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

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 residentsin 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 thegovernments, as this will improve the living conditions of the community

Nigeria Anopheles vector database: an overview of 100 years' research.

Anopheles mosquitoes are important vectors of malaria and lymphatic filariasis (LF), which are major public health diseases in Nigeria. Malaria is caused by infection with a protozoan parasite of the genus Plasmodium and LF by the parasitic worm Wuchereria bancrofti. Updating our knowledge of the Anopheles species is vital in planning and implementing evidence based vector control programs. To present a comprehensive report on the spatial distribution and composition of these vectors, all published data available were collated into a database. Details recorded for each source were the locality, latitude/longitude, time/period of study, species, abundance, sampling/collection methods, morphological and molecular species identification methods, insecticide resistance status, including evidence of the kdr allele, and P. falciparum sporozoite rate and W. bancrofti microfilaria prevalence. This collation resulted in a total of 110 publications, encompassing 484,747 Anopheles mosquitoes in 632 spatially unique descriptions at 142 georeferenced locations being identified across Nigeria from 1900 to 2010. Overall, the highest number of vector species reported included An. gambiae complex (65.2%), An. funestus complex (17.3%), An. gambiae s.s. (6.5%). An. arabiensis (5.0%) and An. funestus s.s. (2.5%), with the molecular forms An. gambiae M and S identified at 120 locations. A variety of sampling/collection and species identification methods were used with an increase in molecular techniques in recent decades. Insecticide resistance to pyrethroids and organochlorines was found in the main Anopheles species across 45 locations. Presence of P. falciparum and W. bancrofti varied between species with the highest sporozoite rates found in An. gambiae s.s, An. funestus s.s. and An. moucheti, and the highest microfilaria prevalence in An. gambiae s.l., An. arabiensis, and An. gambiae s.s. This comprehensive geo-referenced database provides an essential baseline on Anopheles vectors and will be an important resource for malaria and LF vector control programmes in Nigeria