Article
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Consulta de Difusion Veterinaria. 30(287):45-51. En la naturaleza, los cambios en el medio ambiente pueden modificar las dinámicas existentes entre huéspedes y patógenos, dando lugar a la aparición de enfermedades. En las últimas décadas, ha habido cambios ambientales que están afectando a los anfibios y la presencia y persistencia de ciertos patógenos. Algunos patógenos que siempre habían estado presentes sin ocasionar síntomas, ahora pueden ser causa de enfermedad. Otros patógenos aparecen en nuevas áreas geográficas a consecuencia de la actividad humana (transportes a largas distancias, liberaciones o escapes desde la cautividad, etc.). En consecuencia, el delicado equilibrio que existe entre huésped, patógeno y medio ambiente hace de los anfibios unos de los animales más vulnerables a padecer este tipo de dolencias. Los problemas de los anfibios han sido, desde hace mucho tiempo, un medidor indirecto del estado de salud de los ecosistemas, considerando este grupo animal como bioindicadores de las áreas naturales. La aparición evidente y visible de enfermedades en los anfibios en España ha provocado que exista una especial preocupación por cómo estas pueden afectar al estado de conservación de las especies de nuestra geografía. Algunas de ellas son enfermedades de nueva instauración: las enfermedades emergentes. En el presente trabajo se describen las principales enfermedades que ocasionan preocupación a nivel mundial, haciéndose especial énfasis en las que están empezando a detectarse en colecciones privadas o en bajo número en libertad en España, pero que en otros países ya están provocando epidemias. Además, tres de ellas (ocasionadas por dos hongos y un virus) son enfermedades de declaración obligatoria a la Organización Mundial de Sanidad Animal (OIE), y otra es de riesgo zoonótico, lo que hace que la vigilancia de todos los veterinarios clínicos tenga especial importancia para su detección temprana.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

ResearchGate has not been able to resolve any citations for this publication.
Article
Full-text available
Understanding the occurrence and consequence of co-infections can be useful in designing disease management interventions. Amphibians are the most highly threatened vertebrates, and emerging pathogens are a serious threat to their conservation. The amphibian chytrid fungus and the viruses of the Ranavirus genus are already widely distributed, causing disease outbreaks and population declines worldwide. However, we lack information about the occurrence and consequences of coinfection with these pathogens across age-classes of amphibian hosts. Here, we analyze the occurrence of infection of the amphibian chytrid fungus and ranaviruses during one season in two susceptible amphibian species at two different locations at which outbreaks have occurred. We found that the co-occurrence of both pathogens in a particular host is not common except in highly susceptible life-stages, and that single infections are the most common situation. Moreover, we found that the occurrence of one pathogen in a particular host did not predict the occurrence of the other. We attribute these results to the niches in which both pathogens proliferate in amphibian hosts.
Article
Full-text available
Methods to mitigate the impacts of emerging infectious diseases affecting wildlife are urgently needed to combat loss of biodiversity. However, the successful mitigation of wildlife pathogens in situ has rarely occurred. Indeed, most strategies for combating wildlife diseases remain theoretical, despite the wealth of information available for combating infections in livestock and crops. Here, we report the outcome of a 5-year effort to eliminate infection with Batrachochytrium dendrobatidis affecting an island system with a single amphibian host. Our initial efforts to eliminate infection in the larval reservoir using a direct application of an antifungal were successful ex situ but infection returned to previous levels when tadpoles with cleared infections were returned to their natal sites. We subsequently combined antifungal treatment of tadpoles with environmental chemical disinfection. Infection at four of the five pools where infection had previously been recorded was eradicated, and remained so for 2 years post-application.
Article
Full-text available
The emergence of infectious diseases with a broad host range can have a dramatic impact on entire communities and has become one of the main threats to biodiversity [1-4]. Here, we report the simultaneous exploitation of entire communities of potential hosts with associated severe declines following invasion by a novel viral pathogen. We found two phylogenetically related, highly virulent viruses (genus Ranavirus, family Iridoviridae) causing mass mortality in multiple, diverse amphibian hosts in northern Spain, as well as a third, relatively avirulent virus. We document host declines in multiple species at multiple sites in the region. Our work reveals a group of pathogens that seem to have preexisting capacity to infect and evade immunity in multiple diverse and novel hosts, and that are exerting massive impacts on host communities. This report provides an exceptional record of host population trends being tracked in real time following emergence of a wildlife disease and a striking example of a novel, generalist pathogen repeatedly crossing the species barrier with catastrophic consequences at the level of host communities. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.
