WPRO-o145
SECaID WHO/SPC JOINT SEMJNAR <H FILARIASIS
SpOI18ored by the
WORID HEALTH OMANlZATI<H REGIONAL OFFICE FOR THE WESmRN PACIFIC and the
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SwrH PACIFIC CCMtU:SSI<JI
Apia.
Western Samoa
6 - 12 August 1968
NCYr FOR SALE PFUNrED AND DISTRmlTED
by the
REGI<JIA.L OFFICE FOR THE WESTERN PACIFIC of the World Health Organization Manila, Philippines October 1968
WPR/3$O/68
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The views expressed in this report are those of the advisers and participants at the seminar and do not necessarily reflect the policy of the World Health Organization.
.nr.rR:DJC'I'IW. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. • • •
1
1. 2.
REVlEfl OF FIlARIASIS AND :rl'S CaITROL IN THE SWl'H PACIFIC •••••
2 2 2
EP :II>E:rt1.IOI.mY'.. .. .. .. .. .. .. .. .. .. .. .. . .. ..................................................................... .
2.1
Epidemiological eurveys ••••
. . . . . . . . . . . . . . III
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
2.2 2.3
IrmnwloloSl" ...................................................................................... ,. .. Entomological SUI'V'eys~ •••••••••••••••••••••••••••••••••
2.4 3.
4 5 The vectors of filariasis in the South Pacific ••••••••• 5 8
C<JfrROL ........................................................................................................... .. 3.1
3.2 4.
DI'\Jg control..................................................................................... 8 Vector control............................................................................... 1.0
ASSESSMENT OF MEl'H<DS AND RESULTS OF THE FILARIASIS
CONTROL PILar PHOJECT IN WESTERN SAMOA •.•••••••••••••••••••••• 11
4.1 4.2 4.3 4.4 4.5 4.6 4.7 5.
Preliminary preparations ••••.•••••••••.•••..•.........• Procedure of mass drug aQmin1stration ••••••••••••••.••• Assessment of country-wide drug distribution ••••••••••• Assessment of blood surv8¥s •...••.••.••.•••..•••.•••••• Clinical SUI'VEJy's ..................................................... . Skin test ................................................ . Conclusions ............................................. .
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12 12
16 16 16
l.3
TRAINING AND EXCHANGE OF INFORMATION........................... 17
5.1 5.2 6.
Tra.1n1ng. • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • •• 17 Eltch.ange of' information ................................. 17
~ATIONS .................................................... •• 18
ANNEX 1 ANNEX 2
LIB'r OF PAm'ICIPANI'S......... .. . .. . • . . . .. . . . . . . . . . • •• 21
THE ANTIBJDi' RESPOOSE IN RABBITS INFECTED WITH DIROFn..ARIA UNIFORt4IS................ " ..............'.... 25/26 VECTORS OF FILA.RIP.SIS
ANNE){
3
:m
THE SOOTH PACIFIC.. • • • • ••
zr 35/,6
TABlE 1
P~ INFORMATION 00 THE FILARIASIS PREVAIENCE.. 31/32
TABIE 2 TABIE 3 TABlE 4
DISSECTION OF WIlD-CAUGHr MOSQUlTO VECTORS. • • • • • •• 33
DHDG CONTROL MEASURES •••••.•.••..••.••..••.••.•••• MICROFn..ARAl!XCA STUDIES IN 'lWO DISrRIOl'S O£!'
TAHITI AND IN FIVE PILar VILIAGES IN AMERICAN s.AM0A. • • • • • • • .. . • • • • .. • • • .. .. • • • • • • .. .. • • • • • .. • • .. • • • • • • ... "51/-,8
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CONTENTS (continued) ~
TABLE 5 -
FIRST RECURRENCES (RI) 0l3SERVED DURING THPEE YEARS FOI..LCWlNG MASS DruG ADMlNISTRATION IN TAHITI AND AMERICAN SAMOA •••••••••••••••••••••• MICROFn.ARIA CARRIERS IN ANNUAL FOLLOi( UP BLOOD SURVEYS AFTER MASS DRUG ADMlNISTRATIOO CAMPAIGNS IN TAHITI AND AMERICAN SAMOA ••••••••• BLOOD SURVEYS IN 1965, '!WO YEARS AFTER 'IWLVE DOSES OF DIE'I'HYlCARBAMAZlNE; AND IN 1967, AFTER 'lWELVE ADDITIONAL DOSES ••••••••••••••••• ANALYSIS OF DRUG COVERAGE OF A SAMPLE POPULATION, BY THE NUMBER OF DOSES TAKEN, IN THREE Vn...LAGES IN LEUWMOEGA DISTRIor,
37/}8
TABLE 6 -
39/40
TABLE 7 -
39/40
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TABLE 8 -
WBST.ERN SAMOA, 1965 - 1966 ...•...........•...•• TABLE 9 ANAINSIS OF "EI<'..HTERN DOSE COVERAGE" BY AGE GROOPS FROM A SAMPIB POPUIATION OF THREE VILLAGES IN LEUUJMOEGA DIBrRIor, WESTERN SAMOA, 1965 - 1966 •..........................• DISTRlll1l'ION AND VEorORS OF BANCROFT IAN FILARIASIS IN THE PACIFIC •••••••••••••••••••••• RESlJIlrS OF DRUG ADMINISTRATION IN VILLAGE
41/42
43/44 45/46
FIG. 1
-
FIG. 2
OF AMOULI, AMERICAN SAMOA ••.••....•..•....••••• RESULTS OF MASS DruG ADMlNIBrRATION IN DISTRIor OF TAtJ'I1IRA, TAlirrr •••••••••••••••.•••••••••.•••
47 48
FIG. 3
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WPR/FU./7 ,. INrRCDJOl'ION
Page 1
The Second WHO/South Pacific Coamission (spc) Joint Seminar on FillU"iasis. was convened in Apia, Westem Samoa. from 6-12 August 1968. Dr Iakopo Bsera was elected Chairman, Dr M.B. Mackereth. Vice-Chairman and Dr B. McMillan. Rapporteur. In the opening ceremony, the Honourable Luamanuvae Eti, Minister of Health. welcomed the participants and expressed the appreciation of his Government to Dr M. Candau, Direc"tor-General of World Health Organisatiop., Dr F.J. Dy, Director of WHO Regional Office for the Western Pacific, and Sir Gawain Bell, Secretary~ral of the South Pacific CommiSSion, for holding the seminar in Apia, Westem Samoa. Dr J .C. Thieme. Director of Health, briefly reviewed the history of filariasis and the establisbment of the control pilot project in Western Samoa. Addresses sent by Dr Dy and Sir Gawain were read by their representatives. They thanked the Government of Western Samoa for its generosity in acting as host.
Filariasis is an important public health problem not only in the South Pacific but also among the countries of the Western Pacific Region and other Regions. A DIOst significant observation on filariasis in the South Pacific is the fact that both periodic and sub-periodiC forms of Wuchereria bancrofti are found but Br!lgia malayi has not been reported. In view of the magn1tude of the disease problem. the presence of!!. bancrofti only as an agent and the multipliCity of vectors, it was felt it would be useful to organize a semi nar especially for the South Pacific area.
