Leishmaniasis Symptoms in Dogs, Cats and People

In dogs, leishmaniasis usually shows up as dry, flaky, non-itchy hair loss around the eyes, nose and ears, sometimes with sores, overgrown nails, weight loss, low energy, nosebleeds and enlarged lymph nodes. The serious part is often hidden: the parasite can damage the kidneys long before a dog looks very sick. In people, the common form causes slow-healing skin sores, and the rare internal form causes fever, weight loss and a swollen spleen and liver.

Signs can take months or even years to appear after infection, and many infected dogs never get sick at all. That is why the diagnosis comes from a vet and lab tests, not from a symptom list.

What Is Leishmaniasis?

Leishmaniasis is a disease caused by Leishmania, a single-celled (protozoan) parasite. It spreads mainly through the bite of infected female sand flies, tiny biting insects that are most active from dusk to dawn. In dogs the species is almost always Leishmania infantum, which lives inside immune cells and spreads from the skin to the lymph nodes, spleen, liver and bone marrow.

Dogs are the main host, or reservoir, of L. infantum: where sand flies carry the parasite, infected dogs are where the flies pick it up. Vets often call the disease leishmaniosis when they talk about animals. It is the same thing.

Leishmaniasis Symptoms in Dogs

The parasite can affect almost any organ, so signs vary from dog to dog. These are the ones vets see most often.

Skin and nails

• Dry, scaly, flaky skin with hair loss, often starting on the head: around the eyes, on the muzzle and on the ears. The skin is usually not itchy, which helps tell it apart from allergies or mange.
• Sores, bumps or small nodules on the face, ears and legs.
• Ulcers on the nose, footpads, elbows and other bony points, and where skin meets the lips or eyelids.
• Abnormally long, curved or brittle nails.

Whole body

• Weight loss and muscle wasting.
• Low energy, tiring easily on walks, poor appetite.
• Enlarged lymph nodes (the lumps under the jaw, in front of the shoulders and behind the knees).
• Pale gums from anemia.
• Fever, and chronic diarrhea in some dogs.

Eyes, nose and joints

• Red, swollen or crusty eyelids, conjunctivitis, dry eye or a painful, cloudy eye (uveitis).
• Nosebleeds.
• Lameness or swollen joints.

Kidneys

• Drinking and peeing more than usual.
• Later, kidney failure.

Why the kidneys matter most

Antibodies and parasite fragments form immune complexes that settle in the kidney's filters (glomerulonephritis). The first clue is often protein leaking into the urine, which only a urine test picks up. Kidney failure is the main cause of death in dogs with leishmaniasis, and for some dogs kidney disease is the only sign. Our guide to signs of kidney failure in dogs covers what to watch for.

Most infected dogs never get sick

Infection is not the same as disease. The Merck Veterinary Manual puts the share of infected dogs in endemic areas that develop clinical signs at about 10%. Whether a dog gets sick depends mostly on its immune response. Illness is seen most often in dogs younger than 3 or older than 8, and CAPC lists German shepherds, Boxers and Cocker spaniels among the breeds considered more susceptible. Other infections, pregnancy, poor nutrition and stress can tip a carrier dog into illness.

Leishmaniasis in the US: Which Dogs Are at Risk?

In the US, CAPC describes cases as mostly in two groups of dogs.

Foxhounds. Since the 1980s, L. infantum has been found in kenneled foxhounds, and the Companion Animal Parasite Council (CAPC) considers it endemic in many US foxhound kennels. More than 20% of at-risk foxhounds test positive by PCR. In a 2006 study, researchers found infected foxhounds in 18 states and 2 Canadian provinces.

Dogs that traveled or were imported. Dogs of any breed brought in from southern Europe, South America or other places where the disease is common are occasionally diagnosed after they arrive, sometimes years later.

CAPC also notes a growing number of US cases in other breeds with no travel history, so leishmaniasis belongs on the list even for a dog that has never left the country.

How do US dogs get infected?

Sand flies live in many US states, but spread by sand fly has not been confirmed in North America. In US foxhounds, the parasite moves mainly from dog to dog:

• from an infected mother to her puppies before birth,
• through blood, including transfusions from infected donor dogs and bite wounds during fights,
• through breeding.

Dogs that pick it up abroad are usually infected by sand fly bites there. For more on how infections move between dogs, see our overview of transmission of canine diseases.

Can People Get Leishmaniasis From Dogs?

Not by petting or living with them. People get leishmaniasis from the bite of an infected sand fly. Where sand flies spread the parasite, an infected dog can be the source the flies feed on.

Here is what is known for the US:

• No locally acquired cases of visceral (internal organ) leishmaniasis in people have been reported in the US, according to CDC.
• In the 2006 foxhound study, none of the people tested had evidence of infection.
• CAPC notes that dog ownership has not been shown to raise a family's risk, even where the disease is common.
• Most Americans diagnosed with leishmaniasis were infected while traveling or living abroad.
• Locally acquired skin (cutaneous) cases occasionally occur in Texas and, rarely, Oklahoma and Arizona.

CAPC adds one caveat: if North American sand flies ever start transmitting L. infantum, spread from dogs to people would become possible. More background on diseases shared between animals and people is in our article on emerging zoonotic diseases.

