Emerging – Avian metapneumovirus Detected in U.S. Commercial Poultry
Avian metapneumovirus subtype B (AmPV-B) has recently been detected by PCR in broilers, broiler breeders, turkey breeders and/or turkey meat type birds in West Virginia, Virginia, Georgia, South Carolina, and North Carolina. In addition, subtype A was recently detected in Texas and California. At present, the source of virus has not been identified; however, detection of AmPV in wild birds has been reported and suggests a possible role in virus transmission. Avian Metapneumovirus is a highly contagious respiratory viral infection associated with mild respiratory signs (snicking/sneezing, nasal discharge), swollen sinuses and greatly predisposes birds to other secondary opportunistic bacterial infections. Secondary infections can lead to presentations of swollen heads and/or torticollis and neurologic signs. Birds in egg production can experience mild to severe drops in production. Currently, there is no licensed vaccine available for use in the U.S.
General Overview of Diagnostic Tests for AmPV
Diagnostic testing for AmPV includes detection of antibodies by ELISA, detection of nucleic acid by PCR and virus isolation. The following commercial ELISA kits are available for import by CVB permit: 1) Idexx Avian Pneumovirus (APV) antibody test kit (detects antibodies to subtypes A, B, C) and 2) BioChek Avian rhinotracheitis (ART) antibody test kit (detects antibodies to subtypes A and B). Several molecular tests to detect AmPV nucleic acid for subtypes A, B, C and D are available by traditional RT-PCR and/or real time RT-PCR. Virus isolation may also be offered in some labs.
PDRC AmPV Diagnostic Tests
- AmPV reverse transcriptase PCR (RT-PCR) for subtypes A, B or C
- Virus isolation
Instructions for sample collection and shipping to the lab
Preferred samples to collect and submit for testing are whole heads, tracheas, tracheal or oropharyngeal swabs in transport media and nares. The timing of tissue or swab collection is critical for detection and/or virus isolation of AmPV. Collect samples at earliest timepoint following identification of drop in egg production or first sign of respiratory disease. If collecting swabs, be sure to include thorough swabbing of sinus cavity.
It’s important to maintain the cold chain from the point of collection through transport to the diagnostic lab. If shipping same day express for next day delivery, samples can be stored at 4C and shipped on wet ice. If shipping > 24 hours after collection, samples should be frozen at –80C and shipped express on dry ice.
At this time, we recommend requesting AmPV-B RT-PCR and if positive virus isolation (VI; if you are interested in VI).
Real time RT-PCR for subtypes A, B, C and/or D