Examinando por Autor "Aguilar, Emilio"

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    Assessing micro-macroparasite selective pressures and anthropogenic disturbance as drivers of immune gene diversity in a Neotropical wild cat
    (Elsevier B.V., 2023-11-01) Napolitano, Constanza; Sacristán, Irene; Acuña, Francisca; Aguilar, Emilio; García, Sebastián; López-Jara, María José; Cabello, Javier
    Anthropogenic environmental change is reducing available habitat for wild species, providing novel selection pressures such as infectious diseases and causing species to interact in new ways. The potential for emerging infectious diseases and zoonoses at the interface between humans, domestic animals, and wild species is a key global concern. In vertebrates, diversity at the major histocompatibility complex MHC is critical to disease resilience, and its study in wild populations provides insights into eco-evolutionary dynamics that human activities alter. In natural populations, variation at MHC loci is partly maintained by balancing selection, driven by pathogenic selective pressures. We hypothesize that MHC genetic diversity differs between guigna populations inhabiting human-dominated landscapes (higher pathogen pressures) versus more natural habitats (lower pathogen pressures). We predict that MHC diversity in guignas would be highest in human-dominated landscapes compared with continuous forest habitats. We also expected to find higher MHC diversity in guignas infected with micro and macro parasites (higher parasite load) versus non infected guignas. We characterized for the first time the genetic diversity at three MHC class I and II exons in 128 wild guignas (Leopardus guigna) across their distribution range in Chile (32–46° S) and Argentina, representing landscapes with varying levels of human disturbance. We integrated MHC sequence diversity with multiple measures of anthropogenic disturbance and both micro and macro parasite infection data. We also assessed signatures of positive selection acting on MHC genes. We found significantly higher MHC class I diversity in guignas inhabiting landscapes where houses were present, and with lower percentage of vegetation cover, and also in animals with more severe cardiorespiratory helminth infection (richness and intensity) and micro-macroparasite co-infection. This comprehensive, landscape-level assessment further enhances our knowledge on the evolutionary dynamics and adaptive potential of vertebrates in the face of emerging infectious disease threats and increasing anthropogenic impacts.
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    Gastrointestinal and cardiorespiratory endoparasites in the wild felid guigna (Leopardus guigna) in Chile: Richness increases with latitude and first records for the host species
    (Australian Society for Parasitology, 2020-12) Acuña-Olea, Francisca; Sacristán, Irene; Aguilar, Emilio; García, Sebastián; López, María José; Oyarzún-Ruiz, Pablo; Brito, José Luis; Fredes, Fernando; Napolitano, Constanza
    Guignas (Leopardus guigna) are small felids closely associated with native forest habitats. In fragmented land scapes, they use vegetation corridors and forest remnants to move across the landscape. In these contexts, gui gnas may increase contact probabilities with domestic animals, being therefore relevant to assess their pathogens and parasites. The aim of this study was to characterize the helminth fauna in the gastrointestinal tract and cardiorespiratory system of guignas from central and southern Chile. Between 2015 and 2018, 33 dead free ranging guignas were found road-killed or were collected from wildlife rescue centers. Thirty-two gastrointes tinal tracts and 32 cardiorespiratory organs were analyzed through direct analysis and artificial digestion. We found 81.8% (27/33) guignas were positive for helminth endoparasites (84.4% (27/32) positive for gastroin testinal parasites, 37.5% (12/32) positive for cardiorespiratory parasites). Fourteen parasites were identified (7 at genus level and 7 at species level), with Angiostrongylus sp., Molineus sp., Oslerus sp. and Troglostrongylus sp. as first records in guignas. The most prevalent parasites were the species Toxascaris leonina, Toxocara cati and Uncinaria stenocephala. Uncinaria stenocephala showed the highest intensity of infection. Multiparasitism was observed in 76% of the animals. Significant differences in richness of endoparasites and prevalence of cardio respiratory parasites were found between geographic zones; higher values in the southern zone are possibly due to favorable environmental characteristics for endoparasite development. There were no statistically significant differences between sexes. All the parasites found in this study have been previously reported in domestic cats. These results are valuable to understand parasite transmission at the domestic-wildlife interface; the possibility of endoparasite transmission between domestic cats and guignas should be clarified with molecular analysis.
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    Molecular and serological survey of carnivore pathogens in free-roaming domestic cats of rural communities in southern chile
    (Japanese Society of Veterinary Science, 2019-12) Sacristán, Irene; Sieg, Michael; Acuña, Francisca; Aguilar, Emilio; García, Sebastián; López, María José; Cevidanes, Aitor; Hidalgo-Hermoso, Ezequiel; Cabello, Javier; Vahlenkamp, Thomas W.; Millán, Javier; Poulin, Elie; Napolitano, Constanza
    Owned, free-roaming domestic cats are abundant in the Chilean countryside, having high probability of contact with wildlife and potentially participating as reservoirs of zoonotic pathogens. In the present study, 131 cats from two remote study areas (Valdivia and Chiloe Island) in southern Chile were analyzed for infection/exposure to eight pathogens. Serum samples from 112 cats were tested for antigens against feline leukemia virus (FeLV antigen-ELISA) and antibodies against feline immunodeficiency virus (FIV-ELISA) and canine distemper virus (CDV-serum neutralization), yielded occurrence of 8.9, 1.7 and 0.8% respectively. The presence of DNA of five vector-borne pathogens, piroplasmids, Ehrlichia spp., Anaplasma spp., Rickettsia spp. and Bartonella spp. was investigated in thirty cats. Overall observed occurrence was 6.6% (2/30) for both Anaplasma platys, and B. henselae, and 3.3% (1/30) for both Bartonella sp. and Theileria equi. Observed occurrence for all vector-borne pathogens in Valdivia area was significantly higher than in Chiloe Island (5/15 vs 0/15; P=0.04). Our results represent the first description of exposure to CDV and DNA detection of T. equi and A. platys in domestic cats in Chile. The results highlight the importance of performing pathogen screening in owned, free-roaming rural cats to evaluate their potential role as reservoirs of infection and vectors for disease transmission to wildlife.