The U.S. Department of Agriculture’s Animal & Plant Health Inspection Service (APHIS) confirmed Jan. 8 virulent Newcastle disease in a second commercial poultry flock in California.

The latest case is in a commercial layer flock in Riverside County, Cal., APHIS said, and the finding is part of an outbreak in southern California that began in May 2018 in backyard exhibition birds.

Virulent Newcastle disease is not a food safety concern, USDA said, and no human cases of Newcastle disease have ever occurred from eating poultry products.

APHIS is working closely with the California Department of Food & Agriculture (CDFA) to respond to the finding, limit the disease’s spread in commercial poultry and then eradicate it. APHIS said federal and state partners are conducting additional surveillance and testing in the area and are working with nearby commercial farms to increase biosecurity to prevent additional disease spread.

The initial commercial case was reported Dec. 16, 2018, in a flock of 110,000 six-week-old layer chickens in Riverside County, according to information submitted to the World Organization for Animal Health (OIE).

Information on the second case has not yet appeared on the OIE website but is expected to in the next few days.

According to information from APHIS and CDFA, 231 cases of virulent Newcastle disease were reported in backyard birds between May 18 and Dec. 20, but the tally has not been updated since then due to the partial governmental shutdown.

Virulent Newcastle disease is a contagious and fatal viral disease affecting the respiratory, nervous and digestive systems of birds and poultry, APHIS said. The disease is so virulent that many birds and poultry die without showing any clinical signs. A death rate of almost 100% can occur in unvaccinated poultry flocks. Virulent Newcastle disease can infect and cause death even in vaccinated poultry.