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The organization of the present a eminar is most timely because of the information which has been collected in the filariasis control pilot project in Western Samoa. The project was designed to test the effectiveness of the methods of control in tenns of mass drug administration or through vector control or by combining both measures at the same time.
The objective of the present seminar was to offer participants from ten countries and territories (see Annex 1) an opportunity to discuss together their own and otherfind1ngs and experience as well as to review the recoamendations expressed at previous WHO meetings. and SPC conferences. The problems examined in the present Seminar concerned the epidellliology of filariasis and its surveys, control methods. training and co-ordinat1on of filariasis activities, with special reference to the assessment of the findings obtained by the pilot project in Westem Samoa.
WPH/Fil./7 Page 2 1. REVlEW OF FILARIASIS AND
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CON'rROL IN 'l'HE SwrH PACIFIC
Based on replies to questionnaires sent to participants of ten countries and territories in the South Pacific and verbal presentations during the seminar, a review was made of the recent situation of filariasis and its control. Filariasis is common in almost all the tropical and sub-tropical countries and territories under discussion. In most of these areas it is a major public health problems. The two forms (periodic and sub-periodic) of!. bancrofti have distinot ranges of geographical distribution and are not endemically co-existent in any. area. Fig. 1 shows this distribution. Some nineteen species of mosquitoes have been proved or regarded as vectors and they belong to four genera: Aedes, Anopheles. Culex and Mansonia. The most important vectors of the sub-periodic form are Ae. polynesiensis and ~. pseudoscutellaris; of the periodic form, "A. p1..lIlctulatus" group and, to a lesser extent, Q.. Pipiens fatigans (Q.. quinquefasciatus). Extensive and/or systematic control measures have been undertaken only in American Samoa, Cook Islands, French Polynesia and Western Samoa. Others have carried out small-scale trials. These control measures mainly consist of administration of diethylcarbamazine. Vector control, usually by means of environmental sanitation and insecticide application. 1s used as a supplementary method in certain areas. Both Fiji and the Cook Islands are preparing plans for greater activity against filariasis. The level of endemicity within countries and territories based· on recent parasitological surveys is given in detail in Table 1. Dissection records on the vector mosquitoes are presented in Table 2 and information on control measures in Table 3. 2. EPIDEMIOLOOY
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All control programmes must be based on a sound understanding of the epidemiology of filariasis. It is necessary to know the hosts, the paraSites and the vectors which transmit infection. as well as how, when and why this transmission occurs. It is also necessary to establish the importance of filariasis in relation to other public health problems in order to determine its priority in health planning. 2.1 Epidemiological surveys
The planning and the execution of a filariasis control programme requires information, through specific surveys, in order to establish the geographical distribution of the infection, the various levels of endemicity, the public health iroportanae and the determination of baseline data.
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• for the assessment. of future progress. When the cont.rol campaign has commenced. surveys are necessary for the rout.ine assessment. of progress as well as for case finding. Once baseline data have been colleoted it. 1s absolutely essential to follow the same methods and techniques throughout the campaign. of the preliminary decisions for any survey is that. regarding the method of sampling to be adopted. For the establishment of endem10i ty, random selected surveys are most usefUl where the size of the populat.ion precludes complete coverage. Where the populat.ion or area to be surveyed is large, indicator areas may be chosen for rout.ine assessment of progress. Their selection should be made at. the time when baseline data are established. If different types of information, clinical, paraSitological or entomological, are to be collected, particular care should be taken to use the same locations in order that such information can be co-ordinated throughout. One
2.1.1
Clinical surveys
Surveys of the clinical manUestations of filariasis are usefUl in order to determine the pUblic health importance in a given area. They may also be used for long term assessment purposes but it must be realised that such surveys have definite limitations. Limphangitis~ intermittent fever, and adenopathy may also be the result. of infective agents other than~. bancrofti. In addition, determinat.ion of these manifestations varies with circumstances and examiner. Elephantiasis and hydrocele, chronic manifestations of the infection, give a reasonably objective index. However, the true extent ,of the disease in a COIIIIIWl1ty will be larger than these would indicate as they take no account of the acute symptoms. Another source of information on the extent of the disease may be found in hospit.al records bUt., while useful for early determination of the presence of the infection in an area, they do not necessarily present. an accurate indication of prevalence.
2.1.2
ParaSitological surveys
ParaSitological surveys provide a more objective means of measuring the prevalence of the infection in a cOlllllunity than do clinical surveys. The parasitological survey can be either qualitative or quantitative. In the delineation of the geographical extent, and level of endemicity, qUalitative information is adequate and it does not require measurement. of blood volume nor count.ing of microfilaria. For the assessment of control act.ivit.y, it is necessary, however, to apply a quantitative method from the beginning in order to determine Illicroflla::-ia rates and densities. On the bases of these indices, the progress of the control progranme can be measured.
WPH/Fil./7 Page 4 In order to have comparable data between different areas or
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times it is essential to adopt standard methods and techniques. The same applies to the presentation of data obtained in such surveys. The analysis of quantitative survey information has presented difficulty in the past but a satisfactory method has recently been established by drawing log-probit regression lines of frequency distribution of microfilaria counts. This method is described in detail in the Second Report of the WHO Expert Committee on Filariasisl • This report. which also contains detailed suggestions on standard methods and techniques applicable to clinical and parasitological surveys. provided the basis of discussion on epidemiological surveys at the seminar. 2.2 Immunology
The potential usefUlness of irrmunological tests as tools in the epidemiological assessment of filariasis has been recognised. At the present time. the intradermal (skin) test is generally considered to be the most adaptable to field use. In recent years. investigations using an antigen prepared by Professor Sawada from Dirofilaria immitis have been carried out in various parts of , the world. Recently, WHO has initiated a co-ordinated research programme using standard procedures in order to assess the sensitivity that this study may clarify the value and place of skin testing with this particular antigen in the assessment of endemicity and eventually in the evaluation of control achievements.
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Results of experimental work. using~. un1formis in rabbits was presented at the Seminar. These demonstrated the complexity of the immunological mechanisms involved. Because of such investigations, it is hoped that a better understanding of these mechanisms will be obtained. A summary of this subject is given in Annex 2.
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1 Wld Hlth Org. techno Rep. Ser •• 1967. ~.
WPR/Fll./7 Page 5
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2.3
Entomological surveys
Entomological surveys should be carried out at a routine and systematic basis in order to obtain baseline data which will be required for epidemiological and control assessments. Methods for entomological surveys are described in detail in the Second Report of the WHO ExPert COIIIII1ttee on Filariasisl and the report of the Inter-Regional Seminar on Filariasis held in Manila in November 1965~ Because of the diversity of the behaviour and habits of the vectors. the methods for entomological surveys should be flexible. For example. there are many methods in sampling the mosquito population. such as the collection with human bait. animal bait. different types of traps, etc. Experience showed that for measuring the mosquitoes density, human-bait collection gives the most direct measure. However. it should be po~ted out that once ·~e methods used in a locality are established, these should be followed up throughout the programme so that the results obtained before and after control are accurately comparable. 2.4 The vectors of filariasis in the South Paoific
The multiplicity of the vectors for the transmission of filariasis in the South Pacific is a situation existing nowhere else in the world. There are approximately nineteen species of mosquitoes which have been proven or regarded as the vectors. Iyengar summarized the available information on the vector distribution3 • Some of the mosquito species are considered as vectors mainly on epidemiological evidences. It is necessary to determine and confirm the vector species by dissection of wild-caught mosquitoes, supplemented by experimental infection. and development of infective forms. It 1s now known that the vectors of sUb-periodic W. bancrofti involve not only day-biting mosquitoes, Aedes (Stegomyii) group, but also night-biting mosquitoes. Aedes (Finlaya) group. The sUb-periodic form of!!.. bancrofti has no marked microfilarial periodicity (although it may have a minor peak in the later afternoon). and thus provides the possibility of its being transmitted by either day-biting or nightbiting mosquitoes. The nocturnally periodic form of W. bancrofti has its Significant peak periodicity at night, and night-biting mosquitoes, such as the "A. punctulatus" group and £.~. fatigans, are responsible for its transmission.
lwld Hl th Org. techno Rep. Ser. 1967. 2
2?2.
