California officials have ordered testing at dairy farms within six miles of herds infected with H5N1 bird flu, as well as at dairies that share trucks, employees or equipment with facilities affected by the outbreak.
The mandatory testing comes as the total number of infected herds in California has risen to 17. Nationally, officials have reported 218 outbreaks in 18 states. However, in the past 30 days, California has been responsible for all but two of the most recent outbreaks.
Authorities have not yet revealed the location of the herd, other than to say they are somewhere in the Central Valley. They also say the country’s milk and dairy products are safe for consumption; pasteurization inactivates the virus.
When officials conduct mass testing, they examine the pooled milk from several cows on the farm. If this test detects the H5N1 virus, a more precise test is then conducted to identify infected cows or herds for slaughter.
The state is quarantining all farms that have H5N1 or that refuse to be tested. It is also quarantining dairy farms within six miles of an infected herd or that have been in contact with an infected herd.
“Until now, all dairies have been cooperatives,” said Steve Lyle, a spokesman for the California Department of Food and Agriculture. Officials have the right to request an inspection under state law, he said.
Lyle said trials will be conducted on about 100 farms.
In addition to the infection in the flock, a commercial turkey flock also suffered an outbreak of H5N1 on September 18. The number of turkeys in the flock has not yet been disclosed.
Federal and state officials have released county-level data on infections in commercial birds, but not livestock.
John Korslund, a retired U.S. Department of Agriculture veterinary epidemiologist, Who writes about animal diseases on the Internet?He was concerned that California could soon find itself in a situation similar to Colorado’s.
Between May and August, 64 Colorado flocks were infected, as well as six poultry workers.
Colorado has about 100 dairy herds and about 200,000 dairy cows. California has 1,300 dairy herds and about 1.7 million cows.
“The problems in California are just beginning,” Korslund said.
Wastewater testing conducted by both the Centers for Disease Control and Prevention and the Wastewater scanning – the Infectious Disease Monitoring Network – detected the H5N1 virus in samples collected in Turlock and San Diego.
Health officials say they cannot determine the source of the H5N1 in the wastewater, saying it could come from discarded milk or wild animals.
CDC and WastewaterScan only test a few landfills in the Central Valley, including Placer, Yuba, El Dorado and Sacramento counties. However, there are only two sites further south in Merced and Stanislaus counties. There are no participating wastewater sites in Fresno, Kings, Tulare, Kern, Madera or San Joaquin.
Ninety percent of the state’s dairy cows are located in the San Joaquin Valley, which includes San Joaquin, Stanislaus, Merced, Kings, Madera, Fresno, Tulare and Kern counties. Thirty percent of the state’s dairy farms are located in Tulare County.
