Examinando por Autor "Alvarado-Rybak, Mario"
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Ítem A review of piroplasmid infections in wild carnivores worldwide: importance for domestic animal health and wildlife conservation(BIOMED CENTRAL, 2016-10) Alvarado-Rybak, Mario; Solano-Gallego, Laia; Millán, JavierPiroplasmids are tick-borne protozoan parasites that infect blood cells (erythrocytes, lymphocytes or other leukocytes) or endothelial cells of numerous wild and domestic vertebrates worldwide. They cause severe disease in livestock, dogs, cats, wild mammals and, occasionally, in humans. Piroplasmid infections are prevalent in wild carnivores worldwide although there is limited information about their clinical and epidemiological importance. There are currently nine recognized species of Babesia, two of Theileria, two of Cytauxzoon and one of Rangelia infecting captive and wild carnivores, including members of Canidae, Felidae, Mustelidae, Procyonidae, Ursidae, Viverridae, Hyaenidae and Herpestidae in the Americas, Eurasia and Africa. However, the number of piroplasmid species is likely higher than currently accepted due to the reported existence of DNA sequences that may correspond to new species and the lack of studies on many host species and biogeographical areas. Indeed, many species have been recognized in the last few years with the advancement of molecular analyses. Disease and mortality have been documented in some wild carnivores, whereas other species appear to act as natural, subclinical reservoirs. Various factors (e.g. unnatural hosts, stress due to captivity, habitat degradation, climate fluctuation or immunosuppression) have been associated with disease susceptibility to piroplasmid infections in some species in captivity. We aimed to review the current knowledge on the epidemiology of piroplasmid infections in wild carnivores and associated tick vectors. Emphasis is given to the role of wild carnivores as reservoirs of clinical piroplasmosis for domestic dogs and cats, and to the importance of piroplasmids as disease agents for endangered carnivores.Ítem Chytridiomycosis Outbreak in a Chilean Giant Frog (Calyptocephalella gayi) Captive Breeding Program: Genomic Characterization and Pathological Findings(Frontiers Media S.A., 2021-09) Alvarado-Rybak, Mario; Acuña, Paz; Peñafiel-Ricaurte, Alexandra; Sewell, Thomas R.; O'Hanlon, Simon J.; Fisher, Matthew C.; Valenzuela-Sánchez, Andres; Cunningham, Andrew A.Emerging infectious diseases in wildlife are increasingly associated with animal mortality and species declines, but their source and genetic characterization often remains elusive. Amphibian chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has been associated with catastrophic and well-documented amphibian population declines and extinctions at the global scale. We used histology and whole-genome sequencing to describe the lesions caused by, and the genetic variability of, two Bd isolates obtained from a mass mortality event in a captive population of the threatened Chilean giant frog (Calyptocephalella gayi). This was the first time an association between Bd and high mortality had been detected in this charismatic and declining frog species. Pathological examinations revealed that 30 dead metamorphosed frogs presented agnathia or brachygnathia, a condition that is reported for the first time in association with chytridiomycosis. Phylogenomic analyses revealed that Bd isolates (PA1 and PA2) from captive C. gayi group with other Bd isolates (AVS2, AVS4, and AVS7) forming a single highly supported Chilean Bd clade within the global panzootic lineage of Bd (BdGPL). These findings are important to inform the strengthening of biosecurity measures to prevent the impacts of chytridiomycosis in captive breeding programs elsewhere. © Copyright © 2021 Alvarado-Rybak, Acuña, Peñafiel-Ricaurte, Sewell, O'Hanlon, Fisher, Valenzuela-Sánchez, Cunningham and Azat.Ítem First case of male alloparental care in amphibians: tadpole stealing in Darwin’s frogs(Inter-Research, 2021) Cabeza-Alfaro, Osvaldo; Valenzuela-Sánchez, Andrés; Alvarado-Rybak, Mario; Serrano, José M.; Azat, ClaudioAll oparental care, i.e. care directed at non-descendant offspring, has rarely been described in amphibians. Rhinoderma darwinii is an Endangered and endemic frog of the tem - perate forests of Chile and Argentina. This species has evolved a unique reproductive strategy whereby males brood their tadpoles within their vocal sacs (known as neomelia). Since 2009, the National Zoo of Chile has developed an ex situ conservation programme for R. darwinii, in which during reproduction, adults