Wanted: a swift and simple Zika test
If you have fever, rash, joint pain, headache and fatigue, it could be flu, dengue fever or chikungunya. Or it could be Zika virus. The trouble is it can take weeks to find out for sure. For pregnant women in particular, that can feel like an eternity.
The early symptoms of Zika fever are very similar to those caused by other viral infections. The fear, for someone like Jess Edwards and her family, is that Zika has been strongly linked to serious birth defects – including microcephaly.
Jess, her partner and her daughter have been suffering ‘flu-like symptoms’ which bear a worrying similarity to those associated with Zika. After a neighbour was diagnosed with the virus having returned from south America, the family began to worry.
Mosquitoes are a common sight in their neighbourhood, giving rise to concerns that they might bite the infected individual and then spread the virus to others.
“I was very stressed out this morning,” Jess told the Courier Mail newspaper in her native Australia. “I’m hoping that my pregnancy is far enough along and that nobody in the early stages of pregnancy gets it.”
Zika infection appears to be more dangerous to unborn babies if their mothers are infected in the first months of pregnancy.
Experts say the risk of contracting Zika outside Latin America remain low. For now, Jess and her partner Russell Barton have to play a waiting game.
“We’re very nervous…we’re just waiting on getting tests done,” said Russell. “We’ve actually had the flu the last couple of days so we’re very concerned.”
Need to know
Jess’s experience is replicated in every country where mosquitoes are present. In Latin America, fears of Zika infection are reaching fever pitch – especially among pregnant women.
In many parts of Brazil, Honduras and El Salvador, not all patients have easy access to good laboratory tests. And the number of suspected cases threatens to put severe pressure on existing labs.
One lab in Rio is using a smartphone app that combines results from a blood test with information about symptoms to calculate the chance that a patient has Zika, dengue or chikungunya.
While this may not be as accurate as the established test, it helps doctors to decide which patients need to have blood samples sent for more detailed lab analysis.
One of most worrying aspects of Zika for pregnant women is that some people infected with the virus have no symptoms at all. In fact, only around one in five people with Zika become ill. Others barely notice. A simple test could help to screen pregnant women even if they are not displaying classic Zika fever symptoms.
The race is on around the world to come up with a test that is both highly accurate and fast. A German company has unveiled a real-time Zika-specific test that can detect genetic material from the Zika virus. People with other similar diseases, such as dengue, will not test positive using this new system.
Meanwhile, researchers at hospitals in Texas say they have come up with a test that can pick up traces of Zika virus in blood, urine, spinal fluid and amniotic fluid. They say their system cuts the waiting time down from one month to less than one day.
Many other researchers are also working on tests that could help improve early diagnosis – giving pregnant women the answers they need.