Experimental study demonstrates transmission and persistent viral shedding of H5N1 in calves fed raw infected milk, indicating unpasteurized dairy poses critical transmission risks.
Key Points
To determine whether calves are susceptible to highly pathogenic avian influenza H5N1 infection through the consumption of unpasteurized milk from infected dairy cows.
Fed calves unpasteurized milk harvested from cows naturally infected with HPAI H5N1.
Evaluated an additional cohort fed infected milk containing neutralizing antibodies.
Monitored calves for clinical respiratory signs, serological conversion, and persistent nasal viral shedding before and after transition to clean milk.
Calves fed unpasteurized infected milk developed respiratory distress and nasal discharge, seroconverted, and exhibited persistent shedding of live virus in nasal swabs even after transitioning to uninfected milk.
Calves fed milk from infected cows that also shed neutralizing antibodies did not develop clinical illness, shed detectable virus, or seroconvert.