MALARIA IN THE SOUTH EASTERN SAHELIAN PAR T OF THE REPUBLIC-OF-NIGER

The south eastern part of the Republic of Niger was ecologically damag ed by the dryness since 1971. Rainfall decreased by 30 to 40 % as comp ared to 1961-70 and lake Chad retreated 100 km to the south. Now it do es not reach any more ?he Republic of Niger. Malaria studies have been carried out in urban and suburban places in Zinder and in the Diffa a rea at the extreme east. In Zinder parasitic indexes (PI) after the ra iny season were around 30 % to 10 % according to he situation of the c orner in respect with surface waters during the rains. in dry season t he index feii to 3 %. In Diffa in a part of the city at high risk beca use lining the Komadougou river, Pi was only 6,7 % in October after th e rains. Before 1970 Pi recorded in Niamey were up to 50 %. in Diffa a rea they were of 49 % in N'Guigmi and 32 % in Bosso, ecologically simi lar to Diffa. Obviously there was a sharp decrease of malaria which co uld be due to the disappearance of An. funestus after 1970. it was one of the main malaria vectors. its larvae were developing in pools rema ining after the rains with heavy standing vegetation. These breeding s ites have been destroyed by both dryness and human activities. Now the area has became hypoendemic and is suitable for epidemic because popu lation has not much immunity A surveillance system for epidemic contro l should be settle.