It is important veterinarians be aware of the increased incidence and various clinical syndromes caused by the various serovars of Leptospira. However, the statements that dog to human transmission of leptospirosis is rare should be qualified somewhat. Before the widespread use of canine leptospiral vaccines in the United States, dogs were a common source of exposure of humans to this agent.
Leptopspiral vaccines are still in wide use in dogs in the United States.
However, the vaccines do not provide absolute protection from infection and shedding of the organism. There are reports in the literature of humans acquiring leptospirosis from vaccinated dogs. Rodents are not thought to be important carriers of these serovars. As regards the posting on leptospirosis in dogs in Massachusetts, I believe it is very important to emphasize several points. For over a year, I have not been able to obtain vaccine with leptospirosis coverage.