Why University of Calgary scientists are infecting sandflies with deadly parasites
Medical team hopes findings will lead to vaccine for deadly disease
University of Calgary scientists are ready to start infecting a couple thousand sandflies with a deadly parasite.
The medical research team is trying to understand more about how flying insects spread disease — in particular, leishmaniasis, which can cause fatal illness in humans. Symptoms range from a skin rash to organ failure.
In the past, researchers thought they had created a vaccine to the disease, that worked in tests where scientists injected the disease using a needle.
But when testing the vaccine on an infection from a sandfly bite, it didn't work, scientist and lead researcher Nathan Peters told CBC Calgary on Tuesday.
"We've come to realize that the sandfly is not just a flying syringe — or the mosquito or the tick is not just a flying syringe that happens to deposit the bacteria or parasite into the skin," Peters said.
"It's really changing the dynamics and the immune response in the skin to the point where a vaccine may look promising but when we use the natural model, it actually doesn't work at all."
The World Health Organization estimates up to 30,000 people die each year from the disease. About one million become infected, sometimes left with disfiguring scars.
On Tuesday, the medical team showed its special lab to journalists — before starting the tests on the insects.
It's about "the size of a generous en suite bathroom" and you need to pass through two interlocking doors with a pass card in order to enter, said Peters, who is an associate professor with U of C's Cumming School of Medicine.
The insectary, as it's known, is considered to be high containment and the first of its kind. It cost between $230,000 and $240,000, Peters said.
The sandflies are locked inside a box, which is then contained by an incubator. The lab has an HVAC system to maintain negative air pressure, and a variety of other measures are in place to ensure no flies escape to contaminate Calgary, he said.
The team expects to continue working for years to come. One of the questions will be how the disease interacts with other elements the fly injects into a mammal during a bite. For example, its fluids contain a substance that stops blood from clotting so they can suck it up for a meal.
"Of course, ideally we want to develop vaccines and improve drug therapies for the disease," said post-doctoral student Matheus Carneiro, who is from Brazil, where leishmaniasis is a major public health concern.
"But I do believe there are lots of gaps on understanding how the transmission happens and how the immune system responds against infection."
The team also employs post-doctoral fellow Chukwunonso Nzelu, who is an expert on sandfly colonies.
Leishmaniasis primarily affects people in Central and South America, as well as the Mediterranean, where sandflies live. However, the researchers say infectious disease specialists in Calgary each year treat a few patients who become infected while on vacation.
With files from the Calgary Eyeopener and Radio-Canada.
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