are kept in terraria in groups of 2 females with 2 males. In September 2018, one pair engaged in amplexus, with one of the males fertilizing the eggs. Twenty days later, the second male (the alloparent) ingested all of the 8 viable, recently hatched tadpoles, releasing 2 froglets 9 wk later. This unusual behaviour observed in captivity is complemented by observations in the field of male R. darwinii brooding tadpoles of markedly different sizes, possibly reflecting the brooding of tadpoles from different ovipositions. To our knowledge, this is the first documented case of male alloparental care in amphibians and an example of captive breeding programmes contributing important knowledge about the natural history of threatened species. © The authors 2021. Open Access under Creative Commons by Attribution Licence. Use, distribution and reproduction are un - restricted. Authors and original publication must be credited.Ítem High prevalence of chigger mite infection in a forest-specialist frog with evidence of parasite-related granulomatous myositis(Springer Verlag, 2018-05) Alvarado-Rybak, Mario; Valenzuela-Sánchez, Andrés; Cevidanes, Aitor; Peñafiel-Ricaurte, Alexandra; Uribe-Rivera, David E.; Flores, Edgardo; Cunningham, Andrew A.; Soto-Azat, ClaudioAmphibians are hosts for a wide variety of micro- and macro-parasites. Chigger mites from the Hannemania genus are known to infect a wide variety of amphibian species across the Americas. In Chile, three species (H. pattoni, H. gonzaleacunae and H. ortizi) have been described infecting native anurans; however, neither impacts nor the microscopic lesions associated with these parasites have been described. Here, we document 70% prevalence of chigger mite infection in Eupsophus roseus and absence of infection in Rhinoderma darwinii in the Nahuelbuta Range, Chile. Additionally, we describe the macroscopic and microscopic lesions produced by H. ortizi in one of these species, documenting previously undescribed lesions (granulomatous myositis) within the host’s musculature. These findings highlight that further research to better understand the impacts of chigger mite infection on amphibians is urgently required in Chile and elsewhere. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.Ítem Is xenopus laevis introduction linked with Ranavirus incursion, persistence and spread in Chile?(PeerJ Inc., 2023-02) Peñafiel-Ricaurte, Alexandra; Price, Stephen J.; Leung, William T.M.; Alvarado-Rybak, Mario; Espinoza-Zambrano, Andrés; Valdivia, Catalina; Cunningham, Andrew A.; Azat, ClaudioRanaviruses have been associated with amphibian, fish and reptile mortality events worldwide and with amphibian population declines in parts of Europe. Xenopus laevis is a widespread invasive amphibian species in Chile. Recently, Frog virus 3 (FV3), the type species of the Ranavirus genus, was detected in two wild populations of this frog near Santiago in Chile, however, the extent of ranavirus infection in this country remains unknown. To obtain more information about the origin of ranavirus in Chile, its distribution, species affected, and the role of invasive amphibians and freshwater fish in the epidemiology of ranavirus, a surveillance study comprising wild and farmed amphibians and wild fish over a large latitudinal gradient (2,500 km) was carried out in 2015–2017. In total, 1,752 amphibians and 496 fish were tested using a ranavirus-specific qPCR assay, and positive samples were analyzed for virus characterization through whole genome sequencing of viral DNA obtained from infected tissue. Ranavirus was detected at low viral loads in nine of 1,011 X. laevis from four populations in central Chile. No other amphibian or fish species tested were positive for ranavirus, suggesting ranavirus is not threatening native Chilean species yet. Phylogenetic analysis of partial ranavirus sequences showed 100% similarity with FV3. Our results show a restricted range of ranavirus infection in central Chile, coinciding with X. laevis presence, and suggest that FV3 may have entered the country through infected X. laevis, which appears to act as a competent reservoir host, and may contribute to the spread the virus locally as it invades new areas, and globally through the pet trade.Ítem Is Xenopus laevis introduction linked with Ranavirus incursion, persistence and spread in Chile?