Nevada Dairy Worker Infected with Different Bird Flu Strain, CDC Reports

 

Bird flu crossing over from birds to cows

Health officials have confirmed that a dairy worker in Nevada has contracted a distinct strain of bird flu, the Centers for Disease Control and Prevention (CDC) announced Monday.

The individual, who had been handling infected cows, tested positive for the D1.1 strain of avian influenza. This version of the virus has been prevalent in wild bird populations but differs from the B3.13 strain, which has been responsible for most human infections in the U.S.

Scientists have identified a mutation in D1.1 that could enhance its ability to spread among mammals.

The virus was first detected in dairy cattle last month—also in Nevada—through the National Milk Testing Strategy, which routinely screens dairy cow milk for avian influenza.

This marks the second documented instance of bird flu crossing over from birds to cows.

''That’s a big deal,'' said Michael Osterholm, an infectious disease specialist and director of the Center for Infectious Disease Research and Policy at the University of Minnesota. He emphasized that this development underscores the virus’s ongoing evolution.

Uncertainty remains about how long D1.1 has been present in dairy herds or what its long-term consequences might be, according to Andrea Garcia, vice president of science, medicine, and public health at the American Medical Association.

''Some experts do fear that it could mark a new chapter in the outbreak or that bird flu may become endemic in the U.S.,'' Garcia noted in a YouTube video released Monday. ''This is something we are continuing to very closely follow.''

Thus far, the virus has not caused severe illness in dairy cattle, the American Veterinary Medical Association reports. In California, where 738 herds were affected, 236 have fully recovered, according to the state’s Department of Food and Agriculture. Nationally, the U.S. Department of Agriculture has recorded 962 infections in cattle.

However, poultry farms have suffered significantly. Millions of chickens have been culled to contain the outbreak, driving up egg prices and causing shortages.

The Nevada dairy worker experienced only mild symptoms, primarily conjunctivitis (pinkeye), and has since recovered, the CDC stated. No close contacts of the patient have reported any illness, according to the Central Nevada Health District.

Most human cases of bird flu in the past year, regardless of the strain, have resulted in mild symptoms.

However, one fatality linked to the D1.1 strain was reported in Louisiana last month. The patient, over 65 years old with preexisting health conditions, became ill in December after exposure to wild birds and a backyard poultry flock.

The CDC estimates that D1.1 accounted for 15 of the 68 human cases of bird flu detected in the U.S. last year. Cases have also been reported in Oregon, Washington, Iowa, and Wisconsin.

In an effort to improve early detection, the CDC recently recommended increased testing for avian flu in hospitalized patients, ideally within 24 hours of admission.

Despite these cases, the agency maintains that the risk to the general public remains low, as there is no evidence of human-to-human transmission at this time.

Still, public health experts urge preparedness.

''We’re gonna have another influenza pandemic, and when it happens, we shouldn’t be surprised,'' Osterholm cautioned. ''But will it be H5, or not? I don’t know.'