Relationship between the presence of kdr and Ace-1 mutations and the infection with Plasmodium falciparum in Anopheles gambiae s.s. in Benin

Several published reports have been devoted to insecticide resistance in Anopheles gambiae in Africa. However, there are still not enough published reports about the impact of insecticide resistance on malaria transmission. In this study, we proposed to investigate the presence of the circum-sporozoite antigen of Plasmodium falciparum in A. gambiae carrying kdr and Ace-1 genes. A. gambiae (3,112) were analyzed using the enzyme-linked immunosorbent assay (ELISA), circum-sporozoite protein (CSP) test. The DNA from these samples was extracted and a polymerase chain reaction (PCR) was performed using kdr and Ace-1 markers. We used Chi-square statistical test to determine the relationship between the resistance genotypes and the rates of infections with P. falciparum. The results showed that the kdr allele was found at a very high frequency (0.80 on average) in the 14 populations of A. gambiae s.s. sampled inspite of their molecular forms (M or S). The Ace-1 gene was also observed in some localities, but at a low frequency (0.3 on average). The ELISA-CSP tests performed on parous females carrying the kdr gene showed that there was no significant difference between the allele frequencies of infected and non-infected females. kdr and Ace-1 resistance genes did not affect the A. gambiae s.s. infection with P. falciparum.