Implicación epidemiológica de carnívoros silvestres de ambientes atlánticos en el mantenimiento y dispersión de Escherichia coli, Trichinella SPP y Ectoparásitos

Abstract

SUMMARY The rising human population and its huge use of natural resources are triggering human invasion of several ecosystems. Consequently, there is a greater contact between wildlife, domestic animals and man himself, and more intra- and inter-specific transmission of infectious agents. Some generalist carnivore species have increased their populations due to their successful adaptation to anthropogenic environments. As these species are positioned on the top of the food chain, are long-lived and have greater dispersion capacity than other species, these carnivore species act as bio-accumulator and potential transmitters of many infectious agents. Our study aims to demonstrate the epidemiological role played by native and non-native generalist carnivore species in the maintenance and spread of some multi-host zoonotic pathogens in Atlantic bioclimatic areas. It has been partially conducted in Galicia, a Spanish area with one of the highest rural population and traditional extensive and semi-extensive livestock raising. Moreover, Galicia shows the highest density of Iberian Wolf (Canis lupus signatus) and Red Fox (Vulpes vulpes) in the Iberian Peninsula. The presence of verotoxigenc E. coli (VTEC) was evaluated in 260 fecal samples from foxes, using specific cultures and further PCR on the confluent growth of those crops. A result of 6.1% of positive samples was obtained from a total of 6 different VTEC strains. Characterization and comparison of these revealed that 3 of the 6 strains isolated from foxes VTEC, belonging to serotypes O5:HNM, O98: [H21] and O146: [H21], showed genetic profiles similar to other human pathology VTEC strains isolated in the same geographic area; and what is more important, the profile of macrorrestricción of the O5:HNM strain isolated from Fox showed a similarity over 89% with a human strain and a strain isolated from beef.. These results highlight the role of canids as carriers and possible transmitters of seropathotypes involved in clinical cases in the peninsular northwest. A total of 100 wolves and 1,196 foxes were analyzed for Trichinella spp. larvae detection using an artificial digestion method. Trichinella britovi and T. spiralis in wolves, and T. britovi in foxes were identified in 3% and 0.73% positive samples respectively.The prevalence and the largest number of Trichinella spp. identified in wolves, indicate that this carnivore is the main bioaccumulator and, therefore, the target species to investigate in the epidemiology of the Trichinella sylvatic cycle in Galicia. The prevalence of ectoparasites was studied on 224 foxes, obtaining a result of 75.9% of parasitized animals. Four species of ticks (Ixodes hexagonus, Dermacentor reticulatus, Ixodes ricinus and Rhipicephalus turanicus) and six flea species (Ctenocephalides canis, Ctenocephalides felis, Pulex irritans, Paraceras melis, Archeopsylla erinacei and Spilopsyllus cuniculi) were identified. Some of these species are able to parasitize other mammals that share the same habitat. This fact shows the relationship between hosts of different ectoparasite species that coexist in our study area, as well as the role of the fox as a host and dispersal agent of these. Finally, 48 feral cats (Felis catus) were analyzed on the island of Corvo (Azores) to determine the effect of insularity on the ectoparasite richness of non-native carnivores in Atlantic environments. The low species diversity detected, Ctenocephalides felis (91.6%) and Rhipicephalus turanicus (10%), confirms that geographical isolation can reduce drastically the number of ectoparasite species on generalist carnivores. The obtained results also confirm the relationship between the different ectoparasite species host that coexist in the island and the detected parasite abundance.