USDA scientists have completed animal challenge studies showing that infecting dairy cows with H5N1 in a laboratory setting can trigger clinical signs of disease similar to those of naturally infected animals on farms.
Understanding more about how this virus infects cows and how the disease progresses in the animals is essential to developing vaccines. While the study size was limited, the scientists’ validation of a reliable challenge model offers an important step towards filling crucial knowledge gaps that remain, including how to prevent the spread of H5N1.
USDA continues to set up additional studies with more animals and additional endpoints. The virus associated with the dairy cattle outbreak was first detected in a Texas dairy cow on March 25, 2024. Since then, 172 confirmed cases of infected dairy cows have taken place in 13 states. The Centers for Disease Control continues to emphasize the human health risk is low.
