An observational study assessing distribution of mosquito bites on humans to inform personal protection measures against malaria and dengue vectors

Abstract

Aim: The aim of the present study was to investigate the preferred biting sites by both the dengue vector, Ae. aegypti and the malaria vector, An. arabiensis on adult male volunteers in standing or sleeping positions, and further estimated protection limits affordable by either protective clothing or the repellent-treated footwear.Methods: participants who were adults wore shorts and t-shirts and were placed in screened chambers. These chambers contained laboratory-raised mosquitoes that were free from infection. The participants were exposed to the mosquitoes from 6am to noon for day-biting Ae. aegypti mosquitoes, and from 6pm to midnight for night-biting An. arabiensis mosquitoes. Incidents of attempted bites on several anatomical regions were documented. Volunteers were observed wearing sandals sprayed with transfluthrin, a pyrethroid that kills and repels mosquitoes, in order to make comparative observations.Results: In experiments where participants assumed a sleeping posture, a grand total of 3982 insects were collected again. Similarly, in experiments where individuals stood, a total of 5,818 mosquitoes were recovered. While in a state of sleep, the majority of the Ae. aegypti mosquitoes that are actively searching for a host tend to settle on the forearms. The remaining insects are dispersed quite equally among the other parts of the body that are exposed. According to cumulative estimates, just 23% of the landings occurred below the knee. A grand total of 2,725 mosquitoes were taken again in experiments when the volunteers were standing, whereas 3,036 insects were obtained while the participants were sleeping. When in the sleeping posture, the majority of the An. arabiensis mosquitoes that were looking for a host landed on the forearms, while the remaining mosquitoes were uniformly spread among other parts of the body that were exposed. Conclusion: This research contributes to the existing knowledge about variations across species in the distribution of landing and bite locations on the human body when people are standing erect. This research emphasises the significance of using insecticide-treated and untreated personal protection measures to reduce mosquito bites and the transfer of pathogens by Anopheline and Aedes mosquitoes.