Examinando por Autor "Alvarado-Rybak, M."
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Ítem Development and worldwide use of non-lethal, and minimal population-level impact, protocols for the isolation of amphibian chytrid fungi(Nature Publishing Group, 2018-12) Fisher, M.C.; Ghosh, P.; Shelton, J.M.G.; Bates, K.; Brookes, L.; Wierzbicki, C.; Rosa, G.M.; Farrer, R.A.; Aanensen, D.M.; Alvarado-Rybak, M.; Bataille, A.; Berger, L.; Böll, S.; Bosch, J.; Clare, F.C.; Courtois, E.A.; Crottini, A.; Cunningham, A.A.; Doherty-Bone, T.M.; Gebresenbet, F.; Gower, D.J.; Höglund, J.; James, T.Y.; Jenkinson, T.S.; Kosch, T.A.; Lambertini, C.; Laurila, A.; Lin, C.-F.; Loyau, A.; Martel, A.; Meurling, S.; Miaud, C.; Minting, P.; Ndriantsoa, S.; O'Hanlon, S.J.; Pasmans, F.; Rakotonanahary, T.; Rabemananjara, F.C.E.; Ribeiro, L.P.; Schmeller, D.S.; Schmidt, B.R.; Skerratt, L.; Smith, F.; Soto-Azat, C.; Tessa, G.; Toledo, L.F.; Valenzuela-Sánchez, A.; Verster, R.; Vörös, J.; Waldman, B.; Webb, R.J.; Weldon, C.; Wombwell, E.; Zamudio, K.R.; Longcore, J.E.; Garner, T.W.J.Parasitic chytrid fungi have emerged as a significant threat to amphibian species worldwide, necessitating the development of techniques to isolate these pathogens into culture for research purposes. However, early methods of isolating chytrids from their hosts relied on killing amphibians. We modified a pre-existing protocol for isolating chytrids from infected animals to use toe clips and biopsies from toe webbing rather than euthanizing hosts, and distributed the protocol to researchers as part of the BiodivERsA project RACE; here called the RML protocol. In tandem, we developed a lethal procedure for isolating chytrids from tadpole mouthparts. Reviewing a database of use a decade after their inception, we find that these methods have been applied across 5 continents, 23 countries and in 62 amphibian species. Isolation of chytrids by the non-lethal RML protocol occured in 18% of attempts with 207 fungal isolates and three species of chytrid being recovered. Isolation of chytrids from tadpoles occured in 43% of attempts with 334 fungal isolates of one species (Batrachochytrium dendrobatidis) being recovered. Together, these methods have resulted in a significant reduction and refinement of our use of threatened amphibian species and have improved our ability to work with this group of emerging pathogens. © 2018 The Author(s).Ítem Distributional ecology of Andes hantavirus: A macroecological approach(BioMed Central, 2018-06) Astorga, F.; Escobar, L.E.; Poo-Muñoz, D.; Escobar-Dodero, J.; Rojas-Hucks, S.; Alvarado-Rybak, M.; Duclos, M.; Romero-Alvarez, D.; Molina-Burgos, B.E.; Peñafiel-Ricaurte, A.; Toro, F.; Peña-Gómez, F.T.; Peterson, A.T.Background: Hantavirus pulmonary syndrome (HPS) is an infection endemic in Chile and Argentina, caused by Andes hantavirus (ANDV). The rodent Oligoryzomys longicaudatus is suggested as the main reservoir, although several other species of Sigmodontinae are known hosts of ANDV. Here, we explore potential ANDV transmission risk to humans in southern South America, based on eco-epidemiological associations among: six rodent host species, seropositive rodents, and human HPS cases. Methods: We used ecological niche modeling and macroecological approaches to determine potential geographic distributions and assess environmental similarity among rodents and human HPS cases. Results: Highest numbers of rodent species (five) were in Chile between 35° and 41°S latitude. Background similarity tests showed niche similarity in 14 of the 56 possible comparisons: similarity between human HPS cases and the background of all species and seropositive rodents was supported (except for Abrothrix sanborni). Of interest among the results is the likely role of O. longicaudatus, Loxodontomys micropus, Abrothrix olivaceus, and Abrothrix longipilis in HPS transmission to humans. Conclusions: Our results support a role of rodent species' distributions as a risk factor for human HPS at coarse scales, and suggest that the role of the main reservoir (O. longicaudatus) may be supported by the broader rodent host community in some areas. © 2018 The Author(s).