The little ticks that carry Lyme disease are becoming more common in Eastern Ontario, a national expert says, and they’re already emerging this year.



Of the 40 or so tick species in Canada, the ones that worry most people, are called deer ticks. These transmit Lyme disease when they bite animals and humans. Though named for deer, they may be more common as parasites on mice and other rodents.



When Wayne Knee was an undergraduate early in this century, he recalls that the accepted view was that “deer ticks were virtually unheard-of in Canada.” But since then they have spread through this region, and even farther north.



Knee is a scientist at the Canadian National Collection of Insects, Arachnids and Nematodes at Agriculture Canada. His job includes identifying ticks sent to him from across the country.



Although it’s cold this week, “it got warm pretty early,” and that likely brought the ticks out, he said.



There is no official monitoring system for tick numbers in Canada.



“But we do see this change in diversity (of tick species) and abundance,” he said. There are ups and downs from year to year, “but the overall trend over time is an increase.”



He believes a general warming in the climate, especially in winters, has allowed the ticks to survive.



They over-winter either as adults or “nymphs” (immature ticks). Either can transmit infection by biting, “but the highest incidence of transmission is from the nymphs because they are so hard to see. They’re smaller than a sesame seed.”



Ticks commonly attach to the legs of people who walk through tall grass. But from there they often crawl upwards over a period of hours, looking for a spot to anchor before they begin feeding. Common areas include under the arms, behind the ears, and at the hairline at the back of the head, Knee said.



The tick takes a number of hours to attach itself.



“It takes 12 to 24 hours of a tick feeding for transmission to happen,” he said.



Knee says the best defence if bitten (as he has been a number of times) is to remove the tick carefully, with the finest, sharpest tweezers you can find.



“You get right down deep, as close to the skin as possible, and you pull tightly and firmly back. No twisting.” It’s important not to snap off part off the tick and leave the mouth parts in the skin.



He recommends against using chemicals on the tick to kill it, because they’re usually tough enough to survive this approach.



Lyme disease in humans causes a variety of symptoms that can vary from person to person, but may include liver disease and facial palsy.



twitter.com/TomSpears1