Avian encephalomyelitis virus in reared pheasants: a case study.

Area of Science:

• Veterinary Virology
• Avian Pathology
• Disease Outbreak Investigation

Background:

• Avian encephalomyelitis virus (AEV) is a significant pathogen in poultry, primarily affecting chickens.
• Neurological diseases in game birds can have substantial economic impacts on game farms.
• Understanding AEV transmission dynamics is crucial for disease control in various avian species.

Observation:

• An outbreak of neurological disease, including trembling, incoordination, blindness, and cataracts, occurred in pheasant chicks.
• Affected chicks exhibited significant mortality and culling rates, particularly in later hatches.
• Histopathology revealed encephalomyelitis, consistent with AEV infection, though initial virus detection was challenging.

Findings:

• Serological testing (enzyme-linked immunosorbent assay) confirmed the presence of AEV antibodies in affected chicks and adult breeding birds.
• Reverse transcriptase-polymerase chain reaction (RT-PCR) identified AEV nucleotide sequences in affected pheasant tissues.
• The findings suggest a vertically transmitted AEV strain, potentially introduced by carrier pheasants, caused the outbreak.

Implications:

• This research highlights the susceptibility of pheasants to AEV, expanding the known host range of the virus.
• It underscores the importance of diagnostic methods like ELISA and RT-PCR for identifying AEV in non-traditional avian hosts.
• Effective biosecurity and disease surveillance are critical to prevent AEV introduction and spread in game bird populations.