Gradual setting up of a reduced entomological evaluation network in the central regions of the programme

WORLD HEALTH ORGANIZATION ORGANISATION MONDIALE DE LA SANTE C Oi'iTr.?0l PROGRAI'T'IE R]\TfrR BASIN AREI. ONCHOCERCI/TSiS IM t.T.M VOLTA EX,DEIIT A}VIS O]lY COMMITTEE Fourth session uo-e?tie-r--?-ff-g-[ggberr&9{.-199:. ORIGIITIAL: I'nSiiCE ocP/EAc4fi(ocp/er.e) GR-\DU/rl SETTI{G UP 0F A REDUCtrD ENTO}.IOLOGfCAI EVALUATION }M$,fOI1K I}I fi Ctr}iT.K\L NEGIONS OF flfi PAOGR.{'}E 1. $-":qe$ur. Consid.ering the results of entomological and epid.eraiological evaluations after five straigirt years of protection of certain regions of tl:e Programme, it has been d.ecided. to set up a reduced. entoniological su:rreillance system. foese regions are to be forrnd. in the central zones of the Programne on an a^rea covering abou-t 4261500 1cn2 and. not concerned- rdth reinvasiorsor resistaf,r^ce. Tney correspond to almost aII t're Voliaic and iTiger onchocercal foci, to the foci found. in Northern Ghana and, Togo as well as those to be found. in north-west Benin and Eastern Ma1i" In 1!82 statistical analysis coupled. with practical field studies had. led. to a proposal according to wl:ich ti,renty-five out of 110 catching points regularly visited. in this central zone could. be abolished. tlne 25 catching sites axe spread. out in 11 sub-sectors. InL9B5, a policy was adopted vthich aimed at the setting up of this netrvork, following a reconmendation of the meeting of the Expert Committee held in Geneva in Septeurber L)32. 2. 3: qe e: q € fmpl.e{rt qt i qlf j:.II q s_efr! g l.tlfqlig11. From the 110 points, U:e reraainir:g B! belong to the basic entomological netvrork. It is at the leve1 of these sites that henceforth norrnalized. catches on marr are carried out in ord.er to calculate AfPs and the l3P.s. These points are sub-d.ivid.ed. into tuo groups: those visited. on r,reekly basis(points A) and those visited fortnightll' (points 3). The set-baclcS to entomological evaluation in its present form necessitate at least forr catching days a month for each point of the basic network. To these Bl sites should. ba ad.ded. all those outside the zone concerned by the reduced. network. The reorganization of the network takes into consid.eration the basicprinciple which is the relation between costs/effLcacy - the aim of the red.uction - a.nd. the folloluing constraints: - th.e geo-political limits of the alread.y existing' sub-sectors, in preparation for devolutlon; -2- - road inf?astructr:res ; - participation of -i;he beneficia.:ry countries in the costs of logistic means of tire sub-sectors; foe process of ir,rplantation concerns three nain aspects: - the regrouping/abolition of sub-sec'bors; - tlre red.uction of the nu,rrber of catchiqg teams; - the introduction at tlre experjmental sta:p of a trap network lrithin the network of entornological suryeillance, 2,L. ae.ggfp@ of sub-sectors [he sub-sector of Porga. had. been abolisired. since 1982. Plarr::ed. for beginning 1981, the suppression of the sub-sector of Tenkod.ogo ues done at the end of November L)82, ar.d. resulted. in the te:mination of the lease on the build.ing, The watercourses formerly irnd.er sr:rveillance from Tenkod.ogo are no1,r und.er su:sreillance frora Ouagad.ougou. fne presence of three nain roa.ds OuAa/(Po-Bitou-Fada) mad.e ti:is regrouping possible. Ilowever, for more efficacy a site of trre f omer sub-sector of Tenkodogo, that of [a,gou, is nolr under tl:e responsibility of Natiiingou in Benin. f'he head.quarters of the Natitingou- sector has been transferred. further south to Parakou because of 'cire extension of activities toward.s the southern regions. No nod.ification has been d.one on the sub-sector of Sikasso rvhere only one point is to be abolished., nor on the sector of Dapaon which oversees the Keran and. Oti being outsid-e the zone of reduction. Savings resulting fron the suppression of the head.quarters of lapaon would. be insignifica:rt