Newly identified mosquito subspecies highly susceptible to malaria parasite, prefers outdoors

Feb 5 2011

"Researchers have discovered a previously unknown subspecies of mosquito in West Africa that is highly susceptible to the malaria parasite and whose existence may stymie efforts to eradicate the deadly disease," the Los Angeles Times reports (Khan, 2/4).

The findings were published Thursday in the journal Science. For the study, scientists collected mosquitoes from ponds near villages in Burkina Faso. "They found a subtype of Anopheles gambiae mosquitoes unlike any that have turned up in collections before," USA Today's "Science Fair" blog reports (Weise, 2/3). "The newly discovered mosquito group [called Goundry] ... could be one reason why eradication attempts have not been entirely successful. Unlike other A. gambiae, adult Goundry mosquitoes spend their time outside, thus avoiding indoor sprays. Furthermore, when fed blood carrying Plasmodium falciparum, the group acquired the parasite more easily than did its relatives," Nature News writes (Maxmen, 2/3).

The researchers found the "outdoor mosquitoes showed a 'significantly greater' infection rate (58 percent) compared to the indoor types (35 percent)," Agence France-Presse writes (2/3). "They are very susceptible to the human malaria parasite, we know they belong to a species that has an exquisite preference for human blood, and we know they are abundant in the population," said Ken Vernick, a study author from the Unit of Hosts, Vectors and Pathogens at the French National Center for Scientific Research, Reuters reports.

"Vernick said the researchers were not yet able to quantify how much malaria transmission this new mosquito subtype is responsible for, but they feared it might be a major factor. 'What we can say is that it's unlikely they're harmless,' he said in a telephone interview" (Kelland, 2/4). The newly-identified mosquito's "susceptibility to malaria could mean it is 'quite young, evolutionarily,'" according to the researchers, who "urged the collection of more adult mosquitoes in the wild for further analysis," AFP writes (2/3).

"Concern about the possible existence of an outdoor malaria-transmitting mosquito first emerged in the 1970s, after the failure of a US$6-million eradication programme conducted by the WHO in Garki, Nigeria," Nature News notes. "In hindsight, researchers speculated that the Garki project was doomed by elusive mosquitoes resting outside. Early studies on genetic differences underlying indoor and outdoor preferences in A. gambiae lent credence to the idea," the publication adds (2/3).