Leptospirosis in Dogs & Zoonotic Risks

Leptospirosis is a zoonotic disease, which means it can transfer from animals to people and may cause similar sickness in both species.

What is it?

Leptospirosis is an infection caused by a type of spirochete bacteria. Dogs most commonly contract this disease by coming into contact with infected urine of other dogs and wildlife. It may be transmitted by contaminated surfaces in the environment as well. The spirochetes cause infection by penetrating mucus membranes or damaged skin and then spreading to tissues via the bloodstream. They replicate rapidly within many different organ systems, and the body works to clear the infection via antibody production. However, even when antibodies are present, the spirochetes can persist and replicate within the kidneys for several years, remaining infectious when eliminated in the urine.

What are the clinical signs?

Infected dogs often have fevers early in the disease process. Other clinical signs may include muscle pain, lack of appetite, vomiting, uveitis (eye inflammation), hematuria (blood-tinged urine), fever, increased thirst and urination, or petechia (small skin hemorrhages). In advanced stages, outward signs of liver and kidney disease may be seen, including the presence of icterus (yellowing of the mucus membranes and sclera) and poor perfusion or inflammation of the blood vessels.

How is it diagnosed?

When leptospirosis is suspected, dogs should be placed in isolation to avoid the spread of disease while a diagnosis is confirmed. Your veterinarian will likely check bloodwork and a urine sample for signs of infection. There may be increased kidney and liver values, changes in white blood cell counts, and low platelets depending on the stage of disease. A SNAP test or serum titers can be performed to check for exposure to and antibodies against leptospirosis, respectively. Performing PCR on the urine can detect an active infection and is most useful in diagnosis.

How is it treated?

Antibiotics can be administered to eliminate the acute and carrier phases of infection. In some cases, infected dogs may need to be hospitalized on fluid therapy to help flush the kidneys and to replenish any fluid losses that may have occurred through increased urination or vomiting. Affected dogs will need to be isolated until the infection has fully cleared.

Is it preventable?

Vaccinations can be given annually to protect at-risk dogs. In addition, reducing exposure to puddles or other areas where wildlife urine may be present can help prevent this infection.

Common Causes of Skin Allergies in Pets

Below are three of the most common causes of allergic skin disease in pets.


The most common pet allergy is caused by fleas. Fleas are parasites that feed on a pet, and their saliva can trigger an allergic reaction, resulting in hair loss, redness, and intense itching. Hairless regions near the base of the tail are commonly seen in dogs and cats. Cats will sometimes experience hair loss around their chins as well. If your veterinarian suspects a flea allergy, he or she will check for evidence of live fleas and flea dirt. Your veterinarian will be able to make recommendations as far as an effective topical or oral flea preventative product as well as ways to rid the environment of fleas and their larvae. It can unfortunately take several months to resolve a flea infestation.


Another allergy we commonly see in pets is environmental. This is medically referred to as atopic dermatitis. Something in the environment, whether it is grass, pollen, dust, etc, causes a pet to become itchy after multiple exposures. Hairless regions or redness on the paws and inguinal regions are most common since these are the areas allergens touch when a pet is walking or laying down. These allergies can be a little more difficult to conquer. If further testing beyond a primary care veterinarian is necessary, a dermatologist can perform additional allergen testing and make treatment recommendations.


Some pets also develop food allergies after being on the same diet over time. These allergies develop as the body becomes sensitized from repeat exposure to a certain ingredient within the food. Typically the allergic component is the protein. Resolving a food allergy involves strict diet trials over several months. Recurrent ear infections can also be suggestive of possible underlying food allergies.

As always, if you notice changes to your pet’s skin or coat, it is best to schedule a veterinary visit to get to the bottom of it!