There are already places where homes are built on stilts, to avoid seasonal floods. A new study, however, suggests that doing so may also significantly reduce the risk of being bitten by malaria-carrying mosquitos.
According to Britain's Durham University, approximately 80 percent of malaria-causing mosquito bites within Africa occur indoors at night. Additionally, although mosquitos are known to fly up to about 8 meters (25 ft) above the ground, they typically stay much lower. With these facts in mind, scientists from the university collaborated with colleagues from the Royal Danish Academy to build four experimental huts in The Gambia.
Over the course of 40 days, two men slept in each hut every night, under separate mosquito nets. Additionally, each week one hut remained on the soil, while the other three were raised so that their floors were respectively 1, 2 and 3 meters (3.3, 6.6 and 9.9 ft) above the ground. Different huts were set at different levels every week, so each one had a chance to sit at each height.
Every morning, female Anopheles gambiae mosquitos (known for spreading malaria) were collected from light traps placed in each hut. When the insects were counted, it was found that huts raised by 3 meters had 84 percent fewer mosquitos than huts on the ground. The researchers believe this difference may be due to two factors.
"First, malaria mosquitoes have evolved to find humans on the ground," says Durham's Prof. Steve Lindsay, lead author of a paper on the study. "Second, at higher heights, the carbon dioxide odour plumes coming out of the huts are rapidly dispersed by the wind, so mosquitoes find it more difficult to find a person to bite."
That said, the scientists do admit that if the raising of huts were to become standard practise, mosquitos might simply adapt over time and fly higher. Nonetheless, the study does suggest that it's still definitely worth a try. And as an added bonus, because raised huts would likely be cooler than those on the ground, occupants would probably be more willing to spend the night surrounded by insecticide-treated nets.
The paper was recently published in the Journal of the Royal Society Interface.
Source: Durham University