UnpUblished document (WHojFn.j66.47)
31965, South Pacific Commission Tech. Paper No. 148, Noumea. New Caledonia
WPR/Fil./7 Page 6 2.4.1 Vector species
For the sub-periodic fonn of~. bancrofti. Ae. polynesiensis is the most important vector wherever it occurs. ~. pseudoscutellaris comes next. For the periodic fonn. IIA punctulatus" is the most important vectos •. and £.E. fatigans plays the role of transmission to a lesser extent. A list of the vectors in the South Pacific is given in Annex }. l Although Belkin described in detail the morphology and classification of the mosquitoes in the South Pacific, there is still need for additional study of certain groups such as Ae. pseudoscutellaris and the "A. punctulatus" group. As some of thespecies cannot be differentiated morphologically, it is necessary to study them on a genetic basis. More extensive collection and detailed studies of the taxonomy of mosqui toes should be made from islands in the South Pacific where the mosquito fauna is still incompletely known. It is therefore recommended that a reference laboratory for mosquito study should be established in the South Pacific. 2.4.2 (a) Bionomics of the important vectors
Ae. polynesiensis
This is ordinarily a day-time biting mosquito (with a minor peak at (]"{OO-\$OO hours and a major peak at 1600-1800 hOurs). A small number also bite at night. Although this mosquito feeds mostly outdoors, it also enters houses to bite but does not often remain there. It rests in shaded vegetation. crab holes, rat-eaten coconut. etc. The dispersal range is considered to be short, usually not more than 100 metres. The breeding sites are coconut shells, fallen coconut leaf bracts, discarded tins, tree holes, rat-eaten cocoa pods, old automobile t~res. etc. It has also been found breeding in the leaf exils of Pandanus. This mosquito lays eggs mostly in the late afternoon. (b) Ae. pseudoscutellaris
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This is very similar to Ae. polynesiensis, and therefore, early records of dissection for Ae. pseudoscutellaris were not separated from ~. polynesiensis. Little infonnation on the bionomics of this mosquito is available because of the confusion of tilis species with Ae. polynesiensis.
1962, The mosquitoes of the South Pacific. University of California, Press, 2 Vol.
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wpR/Fll·h Page 7 (c) The" A, punctulatus n group
!1. farauti can breed in fresh or brackish water, and pe:nuanent sW8mpsor temporary pools. Its day-time outdoor resting places are cement groUnd basins, shrubs, and roots of certain trees. A small number of this mosquito was found resting in the house. It J"ests for a considerable length of time on indoor surfaces before and after feeding. This mosquito bites man readily indoors and outdoors throughout the night, with a peak during the second quarter of the night.
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!1. punctulatus prefers sun-lit water collection such as hoof prints, borrow pits, and drains along the roadside; its breeding sites are created when the bushes are cleared and exposed to sunlight. This mosquito bites man mostly during the third quarter of the night. koliensis is foUnd generally in temporary pools. It bites man outdoors and indoors throughout the night, being more active after midnight. This mosquito has a strong tendency to select human houses as day-time resting place. The n A. punctulatus" group has a high human blood index. (d) ~.~.
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fatigans
This occurs practically throughout the South Pacific. It breeds in polluted waters including latrine pits. The bionomics of this mosquito has been studied extensively elsewhere. It appears that little information is available on the bionomics of most of' the vectors of the sUb-periodic form. Regarding the bionomics of the important vectors of the periodic form, valuable results have been obtained. Detailed studies on the nA. punctulatus" group have been Undertaken in the Solomons, and Papua and New Guinea, because these are the vectors of malaria. The bionomics of ~.~. fatigans has been studied in detail in Ceylon and Rangoon, Burma. It is necessary to have more systematic and intensive studies of the bionomics of the vectors of the sub-periodic ~. bancrofti, particularly their seasonal prevalence, resting places in the day-time and at night, feeding time (day and/or night) and. locality (indoor and/or outdoor). and dispersal range. 2.4.3 Insecticide susceptibility and response to insecticide application
No tests on insecticide susceptibility have been made on most of the vectors of the sub-periodic form. Results of inseoticide susoeptibility tests of adults and larvae are given below •
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P9lynesiensis
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WPR/Fll./7 Page 8
DDT Locality Year LC-50 LC-90 1.~
DIELDRIN LC-50 0.05% LC-90 0.(1)'/,
Adults: Western Samoa 1968 0.5% Fiji 1961 0.7%
1.9% 0.035 ppm 0.012 ppm
Larvae: Western Samoa 1968 0.0095 ppm 1961 0.005 ppm Fiji
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Remarks: The above data for Western Samoa were provided by Dr T. Suzuki (personal oommunication) and for Fiji by Burnett and Ash (1961, Bull. Wld Hlth Org , 24, 547). BUrnett and Ash (l96l) reported that in FiJi a strain of Ae. pseudoscutellaris has developed resistance to DDT after selection, and the larvae of~. fijiensis is naturally tolerant to DDT (LC-50: 0.)6 ppm). In Western Samoa small-scale laboratory tests of the effectiveness of various insecticides (DDT, lindae. dieldrin. diazinon, malathion, dichlorvos, fenthion, feni trothion, and rormel t to the larvae of ~. polynesiensis showed that fenthion was most effective.
3.
CONTROL
3.1 Drug control Organized programmes for the control of filariasis by the use of diethylcarbamazine against the paraSite have been in operation for about fifteen years. During this time the efficacy of diethylcarbamazine and its suitability in mass treatment l.ave been established. At present, the ideal drug, which would immediately destroy microfilariae and adult worms, without producing toxic or allergiC reactions, is not available. Until such a drug is discovered, diethylcarbamazine remains the drug of choice and quantitative evaluation of well-conducted control programmes has demonstrated its value When given in adequate dosage over a sufficient period of time. As regards practical, effective dosage schedules, both for mass or selective case treatment, it is suggested that at least 72 mgfkg body weight of diethylcarbamazine be administered in individual doses of 5-6 mg/kg at daily, weekly or mon"thly intervals. To minimize the incidence
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WPR/Fll./7 Page 9 of toxic effects, it is suggested that the daily dosage should not exceed 8 mgflrg body weight. In the interest of economy there is sometimes a tendency to submit to the temptation of selecting an inadequate dosage or of limiting the number of doses administered. The use of small inadequate dosage in filariasis control programmes has been disappointing as it resulted in temporary microfilaria reduction for short pariods only. It must be stressed that, within llmits, the success of a filariasis control campaign based on the administration of diethylcarbamazine is directly proportional to the dosage schedule and the thoroughness with which the campaign is implemented. In the course of mass administration, adverse reactions have been noted and these are of two distinct types. The drug itself may produce alimentary upset but, more comnonly, its destructive effect on the parasites may give rise to headache or fever; the intenSity of these symptoms may be related to the density of infection. When they appear, these reactions do so shortly after administration of the drug. Transient inflammatory local episodes may also occasionally occur within a few days.
