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Canine Leishmaniasis |
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The number
of dogs becoming ill due to foreign diseases has shown a marked
increase
since the introduction of the pet travel scheme. Between 2002 and
2003 the reported cases of severe illness due to 'exotic infections' in
recently travelled dogs doubled to 44. The latest figures show an
even more startling rise in the total number of cases of canine
leishmaniosis
occurring between 2005 and 2007 shooting up to 257. This disease is typically found in
warm, coastal areas like Brazil, the Mediterranean, India and the
Sudan. If
you are heading towards southern Europe for your holiday and especially
to the beaches, you should consider buying your dog a Scalibor collar to protect him against the
sandfly.
He will need to wear the collar one week before, during and one
week
after the trip.
Leishmaniasis is an infectious parasitic disease spread by the bite of infected female sand flies. Female sand flies contract the Leishmania parasite as they feed on an infected animal and ingest the intracellular, non-flagellated form of parasite. Once ingested, the parasite transforms into a flagellated form, called promastigote. The promastigotes attach themselves to the gut wall of the sand fly and proceed to multiply and differentiate into infective promastiogotes. When the sand fly feeds on a new host, the promastigotes may be injected into the animal’s skin. Once within their new host, the promastigotes lose their flagella and multiply inside certain types of white blood cells, the macrophages, as amastigotes.
This initial multiplication occurs at or near the site of infection on the skin. The parasites will then spread from the skin to the bone marrow, spleen, and liver. Once in these organs the parasites cause a chronic, debilitating, and potentially fatal disease. The parasites can infect both humans and canines. The disease is particularly common in tropical and subtropical areas with significant sand fly populations. The domestic dog seems to be the main reservoir for human visceral leishmaniasis, rendering disease control that much more vital. Unfortunately efforts to control leishmaniasis in dogs have been largely unsuccessful, though as more research is being done, progress is being and will continue to be made.
There are several different forms of leishmaniasis. The most common forms are cutaneous leishmaniasis, which causes skin sores, and visceral leishmaniasis, which affects some of the internal organs of the body (for example, spleen, liver, bone marrow). Symptoms of leishmaniasis include skin lesions, dermatitis nose bleeds, swollen lymph glands, weight loss, seizures, hair loss, eye, liver and kidney disease, and swollen limbs and joints, decreased appetite and an intolerance of exercise. If left untreated it is fatal and even with therapy there is no cure for leishmaniasis in dogs,but it can be put into remission, with affected animals remaining permanently infected. Symptoms can develop from a few months to several years after infection.
Dr. Edward Breitschwerdt, professor of small animal internal medicine at NC State, says:
"Leishmaniasis is a serious disease that leads to chronic debilitation and kidney failure in dogs, and can lead to their death. Unfortunately the disease is extremely hard to diagnose,"
A visceral leishmaniasis diagnosisis is found by laboratory tests. Most commonly, serologic methods such as IFAT, ELISA and western blotting are used to detect anti-Leishmania antibodies. If the infection is at an advanced stage, it may be possible to isolate the Leishmania organism directly.
Canine leishmaniasis is much more resistant to treatment than the human infection. For this reason a full parasitological cure in dogs is rarely achieved. Drugs such as pentavalent antimonials are frequently used to treat symptoms, and significant clinical improvement often occurs initially. Long term, however, relapses are common and the situation is complicated by the fact that frequent, long term drug use can both be harmful to the dog and create drug resistant microorganisms.
If you live in an area where Leishmania is endemic, or if you have traveled or will soon be traveling to such an area, certain steps may be taken to minimize the risk of exposure. As far as dogs are concerned, if you live in an area at high risk, blood screening should be done on a regular basis. This allows for an infection to be caught and treated early and avoid the risk of spreading the infection. The general health of your companion dog should be kept high, as lowered immune response greatly increases the chance of infection. Preventative collars that repel the sand fly are commercially available and have been used with some success. Sand flies are most active between dusk and dawn, so if possible, limit time spent outdoors during these hours.
Leishmaniasis is an infectious parasitic disease spread by the bite of infected female sand flies. Female sand flies contract the Leishmania parasite as they feed on an infected animal and ingest the intracellular, non-flagellated form of parasite. Once ingested, the parasite transforms into a flagellated form, called promastigote. The promastigotes attach themselves to the gut wall of the sand fly and proceed to multiply and differentiate into infective promastiogotes. When the sand fly feeds on a new host, the promastigotes may be injected into the animal’s skin. Once within their new host, the promastigotes lose their flagella and multiply inside certain types of white blood cells, the macrophages, as amastigotes.
This initial multiplication occurs at or near the site of infection on the skin. The parasites will then spread from the skin to the bone marrow, spleen, and liver. Once in these organs the parasites cause a chronic, debilitating, and potentially fatal disease. The parasites can infect both humans and canines. The disease is particularly common in tropical and subtropical areas with significant sand fly populations. The domestic dog seems to be the main reservoir for human visceral leishmaniasis, rendering disease control that much more vital. Unfortunately efforts to control leishmaniasis in dogs have been largely unsuccessful, though as more research is being done, progress is being and will continue to be made.
There are several different forms of leishmaniasis. The most common forms are cutaneous leishmaniasis, which causes skin sores, and visceral leishmaniasis, which affects some of the internal organs of the body (for example, spleen, liver, bone marrow). Symptoms of leishmaniasis include skin lesions, dermatitis nose bleeds, swollen lymph glands, weight loss, seizures, hair loss, eye, liver and kidney disease, and swollen limbs and joints, decreased appetite and an intolerance of exercise. If left untreated it is fatal and even with therapy there is no cure for leishmaniasis in dogs,but it can be put into remission, with affected animals remaining permanently infected. Symptoms can develop from a few months to several years after infection.
| Other
common indicators of visceral
leishmaniasis |
| depression ocular changes epistaxis excessive thirst excessive urine production diarrhea vomiting sneezing coughing lameness |
| This is by no means an exhaustive list –
leishmaniasis affects so many parts of the body that the variety of
clinical signs is nearly boundless. It should be noted that Leishmania
infection should only be suspected in areas where sand flies are
present
as they are the major vector of infection. |
Dr. Edward Breitschwerdt, professor of small animal internal medicine at NC State, says:
"Leishmaniasis is a serious disease that leads to chronic debilitation and kidney failure in dogs, and can lead to their death. Unfortunately the disease is extremely hard to diagnose,"
A visceral leishmaniasis diagnosisis is found by laboratory tests. Most commonly, serologic methods such as IFAT, ELISA and western blotting are used to detect anti-Leishmania antibodies. If the infection is at an advanced stage, it may be possible to isolate the Leishmania organism directly.
Canine leishmaniasis is much more resistant to treatment than the human infection. For this reason a full parasitological cure in dogs is rarely achieved. Drugs such as pentavalent antimonials are frequently used to treat symptoms, and significant clinical improvement often occurs initially. Long term, however, relapses are common and the situation is complicated by the fact that frequent, long term drug use can both be harmful to the dog and create drug resistant microorganisms.
If you live in an area where Leishmania is endemic, or if you have traveled or will soon be traveling to such an area, certain steps may be taken to minimize the risk of exposure. As far as dogs are concerned, if you live in an area at high risk, blood screening should be done on a regular basis. This allows for an infection to be caught and treated early and avoid the risk of spreading the infection. The general health of your companion dog should be kept high, as lowered immune response greatly increases the chance of infection. Preventative collars that repel the sand fly are commercially available and have been used with some success. Sand flies are most active between dusk and dawn, so if possible, limit time spent outdoors during these hours.
