Ticks and Lyme Disease

The blacklegged tick is the primary vector of Lyme disease in Ontario. This tick was first identified on a human in Ontario in 1904. They are widely distributed, having been found in over 600 locations throughout the province.

Blacklegged ticks feed on both birds and over 50 species of mammals, including mice, raccoons, rabbits, cats, dogs and humans. Ticks, like many parasites, have complex life cycles. From the egg, they pass through larval, nymphal and adult stages. They require a blood meal at each stage after they hatch from the egg. Their life cycle can be completed in 2 to 4 years depending on availability of hosts. Larval ticks are pin head in size while female adults are 2-3mm when unfed and up to 10mm when fully engorged. They are orangish brown in colour with dark legs, but when fully engorged with blood, are dark reddish brown.

Ticks are not very mobile and will wait for hosts as they pass by. They do this by climbing up grass and shrubs along trails frequented by animals and climbing on as the animals pass by. They will also be found in the nest of small animals and birds. Birds can carry both immature ticks and the bacteria which causes Lyme disease. Migrating birds are able to carry both over long distances. When ticks bite, they anaesthetize the area so that the host does not feel the bite. Their mouth parts have backwards pointing barbs which makes them difficult to remove once inserted.

Lyme disease was named after the town of Lyme, Connecticut where it was first identified. It is a bacterial disease that can infect humans, wildlife and domestic animals. There have been over 294 cases reported in Ontario. It is the most commonly reported insect-borne illness in North America. Lyme disease has a variety of symptoms which can make it hard to identify. Early symptoms may occur after 3-30 days. A common sign is a ‘bulls-eye’ like rash around the site of the bite. Some of the more serious late stage symptoms include arthritic, cardiac and neurological conditions. When caught in the early stages, Lyme disease is curable, therefore, it is important to take any tick bite seriously.

Prevention of tick bites is similar to mosquito bite prevention. Wear loose fitting, long- sleeved shirts and long pants. Tuck pant legs into socks. Light coloured clothing will make the dark ticks easier to spot. Use a good repellent such as a DEET based product on exposed skin and/or clothing. If you do outdoor activities, try to check if ticks and Lyme disease are known to occur in that area. Following hikes, do a tick check of your skin and clothing. Preferred areas are folds of skin, the back of the neck, armpits and groin. Check pets carefully if they are in tick infested areas. Wash clothing or put them through the clothes dryer. It is recommended that you have your doctor remove a biting tick. If you try it yourself, use fine-pointed tweezers and grasp the tick as close to the skin as possible and pull straight back. Do not twist or squeeze the ticks’ body as this may inject body fluids into the wound. Apply an antiseptic to the bite area after. Watch for symptoms for 2 to 4 weeks after.

There are numerous sources of information on ticks and Lyme disease. The Lyme Disease Association of Ontario is located in Fergus and has very good and helpful information. You can find them on line or call [519] 843-3646.