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The objective of a chemotherapeutic control programne is to eliminate or to reduce the number of microfllariae in peripheral blood, thus attempting to interrupt or reduce transmission. The mass administration of diethylcarbamazine resul. ts in overall reduction of the microfilaraemia rate within the population to which it is applied. This is paralleled by concomittant reduction of average microfilarial density. An example of such drug action is given in Table 4. Following initial marked reduction in microfilaraemia subsequent to drug administration, there is generally a gradual increase in microfilaria
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rate and, to a lesser extent, of microfilarial density after a variable period of time. Figs. 2 and 3 give example of this trend. This recurrence or persistence of infection may be the result of one or more factors. In the original survey, some infections may have been undetected, new infections or reinfections occur and here immigrant carriers from outside the control area may be important. This phenomenon of recurrence or perSistence is illustrated in Tables 5 and 6. Following initial mass drug administration, recurrent or new infection may be handled either by individual treatment of positive cases or by repeated mass drug programmes. The latter can be either continuation of the initial schedule or periodic mass administration in this wa:y is exemplified in Table 7. Both periodic and continuous mass-treatment of a population in a filariasis control programme have been considered in contrast to the treatment of positives only detected at annual follow-up blood surveys following a single mass-treatment. The larger number of positives from
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wPR/Fll./7 Page 10 immigrants or recurrences and new infections observed in the follow-up surveys from the latter group would lend support to the opinion that either continuous mass-treatment for an extended number of years or a peri04ic mass-treatment every two or three years is preferable. 3.2 Vector control Methods of vector control to be employed have to depend upon the behaviour and habits of the vector species, and each case requires special consideration. 3.2.1 Environmental sanitation This is a fundamental measure for controlling certain vector species, such as £.~. fatigans and ~. polynesiensis, by good drainage; filling tree holes; burying, dumping or destroying discareded tins; burning coconut shells; adequate sewage disposal; etc. 3.2.2 Insecticide application As no adequate experimental controls have been carried out on a large-scale and over a long period in the South Pacific it is difficult to evaluate its effectiveness. Aerial spraying and barrier spraying with DDT and some other insecticides were tried in American Samoa and French Polynesia. Briquettes containing insecticides were laid in tree-holes in Fiji and Tokelau Islands, and it was reported that its effectiveness lasted a year or longer. Because of the highly exophllic habits of ~. polynesiensis, indoor residual spraying is though not to be effective. It might be considered for controlling Ae. samoanus because certain numbers of this mosquito rest inside the houses at night. However, it should be pointed out that the typical village houses ("Fale") in American Samoa and Western Samoa usually have no walls. Insecticide susceptibility tests of the vector mosquitoes are necessary before the application of any insecticide. It is hoped that field trials of vector control being started in Western Samoa will throw light as to whether this method will be practleal, effective and economical. 3.2.3 Biological control In the South Pacific, trials have been made by introducing Coelomomyces stegosyiae to the breeding places of ~. polynesiensis, larvivorous fish, and varanid lizards to control rats which gnaw coconuts and thus provide breeding places for~. polynesiensis. The above are still at an experimental stage.
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WPR/Fil.!7 Page 11 3.2.4 Genetic control Recent trials in a village outside of Rangoon, Burma, by releasing a strain of male 2,.,2. fatigans give promise of satisfactory results. The sterility of the offspring.is due to cytoplasmic factors which cause incompatibility between populations. The opinion was expressed during the seminar on mosquito genetic control held in the University of Notre Dame in Indiana, United States of America that, based on present knowledge and experience, genetic control can be employed to reduce or eliminate certain mosquito species when the mosquito density has been reduced to a very low level by good sanitation or insecticide application. Attention was drawn to the needs for studies on the orossing of the various species or sub-species within the "Ae. pseudoscutellaris" group from different islands in the South Pacific. 4. ~ OF METHODS AND RESULTS OF THE FILARIASIS
CONl'ROL PILOr PROJECT IN WESTERN SAMOA
The filariasis control pilot project in Western Samoa is the first country-wide programme of this kind assisted by WHO and UNICEF. The project was chosen for review and discussion in the seminar as a teaching model and especially as survey data after the first complete round of mass drug administration were available. Before the WHO/UNICEF-assiSted project in Western Samoa was started in August 1965, preliminary studies were undertaken in four villages in April 1964. Based on experience gained druing these studies, it was decided to adopt the dosage schedule for a mass-drug administration with diethylcarbamazine at a dose of 5 mg/kg body weight, once a week for six weeks and followed by once a month for twelve months, with a total of eighteen doses (90 mgfkg body weight). 4.1 Preliminary preparations
The campaign in the districts and villages was organized by medical officers of the filariasis control pilot project. They had discussions at all district headquarters, with the leaders of the village Women's Committees, district medical officers, district nurses and "Pulenu'us" (government village representatives). The purpose of these discussions was to explain the filariasis control programme, to instruct the Women's Conmi ttees in the technique -pf census-taking and to advise the committees on the selection of village drug distribution teams. Forms for census-taking were provided by the project. On these census forms, all inhabitants of the village above the age of one year Wel'8 recorded, individual weight also being inoluded. Presidents of the
WPR/Fil./7 Page 12 Women's Committees act as team leaders of the drug distribution teams. Teams are composed of from four to ten members depending on the size of the village population. The filariasis control programme was explained to the public through local broadcasting and news media. Lectures were delivered by the medical officers in schools, church organizations and youth organizations. The" above pI~paratory work was carried out over a period of six months.
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4.2 Procedure of mass drug administration In addition to distribution of the drug at village level by the Women's Conrni ttees, in business fiI'llls, government departmen"t;s, organized plantations, schools, etc.,the drug distribution is undertaken by a responsible officer. Tablets of aspirin-phenoacetin-eodein(5 grs.) were also issued for the treatment of reactions. According to instructions, administration of the drug is made directly to each individual. This was usually done at the village women's committee "falell , but some villages adopted house-to-house distribution. When central distribution was made, absentees were visited in their homes. The day after each drug administration, teams presented their record books to the district nurse for checking. Drug reactions of a minor nature were reported and a few villages even decided to discontinue taking the tablets because of fear of reactions. However, through persuasion and explanation by the medical officer, these difficulties were solved.
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4.3 Assessment of country-wide drug distribution Out of approximately 270 villages, records from 150 villages covering 65 796 persons were analysed in teI'llls of "population coverage"*, "dose coverage"** and "eighteen dose coverage"***. The average population coverage for the whole country, excluding Apia District where compilations are still in progress, was 95.6;r:. The best coverage of 99.fiJ; was achieved in Sala'ilua District in Savaii.
