Leishmaniasis in dogs: symptoms, testing and prevention

If you've never heard of it, you're not alone: most US dog owners haven't. Leishmaniasis in dogs is uncommon in the United States, but it's one of the most important diseases for dogs in Spain, Italy, Greece and the rest of the Mediterranean, and it's showing up more often in American homes through international adoptions and travel. It's chronic, it can stay hidden for months or years, and when it does appear it can affect the skin, eyes, joints and, above all, the kidneys.

This guide explains how dogs get it, where the risk is, what to know if you adopt a dog from abroad or take yours overseas, which symptoms to watch for, how it's diagnosed and treated, and how to protect your dog.

What leishmaniasis is and how dogs get it

Canine leishmaniasis is caused by a microscopic parasite, Leishmania infantum, which is spread by the bite of phlebotomine sand flies. These insects are tiny, about 1/10 inch (2–3 mm), pale, silent and weak fliers that hop close to the ground. They're often mistaken for mosquitoes, but they're a different insect.

The cycle is straightforward: a female sand fly bites an infected dog, picks up the parasite and passes it on when she bites another dog a few days later. Dogs are the main reservoir. Less common routes include transmission from mother to puppies during pregnancy and through blood transfusions, but the disease doesn't spread through petting, licking or sharing bowls.

Not every infected dog gets sick. It depends largely on the immune response: some dogs keep the parasite in check for years without signs, while others develop full-blown disease. Boxers, German shepherds, rottweilers and cocker spaniels are reported to be affected more often, while the Ibizan hound tends to be more resistant, but any dog can become ill.

Where leishmaniasis is a risk

Canine leishmaniasis is endemic throughout the Mediterranean basin, including Spain, Portugal, southern France, Italy, Greece, Cyprus, Malta, Turkey and North Africa, as well as the Middle East, parts of Asia and much of Latin America, especially Brazil. In southern Europe, sand flies are active roughly from April or May through October or November and bite mostly from dusk to dawn.

In the US, the main documented exception is foxhounds. In 1999 the disease was identified in foxhounds at a New York hunt kennel, and later surveys found infected foxhounds in many states and parts of Canada. In these dogs, the parasite appears to pass mainly from mother to puppies rather than through sand flies. Separately, a different Leishmania species occasionally causes skin infections in people in Texas and Oklahoma, but it isn't a major concern for dogs.

Adopting a dog from an endemic country

Rescue groups regularly bring dogs to the US from places where leishmaniasis is common: Spanish galgos and podencos, street dogs from Greece and Turkey, and dogs from the Middle East or Latin America. If you're adopting one of these dogs, or you already have, keep in mind:

1. Ask for test results before adoption, ideally a quantitative antibody test, and find out the date it was done.
2. Test again after arrival. Because the incubation period is long, a dog can test negative and turn positive later. Many vets recommend repeating the test about six months after the dog's last possible exposure.
3. Tell your vet where your dog came from, so they consider leishmaniasis for any unexplained skin, eye, joint or kidney problem, even years later.
4. Don't use the dog as a blood donor or for breeding unless it has tested negative and your vet agrees.

A positive dog can still be a wonderful companion. If you're considering a dog from Spain, our Spanish greyhound (galgo) breed guide and our guide to adopting a dog will help you prepare.

Symptoms of leishmaniasis in dogs

The incubation period ranges from a few months to several years, so a dog may get sick long after it arrived in the US. Signs vary widely:

One useful clue: unlike mange or allergies, the skin lesions of leishmaniasis usually aren't very itchy at first. If your dog is scratching constantly, another cause is more likely; see why your dog is so itchy.

How vets diagnose leishmaniasis

Diagnosis usually combines several tests, because no single one tells the whole story:

• Quantitative antibody tests (such as IFA or ELISA) measure antibodies against Leishmania. Rapid in-clinic tests are useful for screening but only give a yes-or-no answer, so positives are confirmed with a quantitative test. Several US veterinary diagnostic labs offer these.
• PCR detects the parasite's DNA in samples from lymph nodes, bone marrow, skin or blood.
• Cytology: finding the parasite under a microscope in a lymph node or bone marrow sample.
• General blood and urine tests: complete blood count, chemistry panel, protein levels and a urine protein-to-creatinine ratio to check the kidneys.

