Amphibian Decline
Wikipedia:
- Contested relevance of studies
https://www.thebhs.org/publications/the-herpetological-journal/volume-29-number-4-october-2019/1972-01-emerging-infectious-disease-threats-to-european-herpetofauna/file
</div>Emerging infectious disease threats to European herpetofauna (Allain et al., 2019):
- The decline is exacerbated by anthropogenic environmental stressors
- They claim some strains are okay with Europe for now but there is a chance this might change due to changing climatic conditions
- Infection does not always lead to the development of the disease, which may be why we have not seen the mass-die offs of amphibians such as those elsewhere in the world (in some parts of Europe)
- Ongoing surveillance is needed to ensure the emergence of Bsal is not missed in areas where it has not yet been recorded in the wild. This surveillance can be either active or passive, depending on the time and resources available. Recently in the UK, 2,409 swabs collected from wild newts in 2011 and 43 newts submitted for post- mortem examination (between March 2013–December 2017) all tested negative for Bsal (Cunningham et al., 2019). However, there is experimental evidence to suggest that salamanders infected with low loads of Bsal may go undetected due to latency in detection via qPCR (Thomas et al., 2018).
- Recent research has focused on both the imperfect detectability of infectious diseases (such as Bd) when using swabs and qPCR (DiRenzo et al., 2018) as well as the costs involved to complete the analysis (Sabino- Pinto et al., 2018).
- The global panzootic lineage of Bd (BdGPL) has been attributed to most amphibian declines having likely emerged as a hybrid between less virulent strains (Farrer et al., 2011).
- Gross clinical signs of Bd infection in adult amphibians include, but are not limited to: anorexia, lethargy, unusual skin shedding, reddening of the skin (especially in the vent and upper thigh regions), convulsions and loss of the righting reflex (Fig. 1; Nichols et al., 2011). However, the clinical signs of Bd vary among species, their life history stages, and other factors such as environmental conditions. In larval stages, clinical signs of chytridiomycosis are also variable. They include but are not limited to: depigmentation of mouthparts, swimming difficulties, and lethargy (reviewed in van Rooij et al., 2015).
The US just banned salamander imports, hoping to stave off disaster (Resnick, 2016):
- The US Fish and Wildlife Service, under the authority off the Lacey Act, has issued an interim rule prohibiting the trade of 201 salamander species
- But if Bsal ever did come here, the stakes would be even higher than they are in Europe. Fifty percent of all salamander species in the world are found in North America.
- Gray and Olson are co-authors on the essay published in PLOS Pathogens, calling for action on the Bsal threat. They say a first step to protecting American salamanders from harm is banning international trade, which the US just did. (Gray says that even though the US has tons of salamanders, foreign ones can often be "flashy." Salamanders account for 5.5 percent of amphibian imports.)
- And while the US Department of Agriculture requires shipments of domesticated animals to be certified as disease-free -- HOW?
- Less drastic measures can prevent the need: Gray, Olson, and their colleagues also call for increased surveillance in pet stores and in zoos, identifying more possible routes of entry into the US, and a national response system to deal with a positive diagnosis if it were to occur. "There are a lot of us who would like to implement something for conservation, and it’s just so hard — there are so many species, so many habitats, there’s so much, you just get numb to it," Olson says. "But here’s something that we can be effective on: We can forestall a potential disaster."
Batrachochytrium salamandrivorans and the Risk of a Second Amphibian Pandemic (Yap et al., 2017)
- Bsal is not salamander specific
- With the potential spread of Bsal through wildlife trade and the availability of suitable habitat and hosts, the threat that Bsal poses in North America is high (Yap et al. 2015; Richgels et al. 2016).
- Risk models have identified that the West Coast of the United States, the Southeastern United States, and the highlands of Mexico have the greatest risk of Bsal introduction and spread (Yap et al. 2015; Richgels et al. 2016).