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*Total
number of persons talq,ng drug x 100 Population at census
**Total number of doses taken Population at census x 18
x 100
***Number of persons taking 18 treatments Population at census x 100
!
WPR/Fil./7 Page 1.3 Regarding "dose coverage". the results were not as satisfactory as "population coverage". This index was lowest in Safata District (58.a;.:) and highest in Sala'ilua. village of Saval1 (79.5%). The "eighteen dose coverage" was rather unsatisfactory. In 71 out of 150 villages. none of the population took the complete course. In two districts. Safata and Falealili. no person completed the 18 doses. The district of Lefaga had the best record with 57. 7tf,. The average "eighteen dose coverage" for the whole country was 2l.~. Records of three villages taken at random with a total population of 3994 persons were analyzed by the number of doses taken by age and sex groups. It was foUnd out that ll.~ took the full 18 doses while 0.95% of the sample population never took the drug at all. An overall 5~ of the population took a total dosage of at least 70 mgfkg body weight of the drug (Table 8). AnalySis of the above sample by age group showed that the lowest "18 dose coverage" occurred in the age-group of 15-19 years (8.~) en:i 20-24 years (8.~). An average of 13% of the adult population took the complete number of dosages (Table 9). 4.4 Assessment of blood surveys 4.4.1 Blood survey in the preliminary stUdy areas Blood surveys carried out in 1964 en:i prior to treatment, gave the following results:
Population examined
No. positive
Mf rate ~
Males Females
1 009 1 068
230 20')
22.7 19.5
. TOrAL
2CJl7
439
20.1
•
The youngest age with positive findings was 3 years. There were 15 males and 25 females above the age of 65 years. It is interesting to note that, with two exceptions. all these males. 65 years and over, were positive, giving a percentage positive of 86.7%. Among the 25 elderly females, 10 were posttive (40%). This rate is twice the rate found in the general population. Microfilaria densities were as high as 1041 per 20 cmm. (a male, age 51). the average number of microfilariae per positive was 53.9.
•
wPR/Fil.!7 Page 14 4.4.2 Preliminary blood surveys throughout the country Preliminary blood surveys carried out in 1965 before covered 21 villages in various districts. Findings were as follows: drug
treatment,
Population examined Males Females TOl'AL
No. positive
I I !
Mf rate
%
• 21.1
4 975 5 154 10 129
1 051
• 17.1 19.1
880 1931
I
The highest microfilaria density recorded was in a male, age 62, with 2554 microfilariae per 20 cmm. The average microfilaria count per positive was 57.9. 4.4.3 During mid-treatment The results of blood surveys in the preliminary study areas and in the whole country were as follows: I ,
•
Study area Males Females TOl'AL
Population examined 939 1 009 1 948
No. positive
Mf rate
•
% 0.64 1.28
6 13 19
0.97
•
WPR/Fi1./7 Page 15
Whole country Males Females TorAL
I
Population examined 9989 8 728 18 717
No. positive
Mf rate f, 1.7
i
174
88 262
LO 1.4
!
The average microfilaria count for the whole country was 8.7 per positive. 4.4.4 After treatment Blood surveys undertaken in the preliminary study areas in January 1966 showed 63 persons (38 males and 25 females, l.~) positive for microfilariae. However, of these, only 29 persons were included in the original survey as 34 persons were new residents coming from untreated v111ages. Beginning December 1966, i.e. three months after the completion of mass treatment through the country, follow-up blood surveys were begun. These were continued until the end of 1967 and covered 115 villages. Thus the interval from completion of treatment to the survey varies from three to fifteen months. ResUlts were as follows: I
PopUlation examined Males Females TorAL 21 663 21 034 42 f$7
No. positive
I 454 241 6<)5
I
Mf rate f, 2.0 1.1 1.63
•
WPR/FU./7 Page 16 The average microfilaria count per positive was l}.}. The hignest microfilaria rate (1.8%) was found in Lefaga District and the lowest in Satupa'itea Distriot (O.~).
•
4.5 Clinioal surveyS A total of 71 villages from nine districts were olinioally surveyed from December 1966 to Deoember 1967. Incidences of elephantiasis among 21 877 residents showed 187 persons (0.85%) to be affected in one or more limbs. The youngest person found with elephantiasis was a female of 21 years old from Sala'ilua District on the island of Savaii. The distriot of Safata had the lowest elephantiasis rate (0.27%). while the district of Falealili had the highest incidence with }7 cases (l.~). Incidenoe of hydrocoele among 2486 males was 27 positives (l.~). The lowest age at which hydrocoele was found was 27 years in Apia District.
.
4.6 Skin test A total of }l}2 persons were tested intradermally using Sawada's antigen. Of these, 511 persons (16.3:') showed wheal reaotions of one square centimetre or over. this value being accepted as a positive reaction. Of the total tested, }088 persons had been treated with diethylcarbamazine, of whom 500 persons were skin test positives and 25 were microfilaria positives. Of the 25 microfilaria positive persons, 16 were positive for skin tests while nine had negative reactions. However, these tests are still on a trial basis.
4.7 Conclusions In Western Samoa, mass-drug distribution resulted in a marked reduction in the microfilaria rates, in the average microfilarial count per infected person and in infection rates in mosqUitoes. The microfilaria rates in the preliminary study areas and thro\.lghout Western Samoa before treatment were 2l.~ and 19.~ respectively. At mid-treatment, these rates fell to 0.9~ and l.~'- and after treatment to l.~ and 1.6~. The average microfilarial densities were similarly reduced from 5}.9 and 57.9 per positive person to 14.4 and l}.}. For the whole country, the MFD50 values were 18.4 before treatment, 2.2 after treatment in 1966 and 2.8 in 1967. Thus a slight rise in the microfilaria rate and the average microfilaria density occurred after the initial drop. Follow-up surveys in the preliminary study lU'eas in July 1967, three years after initial treatment, showed that a few persons, previously negative, had developed a microfilaraemia. This has also been demonstrated in other oountries after the use of diethylcarbamazine. 2.~
•
Infeotive rates in mosqUitoes (those with mature larvae) dropped from to 0.082% after treatment.
WPR/Fil./7 Page 17
5. 5.1 Training
TRAmlNG AND EXCHANGE OF INFORMATION
In filariasis proJeots, as in any public health oampaign, training of staff is fundamental and should be considered in the early planning stage. While as much of the training as possible should be oonducted in the country ooncerned, some training at the international level may be neoessary for professional staff. International assistance in training may be provided in various ways; specifio or more general training courses for professional' staff, fellowships, study tours, oonsultant servioes to assist in national training and teaching aid material. Apart from the knowledge of the teohniques and methods in filariasis control and their application, professional staff should have an adequate understanding of the epidemiological aspects involved in conducting a filariasis control campaign. It is therefore, essential. that suoh staff should be given training in modern epidemiological methods including all aspects of planning and conducting surveys and analysis of their results. A well organised and conducted filariasis control programme should be utilised for the purposes of such training. In-service training should be available to new as well as established staff in order to maintain and improve their efficiency. !
