Vaccinating For Leptospirosis In Dogs? Read This First

leptospirosis in dogs

It seems that every year or so, somewhere in the country there are dire warnings about an outbreak of leptospirosis in dogs. This year it’s Chicago’s turn, with TV news stations warning that “your dog could die just from sniffing.”  Sniffing rat urine, they mean.

The warnings about lepto are especially dire because it’s a zoonotic disease, meaning it’s not just infected animals you have to worry about … it can infect humans too.

Screenshot of TV news report with reporters warning about a rise in cases of a bacterial disease that can kill dogs

There are press releases from big veterinary emergency clinics too.

MedVet article on lepto outbreak in dogs

Vets Recommend Lepto Vaccination

And then there’s the inevitable recommendation that you vaccinate your dog.

Recommendation of vaccinating against lepto in dogs

The words “not 100% effective” in the above quote are an understatement. Keep reading to find out why the leptospirosis vaccine is not only ineffective, but potentially quite dangerous for your dog.

So if you’re alarmed by the thought of your dog catching lepto, and wondering whether you should give your dog the leptospirosis vaccine, you may first want to read some facts about the disease and the vaccine.

Leptospirosis vaccine reactions are quite frequent.  It’s important to weigh the risks of vaccinating vs not vaccinating very carefully.

What Is Leptospirosis?

Leptospirosis is a contagious disease that can affect both humans and animals. It’s a disease caused and spread by infection with Leptospira, bacterial pathogens that can cause liver and kidney disease in infected dogs. The bacteria is usually spread through direct contact with infected animal urine or indirectly through contaminated vegetation, soil, food, or contaminated water. In cities, the infected urine of rats and other rodents can spread leptospirosis.

Lepto is most common in warm, moist environments, during rainy seasons and in tropical climates. The organism survives better in stagnant rather than flowing water. It can live 180 days in wet soil or marshy areas.

Leptospirosis In Dogs

Healthy dogs who come in contact with the bacteria may never exhibit symptoms. And in most cases, lepto is highly treatable when it’s recognized early.  

However, you should still learn these symptoms so you can catch it quickly if you’re dealing with an infected dog. The illness can develop quickly so take your dog to the vet immediately if you suspect lepto infection.

These are the common clinical signs of leptospirosis in dogs infected with the illness:

  • Lethargy
  • Depression
  • Loss of appetite
  • Vomiting
  • Diarrhea
  • Fever
  • Increased thirst and urination
  • Blood in urine
  • Jaundice (yellow tinge in the lining of the mouth or whites of the eyes)

There’s a very acute form of the disease where dogs may experience rapid breathing and rapid, irregular pulse, coughing up of blood, tarry feces, nosebleed, red or purple spots on the skin. They may be reluctant to move and very sensitive to pain or touch, and have enlarged lymph nodes. This form of the disease moves very fast and can be fatal.

About Lepto Vaccination

Many dogs are routinely vaccinated for lepto, despite high adverse effects.

Here’s a summary of what you need to know about the lepto vaccine before deciding to give it to your dog.

You Must Vaccinate For Lepto At Least Yearly

Unlike viral vaccines which likely last for the life of the animal, bacterial vaccines such as lepto only last for a year at most. This means that many vets recommend vaccinating every six months to protect your dog.  Leading veterinary immunologist Ronald D Schultz PhD has said that you may need to give a lepto vaccine as often as four times a year. As you’ll see below, the lepto vaccine involves a high level of risk for your dog.

The Vaccine Is Limited

The lepto vaccine may not cover the strain of lepto your dog encounters.

There are 20 different species of Leptospira bacteria and more than 200 different serovars. The original vaccines contained only the L. canicola and L. icterohaemorrhagiae serovars. The current vaccines now contain L. grippotyphosa and L. pomona. The latter two strains are now much more common. Two additional serovars that appear to cause infection, L. bratislava and L. automalis, are not included in the vaccines currently available.

So if you do decide to vaccinate your dog for canine leptospirosis, it’s a very good idea to find out which strains of lepto are in your area so that you don’t give your dog a risky vaccination that won’t even protect him.

Vaccinated Dogs Shed Lepto 

Vaccinated dogs and livestock can shed lepto in their urine. This means a dog’s urine can infect other dogs, wild animals, and even you. So routine lepto vaccination actually increases the threat of lepto on the whole.  The greater the number of vaccinated animals, the greater the spread of lepto.

Adverse Effects

There is a high rate of adverse effects from the lepto vaccine. Veterinarian Patricia Jordan DVM has documented several cases of tumors from the lepto vaccine, especially from combination vaccinations that include leptospirosis. Kidney failure is another common reaction, as you’ll see below. Bacterial vaccinations can also cause autoimmune disease.

