New Horizons Veterinary Behavior Solutions

300 Somonauk St.
Park Forest, IL 60466



The disease, Its Risk to Dogs and Humans, and Vaccination
Click here for VIN's Veterinary Partner Handout on Leptospirosis
Click here for a news article on How to Avoid Lepto in your Dog
Listen to the AVMA's Leptospirosis Podcast 

Pet Owner Info on Leptospirosis from the Worms & Germs Blog


What is Leptospirosis?

Leptospirosis is a disease caused by a spiral shaped bacteria.  The disease can affect both humans and animals.  In humans, the symptoms of Leptospirosis can be flu-like, but more severe life-threatening illness can develop if infections involve the liver, kidneys, brain, lungs, or heart.  In dogs, the signs can range from no symptoms, to increased water drinking and urination, fever, vomiting, abdominal pain, diarrhea, poor appetite, weakness, stiff painful muscles, and depression.  In many cases, life threatening liver and/or kidney failure can develop.  If diagnosed early, and treated with appropriate antibiotic and supportive therapies, some dogs may recover from the illness. However, even with treatment, permanent loss of kidney and liver function may persist.  Leptospirosis is not a common disease in dogs, but the number of cases appears to be on the rise.  We typically see several cases each year at Deer Run Animal Hospital.  Fortunately, Leptospirosis is extremely rare in cats. 


How do People and animals get infected?

The Leptospira bacteria are spread through the urine of infected wild and domestic animals.  The bacteria are shed into water and soil, and can survive there for weeks to months.  The Leptospira bacteria enter the body through skin or mucous membranes (eyes, nose, mouth), especially if the skin is broken from a cut or scratch.  Drinking contaminated water can also cause infection.  Once infected, animals may continue to excrete the bacteria through urine into the environment for a few months to years.  Dogs usually become infected by drinking, swimming, or walking through contaminated water.  Suburban expansion, and development into rural areas, has increased pet exposure to potentially infected wildlife such as raccoons, skunks, squirrels, opossums, rodents, or deer. 


Is there a vaccine for Leptosporosis, and how effective is it?

Yes, there are several vaccines for Leptospirosis.  There are many subtypes of Leptospira bacteria, also called serovars.   There are at least 7 subtypes that can infect dogs. The four most common disease causing subtypes are in the 4 Serovar, or 4-Way Leptospirosis vaccine that we recommend at Deer Run Animal Hospital.  The 4-Way vaccine is strongly recommended over other Lepto vaccines that only cover two of the subtypes.  Protection is never 100% for any vaccine, but the 4-Way vaccine offers the best and broadest protection available for this life threatening, and zoonotic (contagious to humans) disease.  


Are there any risks to Leptospirosis vaccines?

Yes, all vaccines, including standard Rabies and Distemper vaccines, carry some risk along with their benefits.  In most cases, the benefits of vaccination far outweigh the risks. New technology Leptospirosis vaccines are reducing this risk, and reactions are no longer common.  The risk of reactions is the highest in toy breed dogs (especially Dachshunds) and young puppies.  The vaccine should not be given to any dog less than 12 weeks of age due to this risk.  Vaccine reactions are typically mild and involve facial swelling and hives, but can in very rare cases range to severe systemic anaphylaxis and shock.                                            


Is Leptospirosis Vaccination recommended?

Leptospirosis is reportedly on the rise in Indiana.  We now recommend this vaccine for ALL healthy canine patients without a history of vaccine reactions. Even dogs that just spend time in their own backyards may still be exposed to the disease from the urine of  wildlife that may pass through the environment overnight such as raccoons, skunks, squirrels, opossums, rodents, or deer.  It is especially important for dogs that dig in the soil, live near areas that flood, play or hunt in wet marshy areas, go camping, or visit dog parks. 


Leptospirosis vaccination should be considered for all dogs in our area. For some clients, reducing the risk of this deadly disease and the risk of human infection may outweigh their concern for vaccine reaction in their dogs. We encourage our clients to speak with us about this decision.  


How are Leptospirosis vaccines administered?

Vaccines can be started in dogs 12 weeks of age or older. We typically recommend waiting until at least 16 weeks of age, after the other puppy vaccines have been completed.  After the first year the vaccine is given, a 2nd booster must be given 3-4 wks after the initial vaccine.  Yearly boosters are required to maintain immunity. 


Is there anyway to reduce the risk of vaccine reactions?

To reduce the risk of vaccine reaction with Leptospirosis vaccination, we recommend that the vaccine be given apart from other vaccines, at least for the first two boosters. The more vaccines given at one time, the more we stimulate the immune system, and the greater the likelihood we might see an adverse reaction.  Pre-medication with an antihistamine injection, and/or corticosteroid injection, may also reduce the risk of an allergic reaction in a high risk individual. 


Click here for CDC Information on Leptospirosis and its risk to humans. We recommend you discuss with your veterinarian vaccination for you dog for this serious and zoonotic (contagious) disease.