A commonly used malaria drug might protect foetuses from being infected with the Zika viruses, according to new research by scientists at the Washington University School of Medicine. This is an important finding with the possibly simple solution to prevent babies being born with developmental deformities associated with the disease.

India has just recorded its fourth case of Zika. A 27-year-old man in Tamil Nadu was found infected with the Zika virus. Three cases were detected earlier this year in Ahmedabad, Gujarat. Zika was declared a Public Health Emergency of International concern for much of 2016, after Zika infections were reported in many parts of the world and took a heavy toll on Brazil.

Zika often manifests as mild symptoms like fever and rash in adults but babies born to women infected with the virus can ave microcephaly, a condition in which the brain is small and underdeveloped. So far, there has been no vaccine or drug to protect pregnant women and their foetuses from infection.

A team of scientists from Washington University School of Medicine have studied pregnant mice infected with Zika and found that the Zika virus infects a foetus by manipulating the body’s normal barrier to infection. The body normally mobilises many defensive mechanisms to protect a growing foetus and the placenta is the last line of defense against infection being transmitted from the mother. The research team had previously found that the Zika virus can invade rhe placenta and also multiply there.

To learn more about how Zika breaches the placenta, the researchers infected human placental cells with Zika virus and that the virus then activated genes related to autophagy – the process by which cells disposed waste and invading microbes. When they treated the cells with drugs to ramp up the autophagy pathway, they found that a larger number of cells became infected with the Zika virus increased. Drugs that suppressed autophagy resulted in fewer placental cells infected with Zika virus. This showed that the virus was able to manipulate the body’s own defenses against it.

Human placental cells (blue) infected with Zika virus (green) responded to the malaria drug chloroquine (left). (Photo: Bin Cao/Washington University School of Medicine)
Human placental cells (blue) infected with Zika virus (green) responded to the malaria drug chloroquine (left). (Photo: Bin Cao/Washington University School of Medicine)

They then tested the malaria drug hydroxychloroquine – a drug known to suppress autophagy – on pregnant mice. They found significantly lower levels of the virus in foetuses and placentas of mice that had received hydroxychloroquine in comparison to pregnant mice that had been given a placebo. In addition, these placentas of mice that received the malaria drug also showed less damage and the foetuses regained normal growth. Both the untreated and the treated mice mothers had about the same amount of Zika virus in their bloodstreams. The results published in The Journal of Experimental Medicine indicate that hydroxychloroquine was able to protect foetuses even when the virus was circulating through the mother.

The drug is already is approved for use in pregnant women for other medical purposes and the research team suggests further evaluation of the drug in primates and women for use to lower the risks of Zika infection.