Parasite Biology: The Reservoir Hosts

Abstract

Leishmaniases are worldwide vector-borne diseases with diverse clinical manifestations caused by protozoa belonging to genus Leishmania. About 20 named Leishmania species are pathogenic for humans and are annually responsible for 0.7–1.2 million cases of cutaneous and 0.2–0.4 million cases of visceral forms of the disease. According to the transmission cycle involving animals or humans, leishmaniasis can be categorized in two main epidemiological groups: zoonotic (representing the large majority of such entities) and anthroponotic. Leishmaniases have re-emerged in recent years showing a wider geographic distribution and increased global prevalence. Environmental, demographic and human behavioural factors contribute to the changing epidemiology of the disease and to its recent spread throughout the world. Control strategies against anthroponotic leishmaniases should combine case management and vector control in order to reduce or eliminate parasite transmission. For zoonotic leishmaniases control of reservoir hosts has also been recommended, but few advances have been made, namely, in the case of cutaneous forms in both the Old and New Worlds due to the sylvatic nature of the reservoir hosts. On the other hand, strategies to control L. infantum in the domestic canine reservoir host have been developed, namely, topical insecticides against parasite infection and vaccines against disease evolution. Nevertheless and since Leishmania parasites have been found in a variety of wild and domestic animals around the world, it will be important to determine their role in the local epidemiology of leishmaniasis.