A disease potentially harmful to dogs, leptospirosis is caused by a bacterium called
Leptospira interrogans. Omni-present in the environment because it’s borne by numerous
animals, including rats and skunks, raccoons, feral cats and domestic livestock, the
organism is carried in their kidneys and excreted through their urine. Dogs will often
contract the disease by swimming in stagnant water or by drinking from contaminated
puddles of water.
Known to exist as well in dampness and in mud, especially following heavy rainfalls, more
cases of leptospirosis are diagnosed during the late summer and fall, while winter tends to
lower the risk since the bacteria can’t tolerate freezing temperatures.
Although many infected dogs never exhibit any signs of illness, the disease is usually most
severe in unvaccinated puppies younger than 6 months of age, and takes between four and
twelve days following exposure for them to feel sick. While the symptoms may vary from
dog to dog, they usually include lethargy, poor appetite, fever, vomiting, and increased
thirst or urine production. Some dogs may also become jaundiced.
Veterinarians diagnose the disease by running blood tests (these will reveal changes in
kidney values or both kidney and liver values) and urine tests that look specifically for
leptospirosis. They then typically prescribe antibiotics to treat the active infection and
assist in keeping an infected dog from becoming a carrier of the organism.
Unfortunately, leptospirosis is also a zoonotic disease, which means it’s contagious to
humans. While the most common way for people to contract the disease is through
exposure to infected dog or rat urine, any contaminated bodily fluid, including vomit and
saliva, can be the culprit. If your own dog is ill with leptospirosis, it’s essential, then, to
observe such hygiene protocols as wearing protective gloves when cleaning up after him
and not allowing him to lick your face until he’s fully recovered.
Familiar with the old adage, “An ounce of prevention is worth a pound of cure”? Never
was it more applicable than when dealing with leptospirosis. Prevent your own dogs from
contracting the disease by eliminating their access to contaminated water, by keeping your
property free of food, and by using durable garbage containers to reduce attracting rats,
raccoons or feral cats to your area.
If you believe that your dog is at high risk of contracting the disease, you might consider
having him vaccinated for leptospirosis. The American Animal Hospital Association,
however, considers it a “non-core” vaccine, only recommending it if a dog is very likely to
be exposed to leptospirosis. Not only does its effectiveness vary from short term to longer
lasting, there have been reports of reactions to the vaccine that also vary -- from minor to
While a vaccination doesn’t always prevent the disease, it does make the disease much
milder should infection occur. There’s also the potential for vaccinated dogs infected with
leptospirosis to become long-term carriers of the disease, with some experiencing a more
frequent incidents of reproductive failures and stillbirths.
As with all matters concerning your cherished canine companion, discuss the vaccination
with your vet. Your decision should be based on your lifestyle, whether your community is
experiencing any cases of leptospirosis, as well as your vet’s own experiences – positive and
negative -- with dogs and the vaccine.