They’re “sneakier” than mosquitos, and undeterred by a bit of cool, pre-winter weather. When it comes to ticks, public health officials are advising hunters, hikers and other outdoorsy types who like to tromp around in the bush during fall to stay alert. Ticks are not just a summer concern. “If you think you don’t have to worry about them because there’s a bit of snow on the ground, you’re wrong,” Thunder Bay District Health Unit entomologist Ken Deacon said on Wednesday. Ticks, including the black-legged variety that can carry and transmit Lyme disease, don’t usually become dormant until temperatures have been below 4 C for a sustained period, Deacon said. According to Environment Canada, the mercury is set to reach 7 C in Thunder Bay by early next week — about four degrees above normal for this time of year. Lyme disease can harm both the central nervous and cardiovascular systems, as well as cause joint paint. There is no vaccine, but symptoms can be effectively treated with antibiotic drugs if they’re caught early enough, health officials say. Though the Thunder Bay region is not known for being a “high-density” area for black-legged ticks, more than 30 per cent of those that are in the area are infected with Lyme disease, the health unit says. Deacon said the “horrible reality” is that the percentage that are infected could climb as a result of climate change. Currently, black-legged ticks are present in both Thunder Bay and in rural areas just outside the city. “I found one on the ear of my cat last year,” Deacon said. The health unit’s surveillance program has found Thunder Bay’s Rabbit Mountain hiking area to contain a particularly high amount of ticks. The majority found in the Thunder Bay district are wood ticks that don’t carry Lyme bacteria. Some may find it reassuring to know that “if a black-legged tick is carrying the Lyme-causing bacteria and is removed quickly from the body, it is very unlikely it has transmitted Lyme disease to the host,” a health unit backgrounder said. “They have to be embedded and have been feeding (on a person’s skin) for 24 hours,” Deacon said. He added: “You hardly ever feel them — they’re sneakier than a mosquito.” The health unit can positively identify a black-legged tick, but it doesn’t test the insects for the presence of Lyme disease. Ticks can be brought to the health unit in a zipped, plastic bag.