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What is leptospirosis?

  • Leptospirosis is a disease caused by a bacterium (genus Leptospira) that can adversely affect your dog and be transmitted to humans.
  • Wildlife, including raccoons, skunks, foxes, and rodents (mice, rats, moles), carry these bacteria that are shed in their urine.
  • Dogs can become infected by coming in contact with the urine from wildlife or contaminated water or soil.
  • The disease can rapidly become life-threatening to dogs, targeting kidneys, liver, blood vessels, but also lungs and heart.


2021 has been a particularly warm and wet year, an ideal environment for leptospirosis bacteria to thrive. Also, this has been a great acorn year, so all the wildlife are about stocking up for winter and moving through backyards. This is the reason we see an increase in cases in the fall and early winter.

Current situation

Tufts University Cummings School of Medicine is seeing a marked increase of severe leptospirosis cases this year. Many of the cases have multiple organ involvement requiring intensive care and treatment (e.g. dialysis).

How can you protect your dog?

  • All dogs are considered at risk in our area.
  • The leptospirosis vaccination can prevent disease and will protect your dog from severe illness.
  • Make sure your dog has a current leptospirosis vaccine (two initial doses 2 weeks apart, with a booster once a year thereafter).

Please contact your primary care veterinarian for further recommendations and assistance.