The exotic Newcastle virus, which is harmless to humans but contagious and fatal among poultry, threatens the state's $3 billion poultry industry.
It was found in 1 million hens at an egg farm in western San Bernardino County and they were ordered destroyed, authorities said Monday. Ranchers are compensated for all birds that are destroyed, said Larry Hawkins, a spokesman for the U.S. Department of
San Bernardino already was under quarantine, along with Riverside and Los Angeles counties.
State officials expanded the quarantine area to include San Diego County after the virus was found in a commercial flock of 75,000 birds there. Orange County was added to the quarantine list - even though it has no commercial poultry operations - to prevent the potential transport of infected birds.
Poultry and poultry products cannot be moved out of quarantined areas, although eggs can be transported if they are washed and placed in new packaging.
More than 100,000 birds already had been destroyed since the disease was found this fall in a backyard flock of chickens in Compton.
A statewide outbreak of the disease in the 1970s threatened the entire U.S. poultry and egg supply and led authorities to destroy nearly 12 million chickens. That outbreak cost $56 million to stop.
Chicken aren't the only American animals subject to a kill order because of epidemic illness. Deer are also being targeted to halt the spread of chronic wasting disease. Virginia approved a plan earlier this year to destroy poultry struck by avian influenza