis for as long as it will be necessary galvanised the endemic countries, funding agencies and NGDOs and rekindled interest in the control of the disease. The drug is now available for the treatment. The next question was how to carry out mass distribution of ivermectin without knowing the epidemiology, the distribution paffem and intensity of the disease in all the endemic countries. In some countries some information was available but in some, there was no such data. Therefore, in order to identifu areaslzanes where large scale ivermectin could be implemented with adequate coverage, it was necessary to identiff as quickly as possible these areas. With the support of the Task Force for Onchocerciasis Operational Research (OOR) of the UNDPAMoTId BanldWHO Special Programme for Research in Tropical Diseases (TDR), the rapid epidemiological mapping of Onchocerciasis (REMO) based on nodule rates, was developed and adopted as a tool to delineate areas for ivermectin mass distribution. This was successfully tested in Cameroon and the REMO manuals were subsequently developed by Ngoumou and Walsh (1993) and WHO (1995b, 1998). The African Programme for Onchocerciasis Control (APOC) was launched in 1995 to pilot the bold vision of eliminating this disease as a public health problem in 19 endemic African countries. The main objective of APOC was therefore, to weave a partnership with the endemic countries to establish within 4 12 to 15 years, an effective and self sustainable Community Directed Treatment with lvermectin (CDTI) throughout the endemic areas. At its inception, one of the main challenges faced APOC, was to rapidly identiff zones/areas in endemic countries where the risk of Onchocerciasis was high and a significant public health problem to warrant CDTI. Taking into consideration the Scientific and operational advantages of REMO as a diagnostic tool, the Technical Consultative Committee (TCC) of APOC recommended that, a REMO map must be a pre-requisite for the consideration of a project for funding. The REMO map has since formed the basis of delineating CDTI and non CDTI zones and the planning and implementation of Onchocerciasis.control in most of the endemic countries. The studies of Burnham, (1991) *d Courtright et"al., (1995) indicating the presence of Onchocerciasis in Malawi and other works pointing to the presence of this disease in the Ruvuma district of Tanzania, led to the suspicion that Onchocerciasis could be present in Mozambique. This idea was strengthened by the fact that during the long war in the later country many people had taken refuge in these neighbouring countries. Recognising the fact that the flight range of the vector, S. damnosum, of over 100km in some circumstances, increased the fears of Mozambican health authorities. In a personal communication, Noormahomed (December 1998) studied a small cluster of l0 villages in the Milange district and found nodule rates varying from 20 to 50.9%.In March 2001, Noormahomed et al. did some skin snips on 3 16 patients in the same area but from different villages and noted prevalence rates varying from 5.45 to 18.85%. Unfortunatnly these results were never standardised or validated and published. Until the year 2001, therefore, there was no valid parasitological or epidemiological data on Onchocerciasis in Mozambique. The Nation wide REMO of 2001 indicdted that Onchocerciasis was hypo-endemic in this country, with the positive c€rses found only in the Provinces of ZarrbeziaoNiassa and Cabo Delgado. This was the first real indication of the endemicity of the disease. With the above situation in view and the time constraints for this second REMO, it was considered justified to concentrate our efforts on the four Northern Provinces (Cabo Delgado, Niassa, Tete, Z,ambezia), whose epidemiological situation might have changed over the last six years. The present REMO exercise was to plan and train the national team in the Rapid Epidemiological Mapping of Onchocerciasis (REMO). Participate in the execution and supervision of REMO in Mozambique. 