What is Canine Leishmaniasis?
A Mediterranean Disease
Leishmania are little parasites (protozoes) which affect the white blood cells, causing systemic disease, mainly in dogs.
The transmission of Leishmaniosis is made by the Sandfly (phlebotomus), a very tiny fly with white wings. The female sandflies suck blood from their victims in order to breed their eggs later.
The distribution of the sandfly, and with her, the risk of leishmaniosis infection, is prevalent all over the meditteranean areas, South of France, Southern Italy, Southern Spain and Portugal, as well as India and Africa.
In Europe, the sandfly transmits leishmania infantum, whereas in India and Africa there exists different leishmania species, which are more likely to cause infection in humans.
The transmission of leishmaniosis occurs as follows:
A sandfly bites a dog which is carrying leishmaniosis, later, the same sandfly bites a healthy dog and injects leishmania with her saliva under the skin of the dog. From the site of infection, the “chancra”, the leishmania, start a very difficult development in several steps until they reach the blood and after an incubation period of between 3 weeks and 3 months (sometimes 3 years), depending on the state of the dogs defense system, the first visible symptoms occur.
The sandfly is active between April to November (during the warm season), it disappears in winter. The sandfly hides during the daytime and comes out late afternoon with the highest period of activity occurring at night between 2.00am – 4.00am. Therefore, dogs who live outside are much more exposed to sandfly bites than dogs who live inside, especially if the house is well protected against mosquitos with nets or chemical products. The month of August is the worst, as this is when the highest amount of sandfly’s are seen. This is when they are most likely to invade the house as well, they hide in dark bathrooms or wardrobes.
The main symptoms of leishmaniosis in the dog are:
Skin alterations, eye alterations, weight loss, long growth of nails, swollen lymph glands, liver and kidney disease including failure. Alterations in blood coagulation with anaemia, nose bleeding, lameness, chronic diarrhoea etc.
The diagnosis of leishmaniosis is mainly by a bloodtest, together with a general clinical check and control of the liver and kidney functions. Other diagnostical tools are: skin biopsy or bone marrow biopsy which are not routinely employed.
Treatment of leishmaniosis:
Treatment is only effective if it starts at an early stage of infection, better even before they show any symptoms. Therefore, it is very important to make regular blood tests in dogs, once a year and better in the winter months, to find out if the dog was infected during the summer. Early treatment normally avoids symptoms and gives the dog a longer life.
Dogs with mild symptoms can be treated successfully as well, but dogs with serious anaemia or serious alteration of liver/kidney function very often cannot be treated successfully.
Prevention of Leishmaniosis
It is very difficult to prevent leishmaniosis 100 percent, because sandflies are so very tiny they can even penetrate mosquito netting, but there are 3 keypoints to help avoid risk of infection.
– dogs should be kept inside at night to reduce exposure to sandfly bites.
– Provide your dog with a special antisandfly collar which is proven to be more effective than other insecticides. Start in March with the collar application and maintain it until the end of November(ask your vet for the correct collar).
– A yearly blood test to make sure your dog was not in contact with this disease.
There still does not exist a vaccination against Leishmaniosis, but investigation into this subject is advancing.
Can Humans catch leishmaniosis?
The sandfly bites every species,and in theory can infect every species with leishmaniosis.
The dog, living closely with humans, is considered to be a “reservoir”, a source of leishmania supply. A direct infection is not possible, it is always the sandfly which causes it. There are no sandflys in the UK.
Other species, including humans, are considered to be more resistant to the leishmaniosis species which inhabit Europe. Cats, for example, hardly ever contract it, and there are no reports of contraction by other species. Humans with severe immune suppression (AIDS, or after organic transplantation, longtime steroid therapy) can become infected.Therefore it is very important to avoid sandfly bites with mosquito repellents, sprays, mosquito nets etc. as well as treating a dog who shows positive in a blood test. Dogs with treatment are no more a source of infection for the sandfly.
DogWatch dogs are mostly adopted from Spain and Portugal. Every dog has a complete laboratory blood test together with proteinogram which is sent with the dog’s passport and TRACES documentation and in the case where a dog has been diagnosed with a positive result, the dog will have been treated and any ongoing medications and Veterinary advice are also sent giving a full blood history and if positive, the treatment received and treatment which will be ongoing.
There is a Leish support group on Facebook with nearly 6000 members, called Living with Leish, where admin provide free advice from diagnosis, to sourcing of drugs and treatment methods.
There is also a page https://www.facebook.com/Canine-leishmaniasis-253815474643017
For vets who are unfamiliar with Canine Leishmaniasis, there is an information website specifically for vets www.leishvet.org where they can follow diagnostic and treatment protocols. They are a group of highly experienced vets from endemic countries and their website is written by vets and for vets.