High proportion of mosquito vectors in Zika forest, Uganda, feeding on humans has implications for the spread of new arbovirus pathogens

Abstract

There is a steady increase in the contact between humans and wildlife, brought about by encroachment, destruction of natural forests, climatic and environmental changes. Mosquitoes get exposed to hosts and pathogens; creating possibilities for new disease patterns. Therefore, the identification of blood-meal sources is important to determine the linkages between hosts and vectors. Engorged mosquitoes were collected in Zika forest (Uganda) for a period of 12 months using carbon dioxide (CO₂)-baited light traps. Total genomic DNA was extracted from the abdominal contents of the mosquitoes and the diagnostic regions of the mitochondrial genes, cytochrome oxidase subunit 1 (COI) and cytochrome b (cytb) sequenced. The sequences were subsequently blasted in the GenBank. Sequence analyses revealed that feeds were derived from mammalian and avian hosts. Blood-meal sources from Aedes africanus (Theobold) examined were entirely human. There were significant differences between host species from which the mosquito species fed (Krusakal Wallis test, χ² = 19.118, df = 5, p = 0.018). Several mosquitoes were considered as potential bridge vectors for a number of arboviruses and other diseases have been collected from the forest. Taking of mammalian origin blood-meals, including humans, may facilitate exposure to new pathogens and disease patterns.

Keywords: Blood-meal, bridge vectors, cytochrome oxidase sub unit I, cytochrome b, Entebbe.