5 3.0 Materials and Methods: 3.1. Study Area: Mozambique is one of the countries forming the southern tip of the African Continent. It covers a surface area of about799,380 square kilometres and lies between I0" ,27' and 26",,26' S and 30o, 12' and 41" 5l' E. Its neighbouring countries are Tanzariato the North, Swaziland, South Africa to the South, the Indian Ocean to the East and Malawi, Zambia, Zimbabwe to the West. The country consists of a moderate plateau in the Northern Provinces. The plateau descends gradually to form a sub-plateau which eventually fades away into a long coastal plain. Near the inland border withZimbabwe lies Monte Binga (2,436m) the highest peak. Other notable physical features are Monte Namuli (2419m), in Zambezia Province and Serra Zuria (2227m) in Manica and Sofala Provinces respectively. In the Northern Provinces there are several massifs which are a continuation of the Malawi Shire Mountains. The coastal zone is narrow in the north but widens considerably towards the south. The coast is mostly sandy and is bordered by lagoons, swamps, sand bars and chains of coastal islets. The country is characterised by a network of rivers and tributaries, which take their source from neighbouring countries and crossing Mozambique on their way to the Indian Ocean. The largest of these rivers, the Zambezi, is located to the North West and covers a distance of about820 km and is navigable for about 460 km. Other important rivers are, the Ruvuma, Lurio,Pungue, Buzi, Save, Limpopo, Incomati and Maputo. Some of these rivers like, the Zanrbezi, have hydro-electric dams while others have a greatpotential for irrigation and agricultural development. The climate has two distinct seasons: the d.y and wet seasons with the wet season beginning in late October or early November. The counhy lies in the inter-tropical zone giving it a tropical and sub-tropical type of climate. The central and northern provinces experience mostly the tropical climate, while the southern provinces are mostly sub-tropical. The average annual rainfall is between 600 and 1,800 mm. The temperatures are also variable in relation to the altitude. In general the temperatures vary between 27"C and 30'C in the rainy season and lToC and 20"C in the cooler season in the coastal areas. The vegetation of the Northern Provinces is mostly forest (Niassa, Cabo Delgado, Nampula, ffid part of Tete). The other parts of the 6 country consist of grassland savannah and mosaic savannah with forest galleries along the main rivers and their tributaries. The coastal region is dominated by mangrove (Africa Today 1995). There are l0 Administrative Provinces : Maputo, Gaza, Inhambane, Manica, Sofalq Tete, Tanrrbezi4Nampula, Niassa and Cabo Delgado. The Provinces are further divided into Districts and sub-Districts. The Administrative and Economic Capital is Maputo. The total population of Mozambique according to the census of 2007 is about 19 million. 3.2 The REMO survey. The three WHO/APOC Temporary Advisors arrived Maputo on the l}h of October 2007 and had a first contact meeting with the WR's representative and members of the MoH. During this meeting a time table of activities was drawn up. The first point was the training of participants. The later were drawn from the Provinces as well as the MoH. The training took place from the 156 to the 17ft and started with a power point presentation of the epidemiolory of Onchocerciasis, clinical manifestations, the transmission, the biology and ecology of the black fly Simulium damnosum s.l. The participants were presented with photographs showing patients with very evident nodules at various positions of the body.However, since not all nodules are as evident as those in the photographs, participants had a real life situation as they were called upon to palpate a nodule on the knee of one of the Temporary Advisors. The Rapid Epidemiological Assessment (REA) was explained including how to fill in the village and summary forms and keep a log book. The selection of villages was well demonstrated after a clear explanation of the relationship between the disease and the river systems. Copies of WHO/REMO documents (Ngoumou & Walsh, 1993; WHO, 1995b; 1998) translated into Portuguese were given to the participants as support material for the training. The selection of the villages for the REMO proper, was undermined by the fact that there were no maps to the scale I : 250,000. The only maps we could get were with the scale I : 500,000. These were printed at the rate of one map a day and thus it took another 3 days to get the maps. In spite of this set back, the participants diligently selected the villages under the supervision of the Temporary Advisors and all the coordinates were calculated. The training session benefited a greatdeal from the presence of two geographers. The later were able to generate maps by entering the selected villages into a village data base which now exists in the MoH. Three teams (lclinician, I geographer, lbiologist, I Temporary Advisor) were formed after the training and each team was assigned a Province. Each team had 7 a team leader (national) and a supervisor (Temporary Advisor). All the teams will converge on Zarrrbezia Province when they complete the REMO in the other neighbouring Provinces of Tete, Niassa and Cabo Delgado. All the teams flew to the capital cities of the Provinces, contacted the Provincial Directors of Health and collected the funds allocated for the exercise and went to work without delay since time was very short. For better advocacy and mobilisation, each team co-opted one person from the District and also from each village sampled. The REMO exercise was completed on the 3l't October 2007 and the results are given below. 