(2023-02) Peñafiel-Ricaurte, Alexandra; J. Price, Stephen; T.M. Leung, William; Alvarado-Rybak, Mario; Espinoza-Zambrano, Andrés; Valdivia, Catalina; Cunningham, Andrew A.; Azat, ClaudioRanaviruses have been associated with amphibian, fish and reptile mortality events worldwide and with amphibian population declines in parts of Europe. Xenopus laevis is a widespread invasive amphibian species in Chile. Recently, Frog virus 3 (FV3), the type species of the Ranavirus genus, was detected in two wild populations of this frog near Santiago in Chile, however, the extent of ranavirus infection in this country remains unknown. To obtain more information about the origin of ranavirus in Chile, its distribution, species affected, and the role of invasive amphibians and freshwater fish in the epidemiology of ranavirus, a surveillance study comprising wild and farmed amphibians and wild fish over a large latitudinal gradient (2,500 km) was carried out in 2015–2017. In total, 1,752 amphibians and 496 fish were tested using a ranavirus-specific qPCR assay, and positive samples were analyzed for virus characterization through whole genome sequencing of viral DNA obtained from infected tissue. Ranavirus was detected at low viral loads in nine of 1,011 X. laevis from four populations in central Chile. No other amphibian or fish species tested were positive for ranavirus, suggesting ranavirus is not threatening native Chilean species yet. Phylogenetic analysis of partial ranavirus sequences showed 100% similarity with FV3. Our results show a restricted range of ranavirus infection in central Chile, coinciding with X. laevis presence, and suggest that FV3 may have entered the country through infected X. laevis, which appears to act as a competent reservoir host, and may contribute to the spread the virus locally as it invades new areas, and globally through the pet trade. Copyright 2023 Peñafiel-Ricaurte et al.Ítem Molecular evidence for Mycobacterium bovis infection in wild Chilean hawk (Accipiter chilensis)(Universidad Austral de Chile, 2018) Moroni, Manuel; Salgado, Miguel; Albornoz, Alejandro; Tejeda, Carlos; Alvarado-Rybak, MarioThe present study reports a case of tuberculosis in a juvenile Chilean hawk (Accipiter chilensis). Granulomas were identified in the liver, intestine and mesentery. Several of these granulomas contained acid-fast bacilli suggesting a mycobacterial infection through ingestion. Molecular diagnosis detected Mycobacterium bovis as etiological agent. Whether M. bovis infection in this Chilean hawk represents a risk for other wildlife, livestock or humans remains to be determined. © 2017 Austral journal of veterinary sciences. All rights reserved.Ítem Recent Asian origin of chytrid fungi causing global amphibian declines(American Association for the Advancement of Science, 2018-05) O’Hanlon, Simon J.; Rieux, Adrien; Farrer, Rhys A.; Rosa, Gonçalo M.; Waldman, Bruce; Bataille, Arnaud; Kosch, Tiffany A.; Murray, Kris A.; Brankovics, Balázs; Fumagalli, Matteo; Martin, Michael D.; Wales, Nathan; Alvarado-Rybak, Mario; Bates, Kieran A.; Berger, Lee; Böll, Susanne; Brookes, Lola; Clare, Frances; Courtois, Elodie A.; Cunningham, Andrew A.; Doherty-Bone, Thomas M.; Ghosh, Pria; Gower, David J.; Hintz, William E.; Höglund, Jacob; Jenkinson, Thomas S.; Lin, Chun-Fu; Laurila, Anssi; Loyau, Adeline; Martel, An; Meurling, Sara; Miaud, Claude; Minting, Pete; Pasmans, Frank; Schmeller, Dirk S.; Schmidt, Benedikt R.; Shelton, Jennifer M. G.; Skerratt, Lee F.; Smith, Freya; Soto-Azat, Claudio; Spagnoletti, Matteo; Tessa, Giulia; Toledo, Luís Felipe; Valenzuela-Sánchez, Andrés; Verster, Ruhan; Vörös, Judit; Webb, Rebecca J.; Wierzbicki, Claudia; Wombwell, Emma; Zamudio, Kelly R.; Aanensen, David M.; James, Timothy Y.; Thomas P. Gilbert M.; Weldon, Ché; ;Bosch, Jaime; Balloux, François; Garner, Trenton W. J.; Fisher, Matthew C.Globalized infectious diseases are causing species declines worldwide, but their source often remains elusive. We used whole-genome sequencing to solve the spatiotemporal origins of the most devastating panzootic to date, caused by the fungus Batrachochytrium dendrobatidis, a proximate driver of global amphibian declines. We traced the source of B. dendrobatidis to the Korean peninsula, where one lineage, BdASIA-1, exhibits the genetic hallmarks of an ancestral population that seeded the panzootic. We date the emergence of this pathogen to the early 20th century, coinciding with the global expansion of commercial trade in amphibians, and we show that intercontinental transmission is ongoing. Our findings point to East Asia as a geographic hotspot for B. dendrobatidis biodiversity and the original source of these lineages that now parasitize amphibians worldwide. © 2017 The Authors.