Leishmaniasis in dogs is a chronic parasitic disease which can be serious in dogs. The responsible parasite, Leishmania infantum, is transmitted by certain mosquitoes, sandflies. They are mainly present in the Mediterranean Basin, even if their distribution tends to extend little by little towards the north.
In addition, it is a zoonosis, that is to say that it can be transmitted to humans, also by bite of sandflies. It can be serious in humans, especially in immunocompromised people and children.
It is therefore important to know the existence of this disease. The risks of contamination and the means of prevention. Especially if you are staying or going to stay in the Mediterranean Basin.
Causes of leishmaniasis
When a sandfly carries the parasite, it transmits it to the dog during the bite. Parasites, or leishmanias, first multiply in skin cells. A small sore then appears at this location, most often on the ears or nose. But this can remain discreet and go unnoticed. Then it multiplies, disseminates in the body and will distribute in different organs. Thus, the clinical forms differ according to the locations and the animals. The main organs affected are the skin, kidneys, liver, eyes, or even the joints.
Symptoms of leishmaniasis in dogs
Leishmaniasis disease usually starts with a decrease in immunity and most often progresses slowly. The state of the dog’s immune system involves in the clinical expression (appearance of symptoms). In fact, approximately 50% of dogs will eliminate the parasite spontaneously; 40% will remain carriers of the parasite without triggering symptoms. And 10% will remain carriers of the parasite and trigger clinical signs.
The dog may have been infected several months or years before exhibiting symptoms.
Symptoms vary according to the organs mainly affected:
- General symptoms : weight loss, loss of appetite, the presence of lymph nodes all over the animal’s body, nosebleeds, joint pain and swelling, possibly fever. The size of the liver may increase.
- Cutaneous symptoms when the parasites will mainly distribute in the skin. These symptoms are loss of hair, dandruff, thickening of the skin with possibly the presence of dandruff, ulcers, abnormally long and often fragile claws, thickening of the pads.
- Kidney symptoms if the kidneys are affected. The symptoms are increase in the amount of drink and urine, decrease in general condition, possible vomiting.
- Eye symptoms : These are rarer but may appear if the parasites have reached the eyes. The eyes are then red, with discharge and often associated pain.
All symptoms may be present at the same time, or only some. The onset of clinical signs can be very progressive over several months to years, with jagged changes; it can be more brutal.
As the symptoms are very nonspecific, the disease is often difficult to diagnose. During the clinical examination, the veterinarian may suspect the disease in the presence of one or more of the symptoms described above, and especially in the event of a stay in areas where it is present. It is therefore essential that you tell your veterinarian if you have traveled with your dog, even if it was several years ago.
Additional examinations are necessary, on the one hand to confirm or refute the diagnosis of Leishmaniasis, and on the other hand to give a prognosis according to the severity of the attack.
The diagnosis of certainty rests on the demonstration of the presence of the parasites. For this, your veterinarian may take a blood test, skin biopsies, or even a lymph node puncture.
Additional blood tests will also make it possible to check the general condition of the animal. And also it will check the functioning of the kidneys and other organs.
Treatment and prognosis of Leishmaniasis
The prognosis of leishmaniasis in dogs is often reserved. Because the treatment does not completely eradicate the presence of the parasite in the body. It allows to decrease their quantity and to decrease the symptoms. But relapses are possible throughout the life of the animal. A dog carrying parasites will never be “bleached”: therefore, regular medical monitoring is necessary.
The prognosis is even more reserved when there is kidney damage because the lesions of these organs are irreversible.
Treatment is most often in the form of tablets or injections. It is often long, at least 12 months. Sometimes it will even have to be given for life if the animal supports it well. It happens in fact that it is badly tolerated and it must then be stopped.
Prevention of Leishmaniasis
Given the seriousness of this disease and its transmissibility to humans, preventive measures are important. Several means exist and can be combined.
If you live or need to stay in an area where leishmaniasis is present, speak to your veterinarian. He will be able to advise you on the means of prevention best suited to your animal. There is indeed a vaccine against this disease, making it possible to significantly reduce the risk of infection by allowing the body to defend itself more effectively against parasites.
In addition, several measures can be taken to prevent your dog from being bitten by sandflies. Your veterinarian can recommend suitable antiparasitic treatments.
The use of insecticides in the environment, in the form of bombs or sockets, can repel these insects. The use of mosquito nets can be useful to prevent them from entering homes. Plus, since they’re mostly active after dark, keeping your dog indoors at that time of day can help prevent bites.