Canine wasting disease, also known as visceral leishmaniasis, is a deadly infectious disease transmitted by sand flies and by direct dog-to-dog transmission. The infection is typically acquired after one or more sand flies transmit the leishmania parasite into the skin of a host. Both canines and humans can be infected by the illness, which attacks the spleen, liver and bone marrow, and can be fatal. While there's no particular age or breed predilection, male dogs are more likely to develop canine wasting disease.
Canine visceral leishmaniasis was believed to be imported to the United States -- dogs who developed the disease were found to have acquired the infection in another country where the sand fly is prevalent, typically Spain, Portugal and the Mediterranean basin. In 2000, however, the infection caused high rates of death and illness among foxhounds in a New York kennel. The infected dogs never visited any areas where leishmaniasis is epidemic, and the exact origin of the infections still remains unknown, according to the March 2006 issue of "Emerging Infectious Diseases". Today, canine visceral leishmaniasis has been found enzootic in two Canadian provinces and 18 states in America.
The incubation period from infection to symptoms of visceral leishmaniasis can be between one month and several years. Initial symptoms are typically loss of appetite followed by rapid weight loss. As the illness progresses, other symptoms include but are not limited to severe muscle atrophy, diarrhea, vomiting, seizures, nose bleeds, excessive thirst, lameness, swollen lymph nodes, increased urination and skin lesions. Visceral leishmaniasis eventually spreads throughout a dog's body and infects most of his organs. Kidney failure is the leading cause of death.
If your dog begins to lose his appetite or display any other symptoms of visceral leishmaniasis, take him to a veterinarian for a complete physical exam. The vet will conduct a series of laboratory tests, including a urinalysis and complete blood count. Many other illnesses display the same symptoms as those of visceral leishmaniasis and need to be ruled out -- cancer, lupus, distemper and tick fever are among them. Tissue samples from your dog's liver, bone marrow, spleen and lymph nodes will reveal anti-leishmania antibodies and evidence of the parasite.
Visceral leishmaniasis is resistant to treatment, and no permanent cure exists. Even when treatment is successful for the short term, relapses of the illness are common. Another problem is the side effects from long-term drug use to treat the illness, which often creates further health problems for the dog and drug-resistant microorganisms. Dogs who aren't severely ill are usually treated as outpatients. But for dogs who are at advanced stages of the disease, the Centers for Disease Control and Prevention recommends euthanasia.
- Emerging Infectious Diseases: Canine Visceral Leishmaniasis, United States and Canada, 2000-2003
- Cornell University College of Veterinary Medicine: An Overview of Canine Leishmania Infections
- PetMD: Parasite Infection ((Leishmaniasis) in Dogs
- Companion Animal Parasite Council: Canine Leishmaniasis
- Kennel Club: Canine Wasting Disease
- David De Lossy/Photodisc/Getty Images