Prevalence of Wuchereria bancrofti and Plasmodium spp. Infection in Anopheles Mosquitoes and Human Blood Sampled from Selected Regions in Busia County, Western Kenya

Abstract

INTRODUCTION Lymphatic filariasis and malaria are mosquito-borne diseases and are co-endemic in coastal Kenya. We evaluated the occurrence of co-infections with Wuchereria bancrofti and Plasmodium falciparum, the causative agents of Lymphatic filariasis and malaria, respectively, in humans and known Anopheles vectors from Matayos constituency, Busia County, western Kenya. MATERIALS AND METHODS The samples were collected purposively based on clinical case reports. Members of the An. gambiae and An. funestus species complexes present and the presence of W. bancrofti and P. falciparum were detected using Polymerase Chain Reaction (PCR). Positive PCR amplicons were purified and Sanger sequenced. RESULTS In this study, 292 Anopheles mosquitoes were analyzed, and 288 of these (98.63%) were successfully identified by PCR. The majority of mosquitoes identified belonged to the An. funestus complex (85.76%) while An. gambiae complex mosquitoes comprised 14.24%. Two W. bancrofti infections were detected in the mosquitoes, one each in An. leesoni and An. funestus s.s. with an infection rate of 0.46% and 4.17% respectively. No P. falciparum was detected in the mosquito or human blood samples and only 2 blood samples (2.17%) were positive for W. bancrofti. Phylogenetic analysis based on the sequenced 18S rRNA gene showed that all W. bancrofti sequences from this study shared a close relationship with W. bancrofti sequences distributed in other regions. No case of co-infection of P. falciparum and W. bancrofti was found in the mosquito or blood samples analyzed. CONCLUSION This study confirms the presence of W. bancrofti infection in the human population and mosquito vectors in Matayos. The study also indicated that the majority of Anopheles mosquitoes from the study area belong to An. funestus complex. This study recommends additional screening before Mass Drug Administration, and that mosquito control programs be strengthened in the study area.