The United States has reported a rare case of human infection with the avian influenza A (H5N1) virus, marking the second confirmed case in the country. The World Health Organisation (WHO) was alerted to this case on April 1, 2024, by the United States IHR National Focal Point.

The infected individual, over 18 years old, showed symptoms on March 27, including conjunctivitis, after coming into contact with dairy cattle suspected of carrying the virus. This case is unique as it's the first known instance of human infection from contact with infected cattle.

 Samples collected from the patient tested positive for the influenza A (H5N1) virus at the Texas Tech University Bioterrorism Response Laboratory. Further confirmation by the United States Centres for Disease Control and Prevention (US CDC) identified the virus as a high-pathogenicity avian influenza (HPAI) A (H5N1) virus clade 2.3.4.4b. The patient received antiviral treatment and was advised to isolate, showing signs of recovery without hospitalsation.

 No additional cases related to this infection have been identified among household contacts. They've received influenza antiviral prophylaxis as a precaution. Despite detections of the virus in wild birds and sporadic outbreaks among poultry, there's been no evidence of human-to-human transmission.

 The infected cattle were found in multiple states, including Texas, Kansas, Michigan, Idaho, New Mexico, and Ohio. The United States Department of Agriculture (USDA) continues to monitor and test animals on affected farms.

Influenza A virus infection is uncommon in bovine species, making this case particularly noteworthy. The infected dairy cattle were identified in various states, indicating a spread of the virus within the bovine population.

The USDA remains vigilant, conducting tests and surveillance on farms where cattle show signs of illness. The goal is to contain the spread of the virus and prevent further infections among both animals and humans.

This development underscores the importance of continued vigilance and collaboration in monitoring and responding to emerging infectious diseases, safeguarding both human and animal health.