California Probes Likely H5 Infection in Another Dairy Worker

By Lisa Schnirring

The California Department of Public Health (CDPH) on October 5 reported a potential third human H5 avian influenza infection in a worker who had contact with sick cows at a Central Valley farm.

Confirmation testing is underway at the US Centers for Disease Control and Prevention (CDC). If confirmed, the illness would mark the third recent H5 infection in a California dairy worker.

The CDPH said there is no known link to the two recent cases, and that all three patients had contact with infected animals at three different farms. Like the first two cases, the most recent probable patient had mild symptoms that included conjunctivitis. None of the patients were hospitalized.

If confirmed by the CDC, the latest illness would push the nation’s human H5 case count since the first of the year to 17.  All but one—which involves a patient from Missouri—have been connected to contact with sick cows or poultry.

H5N1 infects more dairy cows in California

In related developments, the US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed 26 more H5N1 outbreaks in cows at California dairy farms, pushing the national total to 282 across 14 states.

The latest confirmations make California the hardest hit state, with 82 outbreaks reported so far. California, which has ramped up surveillance around affected farms with weekly bulk-milk testing, now has the most outbreaks of any state, despite the fact that it reported its first outbreaks in cows at the end of August. California is the nation’s largest dairy producer.