Bacteria Experiment May Point Way to Slow Zika's Spread

Infecting mosquitoes led to lower, inactive levels of virus in their bodies, saliva

By Robert Preidt

Wednesday, May 4, 2016

WEDNESDAY, May 4, 2016 (HealthDay News) -- Experiments in mosquitoes suggest that bacteria may help curb the spread of the Zika virus.

The researchers got the idea after a pilot program to reduce the transmission of dengue fever showed promise.

In the dengue program, Wolbachia bacteria were inserted into the eggs of Aedes mosquitoes. The bacteria were passed from female mosquitoes to their offspring, which significantly reduced dengue virus replication in the insects.

"The idea has been to release Aedes mosquitoes with Wolbachia in the field over a period of a few months, so they mate with Aedes mosquitoes without Wolbachia," senior study author Luciano Moreira, of the Oswaldo Cruz Foundation in Brazil, explained in a journal news release.

"Zika and dengue belong in the same family of viruses, so with the outbreak in Brazil, the logical idea was to test the mosquitoes carrying Wolbachia by challenging them with Zika virus," Moreira said.

So, mosquitoes with and without the Wolbachia virus were fed human blood infected with two strains of Zika circulating in Brazil, the study authors said.

After two weeks, the mosquitoes with Wolbachia had lower levels of Zika virus in their bodies and saliva, and the virus in their saliva was inactive. That meant they would not be able to transmit it when they bit someone, the researchers said.

"Wolbachia showed to be as effective on Zika as the most important dengue experiments we did," Moreira said.

He added that the researchers are seeking funding to try to do the same pilot program with Zika.

However, even if Wolbachia proves effective in reducing Zika transmission by mosquitoes, it will not eliminate the virus completely, Moreira said.

"We know that there will not be only one solution for Zika -- we have to do this alongside different approaches, like vaccines or insecticides, besides the public measures to control Aedes breeding sites," he said.

The study was published May 4 in the journal Cell Host & Microbe.

While the Zika virus poses little health risk to most people, it can cause a birth defect called microcephaly, which results in babies born with abnormally small heads and brains. In Brazil, more than 4,000 cases of microcephaly have been linked to a Zika outbreak in that country.

As of April 27, there were 1,025 confirmed cases of Zika in U.S. states and territories, according to the U.S. Centers for Disease Control and Prevention. And one Zika-linked death has been reported in Puerto Rico. Nearly all of these infections were acquired by people who had traveled outside the United States.

SOURCE: Cell Host & Microbe, news release, May 4, 2016

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