In the UK, where leptospirosis vaccination is quite common, Canine Health Concern conducted a survey and found that the vaccine can also cause the disease it’s meant to prevent.

In that survey, 100% of dogs with leptospirosis caught it just after their lepto vaccinatons. Leptospirosis attacks the kidneys and kidney failure was a very common effect after lepto vaccination. Dr Jordan explains that the basement membrane can be damaged by clogging when the immune complexes drain via the lymphatics. The kidneys are a big part of the lymphatic system. The body tries to clear the toxins in the vaccines and the kidneys are damaged by this clearing mechanism.

There’s a long list of other documented adverse effects from the lepto vaccine:

  • Anaphlylaxis
  • Anorexia
  • Dermatitis
  • Infection with flesh-eating bacteria
  • Uncontrollable pruritis (itching)
  • Vomiting
  • Lethargy
  • Lameness
  • Vocalization
  • Fever
  • Dehydration
  • Polyarthritis
  • Kidney Failure
  • Liver Failure
  • Pancreatitis
  • Mast cell disease
  • Urinary tract infections
  • Diarrhea
  • Chronic weight loss
  • Enlarged spleen
  • Cancer
  • Enlarged lymph nodes
  • Death

No Human Lepto Vaccine

There’s no lepto vaccine licensed for humans in the US.  Some of the reasons for this are:

  • Unacceptable side effects
  • Incomplete and short lived protection
  • Increased risk of auto-immune disease
  • Even if the vaccination provides protection, it won’t prevent leptospiuria (Leptospira in the urine) so the disease can still be spread

So the lepto vaccine isn’t safe for humans, but it’s OK to give it to our dogs?

Nosodes – A Safer Alternative 

Homeopathic nosodes are safe and have been shown to be highly effective nosode.  The Cuban government has successfully used homeopathic nosodes to prevent leptospirosis in its citizens.  In 2007 when post-hurricane flooding exposed residents to lepto risk, 2.3 million people were safely immunized for the severe disease at a small fraction of the cost of vaccination.

If you think your dog’s at risk for lepto, you may want to contact a homeopathic veterinarian about using nosodes.  You can find a homeopath at or  Many will do phone consults so they don’t have to be local.

 Click here to download our free Vaccine Guide 


What are the early signs of leptospirosis in dogs?

Early signs of leptospirosis in dogs include lethargy, depression, loss of appetite, vomiting, diarrhea, fever, increased thirst and urination, blood in urine, and jaundice.

Can a dog survive leptospirosis?

Yes, most dogs can survive leptospirosis if it’s recognized and treated early, though the disease can progress quickly and may require immediate veterinary attention.

Do dogs really need leptospirosis vaccines?

Leptospirosis vaccines are controversial due to their high rate of adverse effects and limited efficacy against various strains; it’s essential to weigh the risks and consult with your vet.

What dogs are at high risk for leptospirosis?

Dogs at high risk for leptospirosis are those frequently exposed to standing water, wildlife, or areas with high rodent populations, as well as dogs living in warm, moist environments.


Ford, RB and Schultz, RD. Vaccines and Vaccinations: Issues for the 21st Century. In: JD Bonagura, ed., Kirk’s Current Veterinary Therapy XIII, W.B. Saunders, Philadelphia, 1999. pp. 250-253. 

Rentko, VT and Ross, LA. Canine Leptospirosis. In: JD Bonagura, ed., Kirk’s Current Veterinary Therapy XI, W.B. Saunders, Philadelphia, 1992. pp. 260-263. 

Ribotta MJ, et al. Development of an indirect enzyme-linked immunosorbent assay for the detection of leptospiral antibodies in dogs. Can J Vet Res. 2000 Jan;64(1):32-7. 

Mitchell MA, et al. Serologic survey for selected infectious disease agents in raccoons from Illinois. J Wildl Dis. 1999 Apr;35(2):347-55. 

Carmichael LE. Canine viral vaccines at a turning point–a personal perspective. Adv Vet Med. 1999;41:289-307. 

Gese EM, et al. Serological survey for diseases in free-ranging coyotes (Canis latrans) in Yellowstone National Park, Wyoming. J Wildl Dis. 1997 Jan;33(1):47-56. 

Harkin KR, et al. Canine leptospirosis in New Jersey and Michigan: 17 cases (1990-1995). J Am Anim Hosp Assoc. 1996 Nov-Dec;32(6):495-501. 

Rentko VT, et al. Canine leptospirosis. A retrospective study of 17 cases. J Vet Intern Med. 1992 Jul-Aug;6(4):235-44.

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