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Pathogen pollution across spatial scales: a primer on disease ecology of Batrachochytrium salamandrivorans in Europe

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Pathogen pollution has caused dramatic losses of amphibian diversity on a global scale. The recently emerged chytrid fungus Batrachochytrium salamandrivorans (Bsal) has been hypothesized to have its origin in Asian urodelan populations, from which it may have been introduced to Europe through the trade in live urodelans. We here show that Bsal is present on wild small-webbed fire-bellied toads (Bombina microdeladigitora) from Vietnam and on representatives of the same species that have recently been imported in Germany. This finding suggests that the installment of measures to mitigate the Bsal threat through the amphibian trade should not be limited to urodeles, but should equally take anurans into account. © 2017
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Beukema et al. Introduce the genus salamandra comprising the well-known fire salamanders.
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Amphibian declines and extinctions are emblematic for the current sixth mass extinction event. Infectious drivers of these declines include the recently emerged fungal pathogens Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans (Chytridiomycota). The skin disease caused by these fungi is named chytridiomycosis and affects the vital function of amphibian skin. Not all amphibians respond equally to infection and host responses might range from resistant, over tolerant to susceptible. The clinical outcome of infection is highly dependent on the amphibian host, the fungal virulence and environmental determinants. B. dendrobatidis infects the skin of a large range of anurans, urodeles and caecilians, whereas to date the host range of B. salamandrivorans seems limited to urodeles. So far, the epidemic of B. dendrobatidis is mainly limited to Australian, neotropical, South European and West American amphibians, while for B. salamandrivorans it is limited to European salamanders. Other striking differences between both fungi include gross pathology and thermal preferences. With this review we aim to provide the reader with a state-of-the art of host-pathogen interactions for both fungi, in which new data pertaining to the interaction of B. dendrobatidis and B. salamandrivorans with the host’s skin are integrated. Furthermore, we pinpoint areas in which more detailed studies are necessary or which have not received the attention they merit. Electronic supplementary material The online version of this article (doi:10.1186/s13567-015-0266-0) contains supplementary material, which is available to authorized users.
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The emerging infectious disease chytridiomycosis is one of the major factors triggering global amphibian declines. A recently discovered species of chytrid fungus, Batrachochytrium salamandrivorans( Bsal), likely originated in East Asia, has led to massive declines in populations of fire salamanders ( Salamandra salamandra) after its apparent introduction to the Netherlands and Belgium. Here, we report the first detection of this pathogen in Germany where it caused mass mortality of fire salamanders in a captive collection. Salamanders from this collection showed an almost 100% prevalence of infection with Bsal. Supposed Bsal-induced mortality occurred in multiple Salamandraspecies ( S. salamandra, S. algira, S. corsica, and S. infraimmaculata), while Bsalinfection was confirmed in nine subspecies of S. salamandraand in S. algira. Our study indicates that this pathogen can potentially infect all fire salamander species and subspecies. If Bsalspreads from captive collections to wild populations, then a similar devastating effect associated with high mortality should be expected.
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THE recently discovered fungal pathogen Batrachochytrium salamandrivorans is causing the rapid loss of infected fire salamander (Salamandra salamandra) populations in continental Europe (Martel and others 2013). The fungus is thought to be endemic to Asia, with introduction to Europe via the pet trade. Many species of salamander and newt (urodeles) have been shown experimentally to be …
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Invasive species are one of the most serious threats to amphibian populations. We investigated the effects of two invasive (Pomacea canaliculata and Physella acuta) and one native (Radix sp.) snail species on five species of wetland-breeding frogs in Hong Kong. We quantified embryonic survivorship and determined whether particular attributes of amphibian egg masses influenced consumption by snails. P. canaliculata preyed on four of the species, consuming > 90 % of eggs of Microhyla fissipes and Fejervarya limnocharis, nearly 70 % of eggs of Kaloula pulchra, approximately 40 % of eggs of Duttaphrynus melanostictus, but no eggs of Polypedates megacephalus. P. acuta and Radix sp. consumed only the eggs of K. pulchra, but those eggs were probably non-viable. This study shows that P. canaliculata, which occurs at high densities in tropical East Asia, may be an important predator of amphibian eggs. Future research should evaluate their effects on amphibian populations, community structure, and food web dynamics.
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The emerging infectious amphibian diseases caused by amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranaviruses are responsible for global amphibian population declines and extinctions. Although likely to have been spread by a variety of activities, transcontinental dispersal appears closely associated with the international trade in live amphibians. The territory of Hong Kong reports frequent, high volume trade in amphibians, and yet the presence of Bd and ranavirus have not previously been detected in either traded or free-ranging amphibians. In 2012, a prospective surveillance project was conducted to investigate the presence of these pathogens in commercial shipments of live amphibians exported from Hong Kong International Airport. Analysis of skin (Bd) and cloacal (ranavirus) swabs by quantitative PCR detected pathogen presence in 31/265 (11.7%) and in 105/185 (56.8%) of amphibians, respectively. In addition, the water in which animals were transported tested positive for Bd, demonstrating the risk of pathogen pollution by the disposal of untreated wastewater. It is uncertain whether Bd and ranavirus remain contained within Hong Kong's trade sector, or if native amphibians have already been exposed. Rapid response efforts are now urgently needed to determine current pathogen distribution in Hong Kong, evaluate potential trade-associated exposure to free-ranging amphibians, and identify opportunities to prevent disease establishment.
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With a continuously growing global human population the exploitation of natural resources is likewise increasing. Herein we provide an overview on exploitation and trade of amphibian species in different regions of the world, with a main emphasis on West Africa. Whereas particular West African tribes have always used frogs as food, medicine or for cultural reasons, the current increase in frog hunting seems to be new. Amphibian declines are likely and may result in measurable changes to aquatic and riparian ecosystems. © 2009 Deutsche Gesellschaft für Herpetologie und Terrarienkunde e.V. (DGHT).
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