Sporozoite Infection Rate of Malaria Vectors along Altitudinal Gradients of Plateau State, Nigeria

Abstract

African Plateau areas are known of malaria hypoendemicity due to low temperatures and relative humidity, as these factors have significant impacts on the anopheline reproductive suitability and abundance. However, changes in abiotic factors especially temperature in African highlands could result in temporary favourable conditions for unstable transmission within populations that have acquired little functional immunity. To this end, a descriptive longitudinal study to determine the sporozoite infection rate of malaria vectors along altitudinal gradients of 1330 m, 633 m, 211 m above sea level of Plateau State was conducted between 2018 and 2019 using pyrethrum spray collection (PSC) and CDC light trap.   Of the one thousand one hundred and ninety-two (1,192) adult female mosquitoes collected, the predominant was Cx. quinquefasciatus 948 (79.5%) followed by An. gambiae 241 (20.2%) and the least was An. funestus 3 (0.2%), and differences was significant (P < 0.05). Sporozoite infection rates 0.9% from ELISA result among female mosquitoes where Vwang had 0%, Jing 0.74%, while Pangwasa had the highest sporozoite rate of 1.28%. Anopheles species composition was higher in Pangwasa. There was a significant difference between infected and non-infected Anopheles in the three study areas (P < 0.05). This study shows that Vwang, Jing and Pangwasa, are endemic to malaria with An. gambiae and An. funestus being the primary malaria vectors. These findings shows variation in the sporozoite rates across the three study sites which will also serve as a baseline data for malaria control program implementation and evaluation along altitudinal gradients of Vwang, Jing, and Pangwasa sites.