Bird flu is sweeping the US, with California declaring a state of emergency and the first hospitalization taking place in Louisiana.
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.
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.
The CDC notes that bird flu in humans can range in severity, from no symptoms or mild illness, to severe disease that could result in death
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.
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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.
Earlier today, California declared a state of emergency over bird flu in response to the outbreak among the state’s dairy cattle.
California has identified H5N1 in 645 dairy herds since its first detection in late August, according to the state’s agriculture department.
Nearly half of the cases have been reported in the past 30 days, highlighting the rapid spread of the virus.
Although California was not among the first states to detect H5N1 in dairy cattle, the outbreak has grown significantly since its initial discovery.
The H5NI virus is primarily spread amongst wild birds and poultry on farms, but has also been detected in dairy cows and humans this year
The announcement followed news than an individual in Louisiana was hospitalized with a severe case of H5N1.
The latest case in Louisiana marks the first to be linked to a backyard poultry flock.
The CDC said in the alert: ‘A sporadic case of severe H5N1 bird flu illness in a person is not unexpected.
‘Avian influenza virus infection has previously been associated with severe human illness in other countries during 2024 and prior years, including illness resulting in death.’
They added: ‘No person-to-person spread of H5 bird flu has been detected. This case does not change CDC’s overall assessment of the immediate risk to the public’s health from H5N1 bird flu, which remains low.’
The hospitalized Louisiana patient was first revealed by the state’s health department on Monday, which said they were in the southwest of the state and that samples had been sent to the CDC for testing.
The CDC said the H5N1 infection was confirmed via testing on Friday last week, and that partial viral DNA analysis revealed the patient had the D1.1 variant.
Like all flus, the virus is spread primarily through droplets in the air which are breathed in or get into a person’s mouth, eyes or nose
It also said the case underscored the need to take precautions when around backyard flocks and cattle to limit the risk of infection.
In its alert, they urged people to avoid contact with sick or dead animals, particularly wild birds and poultry, whenever possible.
They also said those with direct contacts with the birds to wear personal protective equipment (PPE) and to avoid touching surfaces – like animal litter or bedding – that may have come into contact with infected animals.
In Canada, the teenager sickened with the same type of bird flu was hospitalized on November 8 after falling ill on November 2.
As of the last report in late November, the teenager was still in the hospital and in a critical condition – requiring help to breathe – but was stable.
It was not clear how they caught the disease, with dogs and reptiles they had come into contact with all testing negative.