Your vet will then place the dog in one of four stages defined by the LeishVet expert group, from mild disease to severe disease with advanced kidney damage. The stage guides treatment and outlook.

Treatment and outlook

Treatment usually combines medications that reduce the number of parasites with others that keep them from multiplying, often for months and sometimes for life. If the kidneys are affected, kidney-protective treatment and diet are added. In most dogs the parasite isn't completely eliminated, but the disease can be controlled. Some of the drugs commonly used in Europe aren't readily available or approved for dogs in the US, so your vet may consult a veterinary internal medicine specialist.

Follow-up is frequent at first, usually about a month after starting treatment and then every few months; once the dog is stable, once or twice a year. Relapses can happen, so don't skip rechecks. The outlook depends mostly on kidney function. Many dogs diagnosed early live normal lives for years with treatment and monitoring, while dogs with advanced kidney failure have a much more guarded prognosis.

How to protect your dog when traveling

If you're taking your dog to the Mediterranean or another endemic area, prevention combines several layers:

Vaccines against canine leishmaniasis are used in Europe, but none is available in the US, and in any case they complement repellents rather than replace them. Also check the import and export rules for your destination well ahead of time; our guide to flying with a dog covers the basics. For a short trip, leaving your dog at home during sand fly season is the simplest protection of all.

Leishmaniasis and people

People can also get leishmaniasis, mainly young children and people with weakened immune systems, but it happens through sand fly bites, not through contact with a dog. In most of the US, where sand flies able to carry this parasite are scarce or absent, an infected dog poses very little risk to the family. Keeping an infected dog on repellent and treatment reduces the chance of the parasite spreading wherever sand flies are present.

Frequently asked questions

Can a dog with leishmaniasis infect other dogs or people?

Not directly. A sand fly has to bite the infected dog and then another animal or person, and suitable sand flies are scarce in most of the US. An infected dog can live with other pets and with your family. The exceptions are mother-to-puppy transmission and blood transfusions, so an infected dog shouldn't be bred or used as a blood donor.

How long can a dog live with leishmaniasis?

It depends on the stage and, above all, on kidney function at diagnosis. Many dogs diagnosed early, treated consistently and monitored regularly live for years with a good quality of life, sometimes a normal lifespan. When the disease is found alongside advanced kidney failure, the outlook is more guarded and the focus shifts to comfort and well-being.

Does a positive test mean my dog is sick?

Not necessarily. A positive result means your dog has been exposed to the parasite, but some infected dogs never develop disease. Your vet will weigh the antibody level, physical exam and blood and urine tests to decide whether your dog needs treatment or just closer monitoring. Don't make big decisions based on a single rapid test.

Is there a leishmaniasis vaccine for dogs in the US?

No. Vaccines are licensed and used in parts of Europe, but none is currently approved in the US. Even where they're available, they don't prevent sand fly bites or infection; they help the immune system keep the parasite under control. Repellents, avoiding dusk exposure and testing remain the core of prevention for any dog traveling to an endemic area.

Should I adopt a dog that has leishmaniasis?

It can be a great choice. Many rescues place dogs that are diagnosed but stable, living normal lives with medication and regular checkups. Before you commit, ask about the dog's stage, recent blood and urine results, current treatment and its approximate cost, and make sure your vet is comfortable managing the disease or can work with a specialist.

Sources

• Centers for Disease Control and Prevention (CDC): leishmaniasis resources, including information on imported dogs.
• LeishVet: guidelines for the clinical management, staging and prevention of canine leishmaniosis.
• Companion Animal Parasite Council (CAPC): leishmaniasis in dogs.
• World Health Organization (WHO): leishmaniasis fact sheet.
• Merck Veterinary Manual: leishmaniosis in dogs.