Valerie Shearn-Bochsler is a Wildlife Pathologist at the National Wildlife Health Center.
Science and Products
Necropsy & Pathology
The Necropsy and Pathology services are performed by board-certified veterinary pathologists and necropsy technical staff whose principal role is to determine the cause of death for animals submitted to the USGS National Wildlife Health Center.
Dataset: Acute oral toxicity and tissue residues of saxitoxin in the mallard (Anas platyrhynchos)
This data set is composed of data collected from an experimental study inoculating mallard ducks (Anas platyrhynchos) with Saxitoxin and associated control ducks. Data includes the specific of inoculation, observational behavioral data, daily weights, dosing, results of inoculation, testing of samples collected throughout the study, and necropsy results.
Data from 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 USA, was reported for the first time in wild native North American rabbits and hares in April 2020 in the southwestern USA. Affected species included the Desert Cottontail (Sylvilagus audubonii), Mountain Cottontail (S. nutallii), Black-tailed Jackrabbit (Lepus californicus), and Antelope Jackrabbit (L. alleni). Desert Cottonta
Occurrence of Chlamydia sp in apparently healthy birds associated with a mortality event caused by chlamydiosis: Data
hese data sets are is a compilation of bird and environmental samples obtained from 6 sites in Maricopa County, Arizona on the dates shown. Sites were only visited and sampled if they had Rosy-cheeked lovebirds coming to bird feeders at the location and with the permission of the property owner. Two swab samples were obtained from each captured bird and 3 swab samples were collected from the envir
West Nile virus susceptibility of American singer canaries: Data
hree datasets are included: 1) survival of domesticated canaries and American crows following sub-cutaneous challenges ranging from 101 105 plaque forming units of West Nile virus. 2) Arbitrary units of WNV detected by RT-PCR or plaque forming units of WNV cultured in vero cells in 4 separate studies. Culture results are indicated for each day post WNV challenge. 3) Weight (mass) changes in gram
Dataset: Mortality trends in the Washington population of northern sea otters (Enhydra lutris kenyoni) during 20022015
These data document cause of death determination for stranded otters salvaged from the coast of Washington state and northern Oregon for post-mortem analysis.
Susceptibility and antibody response of the laboratory model zebra finch
The data set contains the results of experimental challenge of captive
zebra finches with an American crow isolate of West Nile virus. Data include infectivity, mortality,
viremia, oral shedding of virus, and serology for anti- WNV antibodies. Australian and Timor zebra
finches were used in this study and both are useful as a laboratory model of an avian species with
moderate susceptib
Filter Total Items: 30
Acute oral toxicity and tissue residues of saxitoxin in the mallard (Anas platyrhynchos)
Since 2014, widespread, annual mortality events involving multiple species of seabirds have occurred in the Gulf of Alaska, Bering Sea, and Chukchi Sea. Among these die-offs, emaciation was a common finding with starvation often identified as the cause of death. However, saxitoxin (STX) was detected in many carcasses, indicating exposure of these seabirds to STX in the marine environment. Few data
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 cotto
Quarterly wildlife mortality report January 2021
The USGS National Wildlife Health Center (NWHC) Quarterly Mortality Report provides brief summaries of epizootic mortality and morbidity events by quarter. The write-ups, highlighting epizootic events and other wildlife disease topics of interest, are published in the Wildlife Disease Association quarterly newsletter. A link is provided in this WDA newsletter to the Wildlife Health Information Sha
Investigation of the 2018 thick-billed murre (Uria lomvia) die-off on St. Lawrence Island rules out food shortage as the cause
Die-offs of seabirds in Alaska have occurred with increased frequency since 2015. In 2018, on St. Lawrence Island, seabirds were reported washing up dead on beaches starting in late May, peaking in June, and continuing until early August. The cause of death was documented to be starvation, leading to the conclusion that a severe food shortage was to blame. We use physiology and colony-based observ
Lethal infection of wild raptors with highly pathogenic avian influenza H5N8 and H5N2 viruses in the USA, 2014–15
An outbreak of highly pathogenic avian influenza (HPAI) led to heavy losses of poultry in commercial farms in North America in 2014–15. Enhanced surveillance by virologists and pathologists at the US Geological Survey National Wildlife Health Center and its partners resulted in the identification of lethal infections with clade 2.3.4.4 subgroup icA2 H5N8 and novel reassortant H5N2 viruses in diver
High costs of infection: Alphavirus infection reduces digestive function and bone and feather growth in nestling house sparrows (Passer domesticus)
Increasingly, ecoimmunology studies aim to use relevant pathogen exposure to examine the impacts of infection on physiological processes in wild animals. Alphaviruses are arthropod-borne, single-stranded RNA (ssRNA) viruses (“arboviruses”) responsible for millions of cases of human illnesses each year. Buggy Creek virus (BCRV) is a unique alphavirus that is transmitted by a cimicid insect, the swa
Chlamydia psittaci in feral Rosy-faced Lovebirds (Agapornis roseicollis) and other backyard birds in Maricopa County, Arizona
