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New Macaque Study Provides Insights into How the Zika Virus Affects Fetal Brain Development

Joanna Lawrence
12th September, 2016

Researchers have come one step closer to understanding how the Zika virus affects fetal development. For the first time, a team of scientists studied the effects of the virus on brain development in a non-human primate, the pigtail macaque. The details are in a study that was just published in the journal Nature Medicine. The Zika virus is spread by both mosquitoes and sexual contact with an infected person. The virus causes mild symptoms in most people, such as fevers, rashes, and joint pain. If pregnant women become infected, however, the virus causes severe birth defects. Currently, there is no treatment or vaccine available. This has led many doctors to recommend that pregnant women avoid areas with cases of Zika infections. A large team of researchers studied the effects of the Zika virus on a developing primate brain. The study was the first of its kind and designed to provide new insights into the mechanisms of the virus. A pregnant pigtail macaque monkey was inoculated with a dose of Zika virus that was equivalent to a human being bitten by an infected mosquito. The team was surprised to see how quickly the virus crossed the placenta and began causing brain damage in the developing fetus. Within 10 days, there were brain lesions and other developmental problems. The brain’s white matter, important for facilitating communication between neurons, stopped developing within 3 weeks of viral inoculation. The team predicts that this would lead to microcephaly, a condition in which a baby is born with an abnormally small head due to improper brain development. The findings show that the Zika virus is capable of quickly crossing through the placenta and into the fetal brain. The study also provides hard evidence of the virus causing severe brain damage, leading to microcephaly. The virus was fast-acting, resulting in irreparable damage within 10 days of infection. The researchers emphasize the need for a vaccine or treatment that can be given before or just after a pregnant woman becomes infected. By the time patients begin showing symptoms, it’s too late to prevent damage to the fetus. The team is using their findings to research potential treatments. REFERENCE Kristina M Adams Waldorf et al. Fetal brain lesions after subcutaneous inoculation of Zika virus in a pregnant nonhuman primate. Nature Medicine (2016).