if not ni1 for the OCP seeing that the bi:-iId.ing€ and. attached, facilities are prcnrid.ed. by the Togolese government. In ad-d.itionrentornological surveillarrce of the upper basin of the Oti/Pend.jari in Togo should be d.one from Kara. fhe Natitingou sub-sector has already increased. in size because of the add.ition to it of the former sub-sector of Por61a. Most of the catching points in this sub-sector are to be forrnd outsid.e the zone and. so there has been no rnod.ifi- cationo c,L 'L ' g"aqctjorr in lhe nq,&el-gt rgjp@ The reduction of the networlc in 19BJ iras bro$rt 5ho.rt the suppression of posts like messenger, watclinan and. store-keeper of t'he former sub-sector of Tenllodogo as i*relI as the suppression of a total of six catching teams, tirat is 15 catchers and. 5 drivers (Tenkod.ogo, Ilia.arey, Diebor:gou) and the red.uction of manpower equivalent to two catching: tea,ms in the Ta.nale sector. As a natter of fact, a tea.m was often sent as reinforceuent to the sub-sector of Bolgatanga, frorn Ta:aal-e, following tire take-over of this sub-sector, of the catching points -1- of lla,habu, I(u1um and llarifuo, points nhich were overseen b;r -b'.re former sub- sector of Leo. Yery often also a tean from the Taata,Ie sector l.ias gsed. by the sub-sector bearing t're sane neJrre. lastly, the d.eceirtralization of the chief-sector of tsenin has broug:ht about the suppression of a catching tea,rn. 2,1. _Tr?!p:gg The red.uctioir of t:e entomological sr:rveillance network, i.reevlbab\rresultsin the suppression of catciring points in large areas arrd. certa-i-nry croes notfavor:r the quick detection of local problems arising'as a result of an eventual d.eficiency in treattnent, To overcome this inconvenience, it has been decid.edto introduce in the entomological surveillance netr.rorlc a s;rstem of sentry traps which i+ilr detect ar1 foci of t'Lre onchocerciasis vectors. . fhe only available f,rap for the blacl'-f ies is tire Italuminium sheet traprr.A pilot experimentr was dcne in April and l.tay und,er tl:e d.irection of the ma^iler of this plate in the southerrr regions of the sub-sector of Bobo r,rith the activeparticipation of the OCP personrrel working in ti:is region. Tr:re results of this study d.one at the level of t0 sites for tvro nonths have confir:,:ed the role ofthese plates a.s a l^rarning sign. Ind.eed, there lras complete concord.ance between cataches raade with tire t-:lates, t?re appearance of the vectons at the aquatic stage in the breeding sites and. the catches on ma,rl. In most of the cases, the catches on the plates were folIowed by those on man r,rith a snall difference in ti-me of only a few ci.ays. ft sho,,.rec[ that it was possible with on1;r a, team to cover about a d.ozen catching points per week. In certain cases, the ruralpopulations were associated. in the surveiLlance of ilee trapping netr,,'orlc. The erperirnent still continues on a mor€ reduced. number of sites almost atthe end. of the rainy seascn. ,. Cost evaluation In terms of costs, it has been more d.ifficult to naJ:e an evaluation of the reduced. neti,rork because of the fact tirat the experiment b7 trapping should. conti:rrue in the zone concerned.. A1I the sa,rne the data given in 2.L. and.2.2. should nake a cost-evaluation possible. ft should. be noted tha.t the present entomological surveillance netr.rork inthe initial area of 'bhe Programme (trre origirnat 6JQrooO h2) has been ionsri-derably red.uced. compared. to what it was at the beginning of the campaign. fn 1!JJ yhen the r,rhole infrastrr-rcture was in place, the initial area was divid-ed. into 2J sub- sectors, and. 86 catching tea,ns ensru:ed the entonologicaJ. surveillance. For the sarne zone in l9B1 , sr:rveillance is done from lJ sub-sectors lty 59 tea.ras. T..-' -A similar experinent should. have been d.one cn a la;:ger scale in the sub-sector of Oua6adougou, Bolgata4ga and Dapaon fur July/Augus.b bu,c for pclitical reasonsthis d.id. not tejle r:Iace.