Common Malaria Drug Prevents Zika Pregnancy Transmission

Chloroquine could serve as an endemic response to Zika in lieu of a vaccination.

Alysson Muotri, PhD

An inexpensive drug used for malaria treatment could help prevent Zika virus from transmitting from pregnant women to their fetus.

Chloroquine, a proven and safe drug that has been prominent in malaria epidemic control for over 50 years, show a notable reduction in Zika virus the maternal blood and neural progenitor cells in mouse model fetal brains, according to a recent study.

The mouse models, which transmit Zika virus through birth in a similar manner to humans, were given chloroquine through drinking water in doses comparable to rates given to humans. It is the first study of mouse models that transmit the disease in a human way — researchers previously used an interferon-deficient mouse strain that resulted in death from Zika infection.

The study originated from efforts to repurpose US Food and Drug Administration (FDA)-approved drugs to deliver immediate treatment to affect populations, Allyson Muotri, PhD, senior author and Director of the Stem Cell Program in the Institute for Genomic Medicine at the University of California San Diego, told MD Magazine.

“One of the drugs we found, chloroquine, had a great performance on protecting human brain organoids,” Muotri said. “In this work, we explored in more details what is the protective impact of chloroquine on both cellular and animal models against Zika virus.”

The discovery comes during a time of “urgent need” to bolster preparedness and capacity to respond to an outbreak, Terskikh said.

While Zika causes flu-like symptoms in adults, in can cause serious birth defects such as microcephaly, an incurable condition in which newborns have small heads and a development disorder.

Researchers found that chloroquine is efficacious against the “deleterious effects of Zika infection in the brain,” Muotri said, giving credence that it could serve as a prophylaxis.

Chloroquine may serve doubly beneficial due to its inexpensive costs, Muotri said. He noted that it was mixed with cooking salt and distributed to malaria endemic populations in 1950s Brazil.

“With time, malaria-resistance give raise to new drugs that were more effective in some countries, but chloroquine continue to be used in some parts of the world, especially because it is quite inexpensive and safe,” Muotri said. “You could treat a whole country with a very low budget.”

It could now serve a similar service in the event of a Zika virus outbreak, in lieu of a regulated vaccination. The drug has only been been proven efficacious in the early stage of infection though, and Muotri reiterated that is not a cure for Zika.

That said, chloroquine’s reduction of viral particles gives hope it could reduce pregnant women’s chances of vertical transmission in an eventual clinical trial, Muotri said.

While chloroquine for Zika could move forward to formal human studies, the researchers may have found a drug capable of completely eliminating the virus from infected cells and animal subjects, Muotri said.

The drug, which Muotri did not name, is FDA-approved but not fully tested for use during pregnancy.

“A clinical trial is currently being designed,” Muotri said. “If this works in humans, I think this would be phenomenal.”

Related Coverage

Antibody Analysis Could Lead to Strengthened Malaria Vaccine

CDC Updates Healthcare Guidance for Infants of Mothers Exposed to Zika

FDA Approves 2-Dose Hepatitis B Vaccine, Heplisav-B