Geology topics

Saskia Keller

Publications and source records attributed to Saskia Keller.

3 recordsLinked to original sources

USGS2021

Acute mortality in California tiger salamander (Ambystoma californiense) and Santa Cruz long-toed salamander (Ambystoma macrodactylum croceum) caused by Ribeiroia ondatrae (Class: Trematoda)

In early September 2019, a morbidity and mortality event affecting California tiger salamanders ( Ambystoma californiense ) and Santa Cruz long-toed salamanders ( Ambystoma macrodactylum croceum ) in late stages of metamorphosis was reported at a National Wildlife Refuge in Santa Cruz County, California, U.S.A. During the postmortem disease investigation, severe integumentary metacercarial (Class: Trematoda) infection, associated with widespread skin lesions, was observed. Planorbid snails collected from the ponds of the refuge within seven days of the mortality event were infected with Ribeiroia ondatrae, a digenetic trematode that can cause malformation and death in some amphibians. We suggest sustained seasonal high-water levels due to active habitat management along with several years of increased rainfall led to increased bird visitation, increased over-wintering of snails, and prolonged salamander metamorphosis, resulting in a confluence of conditions and cascading of host-parasite dynamics to create a hyper-parasitized state.

California↗

USGS2021

Analysis of archival specimens confirms White-nose syndrome in little brown bats (Myotis lucifugus) from New York, USA, in spring 2007

White-nose syndrome (WNS), an emerging fungal disease of North American bats, was first diagnosed in January 2008, although mortality and photo-documentation suggest the disease may have been present earlier. Using archived samples, we describe a definitive case of WNS in little brown bats (Myotis lucifugus) from New York, USA, in spring 2007.

New York↗

USGS2021

Pathology of Lagovirus europaeus GI.2/RHDV2/b (rabbit hemorrhagic disease virus 2) in native North American lagomorphs

Rabbit hemorrhagic disease, a notifiable foreign animal disease in the US, was reported for the first time in wild native North American lagomorphs in April 2020 in the southwestern US. Affected species included the desert cottontail ( Sylvilagus audubonii ), mountain cottontail ( Sylvilagus nuttallii ), black-tailed jackrabbit ( Lepus californicus ), and antelope jackrabbit ( Lepus alleni ). Desert cottontails ( n =7) and black-tailed jackrabbits ( n =7) collected in April and May 2020 were necropsied at the US Geological Survey National Wildlife Health Center and tested positive for Lagovirus europaeus GI.2, also known as rabbit hemorrhagic disease virus 2 (GI.2/RHDV2/b), by real-time PCR at the US Department of Agriculture's Foreign Animal Disease Diagnostic Laboratory. Gross and microscopic lesions were similar to those reported in European rabbits ( Oryctolagus cuniculus ) and other hare ( Lepus ) species with GI.2/RHDV2/b infection; they included epistaxis (12/13; 92%); massive hepatocellular dissociation (14/14; 100%) and necrosis or apoptosis (11/11; 100%); pulmonary congestion (12/12; 100%), edema (12/13; 92%), and hemorrhage (11/12; 92%); and acute renal tubular injury (3/8; 38%). As in previous reports, massive hepatocellular dissociation and necrosis or apoptosis were the most diagnostically distinct finding. As North American Sylvilagus and Lepus species appear to be susceptible to fatal GI.2/RHDV2/b infection, additional work is needed to understand the host range, pathogenicity, and potential population effects of GI.2/RHDV2/b in North America.

Arizona, New Mexico, Texas↗