Since the initial report of West Nile virus in the northeastern United States in 1999, the virus has spread rapidly westward and southward across the country. In the summer of 2002, several midwestern states reported increased cases of neurologic disease and mortality associated with West Nile virus infection in various native North American owl species. This report summarizes the clinical and pathologic findings for 13 captive and free-ranging owls. Affected species were all in the family Strigidae and included seven snowy owls (Nyctea scandiaca), four great-horned owls (Bubo virginianus), a barred owl (Strix varia), and a short-eared owl (Asio flammeus). Neurologic signs identified included head tilt, uncoordinated flight, paralysis, tremors, and seizures. Owls that died were screened for flaviviral proteins by immunohistochemical staining of formalin-fixed tissues, followed by specific polymerase chain reaction assay to confirm West Nile virus with fresh tissues when available. Microscopic lesions were widespread, involving brain, heart, liver, kidney, and spleen, and were typically nonsuppurative with infiltration by predominantly lymphocytes and plasma cells. Lesions in owls were much more severe than those previously reported in corvids such as crows, which are considered highly susceptible to infection and are routinely used as sentinel species for monitoring for the presence and spread of West Nile virus. This report is the first detailed description of the pathology of West Nile virus infection in Strigiformes and indicates that this bird family is susceptible to natural infection with West Nile virus.

First identified in 2012 in a surveillance study in Hong Kong, porcine deltacoronavirus (PDCoV) is a proposed member of the genus Deltacoronavirus of the family Coronaviridae. In February of 2014, PDCoV was detected in pigs with clinical diarrheal symptoms for the first time in the USA. Since then, it has been detected in more than 20 states in the USA and in other countries, including Canada, South Korea, and mainland China. So far, histological lesions in the intestines of pigs naturally infected with PDCoV under field conditions have not been reported. In this report, we describe the characteristic histological lesions in the small intestine that were associated with PDCoV infection, as evidenced by detection of viral nucleic acid by RT-PCR. In addition, we performed genomic analysis to determine the genetic relationship of all PDCoV strains from the four countries. We found that PDCoV mainly caused histological lesions in the small intestines of naturally infected piglets. Sequence analysis demonstrated that the PDCoV strains of different countries are closely related and shared high nucleotide sequence similarity; however, deletion patterns in the spike and 3' untranslated regions are different among the strains from mainland China, Hong Kong, the USA, and South Korea. Our study highlights the fact that continual surveillance is needed to trace the evolution of this virus.

This report describes the use of polymerase chain reaction and DNA in situ hybridization to diagnose Aleutian mink disease parvovirus DNA in various tissue specimens from 2 companion striped skunks. Clinical, laboratory, and microscopic findings also support a clinical diagnosis of Aleutian disease in these mink.

Riemerella anatipestifer is a gram-negative bacteria that can cause disease in a wide variety of wild and domesticated birds, especially waterfowl. The infection can be peracute, acute, or chronic. Although various routes of transmission have been proposed, to date, there is little information on the effects of route of transmission and challenge dosage on R. anatipestifer infection. Hence, the objective of this study was to determine the effect of route of inoculation and challenge dosage on R. anatipestifer infection and pathology. To achieve this objective, one hundred forty-seven 14-day-old white Pekin ducks (Anas platyrhynchos) were equally divided into 13 experimental groups (12 challenge and 1 control group). Each challenge group had 11 ducks. The control group had 15 ducks. Four routes of inoculation were evaluated (intranasal, oral, subcutaneous, and intravenous). Three dosage levels were evaluated for each inoculation route (10(2), 10(4), and 106 colony forming units [CFU]/ml). At the 106 CFU/ml dosage level, mortality was most associated with the subcutaneous (91%) and intravenous (82%) routes, followed by the nasal (18%) and oral (9%) routes. A unique pathologic lesion was found in the bursa of Fabricius and spleen of affected birds. Within the spleen and bursa of Fabricius, there were varying degrees of lymphoid depletion and necrosis within the cortical and medullary regions. These pathologic lesions have not been previously reported in ducks with R. anatipestifer infection.