Like other mosquito-borne diseases such as dengue and malaria, Zika virus can be hard to detect with most patients developing no symptoms during the initial stages. Worse, Zika virus in pregnant women can cause infants to be born with microcephaly and other congenital malformations, known as congenital Zika syndrome.
But now a diagnostic test, granted market authorisation by the Food and Drug Administration (FDA), promises to resolve this problem. Developed by InBios International and based in part on technology licensed from Washington University School of Medicine in St. Louis, the test can detect signs of Zika infection in serum samples within 12 weeks of infection.
“Pregnant women living in or visiting places where Zika is endemic will want to know if they have been exposed to the virus,” said Dr. Michael S. Diamond, a co-inventor of the technology that underlies the test.
“This test, along with another that detects viral genetic material at very early stages of infection, will help women and their doctors make informed health-care decisions,” Diamond said in a press release issued by Washington University School of Medicine. He is Herbert S. Gasser Professor of Medicine and a professor of molecular microbiology and of pathology and immunology at the School of Medicine.
In 2016, Diamond and co-inventor Daved Fremont, a professor of pathology and immunology, , identified and characterised an antibody that detects Zika virus proteins. They did along with then-graduate student Estefania Fernandez and postdoctoral researcher Haiyan Zhao.
In the first days after Zika virus infection, immune cells produce large amounts of anti-Zika antibodies. The test uses Diamond and Fremont’s antibody – as well as other components – to detect anti-Zika antibodies in the blood of people recently infected with the virus.
Although the consequences of Zika infection are most severe for developing fetuses, in rare cases, the virus also can cause serious illness in children and adults. It has been linked to brain swelling and to Guillain-Barre syndrome, a neurological condition involving muscle weakness and paralysis.
However, the test is not meant to be used as a stand-alone proof of infection. The FDA recommends that it be used only for people with symptoms of recent infection. It can be also be used for people with a history of living in or traveling to geographic regions where Zika circulates.
Positive results should be confirmed in accordance with guidelines from the Centers for Disease Control and Prevention, the FDA says.