Article
Full-text available
Amphibian chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), is an emerging infectious disease that widely threatens amphibian biodiversity. However, population-level outcomes following the introduction of the pathogen are highly context dependent and are mediated by a broad suite of biotic and abiotic variables. Here, we examine the effect of the introduction of Bd on native island populations of the IUCN red-listed amphibian species Alytes muletensis, the Mallorcan midwife toad. We show that the outcome of pathogen introduction is not only dependent on biotic factors, but also environmental factors that vary across local scales. Our experimental infections confirm that the genotype of Bd occurring on Mallorca is hypovirulent in A. muletensis when compared against the lineage found occurring on mainland Iberia. Long-term population data shows that A. muletensis populations on the island are increasing overall, but trends in highly infected populations are conflicting. We use mathematical models and field data to demonstrate that this divergence in population response to infection can be explained by local environmental differences between infected sites, whereas pathogen genetics, host genetics, and intrinsic epidemiological dynamics driven by fungal load are less likely to be the cause of these differing population trajectories. Our results illustrate the need to take into account the appropriate environmental scale and context when assessing the risk that an emerging pathogen presents to a naı¨venaı¨ve population or species.
Article
Full-text available
During the summers of 1997, 1998 and 1999 mass mortality episodes of post-metamorphic common midwife toads (Alytes obstetricans) occurred in a protected area in central Spain. The population suffered a sharp decline, disappearing from 86% of the ponds where they were known to reproduce some years ago. Scanning electron microscopy and histological techniques revealed the presence of a chytridiomycosis infection in the skin of the toads. This evidence supports chytridiomycosis as the most plausible cause of the decline of the species in the area. This is the first report of an apparent chytridium-caused amphibian decline in Europe.
Article
Full-text available
Ecology Letters (2010) 13: 372–382 Amphibian chytridiomycosis is a disease caused by the fungus Batrachochytrium dendrobatidis (Bd). Whether Bd is a new emerging pathogen (the novel pathogen hypothesis; NPH) or whether environmental changes are exacerbating the host-pathogen dynamic (the endemic pathogen hypothesis; EPH) is debated. To disentangle these hypotheses we map the distribution of Bd and chytridiomycosis across the Iberian Peninsula centred on the first European outbreak site. We find that the infection-free state is the norm across both sample sites and individuals. To analyse this dataset, we use Bayesian zero-inflated binomial models to test whether environmental variables can account for heterogeneity in both the presence and prevalence of Bd, and heterogeneity in the occurrence of the disease, chytridiomycosis. We also search for signatures of Bd-spread within Iberia using genotyping. We show (1) no evidence for any relationship between the presence of Bd and environmental variables, (2) a weak relationship between environmental variables and the conditional prevalence of infection, (3) stage-dependent heterogeneity in the infection risk, (4) a strong association between altitude and chytridiomycosis, (5) multiple Iberian genotypes and (6) recent introduction and spread of a single genotype of Bd in the Pyrenees. We conclude that the NPH is consistent with the emergence of Bd in Iberia. However, epizootic forcing of infection is tied to location and shaped by both biotic and abiotic variables. Therefore, the population-level consequences of disease introduction are explained by EPH-like processes. This study demonstrates the power of combining surveillance and molecular data to ascertain the drivers of new emerging infections diseases.
Article
In order to advance understanding of the current infection status related to the presence of Batrachochytrium spp. in different populations, we tested for the presence/absence (qualitative analysis) of Bd and Bsal in 13 monitored populations and measured the Bd infection loads (quantitative analysis) of 16 populations of the Pyrenean Brook Newt in the French and Spanish Pyrenean Mountains and present details of a population health monitoring program. Our study is the first comprehensive study of Bd and Bsal infection in wild populations of Pyrenean Brook Newts from both sides of the Pyrenees.
Infectious and parasitic diseases in captive amphibians: a retrospective study of 131 patients
  • C Juan-Salles
  • V Almagro
  • L Carbonell
Juan-Salles C, Almagro V, Carbonell L, et al. Infectious and parasitic diseases in captive amphibians: a retrospective study of 131 patients. Clin Vet Peq Anim 2020, 40 (1):15-27.
Prospecció sanitària dels amfibis de Catalunya: coneixent la distribució real del fong Batrachochytrium salamandrivorans
  • A Martínez-Silvestre
  • J Bosch
  • R Marschang
  • R Velarde
Martínez-Silvestre A, Bosch J, Marschang R, Velarde R. Prospecció sanitària dels amfibis de Catalunya: coneixent la distribució real del fong Batrachochytrium salamandrivorans. Trobada d' Estudiosos del Montnegre 2019; VII:19-20.