Scientists call for development of quick Zika tests as epidemic rages on

Mauricio Lacerda Nogueira

As the Zika epidemic rages on, health experts are calling for the development of blood tests that can quickly and accurately pinpoint the virus and shed light on an associated condition in infants.

Zika cases have been confirmed using PCR tests, which identify genetic material from the virus. But the tests are only available at major labs and can only be used when Zika is causing symptoms in patients. To better monitor the outbreak and flag potential problems, doctors need serology tests, or a diagnostic that can flag virus antibodies for months or years after an infection, Reuters reports. Labs in Brazil, where the virus is especially prevalent, and other facilities are scrambling to develop the tools.

Part of the reason behind a lack of diagnostics is the uncertainty surrounding Zika. People infected with virus often do not display symptoms. And an existing test can confuse Zika with other, similar-looking viruses such as yellow fever, West Nile and dengue. "There is a test, but it's not a good test. It's not going to work with someone who has been exposed to related viruses," Mauricio Lacerda Nogueira, head of the virology lab at Brazil's São Jose do Rio Preto medical school, told Reuters.

A better diagnostic tool would also help scientists understand the link between Zika and microcephaly, a condition that causes abnormally small head size and corresponding development problems in babies. Brazilian officials said that Zika might be associated with more than 4,000 suspected cases of microcephaly since October, according to the Reuters story.

Some scientists are advocating for new tests for the virus. A Zika diagnostic "is going to be very important for any vaccine research program," Nicholas Jackson, the head of Sanofi's ($SNY) vaccines division told Bloomberg, as researchers look for ways to quell outbreaks. "There is no gold standard and there is no commercially available test" for Zika, Jackson pointed out, which could contribute to the rising number of cases.

Still, researchers should tread a fine line when developing a new test for the virus, some experts say. "You want a test that will pick up all cases, but also one that doesn't alarm too many people," Anthony Costello, head of The World Health Organization's (WHO) department of maternal, newborn, child and adolescent health, told Bloomberg. "It has to be both sensitive and specific," Costello said, as some women who test positive for the virus may consider terminating their pregnancy.

Other scientists do not see the tests being rolled out in the near future. "The likelihood of this happening soon is close to zero," Robert Lanciotti, chief of the Centers for Disease Control and Prevention's (CDC) Fort Collins, CO-based diagnostics lab, told the news outlet. "It's a long-standing problem that many people have been unable to solve even with cutting-edge molecular biology."

- read the Reuters story
- here's the Bloomberg article

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