Centers for Disease Control and Prevention on excessive alert for pandemic ‘purple flags’ after hen flu uptick in US

Weeks after the first severe case of bird flu was reported in Louisiana, the Centers for Disease Control and Prevention are on high alert for pandemic ‘red flags’ related to the virus.

So far 65 confirmed human cases of H5N1 infection have been reported in 2024, following a widespread outbreak across bird and cattle farms in the United States, with California declaring a state of emergency over the virus.

Scientists have warned the virus could be mutating to become more transmissible to humans.

Those mutations are one of the ‘concerning’ trends the CDC has observed and ‘a reminder that A(H5N1) viruses can develop changes during the clinical course of a human infection,’ they told Newsweek. 

While officials say that the current risk level to the American public is still low, they are keeping an eye out for certain signs that could signal a new pandemic. 

So far, they are still waiting for bird flu to become transmissible from person-to-person.

‘Identifying epidemiologically linked clusters of influenza A(H5N1) human cases might indicate the virus is better able to spread between humans,’ a spokesperson from the center’s bird flu response team said.

They are also on the lookout for a spike in cases of humans getting the virus from animals as a sign that it ‘is adapting to spread more easily from animals to people.’  

Weeks after the first severe case of bird flu was reported in Louisiana , the Centers for Disease Control and Prevention are on high alert for pandemic ‘red flags’ related to the virus. Pictured: An animal caretaker collects a blood sample from a dairy calf vaccinated against bird flu

So far 65 confirmed human cases of H5N1 infection have been reported in 2024, following a widespread outbreak across bird and cattle farms in the United States, with California declaring a state of emergency over the virus

Seeing any of those signifiers would ‘raise CDC’s risk assessment for the public,’ although human-to-human infections are rare in this part of the world. 

‘CDC is searching for genetic changes in circulating viruses that suggest it could better transmit between humans,’ the spokesperson said, as its been noted all of the American cases have come from animals. 

‘Thus far these types of mutations have been identified infrequently and have occurred in the context of prolonged infection of individual patients, and not at the time of initial exposure to the influenza A(H5N1) virus circulating in animals,’ they added. 

However, the spokesperson said the initial severe infection in Louisiana was considered a ‘red flag’ by the CDC.

Since April 2024, a total of 61 people have been diagnosed with H5N1 and the CDC has identified another seven as ‘probable’ cases.

Thirty-seven of the 61 cases have been traced to interaction with infected cattle, with the remaining infections either due to touching diseased birds or an unknown origin.

Only one of those patients was severely ill.

One of the most common symptoms of human bird flu in this outbreak has been conjunctivitis or pink eye.

Those mutations are one of the ‘concerning’ trends the CDC has observed and ‘a reminder that A(H5N1) viruses can develop changes during the clinical course of a human infection’

The above map shows the number of people infected with bird flu by state in the US this year. California and Washington state have recorded the most cases. Louisiana was added today (not colored on the map), after recording its first case

Two human cases reported earlier this year in the US only experienced conjunctivitis. Those cases occurred in Texas and in Michigan, and were both in farmworkers who had come into contact with infected cows. 

Other symptoms that have been reported are mild flu-like upper respiratory symptoms, pneumonia requiring hospitalization, and a high temperature of over 100ºF.

Milder symptoms include a cough, sore throat, a runny or stuff nose, muscle or body aches, headaches, fatigue shortness of breath or difficulty breathing. 

Like Covid, bird flu virus infection in people cannot be diagnosed by clinical signs and symptoms alone; laboratory testing is needed. 

Swabs used to test for bird flu can be collected from the throat, nose, or eye of the sick person. 

The CDC highlights that the testing is more accurate when the sample is collected during the first few days of illness.

For critically ill patients, collection and testing of lower respiratory tract specimens also may lead to diagnosis of bird flu virus infection.

However, for some patients who are no longer very sick or who have fully recovered, it may be difficult to detect bird flu virus in a specimen.

So far 61 confirmed human cases of H5N1 infection have been reported in 2024 in the US, following a widespread outbreak across bird and cattle farms in the United States

An H5N1 vaccine is already developed and contracted with manufacturers to make almost 5 million doses, but awaits FDA approval. 

A Louisiana resident was hospitalized with a severe case for the first time earlier this month. The H5N1 patient is in Louisiana, and investigators said they likely caught the disease after handling sick and dead birds in a backyard poultry flock.

In California, officials declared a state of emergency over the spread of bird flu, which is tearing through dairy cows in that state. 

Officials with the Centers for Disease Control and Prevention stressed again this week that the virus poses low risk to the general public.