Entomological activities of national teams in Western Zone

ONCHOCERCIASIS CONTROL PROGRAMME IN WEST AFRICA Expert Advisory Committee Fourteenth session Ouaeadoueou. 7-ll June 1993 Briefing session, 5 June I993 OCP/EACl4/Briefing paper no 6 ORIGINAL: FRENCH ENTOMOLOGICAL ACTIVITIES OF NATIONAL TEAMS IN WESTERN ZONE l. Operational structures and personnel In 1993 the entomological network in Western Zone remains the same as in 1992 with three sectors (two in Guinea, one in Sierra Leone), l2 operational bases (nine in Guinea, three in Sierra Leone) and 35 capture/dissection teams covering 78 capture points. A total of 248 national staff are involved in entomological, hydrological and administration activities in Guinea and Sierra Leone. The capture/dissection circuits have been reduced following the suspension of larviciding in Southern Sierra Leone and entomological surveillance on the Makona in guinea. 2. Training in 1992 a) Trainine at OCP Bamako - 2 technicians from Sierra leone national ONCHO team have been trained for four months on cytological identification of S. damnosum s.l. larvae - 2 technicians from Guinea national ONCHO team have been trained for two months on morphological and morphometrical technics of identification of adult Similium flies. b) In-service trainine - 24 technicians from Guinea and l2 technicians from Sierra Leone were trained at their operational bases on morphological identification of adult Simulium flies. 3. Entomological results The annual transmission potentials (ATP) due to savanna flies from April 1992 to March 1993 shown in annex la indicate that in the Western Zone, only four points over I l8 (30/o) visited have ATP slighly above the treshold of 100. These good results confirm: a) in initial zone, the success of vector control activities shown by the significant decrease of transmission even at the former reinvasion sites on the Baoule and Bagoe Rivers in Mali where high densities of flies were noted; b) in Guinea, the success of combined larviciding and ivermectin treatment OCP/EACl4/Briefing paper no 6 Page 2 In nothern Sierra Leone, excellent results were obtained (no transmission by savanna flies were recorded) despite the long suspension of larviciding due to the rebel incursion from l4 December 1992 to 27 March I993. In the south of Sierra leone, the high transmission recorded are due to forest flies namely S. leonense, S. yahense and S. squamosurn species (see annex lb). 4. Identification of the parasites with DNA probe The identifications of the parasites with DNA probe have revealed an important proportion of animal onchocerca or else wich allowed us to adjust the ATP obtained on various river basins. The identifications results are listed in annex 2 for reference. 5. Impact of ivermectin treatment on transmission In Guinea-Bissau studies on the impact of ivermectin treatment (three times/year) on transmission from November 1990 to December 1992 showed a decrease of about 400/o in the intensity of transmission in Rio Corubal (annex 3). A sub-committee led by Dr Laurence Osei, consultant, met in Ouaga in March 1993 to look into the possibility to continue these studies in other zones where solid base line data are available. It was proposed to gather information on: - Gambia River at Mako, where ivermectin treatment has been done twice a year, for five years; - The Bakoye at pont Toukoto and Seourou where twice-a-year ivermectin treatment should be initiated; - an area where ivermectin treatment is done once a year The sub-Conrmittee will submit its proposals at the briefing session of EACI4 6 Post- treatmen t studies 6.1. Banifine IV After cessation of larviciding in January 1992 post-treatment studies showed an infectivity level of 0.39 infectious females/1000 parous flies. Due to the very low number of the flies (7 670 parous flies, caught) the studies will be planned again in 1993. 