Every year you find yourself sitting in an exam room with your dog. He maniacally begs for the treats he knows are just right there on the counter. A technician runs through a series of questions, asks you if you have concerns and says the veterinarian will be in momentarily. Back up a step or 2, one of those question the technician asks is. “Does your dog have access to ponds, lakes, streams, standing water, or go on camping trips with the family?” Why does the vet care if my dog swims or camps? The answer: Leptospirosis.


Leptospirosis is a bacterial disease that affects dogs, cattle, horses, wildlife, swine and humans and is found worldwide. The bacteria persists in lakes, streams, and ponds. The bacteria are ingested by raccoons, opossums, and other wildlife. While these animals may not get sick from Lepto, they act as hosts for the disease, enabling the bacteria to multiply.

The bacteria are spread through the host animals’ urine during the spring and summer, when the environment is wet due to increased rainfall and warm temperatures. Hunting dogs that retrieve game from water and people who swim in contaminated water are at high risk. Due to their exposure to large groups of other dogs, show dogs and dogs with access to waters such as ponds and creeks also have an increased risk.

Urban sprawl has contributed to a rising incidence of Lepto infections. Houses are built closer to wild areas and, thus, closer to wildlife that carry Lepto. Lepto is most often acquired through oral ingestion but it can also enter through open wounds, abrasions, or mucus membranes.

Leptospirosis can be transmitted either directly between hosts or indirectly in the environment. It can be ingested in contaminated food or water, spread in aerosolized urine or water, or transmitted by direct contact with the skin. The organisms usually enter the body through mucous membranes or abraded skin. Leptospira can infect the blood and spread to the lymph nodes, liver, and kidneys.

The incubation period is 4 to 12 days in dogs. Signs of Lepto include fever, lethargy, GI upset, and loss of appetite. Owners should consult a veterinarian whenever their pet displays signs of liver trouble, such as jaundice (yellowing of the eyes, skin or gums) or yellow foamy vomit, or signs of kidney problems, such as increased urination, dark or bloody urine, or unusual accidents in the house.

Leptospirosis can lead to liver or kidney failure if left untreated. Some infections are asymptomatic or mild, while others are severe or fatal. Initial signs are usually non-specific and may include fever, depression, anorexia, stiffness, shivering and weakness.

Veterinarians can identify Lepto by sending urine or liver or kidney biopsy to a lab. Antibiotic treatment is effective if the disease is caught early but prevention is the best medicine. Make sure dogs do not drink out of puddles or ponds, bring tap water for your dog or horse when you take them on long outings. Always keep wild animals away from barns, food, and water supplies. Vaccination may also be advised. Always filter, boil or treat lake or stream water before drinking it.

****Always have a licensed veterinarian administer vaccines. The leptospirosis vaccine is not right for all breeds. Your veterinarian may recommend avoidance for your pet.