May 3 :
A new research article that was supported by the federal government suggests that the disease, which has already spread to nine states, was probably only present in dairy cows in the United States for approximately four months before officials recognised it. Following reports of lower milk yields in various states, the US Department of Agriculture announced on March 25th that a dairy cow in Texas had contracted the first-ever H5N1 virus infection.
The United States Department of Agriculture has stated its belief that H5N1 was introduced to cattle by infected wild birds. The research, which was published on May 1 and supported by the USDA, the CDC, and the National Institute of Allergy and Infectious Diseases, indicates that the disease spread to other states as cows were transferred there.
"Data support a single introduction event from wild bird origin virus into cattle, likely followed by limited local circulation for approximately four months prior to confirmation by USDA," the study said.
Academic experts lead by evolutionary biologist Michael Worobey of the University of Arizona recently determined that a single transmission event happened in late 2023 after piecing together raw DNA sequences supplied by the USDA on April 21st without dates or locations.
A number of scientists have voiced their disapproval of the USDA's decision to withhold data that could help researchers track the virus's evolutionary history.
During this outbreak, one person—a farm worker from Texas—has tested positive for H5N1. However, their sole symptom was conjunctivitis, which is thought to have been caused by contact with cow milk. According to the CDC, there is minimal risk of infection for the general population.
The spread of bird flu to other mammals is cause for concern because the virus has a lengthy history of being considered a pandemic threat.
University of Minnesota avian influenza specialist Carol Cardona said the virus might spread over the four months it went unnoticed. "By the time it was recognised, we were beyond our ability to contain the outbreak," she pointed out. without mentioning a specific date, members of the USDA's network of laboratories that monitor for diseases found influenza A virus—also known as bird flu—in milk and nasal swabs taken from cows at a dairy in Texas.
According to the report, while epidemiologic investigations were ongoing elsewhere, samples were sent to the National Veterinary Services Laboratories of the United States Department of Agriculture (USDA), which deal with animal-health situations.
