ECOLOGICAL MAPPING OF SIMULIUM SPECIES IN TWO ONCHOCERCIASIS-ENDEMIC COMMUNITIES OF CROSS RIVER STATE, NIGERIA

The distribution of Simulium species was studied at 2 breeding sites in Ugbem and Ukwepeyiere Communities after 10 rounds of Ivermectin distribution. At each breeding site, 2 fly catchers worked alternately for 4 hours, both giving a total of 8 hours from 8 a.m. to 3 p.m., each day. Flies were caught on 3 consecutive days, each month, from 8 a,m. to 3 p.m. between January and June, 2008. A total of 3895 Simulium flies were caught and identified using morphologic characteristics as Simulium sirbanum(70.5%) and S. yahense (29.5). A total of 12.1% of both species were parous while 87.9 % were nulliparous flies. Generally, more flies were caught in the morning (7 a.m. to 11 a.m.) than afternoon (12 noon to 3 p.m.) hours, in both dry and rainy seasons. No larva of Onchocerca volvulus was detected after dissection of both parous and nulliparous flies. This study has identified, for the first time, the species of Simulium flies which are prevalent in the study area