Leptospirosis is a bacterial disease that has been making headlines recently because of outbreaks in several cities in New York and New Jersey. The bacteria are transmitted through contact with water or damp soil that has been contaminated with urine from wildlife including rodents such as rats and mice. Symptoms of the infection include fever, muscle and joint pain, vomiting, jaundice, increased thirst, and diarrhea. Of greatest concern is that leptospirosis can affect both animals and people and it can be fatal if not treated promptly.

There are many different strains of leptospirosis, with some strains posing more of a risk to larger animals such as cattle than dogs. There is a vaccine for the four most common strains that are known to affect dogs. While the vaccine has historically mainly been recommended for dogs in more rural areas, the recent urban outbreaks show that all dogs are potentially at risk.