A new Western University test for the Zika virus isn’t coming a moment too soon for Southwestern Ontario, after the mosquito breed known to carry the disease turned up in Windsor.
An adult Aedes aegypti mosquito was trapped by Windsor public health officials last week — the first sighting of the tropical bug in Canada. The agency would not reveal the exact location of the mosquito trap, but said the insect tested negative for Zika and the West Nile virus.
The surprise sighting comes as London researchers are trying out a new diagnostic tool for the mosquito-borne Zika, which is especially risky for pregnant women and their unborn babies.
Western researchers are eyeing a saliva test that could help doctors worldwide test for the disease long after patients are bitten.
Instead of blood and urine testing, which looks for the virus’s genetic material, Western University researcher Walter Siqueira and study co-author Eric Aarts developed a tool to search for Zika virus proteins instead.
“Our method is different because we’re not interested in looking for the RNA of the virus but the peptides of the virus,” said Siqueira, a dental clinician-scientist and associate professor at Western’s Schulich School of Medicine & Dentistry.
“Proteins and peptides are more stable. They survive for a long time compared to RNA or DNA.”
It turns out that protein principle is paying off.
Siqueira’s screening tool can pinpoint Zika infections for up to nine months after the patient is exposed to the virus and renders results in just 2.5 hours. The common blood test for Zika genes, used by many agencies including the U.S. Centers for Disease Control, renders results in 48 to 72 hours and can only detect the virus up to one week after exposure.
“With our technology, this window of detection increases,” he said, “it’s faster and more reliable.”
Siqueira, who’s originally from Brazil himself, collected more than 100 saliva samples from Zika-infected people at a satellite lab in the South American country and sent them back to Western University for testing.
Now that they’ve isolated and identified Zika proteins, researchers want to develop a simple test that doctors around the world can use. They’ve secured a provisional U.S. patent to develop a portable machine that can test for the virus proteins outside the lab in 30 minutes or less.
“We are trying to make this as small as possible and as fast as possible for the person to get the results,” said Siqueira.
The team will be working with microbiology and engineering partners at Western to develop a prototype by year’s end.
Though the potential for a Zika virus testing device is an exciting development, researchers uncovered other important features of the disease in their study.
As part of the report, published online Tuesday in the Journal of Dental Research, Siqueira studied a Zika-infected mother with twins, one of which was born with microcephaly — a birth defect where a baby’s head is smaller than usual, often resulting in brain damage. Researchers found the structure of the Zika virus proteins in the mother and normal baby were different than the microcephallic twin.
“This amino acid chain that is very small might cause the microcephaly,” said Siqueira, adding more research is needed to prove the theory.
“We’ve identified the fingerprint of the disease using saliva. . . . Every day we’re learning new things in this area that are very fascinating.”