Bacteria ‘could be recruited to attack malaria’

Scientists have identified a type of bacteria in mosquitoes that carry malaria, which could be used to attack the parasite.

The research was published in the Proceedings of the National Academy of Sciences this week (14 May).

Lead researcher Guido Favia and colleagues at the Italy-based University of Camerino found that bacteria ― of the genus Asaia ― inhabit the Anopheles stephensi mosquito. A. stephensi is an important mosquito vector of Plasmodium vivax ― the parasite that causes malaria ― in Asia. 

Favia told SciDev.Net that the bacteria are also present in the main African malaria mosquito vector, Anopheles gambiae.

The researchers say Asaia is an ideal candidate for malaria control because it has a symbiotic relationship with its mosquito host, can be passed between mosquitoes, and colonises the same parts of the mosquito as the malaria parasite.

The researchers found that Asaia colonise the mosquitoes’ gut and salivary glands. These sites are also important for the malaria parasite ― particularly for its development and ability to spread between mosquitoes.

The bacteria can also spread to mosquito offspring, as they were found in the eggs, ovaries and testes of mosquitoes and also in pupae and larvae.

The malaria parasite has become resistant to drugs in some areas and attempts to create a vaccine have so far been unsuccessful.

The researchers suggest that the bacterium could be genetically altered to attack the malaria parasite by producing anti-parasite molecules.

“Instead of spraying chemical or biological pesticides, you could use this symbiotic bacteria that is passed on [between mosquitoes],” Daniele Daffonchio, an author of the paper, told Reuters. “You don’t have to spray every year.”

Effat Soliman, microbial geneticist at Cairo’s National Research Center, welcomed the development but cautioned that safety studies based on scientific facts ― not commercial or political interest ― should determine the future use of the genetically modified bacteria as a weapon against malaria.

Christopher Plowe, from the US-based Center for Vaccine Development at the University of Maryland, said using bacteria to block the passage of malaria parasites is “an intriguing approach to control malaria”, but that the real challenge existed in convincing countries with malaria to release genetically modified bacteria.

“Considering that some countries won’t even accept genetically modified corn during famine, this may not be easy,” he told SciDev.Net.

Link to abstract in PNAS

Reference:  PNAS doi 10.1073/pnas.0610451104 (2007)