Researchers Seek Foolproof Method To Detect Zika Infection

Sep 19, 2016

Determining whether people have been infected with the Zika virus can be difficult.

Here’s why: Most infected people don’t display symptoms or they choose to endure what may seem like nothing more than the flu instead of seeking medical help. Moreover, infected people don’t have much detectable virus, and what’s in the body doesn’t linger.

While there is no commercial test approved by the Food and Drug Administration to detect Zika infections, the agency has given emergency-use authorization for 10 tests to be used by health officials. But processing these tests takes time because they must be shipped to laboratories. In addition, there are concerns about accuracy — one test, developed by the federal Centers for Disease Control and Prevention, which looks for antibodies to the virus, has been plagued by false-positives. It often shows infection by the Zika virus when the culprit is really a closely related microorganism from the same family.

Tulane University virologist Robert Garry wants to streamline the process. He has been working for the last six months to develop a test that searches for the immune system’s reaction to the virus, rather than simply looking for it. He wants to create a test that can be used by all and can be processed within 20 minutes without using a lab.

The procedure Garry wants to develop will seek antibodies because they stay in the body longer, especially in urine.

“The virus goes away quickly, but the damage can be done,” said Garry, a professor of microbiology and immunology.

According to the CDC, Zika antibodies show up in the blood four to five days after the onset of illness and can last 12 weeks — or longer.

The Zika virus is most commonly spread by mosquitoes but can also be transmitted via blood, sexual contact and by mother to fetus.

The CDC has logged more than 2,900 cases in the United States and since July reported cases in Florida that were likely caused locally by mosquito bites. Nearly 16,000 cases have been reported in U.S. territories, primarily Puerto Rico.

Like other Zika-detection tests, Garry said the device he is working on would be similar to a pregnancy test. Blood or urine would be put on a plastic sheet or in a cassette that would show the results.

Results would be ready within 20 minutes without resorting to a lab, he said.

So far, results have been “promising,” Garry said, but he and his colleagues are still working to rule out what is known as cross-reactivity, in which the test reacts to a virus similar to the one that causes Zika.

Garry said he hopes to have a test ready in a few months and then apply for emergency-use authorization from the FDA.