West Nile? Zika? Your immune system might actually make viruses worse

June 23, 2016 at 3:07AM
The itch of a mosquito bite helps spread viruses, a new study revealed.
The itch of a mosquito bite helps spread viruses, a new study revealed. (The Minnesota Star Tribune)

A virus hiding in the saliva of a mosquito can hijack your body's first-responder cells and take a ride throughout your body.

In a surprising discovery, a team of European researchers has unveiled the mechanism that mosquito-borne viruses — including West Nile, dengue and Zika — use to infect the rest of the body, potentially causing greater sickness.

They conducted their experiments on hundreds of mice — half of which had been bitten by mosquitoes. Then they injected a virus into all of the mice. The virus replicated well in the bitten mice and not much in the unbitten mice.

Here's what scientists think happens: In response to the bite, the body sends immunity cells to the infected area (which is what produces the redness and swelling associated with mosquito bites). The virus, which enters the skin through the mosquito saliva, then infects some of the immunity cells that went to bitten area. Those cells, now carrying the virus, spread throughout the body and can lead to illness.

Their findings appeared in the latest issue of the medical journal, Immunity.

The researchers hope the understanding of how viruses replicate using the body's reaction to mosquito bites could pave the way for more effective treatments by addressing the source of the infection — the bite itself.

"To Your Health" offers quick doses of health news several times a week.

Allie Shah • 612-673-4488

@allieshah

about the writer

about the writer

Allie Shah

Deputy editor

Allie Shah is deputy local editor. She previously supervised coverage of K-12 and higher education issues in Minnesota. In her more than 20 year journalism career at the Minnesota Star Tribune, Shah has reported on topics ranging from education to immigration and health.

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