Colorado has reported four confirmed cases of H5N1 bird flu virus infections in poultry workers, and is investigating a fifth suspected case, according to health authorities.
The U.S. Centers for Disease Control and Prevention (CDC) has confirmed the four cases, while the fifth case is pending confirmation by the federal agency. The Colorado Department of Public Health and Environment is supporting further investigation of the matter.
The workers showed mild symptoms, ranging from conjunctivitis (pink-eye) to respiratory signs, but none were hospitalized.
Human infections with the H5N1 avian flu virus could potentially cause severe disease and even a pandemic if the virus were to mutate and acquire the ability to spread easily between people, the CDC has warned.
The Colorado cases are the latest in a growing number of human infections with the highly pathogenic H5N1 virus, which has been spreading rapidly among wild birds and poultry flocks across the United States and other parts of the world in recent months.
While human-to-human transmission of the virus remains rare, health officials are closely monitoring the situation for any signs that the virus is adapting to better infect and spread among people.
The CDC and state health authorities are working to investigate the Colorado cases and implement appropriate public health measures to limit the potential for further spread.