THUNDER BAY - A Thunder Bay entomologist says Canadians will increasingly need to take precautions against mosquito bites that have the potential to transmit disease.
Ken Deacon, coordinator of the vector-borne disease unit at the Thunder Bay District Health Unit, says he expects that, eventually, one type of mosquito that can carry the dreaded Zika virus will show up in northwestern Ontario.
Zika virus was discovered in 1947 in Uganda. According to Public Health Ontario, it is closely related to other mosquito-borne viruses such as dengue and West Nile virus. The agency says there is growing evidence that Zika virus infection can also be sexually transmitted.
The Asian tiger (Aedes albopictus) mosquito species, which is a known Zika carrier, has already turned up in small numbers in Minnesota and Wisconsin.
Deacon told Tbnewswatch that climate change is making it easier for mosquitos not native to this part of North America to survive the winter and expand their range. The Aedes albopictus, he said, "is so close that I assume that it's only a matter of time."
He noted that while the Zika virus itself might not make it through a cold winter, "If a tourist came in with an active case of Zika, it could be transferred to the mosquitos and we could have periodic outbreaks of the problem." Travel to Zika-prone areas of the world could create a new source every year, Deacon said, and the mosquitos could spread the disease "to the unwary."
The district health this summer has resumed its mosquito-trapping program for the West Nile virus. Mosquitos are sent to a southern Ontario lab for analysis, which also enables scientists to track the arrival of new species.
Deacon noted that the Asian rock pool species (Ochlerotatus japonicus), a potential carrier of West Nile, has arrived in Thunder Bay, albeit in low numbers. It is capable of transmitting West Nile.
"It's a daytime flier. It's very aggressive. It seems to be one of those unbelievable mosquitos that can carry almost anything. This is bad news," he said.
Stretches of wet, cool weather in Thunder Bay this spring were ideal for mosquitos, so the number of bugs caught in the first couple of weeks of the current trapping program was four times as many as last year at the same time.
Some dead birds from the area tested positive for West Nile a number of years ago, but mosquitos carrying the virus have yet to be found.
Deacon said "We know that West Nile is out there, and some mosquitos have it, but we also know that the extent of the disease in the mosquito population is pretty low."
Only two people have tested positive for West Nile in the Thunder Bay area since testing began.
However, any major increase in mosquitos that transmit disease will be "a red flag," Deacon said.
"New diseases are emerging from the south. It's time we used a little common sense and realize you have to protect yourself from tick bites and mosquito bites."
