Researchers develop fast, inexpensive diagnostic test for Zika virus

A new proof-of-concept test for Zika virus that can quickly produce results in a matter of minutes has recently been developed by researchers from the Washington University in St. Louis School of Medicine and the School of Engineering and Applied Sciences.

Contemporary Zika virus tests involves sending refrigerated blood samples to a medical center or laboratory, which can take days to receive results.

“Zika infection is often either asymptomatic or mildly symptomatic,” Evan D. Kharasch, senior investigator of the study, said. “The most effective way to diagnose the disease is not to wait for people to develop symptoms but to do population screening.”

Specifically, the test utilizes inexpensive gold nanorods that are coated with a protein that is produced as an immune response to Zika infection. From there, a drop of the patient’s blood in applied to the test. Should a patient be infected, the blood will contain immunoglobulins that subsequently react with the protein to produce a result — no refrigeration required.

“If an assay requires electricity and refrigeration, it defeats the purpose of developing something to use in a resource-limited setting, especially in tropical areas of the world,” Srikanth Singamaneni, associate professor of mechanical engineering and materials science, said. “We wanted to make the test immune from variations in temperature and humidity.”

For the study, researchers tested blood samples taken from four individuals known to have been infected with the virus and compared it to blood taken from five people who have never been infected. The results concluded that blood from Zika patients tested positive while the non-infected group did not. No false-positive results were recorded in their testing.

While the test does use gold, the nanorods are very small and contain only enough to be worth approximately 10 to 15 cents.

According to the research team, similar strategies could potentially be used to develop tests to detect the presence of other problematic infections that emerge around the world.

Zika virus is a member of the flavivirus family of viruses which include dengue fever, chikungunya virus, and Japanese encephalitis. It is most commonly spread through the bite of Aedes aegypti species mosquito and sexual contact.

While many who are infected do not exhibit any symptoms, those who do experience joint pain, rash, fever, and muscle cramps. More seriously, the virus has been linked to malformations of the fetus in pregnant women and Guillain-Barrè syndrome.