Carnivora, Bowdich, 1821

Roque, André Luiz R. & Jansen, Ana Maria, 2014, Wild and synanthropic reservoirs of Leishmania species in the Americas, International Journal for Parasitology: Parasites and Wildlife 3 (3), pp. 251-262 : 257-258

4.5. Order Carnivora

The mammals from this order also comprise a very heterogeneous group, including strict carnivores, such as ocelots ( Leopardus pardalis ) and tayras ( Eira barbara ) and species that supplement their diet with insects and fruits, such as coatis ( Nasua nasua ) and maned wolves ( Chrysocyon brachyurus ). Most have a large biomass and large range, important aspects of parasite dispersion ( Rocha et al., 2013). Moreover, some species such as raccoons and tayras are found both on the ground and in the canopy, favoring the dispersion of parasites among forest strata. Unfortunately, carnivores require large ranges and, because of their potential to predate on livestock (mainly chickens and cattle), are heavily hunted, placing some carnivore species at risk of extinction ( Silva and Adania, 2007).

Two carnivore species are closely linked to humans: dogs and cats. Dogs are the most important reservoirs of L. infantum throughout South America, although they can be infected with at least six other Leishmania species ( Dantas-Torres, 2009). Recently, the importance of cats in Leishmania epidemiology has also been suggested ( Pennisi et al., 2013). Among the wild carnivore hosts of L. infantum , the first description of infection was in the crab-eating fox Cerdocyon thous , although the authors inaccurately reported the host as Lycalopex vetulus ( Courtenay et al., 1996; Deane and Deane, 1955). Since then, many studies have confirmed L. infantum infection in C. thous by parasitological, serological and/or molecular assays. Notably, these animals sometimes develop serious symptoms of the disease and present with amastigotes in intact skin, as also described in domestic dogs. Their prevalence of infection may range from 42% (by parasitological tests) to 78% (by serology) ( Lainson et al., 1990; Quinnell and Courtenay, 2009; Silva et al., 2000). The vector infectivity was proven by xenodiagnosis, although the infection rate of vectors is reported to be lower than that observed for domestic dogs ( Courtenay et al., 2002; Quinnell and Courtenay, 2009).

Apart from C. thous , another wild carnivore that is a potential reservoir of L. infantum is the bush dog Speothos venaticus . An individual kept in a zoo in Rio de Janeiro, Brazil, is the only wild canid, except for C. thous , from which L. infantum was isolated ( Figueiredo et al., 2008). Infection in bush dogs was also confirmed by direct visualization, PCR and serology in two females with clinical signs of visceral leishmaniasis and maintained in other Brazilian zoos ( Lima et al., 2009; Souza et al., 2010). Other wild canid species found to be infected, albeit only by PCR and/or serology, were the hoary fox Pseudalopex vetulus and the maned wolf Chrysocyon brachyurus ( Curi et al., 2006; Luppi et al., 2008) ( Table 1).

Some authors have investigated Leishmania infection in captive wild carnivores. Five of 15 wild canids belonging to the four native species mentioned earlier were found to be infected in a zoo in Belo Horizonte, Brazil. Of these, one bush dog and one hoary fox developed clinical signs of visceral leishmaniasis ( Luppi et al., 2008). Among the wild felines, five pumas ( Puma concolor ) and one jaguar ( Panthera onca ) in a zoo from Cuiabá, Brazil, were PCR-positive in lymph-node puncture biopsy, L. infantum was specifically identified by the digestion of the amplified products with restriction enzymes ( Dahroug et al., 2010). Later, the same authors demonstrated L. infantum infection in one lion, a non-native felid species, kept in the same zoo ( Dahroug et al., 2011).

In addition to L. infantum , at least four other Leishmania species were found in wild carnivores: L. shawi in coatis Nasua nasua (Lainson et al., 1989) ; L. guyanensis in the kinkajou Potos flavus ( Pajot et al., 1982) ; L. amazonensis in kinkajous, crab-eating foxes and skunks Conepatus chinga ( Kreutzer et al., 1991; Rotureau, 2006; Telleria et al., 1999); and L. braziliensis in one Bolivian skunk ( Buitrago et al., 2011) ( Table 1).

Contrary to the numerous reports of infection in dogs and cats, much remains to study in terms of the putative roles of wild carnivores as Leishmania reservoirs. As in all host–parasite interactions, the infection patterns display regional and even individual peculiarities ( Rocha et al., 2013). If we consider that in some biomes (“Pantanal or Chaco ”, “Cerrado”, and “Pampa”) carnivore species are abundant and represent a huge biomass, any study of Leishmania reservoirs must include carnivores, including their Leishmania infection pattern, density and population structure in the area. Despite its inherent difficulties, the study of wild carnivores, especially in the areas where their relative abundance is high, is of fundamental importance to improve understanding of Leishmania ecology.