Leptosporosis is a disease caused by the bacteria Leptospira. There are numerous different sub-species of Leptospira but the main ones affecting our canine friends are L. grippotyphosa, pomona, autumnalis, icterohaemorrhagiae, and bratislava. It is found worldwide in soil and water. The bacteria is shed in the urine of wildlife reservoirs including rodents, opossums, and raccoons as well as cows and pigs. The disease was usually considered mostly for outdoor, hunting dogs but with today’s influx of urban wildlife, we are seeing more city dogs contracting this deadly disease.
Lepto is contracted through exposure with stagnant water sources. However, even wet grass where a shedding animal has urinated can infect our dogs. Common risk factors include exposure to or drinking from rivers, lakes or streams; roaming on rural properties (because of exposure to potentially infected wildlife, farm animals, or water sources); exposure to wild animal or farm animal species, even if in the backyard; and contact with rodents or other dogs (AVMA website). Transmission occurs when the bacteria come in contact with mucous membranes, an open wound/cut, or from eating a carcass. It can cross the placental barrier between mother and fetus.
It is known for causing acute kidney and liver failure. Clinical signs include depression, vomiting, diarrhea, muscle pain, loss of appetite, jaundice, increased thirst, increased urination, fever, and shivering. It can in some instances cause inflammation inside of the eyes, swelling of limbs, and clotting disorders leading to bruising as well as blood tinged vomit, diarrhea, and nose bleeds.
Clinical signs can be quite severe but also very subtle. Some dogs will become acutely ill while others may have lingering illness. Diagnosis is typically reached by interpreting clinical signs, exam findings, bloodwork, and specialized testing using titers and PCR. Many dogs with lepto will have elevated kidney and/or liver values. Titers show an antibody response to the bacteria while PCR identifies the organism itself. Titers may need to be paired 2 weeks apart to identify an increase indicating and active infection. PCR is diagnostic if positive; however due to dilute concentrations of urine there may not be enough detectable organisms to ID. Blood can also be used for PCR however the organism must have entered the blood stream to detect.
Aggressive treatment in the early course of the disease often leads to favorable outcomes but permanent kidney or liver damage still may persist. Treatment often includes hospitalization, aggressive fluid therapy, antibiotics, and symptomatic care for nausea. Depending on the severity, the average lepto case stays in the hospital for 3-7 days or longer.
Fortunately a vaccine is available against leptospirosis. The downside of the vaccine is it only covers four sub-species of lepto so there is always the chance your dog may become infected with other varieties. Many reactions were seen with the early vaccine product. Now days the vaccine has been reformulated and vaccine reactions against the product are few (no more than any other type of vaccine). Vaccination is recommended for at-risk dogs. This includes dogs that frequent wet areas (lakes, streams, ponds, marshes), come in contact with rodents and wildlife (including urban wildlife), and visit dog parks or areas where many dogs gather.
One scary aspect of leptospirosis is that it is a zoonotic disease. This means that if you come in contact with your dog’s urine that is shedding the bacterium, you can be infected as well. If you believe you have been exposed to lepto, contact your physician immediately. Clinical signs in humans include high fever, headache, chills, muscle aches, vomiting, yellow skin and eyes, red eyes, abdominal pain, diarrhea, and rash.
Leptosporosis is very rare in cats. Cats are considered resistant however not much is known about the disease in cats. Most display very mild or no signs at all. There are very few documented cases of cats actually displaying symptoms similar to dogs.