USDA’s Animal and Plant Health Inspection Service (APHIS) said it was working with the California Department of Food and Agriculture to limit the spread of the disease in commercial flocks in the area.
It added that federal and state partners would be conducting additional surveillance and testing in the area, as well as working with commercial farms in Riverside County to increase biosecurity measures.
This is the second case of the disease in Riverside County after APHIS confirmed its first case of virulent Newcastle disease in the US since 2003 in December 2018.
Both findings are part of an outbreak in southern California that began in May 2018 in backyard exhibition birds.
Newcastle disease is a contagious and fatal viral disease affecting the respiratory, nervous and digestive systems of birds and poultry.
USDA said it was “essential” that all bird owners followed good biosecurity measures to help protect their birds from infectious diseases.
“[There are] simple steps like washing hands and scrubbing boots before and after entering a poultry area; and cleaning and disinfecting tyres and equipment before moving them off the property,” said a USDA statement.
“In addition to practising good biosecurity, all bird owners should report sick birds or unusual bird deaths to State/Federal officials, either through their state veterinarian or through USDA’s toll-free number.”
USDA has reassured consumers that virulent Newcastle disease is not a food safety concern and no human cases of the disease have ever occurred from eating poultry products.