Bacteria can block mosquitoes from transmitting Zika virus

New York, July 1

Researchers have confirmed that a benign bacterium can completely block transmission of Zika virus in Aedes aegypti, the mosquito species responsible for passing the virus to humans.

The bacteria, called Wolbachia pipientis, could present a "novel biological control mechanism", aiding efforts to stop the spread of Zika virus, said Matthew Aliota, scientist at the University of Wisconsin-Madison School of Veterinary Medicine (SVM) and first author of the study.

The findings were reported in the journal Scientific Reports.

Wolbachia can be found in up to 60 per cent of insects around the world, including butterflies and bees. 

While not typically found in the Aedes aegypti mosquito -- the species that also transmits dengue, chikungunya and yellow fever viruses -- Scott O'Neill from Monash University in Melbourne, Australia, discovered in the early 1990s that Wolbachia could be introduced to the mosquito in the lab and would prevent the mosquitoes from transmitting dengue virus.

Zika virus belongs to the same family as dengue virus and so researchers wanted to find out whether Wolbachia-harboring Aedes aegypti may also be effective against Zika virus. 

In the study, the team infected mice with Zika virus originally isolated from a human patient and allowed mosquitoes to feed on the mice either two or three days after they were infected. 

The researchers found that mosquitoes carrying Wolbachia were less likely to become infected with Zika virus after feeding on viral blood, and those that were infected were not capable of transmitting the virus in their saliva.

"Mosquitoes with Wolbachia were less capable of harboring Zika virus, and though they do get infected with Zika, it is to a lesser extent than wild-type mosquitoes," Jorge Osorio, Professor at UW-Madison, said.

Researchers led by Osorio are already releasing mosquitoes harbouring the Wolbachia bacterium in pilot studies in Colombia, Brazil, Australia, Vietnam and Indonesia to help control the spread of dengue virus.  — IANS