The relationship between house height and mosquito house entry: an experimental study in rural Gambia.

Majo Carrasco-Tenezaca,Otis Sloan Brittain,Musa Jawara,Sainey Ceesay,Mahamed Y Abdi,David Jeffries,John Bradley,Umberto D'Alessandro,Steve W Lindsay,Hannah Wood,Margaret Pinder,Jakob B Knudsen

doi:10.1098/rsif.2021.0256

Abstract

Most malaria infections in sub-Saharan Africa are acquired indoors, thus finding effective ways of preventing mosquito house entry should reduce transmission. Since most malaria mosquitoes fly less than 1 m from the ground, we tested whether raising buildings off the ground would prevent the entry of Anopheles gambiae, the principal African malaria vector, in rural Gambia. Nightly collections of mosquitoes were made using light traps from four inhabited experimental huts, each of which could be moved up or down. Mosquito house entry declined with increasing height, with a hut at 3 m reducing An. gambiae house entry by 84% when compared with huts on the ground. A propensity for malaria vectors to fly close to the ground and reduced levels of carbon dioxide, a major mosquito attractant, in elevated huts, may explain our findings. Raised buildings may help reduce malaria transmission in Africa.

Highlights

The United Nations has projected that the population of sub-Saharan Africa will more than double between 2019 and 2050, and the region will become the world’s most populated by 2062 [1]
Members of the An. gambiae complex of mosquitoes were identified by PCR analysis as An. coluzzii (68.0%, 157/231), An. arabiensis (29.4%, 68/ 231), and An. gambiae s.s. (2.6%, 6/231)
The number of female An. gambiae entering the huts declined with increasing hut height, declining by 40% with the floor height at 1 m, 68% at 2 m and 84% at 3 m when compared with the hut at 0 m

Summary

Introduction

The United Nations has projected that the population of sub-Saharan Africa will more than double between 2019 and 2050, and the region will become the world’s most populated by 2062 [1]. Coincident with the increasing growth rate, there has been an unprecedented improvement in the housing stock in sub-Saharan Africa, with the proportion of improved houses increasing from 11% in 2000 to 23% in 2015 [2]. With an additional 1.05 billion people in 2050 [1], there has never been a better time to improve the quality of housing in sub-Saharan Africa and make houses healthier for people. In 2019, there were 384 000 deaths from malaria in sub-Saharan Africa, representing 94% of the global total [3]. Since 79% of bites by malaria mosquitoes occur indoors at night [4], reducing mosquito house entry could contribute to greater malaria control

Methods

Results

Conclusion