In 2013, a mortality event of nonnative, feral Rosy-faced Lovebirds (Agapornis roseicollis) in residential backyards in Maricopa County, Arizona, US was attributed to infection with Chlamydia psittaci. In June 2014, additional mortality occurred in the same region. Accordingly, in August 2014 we sampled live lovebirds and sympatric bird species visiting backyard bird feeders to determine the preva
West Nile virus infection in American singer canaries: An experimental model in a highly susceptible avian species
This study investigated the susceptibility of American singer canaries (Serinus canaria) to West Nile virus (WNV) infection. Adult canaries were inoculated with 105, 102, and 101plaque forming units (PFU) of WNV. All birds became infected and mortality occurred by 5 days postinoculation. The load of viral RNA as determined by RT-qPCR was dose dependent, and was higher at all doses than the level o
Grass is not always greener: Rodenticide exposure of a threatened species near marijuana growing operations
ObjectiveMarijuana (Cannabis spp.) growing operations (MGO) in California have increased substantially since the mid-1990s. One environmental side-effect of MGOs is the extensive use of anticoagulant rodenticides (AR) to prevent damage to marijuana plants caused by wild rodents. In association with a long-term demographic study, we report on an observation of brodifacoum AR exposure in a threatene
Mortality trends in northern sea otters (Enhydra lutris kenyoni) collected from the coasts of Washington and Oregon (2002–15)
During 2002−15 we examined the causes of mortality in a population of northern sea otters (Enhydra lutris kenyoni). Beachcast sea otters were collected primarily from the coast of Washington. Although there are no permanent sea otter residents in Oregon, several beachcast otters were collected from the Oregon coast. Infectious diseases were the primary cause of death (56%) for otters we examined.
Novel dermatophilosis and concurrent amyloidosis in Sanderlings (Calidris alba) from Louisiana, USA
We observed Sanderlings (Calidris alba) with facial growths in coastal Louisiana, US during summer of 2016. Severe lesions were associated with lethargy and lack of a flight response. We determined that the skin growth etiology was a bacterium of the genus Dermatophilus, rarely reported infecting birds. Sanderlings also exhibited severe amyloidosis.
Experimental infection of common eider ducklings with Wellfleet Bay virus, a newly characterized orthomyxovirus
Wellfleet Bay virus (WFBV), a novel orthomyxovirus in the genus Quaranjavirus, was first isolated in 2006 from carcasses of common eider (Somateria mollissima) during a mortality event in Wellfleet Bay (Barnstable County, Massachusetts, USA) and has since been repeatedly isolated during recurrent mortality events in this location. Hepatic, pancreatic, splenic, and intestinal necrosis were observed
Science and Products
- Science
Necropsy & Pathology
The Necropsy and Pathology services are performed by board-certified veterinary pathologists and necropsy technical staff whose principal role is to determine the cause of death for animals submitted to the USGS National Wildlife Health Center.
- Data
Dataset: Acute oral toxicity and tissue residues of saxitoxin in the mallard (Anas platyrhynchos)
This data set is composed of data collected from an experimental study inoculating mallard ducks (Anas platyrhynchos) with Saxitoxin and associated control ducks. Data includes the specific of inoculation, observational behavioral data, daily weights, dosing, results of inoculation, testing of samples collected throughout the study, and necropsy results.Data from 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 USA, was reported for the first time in wild native North American rabbits and hares in April 2020 in the southwestern USA. Affected species included the Desert Cottontail (Sylvilagus audubonii), Mountain Cottontail (S. nutallii), Black-tailed Jackrabbit (Lepus californicus), and Antelope Jackrabbit (L. alleni). Desert CottontaOccurrence of Chlamydia sp in apparently healthy birds associated with a mortality event caused by chlamydiosis: Data
hese data sets are is a compilation of bird and environmental samples obtained from 6 sites in Maricopa County, Arizona on the dates shown. Sites were only visited and sampled if they had Rosy-cheeked lovebirds coming to bird feeders at the location and with the permission of the property owner. Two swab samples were obtained from each captured bird and 3 swab samples were collected from the envirWest Nile virus susceptibility of American singer canaries: Data
hree datasets are included: 1) survival of domesticated canaries and American crows following sub-cutaneous challenges ranging from 101 105 plaque forming units of West Nile virus. 2) Arbitrary units of WNV detected by RT-PCR or plaque forming units of WNV cultured in vero cells in 4 separate studies. Culture results are indicated for each day post WNV challenge. 3) Weight (mass) changes in gramDataset: Mortality trends in the Washington population of northern sea otters (Enhydra lutris kenyoni) during 20022015
These data document cause of death determination for stranded otters salvaged from the coast of Washington state and northern Oregon for post-mortem analysis.Susceptibility and antibody response of the laboratory model zebra finch
The data set contains the results of experimental challenge of captive zebra finches with an American crow isolate of West Nile virus. Data include infectivity, mortality, viremia, oral shedding of virus, and serology for anti- WNV antibodies. Australian and Timor zebra finches were used in this study and both are useful as a laboratory model of an avian species with moderate susceptib - Publications
