The Centers for Disease Control and Prevention (CDC) are keeping a close eye on "red flags" relating to the bird flu and whether the illness might develop into a pandemic, according to a report.
The latest numbers show 66 confirmed human cases of bird flu in the U.S. The CDC is taking a holiday break and will resume updates on human cases on Jan. 3.
"Identifying epidemiologically linked clusters of influenza A(H5N1) human cases might indicate the virus is better able to spread between humans," a CDC spokesperson told Newsweek. "CDC is searching for genetic changes in circulating viruses that suggest it could better transmit between humans."
The red flags the CDC is monitoring are outbreaks that are spread from person-to-person and evidence that the virus has mutated, Newsweek reports.
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Last week, the CDC announced that a patient in Louisiana who was hospitalized with severe bird flu illness was found to have a mutated version of the virus. That case fell into the red flag category, the CDC spokesperson told Newsweek.
"The analysis identified low frequency mutations in the hemagglutinin gene of a sample sequenced from the patient, which were not found in virus sequences from poultry samples collected on the patient’s property, suggesting the changes emerged in the patient after infection," the CDC said in an announcement on its website.
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"While these low frequency changes are rare in humans, they have been reported in previous cases of A(H5N1) in other countries and most often during severe disease," the agency added.
The CDC did not immediately get back to a Fox News Digital inquiry, but previously stressed there has been no known transmission of the virus from the Louisiana patient to anyone else.
Avian influenza, also known as HPAI, is a highly contagious virus that can be spread in various ways from flock to flock through contact with infected animals, by equipment, and on the clothing and shoes of caretakers, according to the Michigan Department of Agriculture and Rural Development.
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State officials confirmed infected flocks in two additional Michigan counties on Monday.
According to the CDC, the public health risk associated with avian influenza remains low. No birds or bird products infected with HPAI will enter the commercial food chain.
Fox News' Alexandra Koch, Melissa Rudy and the Associated Press contributed to this report.
