Batrachochytrium salamandrivorans (Bsal) is an emerging pathogen capable of causing significant morbidity and mortality in salamanders.
The US has the largest diversity of salamanders in the world and introduction of Bsal to North America could have severe impacts on biodiversity and amphibian conservation.
In 2013, unexpected mortalities of captive and wild fire salamanders (Salamandra salamandra), ultimately attributed to Bsal, were first observed in Belgium and the Netherlands, leading to significant salamander population declines. Since then, Bsal has also been detected in captive salamanders throughout Europe and has caused outbreaks in wild salamanders in Belgium, Germany, the Netherlands, and Spain. Studies suggest that Bsal is likely endemic to Asia and may have been introduced into Europe through the global pet trade. Subsequent spillover from captive to wild populations is strongly suspected. From 2010 to 2014, over 750,000 salamanders were imported into the U.S., creating a high probability that Bsal could be introduced into the U.S.
How the USGS National Wildlife Health Center is preparing for Bsal and other emerging amphibian diseases
The USGS National Wildlife Health Center (NWHC) is collaborating with multiple federal and state partners, including the multi-agency Bsal Task Force, to conduct diagnostic investigations and monitor for Bsal to better understand the fungus and to raise awareness about this threat to our native salamanders.
The USGS developed a series of risk assessments to predict the potential distribution of Bsal invasion within the US, analyzed the potential consequences of an introduction (Richgels et al., 2016), and evaluated the impacts of risk-mitigation actions (Grear et al., 2021). The assessments concluded that the total risk of Bsal introduction into the U.S. is greatest for the Pacific coast, southern Appalachian Mountains, and mid-Atlantic regions. Overall, the total risk is highest throughout the eastern U.S.
The NWHC provided technical and diagnostic support for an intense surveillance effort from 2016-2017 in collaboration with the USGS Amphibian Research and Monitoring Initiative (ARMI). Sampling focused on sites where the probability of introduction is highest and on salamander species that are most susceptible to the disease. There were no Bsal detections in over 11,000 surveillance samples. In addition to the intensive surveillance project, the NWHC provides ongoing surveillance and diagnostic services for federal, state, and Tribal partners and participates in The Student Network for Amphibian Pathogen Surveillance (SNAPS). Unusual morbidity and mortality events involving salamanders should be reported to the appropriate state or federal agency or to the NWHC.
Batrachochytrium salamandrivorans is closely related to the amphibian pathogen Batrachochytrium dendrobatidis (Bd) which is known to affect more than 200 amphibian species, is linked to spread through the global pet trade, has caused extinctions of numerous amphibian species, and continues to be a leading cause of amphibian mortality events worldwide. Thus, the potential impact of Bsal on salamander biodiversity is a serious concern. Early detection of Bsal would allow for the rapid institution of management actions to prevent and control the spread of the fungus should it be detected in North America.
Batrachochytrium salamandrivorans (Bsal) is an emerging pathogen capable of causing significant morbidity and mortality in salamanders.
The US has the largest diversity of salamanders in the world and introduction of Bsal to North America could have severe impacts on biodiversity and amphibian conservation.
In 2013, unexpected mortalities of captive and wild fire salamanders (Salamandra salamandra), ultimately attributed to Bsal, were first observed in Belgium and the Netherlands, leading to significant salamander population declines. Since then, Bsal has also been detected in captive salamanders throughout Europe and has caused outbreaks in wild salamanders in Belgium, Germany, the Netherlands, and Spain. Studies suggest that Bsal is likely endemic to Asia and may have been introduced into Europe through the global pet trade. Subsequent spillover from captive to wild populations is strongly suspected. From 2010 to 2014, over 750,000 salamanders were imported into the U.S., creating a high probability that Bsal could be introduced into the U.S.
How the USGS National Wildlife Health Center is preparing for Bsal and other emerging amphibian diseases
The USGS National Wildlife Health Center (NWHC) is collaborating with multiple federal and state partners, including the multi-agency Bsal Task Force, to conduct diagnostic investigations and monitor for Bsal to better understand the fungus and to raise awareness about this threat to our native salamanders.
The USGS developed a series of risk assessments to predict the potential distribution of Bsal invasion within the US, analyzed the potential consequences of an introduction (Richgels et al., 2016), and evaluated the impacts of risk-mitigation actions (Grear et al., 2021). The assessments concluded that the total risk of Bsal introduction into the U.S. is greatest for the Pacific coast, southern Appalachian Mountains, and mid-Atlantic regions. Overall, the total risk is highest throughout the eastern U.S.
The NWHC provided technical and diagnostic support for an intense surveillance effort from 2016-2017 in collaboration with the USGS Amphibian Research and Monitoring Initiative (ARMI). Sampling focused on sites where the probability of introduction is highest and on salamander species that are most susceptible to the disease. There were no Bsal detections in over 11,000 surveillance samples. In addition to the intensive surveillance project, the NWHC provides ongoing surveillance and diagnostic services for federal, state, and Tribal partners and participates in The Student Network for Amphibian Pathogen Surveillance (SNAPS). Unusual morbidity and mortality events involving salamanders should be reported to the appropriate state or federal agency or to the NWHC.
Batrachochytrium salamandrivorans is closely related to the amphibian pathogen Batrachochytrium dendrobatidis (Bd) which is known to affect more than 200 amphibian species, is linked to spread through the global pet trade, has caused extinctions of numerous amphibian species, and continues to be a leading cause of amphibian mortality events worldwide. Thus, the potential impact of Bsal on salamander biodiversity is a serious concern. Early detection of Bsal would allow for the rapid institution of management actions to prevent and control the spread of the fungus should it be detected in North America.