There are 31 confirmed cases of bird flu in the country, and experts are concerned that cases may continue to rise, giving opportunities for the flu to mutate, The New York Times reported Oct. 24.
Here are seven things to know:
1. The additional cases of H5N1, which were identified in California, have not changed the CDC's risk assessment for the public. The risk level remains low, CDC experts told the Times.
2. Public health experts are investigating a case in Missouri involving an individual who developed flu-like symptoms after sharing a home with a patient hospitalized with bird flu in August. A handful of healthcare workers also developed flu-like symptoms after caring for the patient, but CDC tests showed they did not have antibodies for bird flu. Researchers are still unsure how the Missouri patient and household member became infected — neither had exposure to an infected animal and did not consume raw milk products that could have carried the virus. Some experts suggest they may have become sick after a rare encounter with wildlife.
3. Genetic analysis of the virus taken from three newly infected Californians shows some mutation, but none that would enable the virus to spread easily among people, according to the CDC. However, experts are concerned about the approaching flu season, as flu viruses can acquire new abilities by swapping genes. If an individual is infected with both H5N1 and the seasonal flu virus, bird flu could gain the ability to spread easily among people.
4. Fifteen human cases have been identified in California among dairy workers who had direct exposure to infected cows. Their symptoms were mild, and none were hospitalized.
5. The CDC warned that the number of human cases could be higher than reported, as some people with flu-like symptoms may not receive H5N1 testing or seek medical care due to mild symptoms.
6. Washington recently became the sixth state with human cases of bird flu. The ongoing H5N1 outbreak has affected more than 300 dairy herds in 14 states since late March, according to the CDC.
7. Some health systems are preparing for the possibility of a bird flu pandemic. New York City-based NYC Health + Hospitals recently tested the system's ability to care for patients with H5N1 and prevent exposures.