We have had our first positive case of leptospirosis at the Dartmouth Veterinary Hospital in the fall of 2006. There have been a handful of cases in the metro area and more in outlying areas in the Annapolis Valley and Truro. Outbreaks in New Brunswick started a few years earlier and it is more established there.

Leptospirosis is a bacterial infection caused by an organism called a spirochete. It is a disease found in wildlife, livestock and domestic animals. There are many different strains or serovars of leptospirosis, and it is not the traditional ones that are tending to cause problems now. Raccoons are one of the main vectors for many of the serovars, while mice, rats, voles and skunks can be involved with others. With expanding urban centers and encroachment on wildlife habitat, this has become a disease of urban and suburban areas, rather than rural.

Prior to 2000, leptospirosis was not considered a problem in Canada, but since then there have been significant out breaks in Ontario, Quebec, British Columbia and New Brunswick. The disease is largely picked up by ingestion of contaminated water. Two main factors have lead to the increase in the disease: 1) warmer summer and falls with increased moisture is a huge factor and 2) increase in wildlife around suburban areas. In parts of suburban Toronto, it is estimated that there are 100 raccoons per square kilometer. The disease can be seen throughout the year, but peak incidence is always in the late summer and into the fall up until frost. The number of positive cases in Ontario went from 11 in 1998 to 267 in 2004, the last year figures are available for. Closer to home we know of four lepto cases in HRM and one in Truro. Larger, active breeds are six times more likely to contract the disease.

The disease tends to affect the kidneys and liver, and animals are often presented with blood in the urine and acute kidney failure. Other animals may show no urinary signs but present in liver failure. It is an extremely serious disease once signs develop, and is also a zoonotic disease, one that can spread to humans. Some older dogs are now being seen in Ontario with kidney disease, and a positive lepto test, showing that they lived through an undiagnosed bout with leptospirosis.

The new leptospirosis vaccines protect against four of the major serovars. Older vaccines used the whole bacteria in their production, which had the potential of more vaccine reactions from the foreign proteins. The new vaccines are what are called sub unit vaccines that greatly reduce risk of vaccine reactions. Animals require two vaccinations, 2-3 weeks apart, and then an annual vaccination. There have been over three million dogs vaccinated against lepto in Canada, and it has been proven to provide protection, although not all serovars are covered. Animals that spend time in the woods or in areas frequented by wildlife are those at the greatest risk.