Leishmania is a protozoal disease spread by sand flies, seen in Southern Europe, some parts of Asia, Africa (particularly the tropical regions and North Africa), the Middle East and some parts of Central and South America. This is also a serious disease in people. There have been cases in the UK where non travelling dogs have caught this disease from other dogs in the home that were rescued from Mediterranean countries, despite no sand flies being present. It is possible that ticks and fleas can transmit this disease too. Sand flies are very small, about a quarter of the size of a mosquito. Cats can be infected but rarely show symptoms and only dogs require preventative care. Some of the collars used to protect dogs can prove fatal to cats (pyrethroid containing collars).

Symptoms

• 50% of dogs can be infected without showing clinical signs. Blood testing is complicated and it is possible to have negative results from infected dogs.
• The most common symptoms include swollen lymph nodes and skin disease. This includes hair loss, thickening, crusting or ulceration, skin irritation is not usually itchy. These usually start a few months to a few years after becoming infected.
• Dogs that do show clinical symptoms have highly variable symptoms as this long-term disease can affect any combination of organ systems. Such symptoms can include weight loss, diarrhoea, kidney failure, arthritis and lameness (involving more than one joint or limb) or neurological complications. Most dogs are anaemic and have low platelets and white blood cells.
• If your dog was adopted from a Mediterranean region or travelled there at some point, make your vet aware of possible exposure should they become unwell with skin or kidney disease, lameness moving between legs or any other disease where diagnosis isn’t obvious.
• Dogs can go into remission but not be cured. Relapses are common, They can serve as a source of infection for healthy dogs and people whilst appearing clinically healthy.

Prevention

• This disease is most typically seen in summer, or when temperatures are above 15C (highest incidence April to November).
• Avoid being outdoors between dusk and dawn, when sand flies are most active.
• Well screened windows and doors and air conditioned spaces indoors are safest, insect nets can be used around pet beds.
• Insect repellent collars can be prescribed to repel sand flies. Some of these are less toxic to water life and sitable for dogs that are likely to swim.
• A vaccination program exists if you spend significant time in endemic areas, it needs to be started at least 4 weeks before travel. Unlike previous vaccines, it is well tolerated and is a single, annual injection. Combined with sand fly protection, this combination gives excellent protection against clinical infection.
• Treatment options exist, but they aim to limit the symptoms and cannot cure infected dogs. Prevention is ideal.