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Testing positive for Zika

Carla BleikerJanuary 30, 2016

For pregnant women especially, the question of whether they caught the Zika virus is of high importance. Thanks to German researchers, getting a definitive answer is now possible for the first time.

Testkit by German biotech company Genekam. (Photo: Genekam)
Image: Genekam Biotechnology AG

Only one in five people infected with the Zika virus will get sick. That's a blessing and a curse at the same time, especially for pregnant women or those who plan on getting pregnant in the near future. They have to wonder whether their bodies could be affected by the virus.

Biotechnology company Genekam from the western German town of Duisburg has come up with a solution to this problem. Researchers there have developed a test that reveals whether there are Zika pathogens in a blood sample, and how many.

The test works in real time, which means it brings quick results, and is the first of its kind for Zika. Until now, patients could not be diagnosed until or unless they developed symptoms.

"Our test examines DNA and works with chemicals that react to the Zika virus only," Sudhir Bhartia, one of the test's co-developers, told DW. "Similar pathogens like Dengue fever won't show up in the results."

The first delivery of kits is already on its way to Brazil. Usually, tests like these have to go through a long testing phase themselves before they're authorized. But because the virus is spreading through South America so quickly, authorities have made an exception.

Infografik Die Ausbreitung des Zika-Virus Englisch

A general practitioner, however, will not be able to use the kit to examine patients.

"The test must only be used by qualified personnel so that mistakes can be avoided," Bhartia, a virologist, stressed.

That's why the mini labs are only sent to institutes and laboratories with sufficient know-how and the right equipment. At least the costs are low. They amount to roughly 5 euros each time the test is used.

For tourists returning home after a vacation in South America, there's another, simpler way to find out as well: wait. Of course, that takes longer.

"If you show no symptoms three weeks after you return, they're not going to manifest anymore," Christian Drosten from the Society for Virology told DW. "And two weeks after that, the virus will no longer be present in your body."

Direct link between Zika and microcephaly not proven

But what if you do get sick? For healthy adults, the virus is usually not dangerous. It'll come with fever, joint pains and a rash. But in Brazil, Zika has now been linked to microcephaly, a severe birth defect. Children who have the disease are born with smaller heads than healthy babies, which can cause brain damage. There are currently roughly 4,000 suspected cases of microcephaly in Brazil.

Experts are saying it's highly likely that the virus and the birth defect are connected, but that the link has not yet been proven.

"There are still too many aspects we don't understand about the Zika virus to say it directly causes microcephaly," Drosten cautions.

A transmission electron micrograph (TEM) shows the Zika virus. (Photo: Reuters/CDC/Cynthia Goldsmith)
The much talked about virus up closeImage: Reuters/CDC/Cynthia Goldsmith

He believes that birth defects would be more likely to occur in a baby whose mother had rubella than in a baby whose mother had been infected with the Zika virus during pregnancy.

A difficult ethical question

So far, the Brazilian health ministry has investigated more than 700 suspected cases of microcephaly. Of those, only 270 babies were diagnosed with microcephaly. In 462 cases, it was ruled out. And experts were able to find a Zika infection in fewer than 10 of the microcephaly cases.

"I think it's possible that there's only a very loose correlation between the Zika virus and microcephaly," Drosten said.

There are no studies yet on how high the likelihood is that an infected mother passes the virus on to her unborn child. Still, Drosden can understand the concerns of those women who caught the Zika virus in South America and are pregnant now.

"The health risk may not be big, but these women have a tough time psychologically and are burdened with ethical concerns," the virologist said.

After considering all the facts, one of the last options is to terminate the pregnancy. But whether the unborn child of a mother infected with the Zika virus is actually suffering from microcephaly cannot be determined at such an early stage - the baby's final head circumference can only be measured at a late point in the pregnancy.

In other words, the woman would have to make a decision on whether to abort without knowing if she had passed on the virus to her unborn child and without knowing if the child would indeed develop microcephaly.