The U.S. Centers for Disease Control on Tuesday advised states to aid in H5N1 bird flu surveillance by increasing testing of influenza A virus samples during the summer season to help detect even rare cases of transmission of the virus in humans.

CDC's Principal Deputy Director Nirav Shah asked for the increased vigilance ahead of the typical seasonal decline in influenza activity and testing due to the ongoing outbreak of H5N1 among poultry and U.S. dairy cattle.

Editor's Note: Doctor Reveals Little-Known Immune Health Secret

Bird flu has been found in dozens of dairy herds in nine states. One person from Texas who had contact with dairy cows was infected with H5N1 bird flu and suffered conjunctivitis.

Public health laboratories handle flu samples from local jurisdictions and subtype them to identify them as either a common virus or a novel virus like H5N1.

The CDC earlier in May had met with state health officials and asked them to facilitate distribution of protective gear for farm workers to avoid infection against bird flu.