A common malaria drug may protect fetuses from Zika virus infection, according to a study published Monday in The Journal of Experimental Medicine.
For the study, researchers from St. Louis-based Washington University School of Medicine infected human placental cells with Zika to examine the cells' immune response. They found the virus activated genes related to the placenta's autophagy process and manipulated the cells' normal infection barrier to survive. When researchers boosted the cells' barrier response, the virus multiplied and spread faster. When they weakened the barrier response, the virus spread more slowly.
Researchers verified these findings in mice, injecting two groups of the pregnant rodents with Zika before giving them a dose of the malaria drug hydroxychloroquine, which weakens the barrier response. One group had normal autophagy infection responses and the other had weakened response systems.
The mice with a weakened response system had roughly the same amount of Zika in their bloodstream as mice with a normal response five days after infection. However, they also had 10 times fewer viruses in the placenta and heads of their fetuses.
"We found that the malaria drug hydroxychloroquine effectively blocks viral transmission to the fetus," said senior author Indira Mysorekar, PhD, an associate professor of obstetrics and gynecology and of pathology and immunology at Washington University School of Medicine. "This drug already is used in pregnant women to treat malaria, and we suggest that it warrants evaluation in primates and women to diminish the risks of Zika infection and disease in developing fetuses."