6.2. Bandama blanc Post-treatment studies organized at Badikaha from January to June l99l and from January to September 1992 showed an infectivity level of 1.08 female with L3 in head/1000 parous flies on a total of 20 335 parous flies dissected. This result confirm that the situation is satisfactory. 6o\ ailg a No\ Eg g 4, r-.1 E{ EI E]o Ar zoH(n ao IJ ?ha H 6o o E, =I NoJ E, lrlz *a lrlo a zo oa = cnz E,t- t!o 3lrlf z.z (t, UJ trz lr,l-o o- oCP/EAC14/Briefing paper no. 6 Page 1) Cr \t t'. I o t/) I t i \(( \ t t ._.,9. 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Ai' - lr'' \\' \, (- dr{ &:t H e drl H Hi ( I I ) O U -}\ .t E q) 'l , t-,--C ( q I U t I 0CP/EAC14/Briefing paper no, 6 Page 4 oIJ zo ct CI' =U'z G,F ulo aJlr, :fzz oJ Lr,l trzlr!Fo o- EDc E 9 o;o .= E € a,c oz I co Eo '6 Io E oc ocoN #5E<<F c=zH ITJ fl65N (L o o o EJ a=()I o z 9 lrJFx UJ aoH TT2 aH H BE Ha trl = U :) .) o o|to83st A\ oo oBoS ?ei 8VYNooo p r'l frl H a4 p H a N/,\) ) C' U @ !t o <r) TL d) ) U) o ,a--@ U h(o ,,o tn ,t ,(1 AI .3 o II ). ) G 6o i-, t ts \ :i;'{'2 ,.-9 )i .( ( i; .4 r" I ( .,t a \ U trJ - r9 rf -\\, 7, I .ir - e i llnl,r I 1+'i (> I ( _U i\. ,J a\ \- t_ I -( ) AI.INEXE 2/ANNEX 2 Resultats des identifications de parasites par sondes a enN Results of identifications of parasites with DNA probe OCP/EACl4/Briefing paper nP 6 Page 5 4/5 de non O. volwlus, 4/5 de non O. volwlus, 4/6 d,e non O. volwlus, 4/5 de non O. volwlus, MALI Baou16 Niger Bagoe COTE-D'IVOIRE Bandama B. Marahoue Sassandra SIERRA LEONE Koloni N'Zana Madina-Diassa Faya Metela Marabadiassa Naramou Badikaha Kato Zuenoula Kongasso Yapleu Massadougou Niamotou Mano Mokassi Gbaima l/5 O. volwlus, l/5 O. volwlus, l/6 O. volwlus, 116 O. ochengi l/5 O. volwlus, I /l O. ochengi 4/4 O. volwlus de savane/Savanna species 2 Ll L2 O. volvulus de savane/Savanna 23/24 O. volvulus de savane/Savanna I /24 O. ochengi 2/2 O. volvulus de savane/Savanna I /l O. volvulus de for0t/Forest 3/3 O. volvulus de savane/Savanna | /l O. volvulus de for6t/Forest 2 Ll O. volvulus de savane/Savanna I / I O. volwlus de savane/Savanna 7 /7 O. ochengi | /l O. volvulus de savane/Savannal/l Non O. volvulus ? : Q6Cuqtion de ltintensit6 de la t T\ .'Reduction of intensity of .El I S S aU/curlrEA-BrESAu Zone Initi 1s r,:.usmissiontransmlssr-onl,-1 t 2LrUlnee (Cade, Cabuca et Cheche ) : 407o (Dagnangofo, &rea Vialadougou, Kongasso et Ngolodougou) : flies t de r6duction du 5 8 Vo nombre de'L3 tOte de r6duction du nombre pour 1 ooo pares de L3 tote pour I ooo /4G'6 reauction of r'J rreaa/t.oo parous flies f58/o reauction "P?ff:a/rooo perous oe/arct4/ Briefing paper no. 5 Pa6e 6 emwr(B) f I 988 I 1989 t99t I 1992 (avalrt trailcrnent) (2/3 ans apris before treatment . traitement) I v e rm ecfiilLtEiriier tue atunent IY]IO,ETTN ALO]M t978179 1982 e 1984 (avant traitenrent) (3/4 ans aprds be&catreatnent -,-traitentettt)^. .b Larvi cidad SElitUc trea b' I"ARECIDES ATONE '