•
Among other possible methods of in-service training, self-instruction and self-testing might be studied as a potential means of stimulation and reinforcement • 5.2 Exchange of information International exchange of information is considered by the seminar as an important and valuable contribution in the promotion of fi.Lariasis control. The World Health Organization and South Pacific Commission facilitate such exchange by way of technioal meetings and dissemination of information on filariasis and related subjects. An essential prerequ1site for fruitful exchange of information is mutual acceptance of terminology. To achieve this, WHO has accepted the responsibility for preparing a glossary of terms to be used in connection with filariasis and its control.
In the South Pacific where there is considerable movement of population between areas, exchange of information on control activities and endemicity is proposed by way of reports and discussions between responsible officers •
..
•
WPR/Fil./1 Page 18 '
6.
RECGlMENDATIONS
At the conclusion of the discussions held during the seminar, the following recommendations were made; (1)
Epidemiological surveys in filariasis investigations shoUld follow the standard procedures laid down in the Second Report of the WHO Expert Committee on Filariasis l in order to obtain comparable results and maximum efficiency. More emphasis shoUld be given to entomological surveys and dissections in order to determine/confirm the vectors species. Intensive studies on the vectors' bionomics and field trial of new insecticides for control methods shoUld be made. Establishment of a reference centre for identification of mosquitoes (specially of certain complex which may have to be studied. on a genetic basis) and for determination of filaria larvae found in mosqUitoes, particUlarly in the South Pacific area. is highly desirable. Early detection and treatment of filariasis cases arriving in areas in which control operations have been instituted is strongly recommended in order to prevent reintroduction of infection. If, in follow-up surveys after a complete round of treatment, a significant number of positive persons, either recurrences, new infections or newly imported cases are observed, repeated mass treatment shoUld be considered. In compliance with the suggestion contained in the Second Report of the WHO Expert Committee on Filariasis. the importance of the total dosage of diethylcarbamazine in mass drug campaigns is stressed. The total amount of the drug administered shoUld not be less than 72 rug/kg body weight.
(2)
•
(3)
(4)
(5)
(6)
• 1
WId Hlth Org. techno Rep. Ser., 1967,
~
•
WPR/Fll./7 Page 19/20 (7) Because of the considerable movement of population in South Pacific, exchange of information on endemicity and control acti vities, by way of reports and discussion, should be stimulated. Recognising the importance of training. assistance from international sources. in addition to the training of national staff, is highly desirable. Preparation and distribution of individual study material is also considered necessary.
(8)
•
•
f
WPR/F11./7
•
Page 2l
ANNEX 1
LIST OF PARrICIPANrS Participants sponsored Countries or Territories American Samoa f
BY WHO Title and Official Address Assistant PUblic Health Officer Department of Medioal Services PMo PagO 96920 Senior Lecturer in Medical Parasitology School of Public Healt.h and Tropioal Medicine University of Sydney Sydney N.S.W. 2006 Medical Officer c/o Medical Department Rarotonga Medical Officer (Special Duties) Medical Department ~
Name of Participant Dr Nofo S11iga
Australia
Dr Bruce McMillan
Cook Islands
Dr Pupuke Robati
Fiji
Dr B.C. Dando
•
Dr J.U. Mataika
Medical Officer Wellcome Virus Research Laboratory Colonial War Memorial Hospital ~
French Polynesia
Mr Benjamin BaInbridge Chief Sanitary Inspector Institut de Recherches Medicales Papeete, Tahiti Dr Faanoa Pine
f
Gilbert and Ellice Islands
Filariasis Campaign Officer c/o Medical Department Bikenibeu, Tarawa
•
J
•
WPR/Fil./7 Page 22
SNNEX Countries or Territories Papua and the Trust Terri tory of New GUinea Tonga Name of Participant Dr J. J. Saave*
1 (cont.)
Title and Official Address Senior Consultant Malaria Servioe Headquarters Konedobu Port Moresby, Papua Medioal Officer-in-oharge of Public Health Section Vaiola Heapi tal Nuku I alota, Tongatapu Medical Officer Moen, Truk District Eastern Caroline Is. Filariasis Control Offioer Health Department Apia Medical Officer Filariasis Control Pilot ProJeot Health Department Apia •
Dr Peni L. Mapa
•
Trust Terri tory of the Paoifio Islands Western Samoa
Dr Ymao AId teldt *
Dr Iakopo Esera
Dr Lanu Penaia
•
*Unable
to attend
t
WPa/F1l./7
•
Page
2~
£!NNEX Participants sponsored by the South Pacific Commission Countries or Territories Nauru Name of Participant Dr Kiki Thoma
1 (cont.)
Title and Official Address Assistant Medical Officer Nauru General Hospital Nauru Medical Superintendent Godden Memorial Hospital Lolowai, via Santo Service de Sante des Iles Wallis and Futuna Mata'utu
•
New Hebrides
Dr M.B. Mackereth
Wallis and Futuna
Dr M. Lhuillier*
Observers Dr Clark Richardson i
Title and Official Address Public Health Officer Tropical Medical Center pagOPagO American Samoa 98)20 United States Peace Corps P.O. Box 880 Apia Western Samoa School of Medicine University of California Los Angeles California, U.S.A. School of Medicine Universi ty of California Los Angeles California, U.S.A.
•
Mr Leslie Kratter
Mr Kevin Murphy
Mrs Trudy Murphy
*Unable
to attend
WPRjFil./1 Page 24 ANNEX 1 (cont.)
The Secretariat Professor C.Y. Chow
Title and Official
A~d.~ss
Regional Entomologist World Health Organization Western Paoific Regional Office Manila, Philippines (Secretary) Epidemiologist Parasitic Diseases Division of Communioable Diseases World Health Organization Geneva, Switzerland Medical Offioer South Pacifio Commission Post Box No. 9 Noumea New Caledonia (Secretary) PrOfessor of Infectious and Tropical Diseases School of Publio Heahh University of California Los Angeles, California 90024 United States of Amerioa (WHO Consultant) Department of Medical Zoology Walter Reed Army Institute of Research Washington. D.C. United States of Amerioa (SPC Consultant) WHO Consultant on Entomology Filariasis Ccptrol Pilot Project P.O. Box 77 Apia Western Samoa WHO Medical Officer Filariasis Control Pilot Project P.O. Box 77 Apia Western Samoa
Dr C.W. G8ckel
•
Dr A. Guinea
Professor J olm F'. Kessel
Dr Daniel J • Stechschulte
Dr Takeshi Suzuki
Dr Tin Maung Maung
.
