Visceral leishmaniasis caused by Leishmania infantum is a potentially fatal disease of dogs and humans transmitted by sand flies. The dog is considered the main peridomestic reservoir for human infection. In 1994, a dog with dermatologic abnormalities referred to the Hebrew University Veterinary Teaching Hospital was the first canine leishmaniasis case reported from central Israel in over 40 years. Since then, research on canine leishmaniasis has been carried out in my laboratory at the Hebrew University School of Veterinary Medicine in collaboration with Prof. Charles Jaffe of the Kuvin Centre. We found that about 20% of the dogs in rural foci were infected and that the disease was spreading. Evidence for infection was found in wild canine species including jackals and foxes. The majority of the affected dogs originated in rural settings, however, recently canine infection appears to be urbanizing. In addition, human infection also emerged in central Israel and to a greater extent among Palestinians in the West Bank. A recent project in collaboration with Prof. Ziad Abdeen of Al Quds University was aimed at identifying ecological risk factors for visceral leishmaniasis in Israel and the Palestinian Authority using geographic information system (GIS).
Research has focused on the study of the cellular and humoral immune responses in canine leishmanisis. Our aim is to understand the role of cytokines and chemokines in the progression of infection, and to evaluate protective mechanisms that may be enhanced by vaccines or cytokine therapy. Screening for early markers of infection is carried out using recombinant L. infantum proteins and whole parasite antigens. A non-invasive PCR from conjuctival swabs has been found as a sensitive diagnostic technique for the molecular detection of L. infantum infection.
Other Leishmania-related research carried out in my laboratory includes the study of Leishmania tropica infection and the search for an animal reservoir for this agent of human cutaneous leishmaniasis in Israel with special emphasis on infection in rock hyraxes. In addition to that, studies on other vector-borne infections of domestic animals include research on hepatozoonosis, babesiosis and relapsing fever borreliosis. The transmission of Hepatozoon canis by ingestion of the tick final host and the parasite life cycle were studied in dogs and Rhipichephalus sanguineus ticks. The different life stages of H. canis were reported and a cyst stage was described in the tissues of dog. Antibody responses to infection were studied and immunodominant antigens were identified. Phylogenetic analyses facilitated the comparison of H. canis to other related species and research in collaboration with scientist from Auburn University in Alabama resulted in the separation of H. canis from the North American species Hepatozoon americanum. Tick-borne Babesia canis infection in dogs and cats is currently being studied. Borrelia persica, the cause of Persian relapsing fever transmitted by the soft tick Ornithodoros tholozani in Israel has recently been detected in dogs and cats in my laboratory. Ongoing studies are aimed at investigating the possible role of animals in this infection.