Wolbachia bacteria reduce parasite levels and kill the mosquito that spreads malaria

Wolbachia are bacteria that infect many insects, including mosquitoes. However, Wolbachia do not naturally infect Anopheles mosquitoes, which are the type that spreads malaria to humans. Researchers at the Johns Hopkins Bloomberg School of Public Health found that artificial infection with different Wolbachia strains can significantly reduce levels of the human malaria parasite, Plasmodium falciparum, in the mosquito, Anopheles gambiae. The investigators also determined that one of the Wolbachia strains rapidly killed the mosquito after it fed on blood. According to the researchers, Wolbachia could potentially be used as part of a strategy to control malaria if stable infections can be established in Anopheles. Their study is published in the May 19 edition PLoS Pathogens.

"This is the first time anyone has shown that Wolbachia infections can reduce levels of the human malaria parasite (Plasmodium falciparum) in Anopheles mosquitoes," said Jason Rasgon, PhD, senior author of the study and associate professor with the Johns Hopkins Malaria Research Institute and the Bloomberg School's W. Harry Feinstone Department of and Immunology.

For the study, Rasgon and his colleagues infected mosquitoes with two different Wolbachia strains (wMelPop and wAlbB). After infection, Wolbachia disseminated widely in the mosquitoes and infected diverse tissues and organs. Wolbachia also seemed to actively manipulate the mosquito's immune system to facilitate its own replication. Both Wolbachia strains were able to significantly inhibit malaria parasite levels in the mosquito gut. Although not virulent in sugar-fed mosquitoes, the wMelPop strain killed most mosquitoes within a day after the mosquito was blood-fed.

"These experiments show that Wolbachia could be used in multiple ways to control malaria, perhaps by blocking transmission or by killing infected mosquitoes," said Rasgon.

Worldwide, malaria afflicts more than 225 million people. Each year, the disease kills nearly 800,000, many of whom are children living in Africa.

More information: "Wolbachia infections are virulent and inhabit the human malaria parasite Plasmodium falciparum in Anopheles gambiae", PLoS Pathogens.

Related Stories

Malaria researchers identify new mosquito virus

Aug 22, 2008

Researchers at the Johns Hopkins Bloomberg School of Public Health's Malaria Research Institute have identified a previously unknown virus that is infectious to Anopheles gambiae—the mosquito primarily respon ...

Scientists find bacterium can halt dengue virus transmission

Apr 01, 2010

Dengue fever -- caused by a virus transmitted by mosquitoes -- threatens 2.5 billion people each year and there is no vaccine or treatment. New research by Michigan State University entomologists has found that a bacterium ...

Malaria immunity trigger found for multiple mosquito species

Mar 13, 2009

(PhysOrg.com) -- Researchers at the Johns Hopkins Bloomberg School of Public Health have for the first time identified a molecular pathway that triggers an immune response in multiple mosquito species capable of stopping ...

Recommended for you

Presence of peers ups health workers' hand hygiene

8 hours ago

(HealthDay)—The presence of other health care workers improves hand hygiene adherence, according to a study published in the October issue of Infection Control and Hospital Epidemiology.

Sierra Leone streets deserted as shutdown begins

16 hours ago

Sierra Leone's normally chaotic capital resembled a ghost town on Friday as residents were confined to their homes for the start of a three-day lockdown aimed at halting the deadly Ebola epidemic.

Sierra Leone launches controversial Ebola shutdown

18 hours ago

Sierra Leone on Friday launched a controversial three-day shutdown to contain the deadly spread of the Ebola virus, as the UN Security Council declared the deadly outbreak a threat to world peace.

User comments