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Deadly Leptospirosis in Dogs: What You Need to Know to Protect Your Dog

Reviewed by Dr. Sarah Tasse, DVM on Tuesday, February 17, 2015
Posted February 19, 2015 in Dog Diseases & Conditions A-Z

Dog drinking for a muddy puddle

What is leptospirosis?
Leptospirosis is an infectious disease that can affect many animals including wildlife, rodents, dogs and people. The disease is caused not just by one specific strain of Leptospira spp. but rather by any of a number of different serovars (types) within this bacterial genus. They exist everywhere in the world but are most commonly prevalent during periods of heavy rainfall1.

How does leptospirosis spread?
Your dog can contract the organism through direct contact with another infected animal, by eating infected meat or most commonly through contact with anything that has been contaminated by the urine of an infected animal. Most infections occur when dogs go swimming in and/or drink infected water, but in reality most anything (plants, dirt, objects or water) can be a potential source of infection2.  

Additionally, it is important to note that once they are infected, wild animals can serve as reservoirs and may continue to excrete the bacteria into the environment for months or even years, which may then live in the environment for weeks to months1.

According to the CDC, people can contract leptospirosis in the same ways your dog can, through contact with urine or other body fluids (except saliva) from an infected animal or by contact with other contaminated sources. Person to person transmission is apparently rare.

What are the symptoms of leptospirosis infection in dogs?
Unfortunately, leptospirosis infections may present with any of a number of rather vague, non-specific symptoms that can vary in intensity. Some of these may include the following2:

How is leptospirosis diagnosed in dogs?
In order to arrive at a diagnosis of leptospirosis, your veterinarian will consider your dog’s leptospirosis vaccination status, information from your dog’s history, the likelihood of exposure, clinical symptoms and physical examination findings along with some routine and other more specialized blood tests. These specialized tests may include serology tests, which detect antibodies against the organism, or real-time PCR tests, which may detect the actual organism in a blood and/or urine sample. Treatment is often started before all of the specialized test results are back due the potential severity of this disease and the increased risk of infection to people (veterinary staff and pet owners alike) exposed to the dog.

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Mike has more than 35 years of experience in companion animal veterinary practice and is a valued member of IDEXX’s Pet Health Network team since 2013.