First Severe Case of Avian Influenza Reported... California, USA Declares 'State of Emergency'

Foreign media reported that the first severe patient infected with highly pathogenic avian influenza (H5N1) has occurred in the United States.

On the 18th (local time), according to AP News and CNN, the U.S. Centers for Disease Control and Prevention (CDC) announced that a patient in Louisiana is in critical condition after being infected with avian influenza (H5N1). This is the first time in the U.S. that an H5N1 infected person has been hospitalized with severe symptoms. The patient is over 65 years old and has underlying health conditions, making the situation more serious.

Image of avian influenza H5N1 virus transmitted through a microscope. Photo by AFP Yonhap News

The CDC believes the patient was infected after exposure to poultry raised in their backyard that became sick or died. The poultry the patient came into contact with were not commercial, and there was no exposure to dairy cattle or related products.

Since April of this year, 61 H5N1 infections have been reported in the U.S. The virus has spread to hundreds of dairy farms and has been transmitted to humans, with most infected individuals being dairy workers or those involved in slaughtering infected poultry. However, before this Louisiana case, all patients showed only mild symptoms.

The 'D.1.1' virus detected this time is known to be a different type from the 'B3.13' virus previously found in U.S. dairy cattle, some poultry, and people in contact with them. It is identified as the same type as the human infection cases recently reported in Canada and Washington State. The CDC is conducting additional genetic analysis to prepare for any eventuality.

California, the state with the highest number of avian influenza infections in the U.S., declared a state of emergency on the same day. Of the 61 cases reported in the U.S. this year, 34 occurred in California, and one case's source of infection has not yet been identified. However, no severe patients have been reported in this area so far.

In a statement, the CDC said, "The overall assessment of the immediate public health risk posed by H5N1 avian influenza has not changed," but emphasized that "the best way to prevent infection is to avoid exposure as much as possible."

Avian influenza, commonly called "bird flu," is an acute viral disease. Symptoms are similar to the flu but can range from asymptomatic to severe. There have been no cases of human-to-human transmission so far, but transmission from animals to humans has occasionally occurred. According to the World Health Organization (WHO), the mortality rate for humans infected with avian influenza is as high as 52%.