Biology subjects

Baker, P. H.

Publications and source records attributed to Baker, P. H..

2 recordsLinked to original sources

bioRxiv2025

Pregnant Dairy Heifers Express Influenza A Virus Receptors in the Mammary Gland

Highly pathogenic avian influenza (HPAI) A(H5N1) virus emerged in lactating dairy cattle in March 2024, causing mastitis-related disease and infections in other farm animals and workers. Recent work identified 2,6 and 2,3-linked sialic acids (SA), which serve as influenza virus receptors, in the lactating bovine mammary gland; however, their distribution across stages of mammary growth and development remains unknown. We compared the distribution of tissue sialylation in mammary glands of prepubertal dairy calves, pregnant dairy heifers, and lactating cows. Mammary glands at all physiological stages expressed both 2,6 SA, the preferred receptor linkage for human influenza viruses, and 2,3 SA, the preferred receptor linkage for avian influenza viruses. Importantly, mammary glands of pregnant dairy heifers exhibited the highest overall expression of 2,3 SA, observed in both tissue and alveolar lumens. Our results suggest that pregnant dairy heifers, like lactating dairy cows, are susceptible to H5N1 infection in the mammary gland.

pathology↗

bioRxiv2024

Bovine H5N1 influenza virus infection is transmitted by milk causing mortality in suckling neonates

The spread of H5N1 clade 2.3.4.4b in dairy herds raises concerns about zoonotic transmission due to its high viral load in milk, a key contact point between livestock and humans. H5N1 clade 2.3.4.4b exhibits tropism for the mammary gland, with milk from infected animals containing high levels of infectious virus, posing potential risks to offspring via breastfeeding. Using a lactating ferret model, we demonstrate that mammary gland infection with bovine H5N1 transmits the virus to suckling kits, resulting in neonatal mortality. Viral RNA levels increased in milk and remained high in mammary tissue, with infected kits exhibiting elevated viral RNA in the oral and nasal cavities and feces. Additionally, we detected the H5N1 receptor, 2,3 sialic acid, in ferret and human mammary tissue. These data demonstrate that H5N1 clade 2.3.4.4b infection in lactating dams leads to mastitis-related disease and transmits to suckling pups, resulting in mortality among neonates.

microbiology↗