4.0 Results: The results of the REMO exercise are presented in tables I and Z.Table 1 shows the number of villages selected in each Province. The villages are spread out as follows: Cabo Delgado 3 0, Niass a 29 , Tete 25 ard Zarnbezia 30. tn all 1 I 4 villages were selected but l7 (14.9%) were inaccessible. All the accessible villages (97) were included in the study and 57 of these did not have any persons with O. volvulus nodules. The 40 (41.2%) villages that had positive cases were distribnted as follows: Cabo Delgado 12, Niassa 8, Tete 13 and ZarbeziaT.lt was also observed that9lYo (38) of the villages had a nodule rate ranging between I -9%.2 villages had a nodule rate of l0 - lgyo. There were no villages with nodule rates of 20Yo and above. Table 2 indicates that a total number of 3780 persons were examined during this study. Of these, 61 (1 .6%) were found positive for O. volvulus. Tete had the highest number of cases (19) followed by Cabo Delgado (18), Niassa 15, while Zambezia had 9. 5.0 Discussion: The nearest known foci of Onchocerciasis to Mozambique are the Thyolo and Ruvuma in Malawi and Tanzarriarespectively (Burnharn,1991; Courtright et al. 1995). Northern Mozambique is surrounded by the above countries making it possible for cross boarder transmission of the disease. It is therefore, legitimate for the health authorities to be concerned with the probable presence or potential implantation of Onchocerciasis at least in the North of the country. The vast movements in and out of the neighbouring countries during and after the war, lends more credence to these fears. Up to the execution of the200l REMO, there were only anecdotal claims of the existence of Onchocerciasis inZanbezia Province. The results of that REMO 8 exercise demonstrated that the Southern Provinces could be considered devoid of Onchocerciasis. The conclusion of that study, indicated that the Provinces of Cabo Delgado, Zantbezia and Niassa had more than90%o of the positive cases observed. The present evaluation corroborates these findings and reveals that Tete Province too has quite a number of cases. The main finding of the 2001REMO exercise was that Onchocerciasis was hypo-endemic in Mozambique. The social and cultural ties of the populations in the northem Provinces and their kith and kin in the neighbouring countries, augur for the implantation of the disease in this counfiy. InZalarrbezi4it is not uncommon to find people who will give the price of an article,in Kwacha or tell you their ages in English. However, Onchocerciasis is not a flu which can cross boarders easily and infect people. A suitable ecology, topography and especially the presence of an anthropophilic Simuliumvectiti including the parasite must be present to lead to the implantation and transmission of the disease. Up to this moment, there is no evidence of the presence of anthropophilic Simultwn species in Mozambique. There are big and small rivers in the Norttrem Provinces with many potential breeding sites for S. damnosum s.l. and even S. neqvei. In this context one Simuliwt fly was caught in the car by the entomologist of the group but it could not be preserved for detailed identification for lack of the necessary materials and equipment. In trying to clariff the status of the disease inZanrbezia Province, 3 (Mambucha, Vulalo, Matage) of the villages which had nodule rates bet'ween 33 and 5lYo accnrding to Noormatromed et al. 1998 (unpublished document) were visited. OrIy I infected person was found in Vulalo out of 30 persons examined. The other 2 villages were negative. The spatial presentation of the villages will be clearer when the data will be put into Atlas GIS programme. However, it is observed that in Niassa, there seems to be a focal area between Maniamba and Lussimbesse where a a small cluster of villages had positive cases. There will be need for a more thorough study including skin snips and entomology in such a focal area. The villages selected along the Lurio (an important river with many potential breeding sites, did not reveal any positive villages. rn conclusion, it could be said that this study, like the REMO of 2fi)1, has shown that Onchocerciasis exists in Mozambique but it is hypo-endemic. 