A dairy worker in Nevada has been infected with a new strain of bird flu, marking the first known case of this variant affecting a cow in the U.S., health officials report. The individual, who experienced mild symptoms, has since recovered without the need for hospitalization.
The case involves a strain of the virus known as D1.1, which has previously been observed in poultry-related infections. The Centers for Disease Control and Prevention (CDC) stated that the person’s primary symptom was eye redness and irritation, consistent with other bird flu cases linked to dairy cows.
While this new strain had been found in over a dozen people exposed to poultry, the CDC confirmed that there is no evidence of transmission to other individuals. The agency maintains that the general public faces a low risk from the virus.
The bird flu strain in question is part of the Type A H5N1 influenza, which has been circulating among wild birds and livestock worldwide. This specific strain, B3.13, began spreading to cattle in 2023 and has affected 962 herds in 16 states, primarily in California. In late January, the D1.1 variant was identified in Nevada’s cattle after being detected in milk as part of a monitoring initiative.
Health officials expressed concerns about the possibility of further spread, noting the challenges of managing infections in both animals and those who work closely with them. This latest case follows a rise in bird flu cases, including a fatality in Louisiana and a severe illness in Canada linked to the virus.
To date, 68 people in the U.S. have been reported to have contracted bird flu, the majority of whom had close contact with infected animals. However, CDC data shows the risk to the general public remains low, particularly for those without prolonged exposure to infected animals.
