In the months of April and May alone, three human cases of bird flu have now been reported in the United States, according to the CDC. All three cases have occurred in individuals who had direct exposure to infected dairy cows in the states of Texas and Michigan, and all cases have presumably been from cow-to-human transmission. In the United States, there have been no cases of human-to-human transmission of the highly pathogenic avian influenza H5N1 virus.
The first two human cases reported this year presented with conjunctivitis, or eye discomfort and watery discharge from the eyes. In the most recent case reported from a farm worker in Michigan, the patient reported upper respiratory symptoms such as cough in addition to eye discomfort and eye discharge.
Although symptoms have been mild for all three cases of bird flu reported thus far in humans, the emergence of respiratory symptoms in the last case should be of concern to the general public. The presence of cough would allow the virus to spread more easily and potentially infect other individuals if bystanders breathe in the infected virus particles.