Ítem Pathological Findings in Cetaceans Sporadically Stranded Along the Chilean Coast(Frontiers Media S.A., 2020-08) Alvarado-Rybak, M.; Toro, F.; Abarca, P.; Paredes E.; Español-Jiménez, S.; Seguel, M.Chile has one of the largest coastlines in the world with at least 50% of the world cetacean species occurring within its jurisdictional waters. However, little is known regarding the health status and main causes of death in cetaceans off continental Chile. In this report, we summarize the major pathological findings and most likely causes of death of 15 cetaceans stranded along the Chilean coast between 2010 and 2019. Drowning, due to fishing gear entanglement, was the most likely cause of death in 3 Burmeister’s porpoises (Phocoena spinipinnis), a Risso’s dolphin (Grampus griseus) and a short-beaked common dolphin (Delphinus delphis). Additionally, the 3 Burmeister’s porpoises had mild to moderate eosinophilic and histiocytic pneumonia with pulmonary vasculitis associated with the nematode Pseudalius inflexus. A fourth Burmeister’s porpoise died of drowning after stranding alive at a sandy beach. Two fin whales (Balaenoptera physalus) died most likely of trauma associated with large vessel collision. A long-finned pilot whale (Globicephala melas) and an Orca (Orcinus orca) stranded most likely due to traumatic intra/interspecific interaction with other odontocete although for the pilot whale, osteoporosis with loss of alveolar bone and all teeth could have played a role. For a Strap-toothed beaked whale (Mesoplodon layardi), Dwarf sperm whale (Kogia sima), Southern right-whale dolphin (Lissodelphis peronii), Peale’s dolphin (Lagenorhynchus australis) and a dusky dolphin (Lagenorhynchus obscurus), the cause of stranding could not be determined. This study shows, despite the small number of examined carcasses that in Chile, human related trauma is an important cause of single cetacean stranding events. © Copyright © 2020 Alvarado-Rybak, Toro, Abarca, Paredes, Español-Jiménez and Seguel.Ítem Trophic ecology of the Endangered Darwin's frog inferred by stable isotopes(Inter-Research, 2018) Molina-Burgos, B.E.; Valenzuela-Sánchez, A.; Alvarado-Rybak, M.; Klarian, S.; Soto-Azat, C.Darwin's frogs Rhinoderma spp. are the only known mouth-brooding frogs on Earth. The southern Darwin's frog, R. darwinii, is found in the temperate forests of southern South America, is listed as Endangered and could be the only extant representative of this genus. Based on stomach contents, invertebrate prey availability and stable isotope analysis, we determined for the first time trophic ecological parameters for this species. Our results showed that R. darwinii is a generalist sit-and-wait predator and a secondary consumer, with a trophic position of 2.9. Carbon and nitrogen isotope composition indicated that herbivore invertebrates are their main prey, detected in 68.1% of their assimilated food. The most consumed prey included mosquitoes, flies, crickets, grasshoppers and ants. Detritivore and carnivore invertebrates were also ingested, but in lower proportions. Our results contribute to a better understanding of the feeding habits of this fully terrestrial amphibian and provide the first insight into their role linking low forest trophic positions with intermediate predators. We provide valuable biological information for in situ and ex situ conservation which can be used when developing habitat protection, reintroduction and captive breeding programmes. As revealed here, stable isotope analysis is a valuable tool to study the trophic ecology of highly endangered and cryptic species. © The authors 2018.