The latest newsletter from the University of Guelph‘s Animal Health Laboratory contains a brief update on the percentage of positive MAT tests for canine leptospirosis that the lab has seen in the first half of 2009.  Approximately 30% of the tests have been positive, which is up from the previous two years.  However, the prime time for lepto cases (and therefore typically also lepto testing) is just starting: the cool damp fall weather provides a great environment for lepto bacteria to survive outdoors for the next several weeks.

Prevention of lepto in dogs, as with most diseases, is preferred to trying to treat sick animals.  The best way to avoid the bacterium is to keep your dog out of areas where infected wildlife may urinate frequently, particularly out in the bush.  But of course, skunks and raccoons can be found as close as the backyard as well, so even in the city the risk isn’t zero.

If your dog does frequently go into the bush and is at increased risk for leptospirosis, hopefully you’ve already discussed vaccination with your veterinarian.  While the vaccine available doesn’t protect against all types of lepto, it does help protect against the most common ones – in Ontario, these are believed to be the lepto serovars grippotyphosa and pomona.  We also received the following question from a reader the other day:

"Should a dog who has shown positive for early stages of kidney disease be vaccinated against leptospirosis?  Can the vaccine accelerate the illness to acute renal failure?"

I can see where the question comes from, but the simple answer to the second part of the question is no.  Although the infection can certainly affect the animal’s renal function (and can push even healthy dogs into renal failure if it is severe), the vaccine works on the dog’s immune system and does not affect the kidneys directly.  The answer to the first part of the question is, of course, much more complicated, and depends on many other factors including the dog’s overall health status, lifestyle and other risk factors, and vaccination history.  The decision about whether or not to vaccinate your dog should be discussed on an individual basis with your veterinarian.

More information about leptospirosis is available on the Worms & Germs Resources page and in our archives.

Image: Scanning electron micrograph of Leptospira sp. bacteria (source: CDC Public Health Image Library ID#138))