MALARIA TRANSMISSION BY ANOPHELES-SUBPICTUS (DIPTERA, CULICIDAE) IN A NEW IRRIGATION PROJECT IN SRI-LANKA

Indoor resting Anopheles subpictus in a new irrigation scheme in Sri Lanka were investigated during 1989-1990 for malaria infection by dissection and ELISA, and human feeding rates by ELISA analysis of blood meals. Indoor resting abundance was 22.3 females per house per 15-min catch in April-June 1989,2.2 in November-December 1989, and 7.5 in April-June 1990. ELISA-based malaria infection rates (Plasmodium vivax and P. falciparum combined) were 1.4% during April-June and 3.2% during November-December 1989, and 12.5% during April-June 1990. Dissection and ELISA confirmed the presence of oocysts and sporozoites of P.falciparum in 1990. Human blood was detected in 4.3, 0.8, and 5.2% of analyzed meals, respectively, during the three sampling periods. Estimates of the entomological inoculation rate (EIR) ranged from 0.00006 to 0.005 in different samples and vectorial capacity (VC) was 0.0005 for the 1990 sample. Thus, An. subpictus is incriminated as a vector of human malaria in Sri Lanka.