Leishmaniasis is a disease caused by a parasite. The parasite is a single-celled protozoan that gets into the bloodstream of dogs and leads to serious illness. It can also affect cats and humans.

Sand flies and other insects transmit the parasite. They deposit the microscopic organisms when they bite a dog, cat, or human. Pregnant or nursing dogs can transmit it to puppies. Leishmaniasis can incubate for a very long time. Dogs may not show symptoms for months or years after being infected. Transmission is most common in tropical climates, particularly in the Mediterranean, South and Central America, the Middle East, and southern Mexico.

What Are Leishmaniasis Symptoms in Dogs?

Canine leishmaniasis early symptoms may include skin lesions and fatigue.

When symptoms eventually develop, they depend on what type of leishmaniasis the dog has — visceral or cutaneous. Most dogs develop the visceral form, meaning that the parasite causes infections of the internal organs. The cutaneous form affects a dog’s skin. Many affected dogs show both types of symptoms.

The most common systems of visceral leishmaniasis include:

• Diarrhoea
• Exercise intolerance
• Loss of appetite or anorexia
• Nose bleeds
• Severe weight loss
• Tarry stools
• Vomiting
• Fever
• Ocular changes

The most common symptoms of cutaneous leishmaniasis include:

• Hair loss
• Hyperkeratosis in the form of scaly skin, thickened skin on paw pads, chapped skin on muzzle, discoloration
• Long or brittle nails
• Nodules on the skin surface
• Skin ulcers

Dogs can also develop pain in the joints and extremities, inflammation of muscles, fever, enlarged spleen, or renal failure.

You may not suspect leishmaniasis in your dog right away. The long incubation period means that symptoms will appear quite a while after exposure to the parasite. You may not connect your dog’s illness to an earlier visit to a place where leishmaniasis is common.

To diagnose the condition, your vet will ask if you have travelled with your dog and were. Your travel history can reveal possible exposure. They will also do blood tests, urine tests, and skin biopsies to identify the parasite. They may also test for more common conditions like cancer, tick-borne illnesses, or canine distemper to rule out those diseases. You must report a diagnosis to the Centre for Disease Control and Prevention (CDC). Your vet can help you with that process.

What Is the Treatment for Leishmaniasis in Dogs?

Some medicines can treat dog leishmaniasis. The course of medication will last 6–12 months. While it will address symptoms, it won’t be able to eliminate the parasites. Your dog may develop symptoms again in the future. If that happens, they will need to be treated again.

In some cases, the disease can be too advanced for treatment to be effective. If your dog is too sick for treatment, you can talk to your vet about your options. Humane euthanasia may be the best choice to prevent further suffering.

If you suspect your dog has been exposed to leishmaniasis, talk to your vet as soon as possible. Early treatment is the most effective way to keep symptoms from progressing. You will also be able to take steps to ensure no insects bite your dog and pass the disease on to others.

How Do You Prevent Leishmaniasis?

Leishmaniasis can affect humans, too. Dogs can’t pass the disease to their human, so there isn’t danger of handling a sick dog. The risk arises if an insect bites an infected animal. The insect can pass the parasite on to the next creature it bites, including people.

If you live in an area with known leishmaniasis, you can reduce your risk of getting it by using insecticides to repel sand flies. There are topical sprays or lotions that you can use on your skin or on your dog to keep the insects from biting you and your pet. Avoiding areas with sand flies will help reduce risk.

The European Union and Brazil have approved vaccines that prevent leishmaniasis in dogs. There are other vaccines in development.

If you will be traveling to a part of the world where leishmaniasis is present, talk to your vet before bringing your dog with you. They can help you decide if your pet will be safe or if you should plan for someone to care for your dog at home while you travel.

If you have concerns about leishmaniasis, call your vet right away. Getting early testing and treatment could save your dog’s life.