TRT virus serology: discrepancy between ELISA and indirect immunofluorescence

Area of Science:

• Veterinary Virology
• Avian Immunology
• Molecular Diagnostics

Background:

• Turkey Rhinotracheitis (TRT) virus causes significant respiratory disease in poultry.
• Serological surveys are crucial for understanding virus circulation and disease emergence.
• Previous diagnostic methods for TRT virus antibodies had limitations.

Purpose of the Study:

• To investigate the presence of antibodies to TRT virus in turkeys and chickens from Northern Ireland and England prior to widespread TRT infection.
• To evaluate the efficacy of indirect immunofluorescence (IIF) compared to ELISA for TRT virus antibody detection.
• To confirm the specificity of detected antibodies against TRT virus.

Main Methods:

• Sera from turkeys and chickens were tested using a streptavidin/biotin based ELISA.
• Indirect immunofluorescence (IIF) was employed to detect TRT virus antibodies.
• Double staining assays with monoclonal antibodies and purified IgG fractions were used to confirm specificity.

Main Results:

• All sera tested negative by ELISA.
• IIF detected antibodies in 16.7% of Northern Ireland turkeys, 12.6% of Northern Ireland chickens, and 7% of England turkeys.
• IIF-positive sera did not cross-react with other avian myxoviruses, and double staining confirmed specificity for TRT virus.

Conclusions:

• Indirect immunofluorescence is a sensitive method for detecting TRT virus antibodies in poultry.
• The findings suggest the circulation of an antigenically related virus to TRT virus in poultry populations in Northern Ireland and England.
• This highlights the potential for novel or related TRT virus strains in these regions.