New York, Nov 8 (IANS) Researchers, including one of Indian origin, have identified a human antibody that in pregnant mice prevents the foetus from becoming infected with Zika virus and damaging the placenta.

Zika is a mosquito-borne virus that has emerged as a global public health threat. 

The antibody, called ZIKV-117, also protected adult mice from Zika disease, the researchers said.

"The anti-Zika antibodies are able to keep the foetus safe from harm by blocking the virus from crossing the placenta," said Indira Mysorekar, Associate Professor at Washington University in St. Louis.

"This is the first antiviral that has been seen to work in pregnancy to protect developing foetuses from Zika virus," added Michael Diamond, Professor at Washington University.

In the study, the antibody ZIKV-117 neutralised all strains of Zika virus tested, including African, Asian and American lineages.

Pregnant mice that received the antibody and were then infected with Zika virus showed lower levels of Zika virus in their blood and brain tissues than mice not treated with ZIKV-117.

Further, the treated mice showed protective levels of ZIKV-117 in foetal tissues and markedly reduced levels of virus in the placenta and the foetal brain. 

The placentas from the treated females appeared normal and healthy, unlike those from the untreated females, which showed destruction of the placental structure. 

"We did not see any damage to the foetal blood vessels, thinning of the placenta or any growth restriction in the foetuses of the antibody-treated mice," Mysorekar said. 

In addition, male mice that received a single dose of ZIKV-117 even five days after Zika infection were more likely to survive than those given a control antibody, suggesting that ZIKV-117 could treat active Zika infection.

These findings suggested that ZIKV-117 may reduce mother-to-foetus virus transmission and also neutralise Zika virus that reaches the foetus, the researchers said, adding that the study may also aid development of vaccines and therapies for Zika virus infection.

The study appears in the journal 'Nature'.