The authors screened 1,397 feral horses (Equus caballus) on Sheldon National Wildlife Refuge, Nevada, United States, for IgM and IgG against flavivirus during 2004-2006, 2008, and 2009. Positive serum samples were tested for neutralizing antibodies to West Nile virus (WNV) and St. Louis encephalitis virus (SLEV). One animal was positive for antibody against WNV in 2004, but all others tested in 2004-2006 were negative. In 2008 and 2009, the authors found evidence of increasing seropositive horses with age, whereas seroprevalence of WNV decreased from 19% in 2008 to 7.2% in 2009. No horses were positive for antibody against SLEV. Being unvaccinated, feral horses can be useful for WNV surveillance.

To investigate the role of migratory birds in the dissemination of West Nile virus (WNV), we measured the prevalence of infectious WNV and specific WNV neutralizing antibodies in birds, principally Passeriformes, during spring and fall migrations in the Atlantic and Mississippi flyways from 2001-2003. Blood samples were obtained from 13,403 birds, representing 133 species. Specific WNV neutralizing antibody was detected in 254 resident and migratory birds, representing 39 species, and was most commonly detected in northern cardinals ( Cardinalis cardinalis ) (9.8%, N = 762) and gray catbirds ( Dumetella carolinensis ) (3.2%, N = 3188). West Nile virus viremias were detected in 19 birds, including 8 gray catbirds, and only during the fall migratory period. These results provide additional evidence that migratory birds may have been a principal agent for the spread of WNV in North America and provide data on the occurrence of WNV in a variety of bird species.

To investigate the role of migratory birds in the dissemination of West Nile virus (WNV), we measured the prevalence of infectious WNV and specific WNV neutralizing antibodies in birds, principally Passeriformes, during spring and fall migrations in the Atlantic and Mississippi flyways from 2001-2003. Blood samples were obtained from 13,403 birds, representing 133 species. Specific WNV neutralizing antibody was detected in 254 resident and migratory birds, representing 39 species, and was most commonly detected in northern cardinals ( Cardinalis cardinalis ) (9.8%, N = 762) and gray catbirds ( Dumetella carolinensis ) (3.2%, N = 3188). West Nile virus viremias were detected in 19 birds, including 8 gray catbirds, and only during the fall migratory period. These results provide additional evidence that migratory birds may have been a principal agent for the spread of WNV in North America and provide data on the occurrence of WNV in a variety of bird species.

Three 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 grams in canaries and crows each day following WNV challenge. Day 0 (inoculation) set to 0 gms, then each subsequent day is change in gms from previous day.

Three 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 grams in canaries and crows each day following WNV challenge. Day 0 (inoculation) set to 0 gms, then each subsequent day is change in gms from previous day.

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 Cottontails (n=7) and Black-tailed Jackrabbits (n=7) collected in April and May 2020 were necropsied at the U.S. Geological Survey National Wildlife Health Center (NWHC) 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 U.S. 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 and included epistaxis (12/13; 92%), massive hepatocellular dissociation (14/14; 100%) and necrosis/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 and when compared to historical cases in the NWHC diagnostic database, massive hepatocellular dissociation and necrosis/apoptosis was the most diagnostically distinct finding in GI.2/RHDV2/b-positive rabbits and hares. Based on the apparent susceptibility of North American Sylvilagus and Lepus species to fatal GI.2/RHDV2/b infection, additional work is needed to understand the host range, pathogenicity, and potential population impacts of GI.2/RHDV2/b in North America.

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 Cottontails (n=7) and Black-tailed Jackrabbits (n=7) collected in April and May 2020 were necropsied at the U.S. Geological Survey National Wildlife Health Center (NWHC) 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 U.S. 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 and included epistaxis (12/13; 92%), massive hepatocellular dissociation (14/14; 100%) and necrosis/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 and when compared to historical cases in the NWHC diagnostic database, massive hepatocellular dissociation and necrosis/apoptosis was the most diagnostically distinct finding in GI.2/RHDV2/b-positive rabbits and hares. Based on the apparent susceptibility of North American Sylvilagus and Lepus species to fatal GI.2/RHDV2/b infection, additional work is needed to understand the host range, pathogenicity, and potential population impacts of GI.2/RHDV2/b in North America.

The data set contains the results of experimental challenge of captive zebra finches with an American crow isolate of West Nile virus (WNV). 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 susceptibility to WNV.

The data set contains the results of experimental challenge of captive zebra finches with an American crow isolate of West Nile virus (WNV). 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 susceptibility to WNV.