Survivorship and vectorial capacity of <i>Anopheles gambiae</i> in Bali district, Taraba State, Nigeria

Abstract

The principal malaria vector in Africa south of the Sahara is Anopheles gambiae. This study aimed at determining the parity rates, survival rates and vector potentials of An. gambiae in Bali district Taraba State, Nigeria. Indoor mosquito collections were carried out between June and December 2018 using Pyrethrum Spray Catch in Daniya Bali, Fundalara and Gazabubarkeji communities. The number of people that slept overnight in the room was noted. Collected and freshly preserved mosquitoes were morphologically identified and female An. gambiae was counted. The ovaries of fed and unfed An. gambiae were extracted and quickly transferred to drop of distilled water on the slide and examined under high magnification for tracheal skein and classified as parous or nulliparous. The blood meal source of blood fed samples was determined using CSPELISA. A total number of 485 adult An. gambiae species were identified. The probabilities of daily survival of individuals of the mosquito, 0.75 and 0.688 during wet and dry seasons were not significantly different (p>0.05). The life expectancy of adult mosquitoes was 8.0 and 5.9 days during wet and dry seasons and was significantly different (p<0.05). During wet season the mosquitoes survive long enough to become infectious than during dry season. The vectorial capacities was higher significantly in wet season 1.98 than that of the dry season 0.09 (p<0.05). The An. gambiae population in Bali district was dominantly old ones due to high rates of daily survival. The longevity of the mosquito makes for high vectorial potential.

Keywords: Anopheles gambiae, Plasmodium, Life expectancy, Infection potentials, Guinea savannah