Louisiana reports its first probable human H5N1 case as California logs 2 more

Bird being tested for bird flu

Merrimon / iStock

Today, the Louisiana Department of Health (LDH) announced the state's first presumptive human H5N1 highly pathogenic avian flu case. The patient, a resident of southwestern Louisiana who was exposed to sick and dead birds with suspected infection, has been hospitalized.

Also today, the California Department of Public Health reported 2 more probable human case of H5N1 in a dairy farm worker, raising the state's total to 34, all but 1 in people with occupational exposure. The sample tested positive at a local lab, but confirmatory testing at the US Centers for Disease Control and Prevention (CDC) was negative.

CDC couldn't confirm positive result in child

Meanwhile, a CDC official told Stat that confirmatory tests on samples from a California child with suspected avian flu after drinking raw milk were negative.

The first test run on a sample from the California child, who had fever and vomiting, was positive for influenza A. But tests run on samples at a local lab, the California Department of Public Health, and the CDC couldn't confirm the positive result, Stat reports. 

While the result doesn't definitively rule out H5N1 infection, the case won't be added to the national list of confirmed human cases.

Lisa Santora, public health officer for Marin County, told Stat that the amount of virus in the original sample was low and noted that samples degrade with time. Locally, the child's situation will be classified as a suspected H5N1 case.

More detections in animals

The US Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) confirmed 13 more H5N1 outbreaks in dairy cattle in California, four outbreaks in birds in three states, and five more detections in mammals, including a polar bear and a coyote.

The 13 additional H5N1 outbreaks in California cattle bring the national total to 845 in 16 states and California's total to 630.

Yesterday, the Wisconsin Department of Agriculture, Trade and Consumer Protection reported an H5N1 outbreak at a commercial poultry farm in Barron County, the first in the state since January. Barron County is located in the northwestern part of the state.

The 13 additional H5N1 outbreaks in California cattle bring the national total to 845 in 16 states and California's total to 630. The bird outbreaks were reported yesterday in two backyard flocks in Arkansas's Craighead and Pope counties and commercial turkey farms in Sac County, Iowa, and Kingsbury County, South Dakota.

The five additional H5N1 detections in mammals involve an Alaskan polar bear sampled a year ago (the second positive polar bear), a Montana mountain lion sampled in April, and, more recently, a domestic cat from California's Tulare County and a mouse and a coyote from Franklin County in Washington state.

Note: This story and its headline were corrected on December 16, 2024, to note two new California cases, not one.

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