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Canine Leptospirosis-What You Need to Know

: Christie Roening, for TAP

Leptospirosis can be a serious, HIGHLY contagious, potentially lethal disease that could harm your beloved pup! San Diego is experiencing an outbreak of leptospirosis through doggie daycares, dog parks, and other dog hangouts. Read on for important information regarding causes, signs and treatment. 

Of course, you should ALWAYS CONSULT YOUR VET IMMEDIATELY if you suspect a lepto infection or want to know if the vaccine is right for your pet!

What is Leptospirosis?

Leptospirosis is an infectious disease caused by leptospira bacteria that can cause major damage to the kidneys and liver, and may be fatal. Leptospira is found in warm, moist soil, marshes, and stagnant water. The bacteria prefers warm climates with significant rainfall, although the bacteria can live anywhere. 

Leptospirosis is zoonotic, meaning transmission is possible from animals to humans. However, contracting an infection from an animal is uncommon, be aware that it has and can happen!

Causes of Infection

Dogs typically get leptospirosis through direct contact with another infected animal’s urine, such as from wildlife, rodents and other dogs. Open sores and cuts can increase the spread. 

Other risk factors include swimming in or drinking infected water or mud, eating a wild carcass with leptospira and a bite from an infected animal. 

Signs of Infection

Some dogs are asymptomatic or show mild signs when infected with leptospirosis. However, some dogs also develop serious symptoms that must be treated as soon as possible. The infection can develop rapidly and become fatal. Here are signs to look for with your pup:

  • Dehydration
  • Depression
  • Diarrhea
  • Excess fluid accumulation in abdomen
  • Extreme thirst
  • Eye inflammation
  • Fever
  • Jaundice (yellowing of skin and mucous membranes)
  • Lethargy
  • Nosebleeds
  • Swollen legs
  • Urination frequency changes
  • Vomiting

If you notice ANY of the above signs, contact your vet ASAP! Your vet will run diagnostic tests such as a physical exam, blood draws for blood counts, bacterial cultures, imaging, antibody tests, or other tests to determine an accurate diagnosis and infection level.

Treatment and Prevention


Leptospirosis can usually be treated effectively, when caught early enough. Antibiotics are the most common treatment and are administered in two phases. The first phase eliminates the acute infection (most serious). The second phase stamps out the low-grade infection, found in 

carrier dogs. Other treatments might also be implemented such as for dehydration and vomiting.

While treating your pup, it’s important to adhere to the following:

  • Administer all medications as directed by your vet
  • Avoid contact with your dog’s urine; if your dog urinates in the house, wear gloves and clean as soon as possible to prevent exposure
  • Lead your dog away from standing water or other areas where people and other dogs gather
  • Wash your hands and home surfaces frequently (this sounds familiar in 2020!)

Severe cases of kidney or liver damage may require hospitalization. Intravenous fluid treatment and other therapies may be needed urgently.


Keeping your distance from ALL people, ALL dogs, every, single body of standing water at all times is impossible and is not conducive for a happy, healthy, thriving dog. Vaccination can help prevent infection and relieve anxiety when out and about with your pup. Of course, even if vaccinated, avoid known areas where transmission has occurred.

Leptospirosis vaccines have been available since the 1970’s, though they are not commonly included with recurrent canine vaccines. The vaccine must be administered every 12 months. Many vets, especially in the San Diego area, are beginning to include the Leptospirosis vaccine as a common core shot, due to the increasing transmissions. 

Many strains of leptospirosis exist, therefore the vaccine is not 100% effective, though the most common strains are covered. Myths have been circulating for a few years about vaccinating against canine leptospirosis, that simply have no evidence to back the theories. As with any vaccination, there is a small risk of adverse reaction, but the pros largely outweigh the cons when your pup’s health is at stake! Check out AZVMA Leptospirosis Vaccine Myths for more information. 

Any dog breed, size and age can contract this vicious, easily transmissible disease. Education and close communication with your vet can help prevent or treat your furbaby quickly and efficiently. 


Leptospirosis, American Veterinary Medical Association

PetMD, Leptospirosis in Dogs

Today’s Veterinary Nurse – Leptospirosis in Dogs