I
I
•
WPH/Fll./7 Page 25/26
THE ANrll30DY HESPCNSE IN RABB:frS lNFEC'l'ED WITH
Dll!&!~ UNIlORM~l
•
•
Experimental study is of practical value as a model to investigate the immunological response to filarial infeotion. The experimental work showed that infeoted rabbits produoe at least two types of antibodies. Although both types can be detected by the same antigen complex, different methods of detection must be used. One type of antibody (skin sensitizing of homooytotropic) is detected by passive outaneous anaphylaxis bUt not by the soluble antigen fluorescent antibody (SAFA) reaction. The seoond type of antibody (rG or IrQ) is detected by the SAFA test but not by cutaneous anaphylaxis. These ant1bodies are initially produced at the same time following infection but the rG antibody persists for a longer duration than the skin sensitizing antibody. The skin sensitizing antibody in the rabbit can probably be compared to antibodies responsible for the 1mmedi~te type reaotions seen in humans tested with the Sawada antigen. If this is true. then the studies in the rabbit indicate that the Sawada skin test might well be negative in previously infeoted individuals. if sufficient time has elapsed between infection and skin testing. The multiple antibody response noted in the rabbit indioates that a serological test in combination wit.h the skin test might provide a more oomplete picture in an epidemiological survey. The paper reports skin tests mediated by antibodies. A skin reaction which is entirely different mechanistically was mentioned. This is the delayed type reaotion and has not been reported in filarias1s. Assuming that the infection stimulates the development of delayed type hypersentis1'tivy, the inability of workers to detect this type of reaction indicates that the antigen being used is incomplete or inadequate. This should provide fUrther stimulation of antigen fractionation and preparation. Little or nothing is known about the production of protective antibodies during the infeotion.
,
~ Dr Daniel J. Stechschulte, Department of MedioalZoology. Walter Reed Army Institute of Research. Washington D.C. 20012
WPR/FU./7 Page Z7
, ANNEX ,
VECTORS OF FILARIASIS A. Vectors of the sub-periodic form of (a) Major vectors (1)
m THE SWl'H PACIFIC
li.
bancroft!
Ae. (Stego!!lYia) polynesiensis Marks, 1951 Details given in the text.
(2)
~. (~.) pseudoscutellaris (Theobald, 1910)
Only in Fiji. (3) ~. (Finlaya) samoanus (Gruenberg, 1913)
In American Samoa and Western Samoa: breeding in leaf axils of family Pandanaceae including Freycinetia and cOJIIIIOn Pandanus (only in Upolu island, Western Samoa where breeding was found in coumon Pandanus): a night biter with a peak at 2300 hours; a small number found resting in houses at night and in early morning.
(4)
~.
(§..) tabu Ramalingan, 1965
•
Only in Tonga: day-biting mosquito: breeding in rain water containers, coconut Shells, discarded tins, and tree holes •
•
(5)
Ae. (Oohlerotatus) vig1lax (Skuse, 100})
In New Caledonia and Royalty Island: primarily a bracldSh water breeder. although found in rock holes and fresh water
pools; highest density during the 5U111Der months: feeding mainly in the day time: resting outdoors during the day in grass and low vegetables; a strong flyer.
(b)
r~illor ~.
vector
(§..) upolensis Marks, 1957
In American Samoa and Western Samoa; breeding in fallen tree trunks and fern tree stumps, rather in deep forest. (e) Suspected vectors (1) Ae. (~.) fijiensis Marks, 1947 Only in Fiji; breeding predominantly in Pandanus, and less cOlllllonly in the axils of Alocasia indica: biting man at night.
wPR/Fil.!7 Page 28 .
• (2)
Ae. (§..) cooId Belkin, 1962
In Niue; breeding in rain water containers, coconut shells, and tins, high density during the sUlllllElr months.
(3)
M. (§..)
rotumae Belkin, 1962
In Rotuma; breeding in rain water containers, tins and
coconut shells. (4) ~.
(§..) futunae Belkin 1962
In the Futuna Group.
" 1926
(5)
M' (§..) tongae In Tonga.
Edwar~s,
•
(6)
~.
tutullae Ramalingan, 1965
In American Samoa; breeding in common Pandanus.
B.
Vectors of the periodic form of W. bancrofti (a) Major vectors (1) The" Anopheles punctulatus" group
~. (Ce11ia) farauti Laveran, 1902 - in New Guinea, West Irian, Bismarck Archipelago, Solomon Islands and New Hebrides.
•
A. (~.) punctulatus Donitz, 1901 - in New Gu1nea, West Irian and Solomon Islands. ~. (£.) koliensis Owen, 1945 - in New Guinea, West Irian and SololllOn Islands.
(2)
£.
E' fatigans
II
In the Micronesian Islands (Carolina Islands, Mariana Islands, Gilbert Islands and Nauru).
(b)
Minor vectors (1) (2) ~.
(Anopheles) bancroft1 (Giles, 1902)
Mansonia (Mansonioides) uniformis (Theobald, 1901) ~. (~.)
(3)
kochi (DBnitz, 1901)
..
•
• (4) (5) Q. (Q.) annullrostris Skuse, 1889 C. (Q.) bitaeniorbynohus Giles. 1901
The above species are more or less of local importance in West Irian •
•
wPR/FU.!7 Page '1['2
• TABLE 1
PRESENT INFOBMATIOO 00 THE FnARIASIS PREVALENCE Average mf. density 20 rmi;)!inf. pers • 8.5 8.0 5.0
Country
Year
Area
Number examined
mf. rate '%
American Samoa
1965 1965 1967 1967
Eastern Western Ofu and 010sega
. 1 206 594 857 1 oSS 1 221 12849 4044 4 093 739 898 2.5 5.5 ~.4
Islands Eastern Taveun1 Tahiti Moorea Australes Tautira Funafuti Nukufetau Vaitupu Hiw, Torres
0.) 18.2 5.8 5.0 2.7 4.4 12.7 26.9 40.6 19.0 54.0 21.1 26.3 24.8 1.6}
C.O 21.6 16.8 l.3.6
Fiji French Polynesia
1968 1967 1967 1967 1968
6.2 10.0 21.1 22.0
Gilbert and Ellice 1967 Islands* 1961 1967
6zr
803 43 141 326 781 705 42 (;$7
37.4 47.0 54.0 1.5*3.1-* 1.7*** . 13.}
• !
New Hebr1des**
1966 19661967 1967 1961 1967 1967
Santa Maria, Binks West Sep1k Markham Valley West New Britain Country wide
Papua and New Guinea Western Samoa
* Data based on examinat10n of 5 ~ of blood. ** Age group 0-5 years excluded from survey.
..
***
Figures refer to average m!'. dens 1ty per person examined •
WPR/Fll./7 Page 33 DISSECrION OF WIID-CAUGHr MOSQUITO VECTORS Country or Territory· American Samoa Species Date Locality ~issected
Number
TABIE·2 Infection rate .IrU'ective rate (Pos. with all (Pos. with stage larvae) infective larvae)
Remarks
:t:
:t: 2.1 0.6 0.0 Before control Three years after control Five years after control
8!.. polynesiensis
7/62 Four villages
/ 7/65 Same four villages 1967- Same four villages plw 1968 five others
3ZT 375 1392
8.3 1.5 0.8
Cook Islands
Dissection by Dr McCarthy, results not available yet Ae. ;eol;me12/67- Taveuni, Qamea, siensis 7/68 Savusavu, and 2,. ~. fatisaOs l2/ff{. Natewa Bay 3/68 II 8!.. fiJiensis 8!.. .l2seudoscutellaris " Ae. polynesiensis 1953- TallHi (Vairao) 1956 1968 Tahiti (Tautira 1536 377 14 36 4.3 3.4 7.0 2.7 0.45 0.0 0.0 . 0.0 Before control
F i
j
i
I
French Polynesia
4 733 299
ll.l 1.0
. 3.1 0.3
Before control After control
Gilbert and Ellice Islands Nauru New Hebrides •
No information available Dissected by Dr Chapman in 1966, results not available yet
A.
