As part of routine surveillance for H5/H7 avian influenza, H5 low-pathogenic avian influenza (LPAI) was detected in a commercial duck breeder flock in Monterey County, Cal., exposing 9,746 birds, according to information the U.S. Department of Agriculture submitted to the World Organization for Animal Health (OIE) on April 24.
According to the OIE report, partial HA sequencing determined the H5 to be a LPAI virus of North American wild bird lineage, but further characterization is pending virus recovery. There have been no clinical signs of illness or increased mortality on the premises, the report said.
USDA's Animal & Plant Health Inspection Service (APHIS) and the California Department of Food & Agriculture are conducting a comprehensive epidemiological investigation and have implemented enhanced surveillance and testing related to this finding, the OIE report said.
Two additional commercial poultry premises associated with the initial premises have been quarantined and sampled for avian influenza virus, and the results are pending.
Control measures applied in the case include movement controls, surveillance and quarantine.
LPAI viruses typically cause few or no clinical signs in infected poultry. The LPAI virus is excreted through infected birds’ feces and respiratory secretions and spreads primarily through direct contact among healthy and infected birds, according to APHIS. LPAI can also be spread through indirect contact with contaminated equipment and materials.
To prevent cases of LPAI, poultry producers must use special preventative measures and precautions on the farm, APHIS said. If LPAI is detected, farms must be thoroughly cleaned and disinfected. Avian influenza viruses are inactivated by heat and drying. They are also very sensitive to most disinfectants and detergents. To ensure thorough disinfection, organic material must first be cleaned from the environment.
On the other hand, highly pathogenic avian influenza is a serious disease and requires rapid response because it is highly contagious and often fatal to chickens and turkeys, APHIS said.