Malaria Transmission Potential in Adim Community of Biase Local Government Area of Cross River State of Nigeria

Abstract

Malaria transmission in Adim, a rural community in Cross River State of Nigeria was evaluated using transmission markers. It is hypothesized that the marshy ricefields in the area would permit the persistence of anopheline larval development all year round and therefore malaria transmission is bound to be high. Over a 12-month period, 668 residents in Adim were screened for malaria parasites, using thick and thin blood smears. Mosquito vectors of malaria were collected and separated from non-malaria vectors. Of 326 mosquitoes collected, 68 were found to be female anopheline identified morphologically into two groups; Anopheles gambiae s. s. and Anopheles funestus in the proportion 2:1. On dissection of these mosquitoes, 15 (22%) were found to carry sporozoites. The mean sporozoite inoculation rate (EIR) over the 12-month study period was 0.34 infective bites per person per night (ib/p/night), giving an average of 124.1 ib/p/year at Adim. The implication of this is that an individual living in Biase would expect to receive 124.1 infective bites by the malaria vectors in a year with an average time to a single infective inoculation of 2.9 days. In the month of May, this range would be 1.3 days, while in June, it would be as long as 8.8 days if he is not protected against the mosquito bite. Malaria parasite prevalence rate in the community was 42.5% and a gametocyte rate of 3.4%. It was concluded that the high malariometric indices actually favour the potentials for high malaria transmission and should attract malaria control programmes from the governments, as this will improve the living conditions of the community.