Basic Pet Care

Five Things You Didn't Know About Lepto

Five Things You Didn't Know About Lepto

-By, Nyssa Reine-Salz, DVM, DACVIM

Leptospirosis, also called Lepto, is an infectious disease of humans and animals. Leptospirosis can be serious and can lead to kidney and liver disease. The following are some facts about this potentially dangerous disease:

1. Lepto is found worldwide

Leptospirosis, is a worldwide disease of affecting people and animals. It is caused by a spiral-shaped bacteria of the species Leptospira.1,2

2. Lepto risk increases after flooding or heavy rainstorms.

Leptospira bacteria prefer warm weather and wet environments. These bacteria can be found almost anywhere there is water: rivers, lakes, creeks, and puddles. Flooding and heavy rainstorms often spread the bacteria through contaminated water.2 The infective Leptospires can remain viable for months under optimal conditions.1

3. Lepto is transmitted by wild animals.

Leptospirosis can be transmitted by a variety of domestic and wild animals, including rats, mice and racoons.1,2 Dogs that are exposed to wildlife and livestock are considered to be at risk for lepto.3 Dogs that have contact with wildlife, swim, or roam would be especially at risk. Infected animals shed leptospires, the infective stage of the bacteria, in their urine.

4. Lepto is both a city and a country dog disease

Dogs in urban environments are also at risk for this disease because of wild animals or other domestic animals with the disease. City dogs are most likely to contract leptospirosis through contact with urine of infected rodents.4

5. Leptospirosis vaccines can help prevent disease

Lepto vaccines are effective in helping prevent disease and some vaccines are actually proven to prevent shedding of the disease. Because Lepto can be spread through the urine of infected wild and domestic animals, and every dog is at risk, prevention through vaccination is extremely helpful.4

Dogs that have contact with wildlife, swim, or roam would be especially at risk. However, even those dogs that live in urban areas may be at risk, since the disease can be spread through rat urine. Dogs will receive an initial vaccination and then a booster, usually within 2-4 weeks, and then they would receive the leptospirosis vaccine on an annual basis. Always speak to your veterinarian about vaccinations recommended for your pet.

To learn more about leptospirosis, you can visit the Centers for Disease Control's website:


  1. Green CE: Leptospirosis: Lessons I Learned, Proceedings ACVIM 2011.
  2. Sykes Jane E, Leptospirosis, World Small Animal Veterinary Association World Congress Proceedings 2014.
  3. Stokes JE, Kaneene JB, Schall WD, et. al: Prevalence of serum antibodies against six Leptospira serovars in healthy dogs . J Am Vet Med Assoc 2007 Vol 230 (11) pp. 1657-1884.
  4. Greene CE, Sykes JE, Brown CA: Leptospirosis. Infectious Diseases of the Dog and Cat, 3rd ed. Philadelpia, WB Saunders 2006 pp. 402-416.