The sudden and rampant outbreak of Zika virus in 2016 terrified pregnant women, particularly those residing in Zika-endemic regions, such as Brazil, as well as those in the U.S. Their fear was justified given the link between Zika virus infection during pregnancy with having a small head, a condition known as microcephaly, and other congenital defects.
The absence of early prenatal diagnosis, or treatment, for birth defects has left thousands of mothers-to-be worrying about their baby’s well-being. Others, meanwhile, have terminated their pregnancy rather than risk having a child with birth defects.
Our research revolves around mosquito-borne viruses such as Chikungunya virus and Zika virus. Each causes a distinct set of symptoms. Chikungunya virus produces debilitating persistent joint pain in adults and neurological symptoms in children; Zika virus causes defects in babies. In Jae Jung’s lab at the University of Southern California, we are investigating the mechanisms that underlie the devastating consequences of these viral infections and developing new prenatal diagnostic tests to determine whether Zika babies are in good health.
Zika and pregnancy
Zika is the first mosquito-borne virus known to cause congenital defects. Aedes aegypti, one of the most invasive and widespread species of mosquito, is the primary vector for transmitting Zika. When healthy individuals, who are not pregnant, are infected with the Zika virus the infection often escapes notice because the symptoms are mild or negligible. However, infection during the first and second trimester of pregnancy boosts the risk of miscarriages and diverse fetal defects such as eye abnormalities, neurological impairment and in more severe cases, microcephaly.
Health workers try to assess the health of Zika babies using ultrasound during the second trimester or later. But it is difficult to see from these images whether the baby has developmental abnormalities.
On the other hand, fetal MRI captures high-resolution snapshots of the fetus. But this imaging technique can only be used in the second or third trimesters – when it is more difficult to terminate a pregnancy. A diagnostic assay that could detect abnormalities early in the pregnancy could alleviate the mother’s stress and make it easier to make swift reproductive decisions.