Ítem Spatial and Temporal Effects of Whale Watching on a Tourism-Naive Resident Population of Bottlenose Dolphins (Tursiops truncatus) in the Humboldt Penguin National Reserve, Chile(Frontiers Media S.A., 2021-04) Toro, Frederick; Alarcón, Jaime; Toro-Barros, Bárbara; Mallea, Gabriela; Capella, Juan; Umaran-Young, Clara; Abarca, Paulette; Lakestani, Nelly; Peña, Claudia; Alvarado-Rybak, Mario; Cruz, Franco; Vilina, Yerko; Gibbons, JorgeStandardized measures of behavior can be powerful tools for assessing the impact of whale watching activities on natural populations of cetaceans. To determine the possible impact of tourism on dolphins between a period without whale watching (1989–1992) (T1) and a period with whale watching (2010–2020) (T2), we examined the changes in the rate of surface behaviors, the group size of long-time resident bottlenose dolphins living in the waters of the Humboldt Current off Chile, and for T2 alone, we compared these differences between two localities, the Punta de Choros and Chañaral de Aceituno coves. We observed a significant decrease in the group size of the resident population and in the frequency of surface events associated with the absence and presence of tourism. For T2, we observed significant differences for the frequency of surface events between the Chañaral de Aceituno and Punta de Choros coves and differences in the frequency of surface events at different hours of the day. This was associated with the number of vessels at the time of the encounter. In addition, we observed for T2 that the most observed instantaneous response of the dolphins to the presence of tourist vessels was to avoid the boats, while approaching the boats was the least observed response. The number of vessels present in each dolphin encounter was the most important variable for our model as it explains these differences. These results show that tourism vessels have a significant impact on dolphin behavior and sociability, while the same population of dolphins have different spatial and temporal responses to different impacts of tourism. Further studies are needed to establish whether changes in the rate of surface behaviors are associated with higher levels of stress in dolphins and with effects on their health and reproductive success in the long term. © Copyright © 2021 Toro, Alarcón, Toro-Barros, Mallea, Capella, Umaran-Young, Abarca, Lakestani, Peña, Alvarado-Rybak, Cruz, Vilina and Gibbons.Ítem Synthesis of Batrachochytrium dendrobatidis infection in South America: amphibian species under risk and areas to focus research and disease mitigation(John Wiley and Sons Inc, 2022-07) Azat, Claudio; Alvarado-Rybak, Mario; Solano-Iguaran, Jaiber J.; Velasco, Aníbal; Valenzuela-Sánchez, Andrés; Flechas, Sandra V.; Peñafiel-Ricaurte, Alexandra; Cunningham, Andrew A.; Bacigalupe, Leonardo D.Amphibian chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), has been recognized as the infectious disease causing the most catastrophic loss of biodiversity known to science, with South America being the most impacted region. We tested whether Bd prevalence is distributed among host taxonomy, ecoregion, conservation status and habitat preference in South America. Here we provide a synthesis on the extent of Bd infection across South America based on 21 648 molecular diagnostic assays, roles of certain species in the epidemiology of Bd and explore its association with the reported amphibian catastrophic declines in the region. We show that Bd is widespread, with a continental prevalence of 23.2%. Its occurrence in the region shows a phylogenetic signal and the probability of infection is determined by ecoregion, preferred habitat and extinction risk hosts' traits. The taxa exhibiting highest Bd occurrence were mostly aquatic amphibians, including Ranidae, Telmatobiidae, Hylodidae, Calyptocephalellidae and Pipidae. Surprisingly, families exhibiting unusually low Bd prevalence included species in which lethal chytridiomycosis and population declines have been described (genera Atelopus, Rhinoderma and Eleutherodactylus). Higher than expected prevalence of Bd occurred mainly in amphibians living in association with mountain environments in the Andes and Atlantic forests, reflecting highly favourable Bd habitats in these areas. Invasive amphibian species (e.g. Lithobates catesbeianus and Xenopus laevis) exhibited high Bd prevalence; thus we suggest using these as sentinels to understand their potential role as reservoirs, vectors or spreaders of Bd that can be subjected to management. Our results guide on the prioritization of conservation actions to prevent further biodiversity loss due to chytridiomycosis in the world's most amphibian diverse region. © 2022 The Authors. Ecography published by John Wiley & Sons Ltd on behalf of Nordic Society Oikos.