Filter Total Items: 30
Acute oral toxicity and tissue residues of saxitoxin in the mallard (Anas platyrhynchos)
Since 2014, widespread, annual mortality events involving multiple species of seabirds have occurred in the Gulf of Alaska, Bering Sea, and Chukchi Sea. Among these die-offs, emaciation was a common finding with starvation often identified as the cause of death. However, saxitoxin (STX) was detected in many carcasses, indicating exposure of these seabirds to STX in the marine environment. Few dataPathology 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 cottoQuarterly wildlife mortality report January 2021
The USGS National Wildlife Health Center (NWHC) Quarterly Mortality Report provides brief summaries of epizootic mortality and morbidity events by quarter. The write-ups, highlighting epizootic events and other wildlife disease topics of interest, are published in the Wildlife Disease Association quarterly newsletter. A link is provided in this WDA newsletter to the Wildlife Health Information ShaInvestigation of the 2018 thick-billed murre (Uria lomvia) die-off on St. Lawrence Island rules out food shortage as the cause
Die-offs of seabirds in Alaska have occurred with increased frequency since 2015. In 2018, on St. Lawrence Island, seabirds were reported washing up dead on beaches starting in late May, peaking in June, and continuing until early August. The cause of death was documented to be starvation, leading to the conclusion that a severe food shortage was to blame. We use physiology and colony-based observLethal infection of wild raptors with highly pathogenic avian influenza H5N8 and H5N2 viruses in the USA, 2014–15
An outbreak of highly pathogenic avian influenza (HPAI) led to heavy losses of poultry in commercial farms in North America in 2014–15. Enhanced surveillance by virologists and pathologists at the US Geological Survey National Wildlife Health Center and its partners resulted in the identification of lethal infections with clade 2.3.4.4 subgroup icA2 H5N8 and novel reassortant H5N2 viruses in diverHigh costs of infection: Alphavirus infection reduces digestive function and bone and feather growth in nestling house sparrows (Passer domesticus)
Increasingly, ecoimmunology studies aim to use relevant pathogen exposure to examine the impacts of infection on physiological processes in wild animals. Alphaviruses are arthropod-borne, single-stranded RNA (ssRNA) viruses (“arboviruses”) responsible for millions of cases of human illnesses each year. Buggy Creek virus (BCRV) is a unique alphavirus that is transmitted by a cimicid insect, the swaChlamydia psittaci in feral Rosy-faced Lovebirds (Agapornis roseicollis) and other backyard birds in Maricopa County, Arizona
In 2013, a mortality event of nonnative, feral Rosy-faced Lovebirds (Agapornis roseicollis) in residential backyards in Maricopa County, Arizona, US was attributed to infection with Chlamydia psittaci. In June 2014, additional mortality occurred in the same region. Accordingly, in August 2014 we sampled live lovebirds and sympatric bird species visiting backyard bird feeders to determine the prevaWest Nile virus infection in American singer canaries: An experimental model in a highly susceptible avian species
This study investigated the susceptibility of American singer canaries (Serinus canaria) to West Nile virus (WNV) infection. Adult canaries were inoculated with 105, 102, and 101plaque forming units (PFU) of WNV. All birds became infected and mortality occurred by 5 days postinoculation. The load of viral RNA as determined by RT-qPCR was dose dependent, and was higher at all doses than the level oGrass is not always greener: Rodenticide exposure of a threatened species near marijuana growing operations
ObjectiveMarijuana (Cannabis spp.) growing operations (MGO) in California have increased substantially since the mid-1990s. One environmental side-effect of MGOs is the extensive use of anticoagulant rodenticides (AR) to prevent damage to marijuana plants caused by wild rodents. In association with a long-term demographic study, we report on an observation of brodifacoum AR exposure in a threateneMortality trends in northern sea otters (Enhydra lutris kenyoni) collected from the coasts of Washington and Oregon (2002–15)
During 2002−15 we examined the causes of mortality in a population of northern sea otters (Enhydra lutris kenyoni). Beachcast sea otters were collected primarily from the coast of Washington. Although there are no permanent sea otter residents in Oregon, several beachcast otters were collected from the Oregon coast. Infectious diseases were the primary cause of death (56%) for otters we examined.Novel dermatophilosis and concurrent amyloidosis in Sanderlings (Calidris alba) from Louisiana, USA
We observed Sanderlings (Calidris alba) with facial growths in coastal Louisiana, US during summer of 2016. Severe lesions were associated with lethargy and lack of a flight response. We determined that the skin growth etiology was a bacterium of the genus Dermatophilus, rarely reported infecting birds. Sanderlings also exhibited severe amyloidosis.Experimental infection of common eider ducklings with Wellfleet Bay virus, a newly characterized orthomyxovirus
Wellfleet Bay virus (WFBV), a novel orthomyxovirus in the genus Quaranjavirus, was first isolated in 2006 from carcasses of common eider (Somateria mollissima) during a mortality event in Wellfleet Bay (Barnstable County, Massachusetts, USA) and has since been repeatedly isolated during recurrent mortality events in this location. Hepatic, pancreatic, splenic, and intestinal necrosis were observed - News
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