Since late 2004, more than 50 cases of leptospirosis in dogs have been reported, mostly from western Washington. Historically, serological data from the Washington Animal Disease Diagnostic Laboratory shows that in Washington, canine exposure to leptospires is not uncommon, and there seem to be more test submissions with high titer results than usual in recent months. This may be due to climate changes, unusually wet weather, low vaccination rates, increased reporting, or some combination of these factors.

Should I recommend canine leptospirosis vaccination to my clients?

Yes. The Washington State University Veterinary Teaching Hospital recommends the four-way subunit vaccine with icterhemorrhagica, canicola, pomona and grippotyphosa for dogs at risk for exposure (http://www.vetmed.wsu.edu/depts-vth/vaccinations.asp). The American Animal Hospital Association also recommends this vaccine for dogs who may become exposed: http://www.aahanet.org/About_aaha/About_Guidelines_Canine06.html

Are canine lepto vaccines likely to cause adverse vaccine reactions?

There is no evidence that vaccines against lepto are more likely to cause adverse reactions than any other routine canine vaccine. A recent publication (Moore et al. JAVMA 2005;227:1102-1108) reported on data from 3,439,576 vaccine doses given to dogs. The lepto vaccine in combination with DAPP had an adverse reaction rate of 28.8/10,000, or less than 0.3%. This was no different than the rabies or coronavirus vaccines.

Do the serovars in the four-way vaccine protect against the serovars that are infecting dogs in Washington now?

Many leptospira serovars cross-react with each other in the serological test, so we are not certain which serovars are important in the recent canine infections in Washington state. In the context of multiple reported clinical cases, and because of the potential zoonotic risk associated with leptospirosis, all dogs who go outdoors frequently should be vaccinated against leptospirosis.