Ticks and Lyme disease

Would you want to know if your family and your dog had been exposed to something that could cause all of you harm? Of course you would!

Approximately 5 years ago, veterinarians began to realize that there was an emerging animal health issue in Ontario. This was the arrival of more and more ticks along the southern border of the province. These ticks have been carried into Ontario by migrating birds, setting up some permanent populations in the southeast and southwest areas of the province, but their ability to ride with birds means that they can temporarily be dropped in any area of the province, including your backyard, cottage area or in Toronto’s ravines.

In addition to being bothersome and ugly, ticks also have the capacity to carry a number of diseases; the best known of these is Lyme Disease, which may be transmitted by the bite of a tick. Lyme disease is caused by a bacterium named Borrelia burgdorferi. Once in the blood stream, the Lyme disease organism is carried to many parts of the body and is likely to localize in joints. It was first thought that only a few types of ticks could transmit this disease, but now it appears that several common species may be involved.

For the past several years, we have been recommending routine blood screening of all our canine patients for Lyme (along with two other tick-borne illnesses) while doing heartworm blood screening. This strategy has two important purposes as we try to identify dogs exposed to the Lyme bacterium:

(a)    Any dog positive for exposure to Lyme can then be tested further to establish whether there is the possibility that this exposure may cause them harm. Each year since we have started this protocol, we have found dogs that required antibiotic treatment, including two already in 2014. Both were dogs who have not left the GTA. One owner was aware of a tick pulled off the dog last summer, the second had not seen any ticks.

(b)   All of the dogs positive for exposure to Lyme were likely accompanied in the outdoors by one or more members of their family. These people walking in tick areas may have also unknowingly been bitten by a tick, as some of the immature forms of ticks can be very tiny. Lyme disease in people can be a very serious, debilitating illness; unfortunately it is also a health issue not easily identified by our medical doctors at this time. Therefore, we can use our canine patients as “sentinels” to warn family members and their friends to exposure.

We believe that veterinarians have a role in public health, just as we participate in food safety, public health education and parasite control. Our commitment to Lyme Disease screening and tick control for our patients is one of the pieces of this puzzle.