Introduction and spread of visceral leishmaniasis in dogs in North America
Peter Schantz, PSchantz@cdc.gov, Centers for Disease Control and Prevention, Division of Parasitic Diseases/NCZVED/CCID, 4770 Buford Highway, Atlanta, GA
Until recently, visceral leishmaniaisis had been thought to be primarily an imported disease in North America. Dogs diagnosed with the infection had usually been imported from regions in southern Europe or South America where Leishmania infantum was known to be endemic. However, in addition to infection in imported dogs, there had been several reports of leishmaniasis in dogs at Foxhound kennels and hunt clubs in at least 10 states in the past 20 years. Serologic surveys of Foxhounds, other breeds of dogs, and wild canids, in the United States and Canada, revealed that canine visceral leishmaniasis is enzootic in Foxhounds in North America occuring widely in 18 states and 2 Canadian provinces; autochthonous L. infantum infections in canines are predominantly limited to Foxhounds. The epidemiologic data collected in our investigation and the apparent absence of active vector transmission suggest that spread of infection occurred and is ongoing by direct dog-to-dog transmission. Possible modes of direct dog-to-dog transmission include exchange of blood and secretions by biting, re-use of needles for inoculations, blood transfusions, breeding, and tattooing. Recommendations to segregate infected animals, suspend dog shows and hunting for clubs or kennels with dogs with leishmaniasis, and avoid co-mingling of animals between hunts were implemented initially by most of the hunts or kennels.