2.:.~.
farauti fatigans
Bout»
Santo _I
1239 70
13.7 12.9
0.16 0.0
.'
•
t,
..
.'
.
•
WPR/Fll./7 Page 34 ---
~-
Country or Territory Papua and New Guinea
Species
Date
Locality
Number disseoted
Infection rate (Pos. with all stage larvae)
Infective rate (Pos. with infective larvae)
Remarks
% A. farauti koliensis ~. farauti ~.
% 2 1
1960 1967
punctulatus A. koliel1$is ~.
--
Finschahafen Subdistrict Northern District Markham Valley
2.3}
11
2.35 93
8 0.2 4.7
1Zl 1.39
-
I I
4.3
Tonaa Wallis and Futuna Western Samoa ~.
Dissection by Dr Hitchcock in 1968. results not available yet N pOlynesiensis 1965 12/664/68 samoanus 1965 12/664/68 0
i n for mat ion 1 120 2 425 466 152 9·5 0.74 4.} 2.6 0.08 0.9 0.0 -
Before control After control Before control After control
~.
1.3
-
--- -
------
I.
•
r..
.
..
..
..
•
WPR/FU./7 Page 35/}6 TAmE 3 DRUG CCNrROL MEASURES
(Diethylcarbamazine)
Country or Terri tory
Dosage
Schedule
Application
•
American Samoa
6 mg/kg
1 dose/day for 6 Mass treatment days, repeated once monthly for 6 months, after 2 years repeated once monthly for 12 months (total: 24 dosages) 1 dose daily for 2 weeks 1 dose every 3 months 1 dose daily for 2 weeks followed by 50 mg once monthly Individual treatment Mass treat.ent Small scale trial
Fiji French Polynesia Gilbert and Ellice Islands
5 mg/kg
6 mg/kg 150 mg daily
!
New Hebrides Papua and New Guinea Tonga Western Samoa
6 mgfkg 1 dose monthly for (max 500 mg) 2 years 6 mgfkg 300 IIIg
Mass treatment in lim1ted areas Small scale trial Individual treatment Mass treatment
1 dose daily for 2 weeks 1.
daily
dose daily for 2 weeks
5 mgfkg
1 dose weekly for 6 weeks followed by 1 dose monthly for 12 months . (total: 18 dosages)
,
WPR/Fll./7 ! Page
'J7/?J8
TAmiE4
MICROFIIABAEMIA 81'UDIES IN 'lw0 DISTRIcrr8 OF TAHITI AND :IN FIVE PILar VILLAGES IN AMERICAN SAMOA
Districts and
Before diethylcarbamazine Year 1949 1950 1962-63 --.-.. -
After diethylcarbamazine Year 1966 1966 1965-66 ==
villages Mataiea Tautira 5 villages in American Samoa
No. examined
% Pos. 39.3 26.6 21.0
MFD 50* 23
No. ~ exam:ined Pos. 976 794 1 243 6.5 4.0 7.4
MFD 50* 3.5 3.5 2.1
619 581 1 191 ;:===
19 20
==
--
- -_.
=-
-==, Org.
MFD 50:
Details of this expreSSion can be found in Wld Hlth techno ReR. Ser., 1967,..222..
TAmE 5 !
FIRSr RECURRENCES (RI) OBSERVED DURING THREE YEARS FOLLCMING MASS DRUG ADMINISTRATIOO IN TAHITI AND AMERICAN SAMOA
wcality
Diethylcarbamazine
Total persons negative after one regimen of treatment 163
Recurrences by years beginning first year after close of treatment First 3 ~otal:
Tautira and Mataia (Tahiti)
144 mgfkg
Second 16 32 =0
Third
13
2~
American Samoa f
72 mgfkg
174
17 ~otal;
26
21 .
64
= 37~
=::--============z=:::::.=:======_=======--:::=-=
=
~;;:;c:::::.;.;n-===-==
•
1 1
WPR/Fil./7 Page ?:$/40 TABLE
6
MICROFILARIA CARRIERS IN ANNUAL FOIJ:.aol UP BLOOD SURVEYS AFTER MASS DFlI.JG ADMINISTRATION CAMPAIGNS IN TAHITI AND AMERICAN SAMOA
Tahiti Tautira 1966 Total subjects examined Immigrants
American Samoa Mataiea 1966 976 11
5 Pilot villages 1965-1966 1 243 31 41
1968 7;$ 9
794 12 3 6 5 6
Recurrences New infections Untreated* Treatment in progress
8 6 6
7 9
23 ?
4 32 .
4
?
~tal • !
--=========;:::;===== ====::.--==
microfi1aria carriers
32
33
63
?
"',...--=== 1=,
======= ='--=======---=
*Missed,
excused, or refused treatment
TABLE 7
BL<XD SURVE:{S IN 1965, 'lWO YEARS AFTER'l'WELVE DOSES OF DIEl'HYLCAR8AMAZINE; AND IN 1967, AFrER 'lWELVE ADDITIONAL DOSES (in American Samoa)
Village Village Onenoa Tula Alao A1ofao Utumea
1965 5/155 11/283 2/354 9/306 3/108 30/1206
1965 .
1967 0/144 1/268 0/278 1/';$8 1/97
=
2.~
3/1085 = 0."»
WPR/Fll./7
Page 41[42 TAmE 8
ANALYSIS OF DRUG COVERAGE OF A SAMPLE POPULATION. B':l THE NUMBER OF DOSES TAKEN. IN THREE VILIAGES m LEUWMOEGA DISTRICT, WESTERN SAMOA, 1965 - 1966
Dos e
Per c e n tag e
r============================ ====================.
0 1 2 3 4 5 6
7 8 9 10 !
11
12 13 14 15 16 17 18
0.95 1.55 2.03 1.27 0.82 1.52 1.47 2.08 0.95 1.42 1.87 5.51 6.64 15.63 14.48 10.72 7.39 11.85 11.80
!
WPR/Fll./7 Page 4}/44
TABLE 9
ANAIHSIS OF "EIGHrEEN DOOE CCN.ERAGE" BY' AGE GROOPS FR<J4 A SAMPLE POPULATIaf OF THREE VILLAGES m LEX1WMOEGA DISTRICT. WESTERN SAMOA - 1965-1966
Age
groups
Percentage
0-4 5 - 9 10 - 14 15 - 19 20 - 24 25 - 29 }O -
12.9 1}.0 9.4 8.9 8.6 9.5 9.9 14.2 14.0 14.0 12.9
.34
35
-}9
40 - 44 !
45 - 49 50 - 54 55 - 59
60-64
17.} 17.7 8.6
65-69
=llo FIG. I China
h
DISTRIBUTION AND VECTORS OF BANCROFTIAN FILARIASIS IN THE PAC I FIC
Pae Hawaiian
'\ 'UII
o
i
'Mariana II.
IA C. qulfH/u.ft/llr:it11ulI • • I Marshall II.
I
I
Q
I
I
LYNESIA A./H#Y"'lIiHlli, A. f iji.nll;'
Caroline II.
O·,<;i., ... ?kfC:1~ <J
IE _ K
A. ft/nuli
-- ...
Q
c!; ~
...
,$ I I
I
I
.... ~
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