In a controlled experiment, researchers working in Burkina Faso discovered that men who had consumed
, the local sorghum beer, were
much more attractive
mosquitoes than men who were drinking tap water (story via the
Los Angeles Times
Presented with the odor of a beer drinker, 47 percent of mosquitoes roused themselves, versus 35 to 38 percent of mosquitoes exposed to the odor of someone who was not drinking beer. And given two directions to go, 65 percent of the flying mosquitoes who smelled a beer drinker headed toward him. Only 47 percent of flying mosquitoes headed toward water drinkers.
The attractiveness of each volunteer was tested twice: before (first trial) and 15 minutes after (second trial) the consumption of either one litre of dolo (the average amount ingested by consumers at a "cabaret") or one litre of water. Following oral administration, alcohol is quickly absorbed from the gastrointestinal tract into the blood and metabolised. Fifteen minutes is a sufficient interval for alcohol to be present in blood, breath, urine and sweat.
We found that beer consumption not only enhanced the number of mosquitoes that engage in odour-mediated upwind flight (mosquito activation ) but also enhanced the strength of their odour-mediated anemotactic response (mosquito orientation ). Mosquito activation and orientation are important parts of the natural host-seeking process of An. gambiae and any increases in these behaviours will facilitate vector-human contacts. Water consumption did not affect these mosquito behavioural responses, demonstrating that beer was solely responsible for increased human attractiveness .