The World Health Organization (WHO) announced that it has been informed of a confirmed human case of the H5N1 avian influenza virus. The notification was received on April 1, 2024, from the National Contact Center concerning International Health Regulations in the United States. The organization stated in a release on Friday that symptoms appeared on the patient on March 27, and there was a history of exposure to livestock presumed to be infected with the virus.
The WHO indicated that the virus was transmitted from a cow to a person who worked on a cattle farm in Texas, noting that infections have been reported in 29 herds across 8 different U.S. states since last March. The organization clarified that the avian influenza viruses identified in the cattle and the human case have not shown any increased adaptation to mammals but advised farm workers and others in close contact with cattle to take necessary precautions in case of infected animals.
The head of the WHO’s Global Influenza Program, Wenqing Zhang, confirmed that the human case in Texas is the first instance of a person contracting avian influenza via a cow. He pointed out that transmission has also been recorded from birds to cattle, from cattle to cattle, and from cattle to birds during ongoing outbreaks, suggesting that the virus might have found other transmission pathways than previously thought.
The organization noted that while this situation appears concerning, it simultaneously demonstrates the strength of disease surveillance, allowing for detection while risk assessments of the virus are being conducted. According to the WHO, human infections with the H5N1 virus or avian influenza are rare and related to exposure to infected environments and animals, with only about 900 cases reported since 2003, ranging from mild to asymptomatic to severe.
