Health officials say an ongoing bird flu outbreak in daily cattle does not present a serious risk to human health and are not recommending vaccination for any groups of people. A dairy worker in Colorado has been infected with bird flu, marking the fourth human case in an ongoing outbreak that started with detection of the disease in cattle this spring.
In 2022, a poultry worker in Colorado tested positive for the same strain of avian influenza. Across the world, cases of human illness have ranged from mild infections to more severe illness, including pneumonia. Dairy farm workers typically express milk by hand from cow teats before attaching milking equipment. A splash of contaminated milk could get into the eye directly, or the virus could enter when workers touch their eyes with a contaminated hand. Eye infections have been associated with previous human infections of bird flu.