Canine leishmaniasis (LEESH-ma-NIGH-ah-sis) is a zoonotic disease (see human leishmaniasis) caused by Leishmania parasites transmitted by the bite of an infected phlebotomine sandfly. Canine leishmaniasis was first identified in Europe in 1903, and in 1940, 40% of all dogs in Rome were determined to be positive for leishmaniasis. Traditionally thought of as a disease only found near the Mediterranean basin, 2008 research claims new findings are evidence that canine leishmaniasis is currently expanding in continental climate areas of northwestern Italy, far from the recognized disease-endemic areas along the Mediterranean coasts. Cases of leishmaniasis began appearing in North America in 2000, and, as of 2008, Leishmania-positive foxhounds have been reported in 22 U.S. states and two Canadian provinces.
Cutaneous
Visceral
Numerous strains and subgenus strains of Leishmania exist; with sandfly genome projects still underway, strains are still being discovered.
In the Old World, leishmaniasis transmitted by sandflies of the genus Phlebotomus documented in dogs are:
New World leishmaniasis strains are spread by Lutzomyia; however, research speculates the North American sandfly could be capable of spreading, but this is to date unconfirmed. Dogs are known resorvoirs of L. infantum, and the spread of disease from dog to dog has been confirmed in the United States.
The Mexicana (L. mexicana, L. amazonensis, L. venezuelensis, and L. pifanoi) and Viannia (L. braziliensis, L. guyanensis, L. panamensis and L. peruviana) strains are not commonly found in dogs. Subgenus Viannia strains are found only in Central and South America, all of which cause leishmaniasis in humans.
Traditionally, canine transmission is directly from sandfly to dog. Cases in the United States have proven L. infantum transmission from dog to dog by direct contamination with blood and secretions, as well as transplacentally from an infected bitch to her pups. This mode of transmission seems to be unique to the L. infantum Mon1 strain found in the United States. Although in utero transmission is likely the predominant method of disease spread amount the L. infantum Mon1 strain, it is still a viable parasite (has not lost virulence factors associated with sandfly-uptake) which can be transmitted via sandfly bite. A Brazilian study of 63 puppies from 18 L. donovani-infected parents found no evidence of congential or transplacental infection.