New Hampshire is gearing up to join a federal program testing dairy cattle for virulent strains of bird flu, which so far has been detected here only in some wild birds in early 2024.

In other parts of the country, concern about Highly Pathogenic Avian Influenza is spreading. At least 875 dairy cattle herds in 16 states have tested positive; some zoos are reporting fatalities among birds and animals that became infected by wild birds in their enclosures; and at least two housecats on the West Coast have died after getting infected with the virus in pet food based on raw turkey meat.

A backyard chicken flock was destroyed in late December in Vermont because it was infected with bird flu.

As of Monday, the CDC listed 64 workers in dairies or poultry barns confirmed to have been infected by the bird flu virus, most out West. None have died or been seriously ill and there is no sign of person-to-person transmission, so the CDC says the public health risk remains low. As we saw with COVID, however, the concern is that the virus could mutate and become more dangerous or more infectious as it moves between species.

The Food and Drug Administration is cautioning against consumption of raw milk – milk that has not been pasteurized to kill pathogens – because it might contain the bird flu virus, known as H5N1. It’s unclear yet whether drinking infected milk can make people sick. Similar concerns are raised about eating undercooked meat or eggs.

Findings of the bird flu are reportable to USDA and listed on a website, 2022–2024 Detections of Highly Pathogenic Avian Influenza. The most recent reports from New Hampshire involve wild ducks collected in Sullivan County in February, 2024. 

State veterinarian Steve Crawford said New Hampshire “has not had any domestic animal detections in several years.”

USDA and state Department of Health and Human Services Dairy Sanitation staff are preparing for surveillance of all state dairies, following a December 2024 federal order.

“Our hope is to stand up that program with USDA approval before February 1,” Crawford said. “In the meantime, New Hampshire dairies have been complying with the April 2024 Federal Order that requires testing of individual animals prior to interstate movements. We have also had some dairies participating in a state-run voluntary herd surveillance program for about 5 months.”

Massachusetts and Vermont have been testing dairy herds for some weeks. 

One area of concern involves pet cats because felines appear particularly susceptible to the virus.

Bird flu has killed 20 big cats, including cougars and a half-Bengal tiger, at a rehabilitation clinic in Washington state. Domestic cats that kill infected birds can also get infected, leading officials to advise people to keep cats inside in areas where bird flu has been found.

Calls to several Concord-area veterinary clinics found little concern so far with few if any cat owners calling for information or concern.

David Brooks can be reached at dbrooks@cmonitor.com