6.0 Recommendations: 6.1 An entomological team with a medical entomologist who is very experienced in Onchocerciasis transmission should be sent to explore some main rivers in Cabo Delgado, Niassa, Tete and Zambezia for ^S.damnosum.In the event that there is S. damnosum, some collections and dissections should be carried out to ascertain the vectorial capacity 9 of this vector. 6.2 An epidemiological and parasitological investigation, including standardised skin snips, should be carried out in focal areas (Villages between Maniamba and Lussimbesse in Niassa Province) to determine the extent of the infection. 6.3 Envisage some clinic based treatment with ivermectin for the present cases and others that may be detected. 7.0 ConStraints : 7.1 The l: 250,000 maps which are the basis of the selection of villages for REMO were not available. It took one week to print the l: 500,000 maps which we used. This rendered the village selection difficult. 6.4 The District services will need to be informed in advance so as to ges their accord before the team comes. This will help avoid the long distances to and from the District Headquarters for the stamp of approval. 6.5 The study was executed during the planting season when the men go to the field very early in the morning and return very late or not at all. It would be better to carry out future studies outside the planting or harvesting season. 8.0 Acknowledgements: This study was jointly sponsored by the African Programme for Onchocerciasis Control (APOC), the WHO Office, Maputo and the Minisfiry of Health, Mozambique. Our sincere thanks go to the WHO Representatives in Maputo, Lagos and Yaounde and their staff for accelerating the administrative procedures which allowed the team members to travel at short notice. Our deep appreciation goes to the Provincial Directors of Health, to the National, Provincial and District team members, District and Village guides for their close collaboration and support. The Medal of Valour goes to the Drivers in Maputo, Niassa, Cabo Delgado, Tete and Zambezia for piloting us tirelessly through the entire mission. To all those who helped us in one way or another but have not been mentioned here, we say a huge thank you. l0 8.0 References : Duke B.O.L., (1990), Human Onchocerciasis - an overview of the disease. Acta Leidensia. 59:9-24. Burnham, G.M. (1991). Onchocerciasis in Malawi : Prevalence, intensity and geographical distribution of O. volvulus infection in the Thyolo highlands. Trans. Roy. Trop. Med. Hygiene. 85:493-496. Courtright et al. (1995), A new focus of Onchocerciasis in Mwanza District, Malawi. Trans.. Roy. Trop. Med. Hygiene. 59:34-3$. Lindley, D. (1987). Merck's new drug free to WHO for river blindness progftrrnme. Nature, 329: 7 52. Ngoumou, P. & Walsh, J.F. (1993). A manual for Rapid Epidemiological mapping of Onchocerciasis (REMO). TDR/TDR ONCHO/93.4 WHO Geneva. Nwoke, B.E.B., Dozie,I.N.S., Jiyq J.Y. & Gemade, E.I.I. (1999), The present status of human Onchocerciasis in South Eastern Ngeria using Rapid Epidemiological mapping of Onchocerciasis (REMO). Nigerian Journal of Parasitolory. l9: I 1-18. Nwoke, B.E.B., Enyong P. & Tambala P. (2001), Nation-wide Rapid Epidemiological Mapping of Onchocerciasis (REMO) in Mozambique, May 30 July 24,2001: Mission Report WHO/APOC 2001. Prost, A. (1986). The burden of blindness in adult males in the Savannah villages of West Africa exposed to Onchocerciasis. Trans. Roy. Trop. Med. Hygiene. 18: 522-527. WHO (1995a). Onchocerciasis and its control: WHO Expert Committee on Onchocerciasis. WHO Tech. Report Series No. 852 WHO Geneva. WHO (1995b). Supplemental Guidelines for Rapid Epidemiological Mapping of Onchocerciasis (REMO). TDR/TDE ONCHO/95.1 WHO Geneva. WHO (1998). Guidelines for the analysis of REMO data using GIS. TDR/TDF/ COMDT/I 998.3 WHO Geneva. ll -9.0 Appendices: 9.1 List of National Team: Tete team 1. Acasio Benito (Team Leader) 2. Dr. Carlitos Dos Santos (Member) 3. Kennysonny Varela (Member) Team to Cabo Delgado l. Mercia Muchine (Team Leader) 2. Augusto Francisco (Member) 3. Armindo Chicava (Member) Team to Niassa 1. Dr Rasul Nala (Team leader) 2. Mussagy Mahomed (Member) 3. Raymondu Mabota 9.2 Time table of Activities. 12ft October 2007 ........Arival of Temporary Advisors 13tr October 2007 Contact meeting in MoH. 14tr Oct to 17ft Oct2007 Training and village selection 18ft Oct to 31 Oct2007 REMO exercise 1 Nov to 4 Nov 2007 .....Data entry, analysis and report writing 5 Nov 2007 .....Debriefing and presentation of report 6 Nov 2007 .. 9.3 Tables Temporary Advisors depart t2 5(r)NJ { @r m :: @tr 3 3 A' a o 7ootr o o F} o nll!, CL mg. 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