Published: Tue, November 08, 2016
Medical | By Garry George

Zika virus confirmed in Palau

Zika virus confirmed in Palau

Now, researchers from Washington University School of Medicine in St. Louis and Vanderbilt University School of Medicine in Nashville, TN, say they have uncovered a naturally occurring antibody called ZIKV-177 that could protect the developing fetus from Zika virus, bring us closer to a Zika vaccine.

A new study of the Zika virus in mice raises hope for a way to protect pregnant women and their babies from the possible repercussions of being infected, US researchers said on Monday.

The Crowe and Diamond laboratories have collaborated recently on several projects including the generation of protective human monoclonal antibodies against Dengue, West Nile, Chikungunya and now Zika viruses.

Similar protection studies in primates are warranted, and if the findings hold up, ZIKV-177 could be developed as a protective antibody treatment for pregnant women at risk of Zika infection, the researchers concluded. In mice infected by the Zika virus, injection of the antibody markedly reduced disease and mortality, and reduced transmission from mother to fetus.

The antibody also protected adult male mice against a lethal dose of the virus, even when given five days after the infection.

Their placentas appeared normal and healthy, while the placentas of those infected and not given the antibody showed destruction.

"The anti-Zika antibodies are able to keep the fetus safe from harm by blocking the virus from crossing the placenta", Diamond added.

Since a major outbreak was reported in Brazil previous year, Zika infections transmitted by mosquitoes have been reported throughout Africa, Asia, the Pacific, and the Americas, including Miami-Dade County, Florida. It is especially risky for pregnant women whose children could be born with very small heads, a condition called microcephaly.

There is now no Zika vaccine; in the USA, the FDA is trying to fight the disease using genetically modified mosquitoes. Most people who get Zika don't have any symptoms, and if they do it's just a mild flu-like illness.

The researchers hope to proceed to human clinical trials for the antibody therapy within a year, Crowe said.

It's the first time an antiviral has been shown to protect developing fetuses from Zika.

A Zika vaccine is likely to be the cheapest and simplest method of preventing Zika-related birth defects. The phenomenon, known as antibody-dependent enhancement, has been observed with Zika in a petri dish but never in living animals or in epidemiologic surveys of people in Zika-endemic regions.

What is more, the results suggest that a vaccine that evokes protective antibodies - such as ZIKV-177 - has the potential to prevent Zika infection in expectant mothers and their fetuses, as well as treat fetuses that have already been infected. Meanwhile, Diamond is focusing on determining whether antibodies could be used to clear persistent Zika infection.

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