August 22, 2013

Ticks & Lyme Disease

Lyme Disease is an infectious, tick-bourne disease that is caused by the Borrelia burgdorferi bacterium. The disease is tranmitted when an infect tick takes a blood meal from a host, injecting infected material into the host in the process. Symptoms of Lyme Disease include a characteristic bulls-eye rash (erythema migrans), fever, chills, fatigue, joint pain, and headache. Not all symptoms are necessarily present.

Ticks are eight-legged arachnids (relatives of spiders) who require a blood meal to reproduce. There several types of tick found in Nova Scotia. Only the Black-legged Tick (sometimes called the Deer Tick) carries the Borrelia burgdorferi bacteria that causes Lyme Disease, and not all Black-legged Ticks are infected. The Wood Tick (sometimes called the Dog Tick) does not carry the bacteria that causes Lyme Disease. The image to the right is of a Wood Tick removed from a patient earlier this month. Note the hypostome, or straw-like mouth part, between the mandibles that is used to draw blood from a host.

The number of ticks in Nova Scotia, and the number of (human) cases of Lyme Disease reported to Nova Scotia Health and Wellness have been increasing. NS Health and Wellness published a report April 2012 which shows the increase in reported cases and the endemic areas where Lyme Disease is known to be established. Only data from human cases are included in the report.
Reported human cases of Lyme Disease in Nova Scotia, 2002 - 2011. A report on Lyme Disease Epidemiology and Surveillance in Nova Scotia, April 2012.
Lyme Disease Endemic Areas in Nova Scotia where Lyme Disease is known to be established.

Prevention Tips

You can help decrease the the risk of Lyme Disease for both you and your pets by taking a few precautions:

1. Avoid long grass and scrubby areas. Ticks can not jump or fly. Instead, they will perch on the ends of twigs or leaves with their forelegs raised, waiting for an animal to brush past. They will then grab hold of the animal and climb aboard. This is known as questing.
2. Check you and your pets for ticks after going outside. Ticks will not necessarily bite as soon as they land on an unsuspecting animal: they like to search for the perfect spot to dine.
3. Remove ticks as soon as you find them. It takes ticks some time to establish the "pump system" they use to draw blood once they do bite. Most sources agree that the risk of infection is lower during the first 24 hours after a tick has bitten. Left undisturbed, ticks will feed for days, becoming engorged with blood, before falling off the host.
4. Use forceps or tweezers to remove the tick. Grasps the tick with the forceps or tweezers as close to the skin as you can. Make sure you are holding the tick by the head and not the body; the head can detach from the body if the tick is grasped too far back. Pull the tick out without twisting. Try to pull the tick backwards, in the opposite direction that the tick's hypostome (the straw-like mouth part) enters the skin, to ensure that none of the tick breaks off and remains under the skin. Forked ticks "twisters" are also good tools to remove ticks. These tools have a slot cut in them that fits around the tick's head. Check the make sure that none of the tick remains in the bite. You can clean the bit will warm water and gentle antiseptic soap once the tick is removed.
5. Do not burn or smother the tick to remove it. Distressed ticks may regurgitate into the host, injecting infected material.
6. Consider a tick prevention product. Some flea and worm products will also kill ticks. Most of these products are administered monthly. Be sure to read the label carefully before using a product. Many tick (and flea) products for dogs contain permethrin, which is toxic to cats. It is safest not to use a permethrin based product on your dog if you also have a cat in your household.
7. Consider Lyme disease vaccination. There are canine vaccinations for Lyme Disease. As the vaccination is not as effective as the regular vaccinations (rabies, leptospirosis, distemper-adenovirus-parvovirus-parainfluenza, and bordetella) that most dogs receive, it is not given to most dogs. However, if you dog is frequently coming home with ticks and you like in a high risk area for Lyme Disease, vaccination could provide your dog with some extra protection.

More Tick and Lyme Disease Reading

Lifelearn article on our website: Lyme Disease in Dogs
Public Health Agency of Canada: Lyme Disease Frequently Asked Questions
Nova Scotia Health and Wellness: Communicable Disease Prevention and Control
Center for Disease Control and Prevention: Lyme Disease
Pet Health Network: Lyme Disease in Dogs
Canine Vector-Bourne Disease: Tick-Bourne Disease

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