In a recent study published in Emerging Infectious Diseases , a group of researchers compared the distribution of sialic acid (SA) receptors in the respiratory tract and mammary glands of dairy cattle naturally infected with the highly pathogenic avian influenza (HPAI) A(H5N1) virus (highly contagious and deadly avian influenza virus strain H5N1). In March 2024, the United States (US) Department of Agriculture reported the first detection of HPAI H5N1 virus in dairy cattle in the US. The presence of specific virus receptors on host cells influences the susceptibility to HPAI H5N1 infection.
Still, the distribution of SA receptors in dairy cattle, particularly in mammary glands, remains poorly understood. Further research is needed to clarify the mechanisms of HPAI H5N1 transmission and persistence in dairy cattle and its implications for public health and the dairy industry. In March 2024, two adult Holstein dairy cows in Texas, were diagnosed with HPAI H5N1 virus infection at the Iowa State University Veterinary Diagnostic Laboratory.
The cows exhibited symptoms including reduced lactation and yellow, thickened milk. The diagnosis was confirmed through real-time reverse transcription polymerase chain reaction (rRT-PCR) and immunohistochemistry in the mammary glands and lungs. Formalin-fixed and paraffin-embedded tissue sections of trachea, lung, and mammary gland tissues, as well as milk samples, were collected for further analysis.
Tissue sections were verified to be positi.