Leishmaniasis Symptoms in People

CDC describes three main forms:

• Cutaneous (skin), the most common form: sores that appear a few weeks to months after a sand fly bite. They often start as bumps and turn into ulcers with a raised edge and a crater in the middle, sometimes with a scab. They are usually painless and can leave scars.
• Mucosal: sores in the nose, mouth or throat, mainly with parasites from Central and South America.
• Visceral (internal organs), the most serious form: fever, weight loss, an enlarged spleen and liver, and low blood counts. It usually starts months after the bite but can take years. Without treatment, visceral leishmaniasis is fatal in more than 95% of cases, according to the WHO.

Some people are infected and never have symptoms. If you have a sore that won't heal or an unexplained fever and weight loss after time in an area with sand flies, see a doctor and mention where you traveled.

Leishmaniasis in Cats

Cats can be infected, but illness is rare, even in regions where many dogs carry the parasite. When cats do get sick, the most common signs are:

• ulcers and lumps on the skin, mostly on the head and lower legs,
• enlarged lymph nodes,
• eye inflammation (uveitis).

About half of reported sick cats also had a weakened immune system, for example from FIV or FeLV. A cat with skin sores that won't heal, especially one that came from abroad, needs a vet visit.

How Vets Diagnose Leishmaniasis

There is no single quick test. Your vet puts the picture together:

1. History and exam. Travel, where the dog came from, its mother's history and any transfusions, plus a full physical exam.
2. Bloodwork and urine. Anemia, high globulin (antibody) levels with low albumin, and protein in the urine point toward leishmaniasis. The urine protein test also shows how much the kidneys are affected.
3. Antibody test (serology). A blood test for antibodies against Leishmania. A high result in a dog with typical signs supports the diagnosis; a low result needs another test to confirm.
4. PCR. Finds parasite DNA. Samples from the lymph nodes, bone marrow, spleen or skin are more reliable than blood.
5. Cytology or biopsy. Seeing the parasites under the microscope in a needle sample or skin biopsy confirms it.

Dogs used as blood donors can be screened for Leishmania with antibody tests and PCR, because the parasite can spread through transfusions.

Stages of Leishmaniasis in Dogs (LeishVet)

Vets use the LeishVet staging system to plan treatment and give an outlook. It applies to dogs that are sick or have abnormal lab results, not to healthy carriers. Kidney function drives much of the staging.

A dog can move between stages over its life, so your vet will restage it at checkups.

Treatment and Outlook

Leishmaniasis is treatable but rarely curable. Your veterinarian chooses the medicines and doses based on the stage, the kidneys and the dog's other health problems. Treatment usually runs for many months and often makes dogs look and feel much better, but the parasite tends to stay in the body, so relapses are common. Every treated dog needs regular rechecks of bloodwork and urine, and dogs with kidney disease also need kidney care.

How to Protect Your Dog (and Yourself)

For dogs

• If your dog travels to, or comes from, an area where leishmaniasis is common, ask your vet about a sand fly repellent collar or spot-on before the trip. Vaccines exist in parts of Europe and Brazil.
• In sand fly areas, keep dogs indoors from dusk to dawn, when the flies bite most.
• Talk to your vet before breeding a dog that tested positive, since the parasite passes from mother to puppies, and make sure donor blood is screened.
• Tell your vet if your dog was adopted from abroad, even years ago.

More on everyday parasite prevention is in our guide to external parasites prevention for dogs.

A warning for cat households: some dog sand fly and flea products contain permethrin, which can be deadly to cats. Never put a dog product on a cat, and ask your vet which product is safe if you have both. See our cat parasite prevention guide.

For people

• There is no vaccine. When traveling to areas with sand flies, limit time outside from dusk to dawn, wear long sleeves and pants, and use an insect repellent.

When to Call the Vet

Call your vet soon if your dog has non-itchy hair loss around the eyes, nose or ears, overgrown nails, weight loss, swollen lymph nodes or nosebleeds, especially if it is a foxhound or came from abroad.

Call today if your dog has a heavy or repeated nosebleed, is drinking and peeing much more than usual, has stopped eating, or has a red, painful or cloudy eye.

For yourself or a family member, see a doctor about any sore that won't heal or unexplained fever and weight loss after travel.

Leishmaniasis FAQ

Is leishmaniasis contagious between dogs? In the US it can be, through the routes above: mother to puppies, blood and breeding. If one dog in your home is diagnosed, ask your vet whether the others should be tested.

Can leishmaniasis in dogs be cured? Usually not completely. Treatment controls the disease, but signs can come back, so lifelong monitoring is the norm.

How long can a dog live with leishmaniasis? It depends mostly on the kidneys, which is why the stage matters so much: see the outlook column in the table above.

Sources

• CDC: Signs and Symptoms of Leishmaniasis
• CDC: About Leishmaniasis
• Companion Animal Parasite Council: Leishmaniasis
• Merck Veterinary Manual: Leishmaniosis in Dogs
• Merck Veterinary Manual (dog owners): Leishmaniosis in Dogs
• Solano-Gallego et al., LeishVet guidelines for the practical management of canine leishmaniosis, Parasites & Vectors 2011
• LeishVet: Clinical staging
• LeishVet: Leishmaniosis in Cats
• Duprey et al., Canine Visceral Leishmaniasis, United States and Canada, 2000-2003, Emerging Infectious Diseases 2006
• WHO: Leishmaniasis fact sheet
• Petersen Laboratory, University of Iowa: About Leishmaniasis
• Richardson, Permethrin spot-on toxicoses in cats, Journal of Veterinary Emergency and Critical Care 2000 (ASPCA)

This article is for general information and is not a substitute for advice from your veterinarian.