A University of Washington-led study documented abnormal brain development in the offspring of a non-human primate following a Zika infection during pregnancy. The researchers’ observations of how Zika virus affected fetal brain formation in a pigtail macaque could provide a model for testing therapeutic interventions.
“This is the only direct evidence that shows that the Zika virus can cross the placenta late in pregnancy and affect the fetal brain by shutting down certain aspects of brain development,” said one of the study’s senior authors, Dr. Michael Gale Jr., a professor of immunology at UW Medicine and adjunct professor of global health at the University of Washington School of Public Health.
The study was led by Dr. Gale; Dr. Lakshmi Rajagopal, associate professor of pediatrics and adjunct associate professor of global health; and Dr. Kristina Adams Waldorf, professor of obstetrics and gynecology.
“Our results remove any lingering doubt that the Zika virus is incredibly dangerous to the developing fetus and provides details as to how the brain injury develops,” said first author Dr. Waldorf. “This study brings us closer to determining if a Zika vaccine or therapy will prevent fetal brain injury, but also safe to take in pregnancy.”
The Zika prenatal study took place in the equivalent of the third trimester of a human gestation. The amount of virus inoculated was similar to the amount a person might contract from a mosquito bite. The pregnant animal did not show any significant symptoms of infection, but the white matter of the fetal brain stopped growing about three weeks after viral inoculation.
“We were shocked when we saw the first MRI of the fetal brain 10 days after viral inoculation,” Dr. Rajagopal said. “We had not predicted that such a large area of the fetal brain would be damaged so quickly. Our results suggest that a therapy to prevent fetal brain injury must either be a vaccine or a prophylactic medicine taken at the time of the mosquito bite to neutralize the virus.”
The results were published Sept. 12 in Nature Medicine. Other contributing authors from the UW School of Public Health were Mr. Jay Vornhagen and Ms. Blair Armistead, both PhD students in pathobiology.