Intramammary #infection of bovine #H5N1 #influenza virus in #ferrets leads to transmission in suckling neonates
Abstract 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, α2,3 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 neonate...