Context

Centers for Disease Control and Prevention (CDC) recently said that the first known human case of H5 bird flu in the United States has appeared in a person in Colorado.

About

About H5 Bird Flu:

• Bird flu or avian influenza is a disease which is caused by avian influenza Type A virusesfound naturally in the wild birds worldwide.
• The virus can infect domestic poultry which includes chickens, ducks and turkeys.
• Avian Influenza type A viruseswhich are classified based on two proteins on their surfaces:
• Hemagglutinin(HA)
• Neuraminidase(NA)
• There are about 18 HA subtypes and 11 NA subtypes.
• Several combinations of these two proteins are also possible e.g., H5N1, H7N2, H9N6, H17N10, etc.
• The virus was first detected in geese in China in 1996.
• Symptoms of avian influenza: Fever, cough, sore throat, nausea, abdominal pain, muscle aches, diarrhea, vomiting Severe respiratory illness (respiratory distress, viral pneumonia, respiratory failure), Neurologic changes (altered mental status, seizures).
• Risk groups: Children and adults below 40 are seen to be the most affected and mortality was high in 10-19 years old.

Is it the first time?

• This is the second human case associated with this specific group of H5 viruses that are currently predominant, and the first case in the United States.
• The first case internationally occurred in December 2021 in the United Kingdom in a person who did not have any symptoms and who raised birds that became infected with H5N1 virus.
• More than 880 human infections with earlier H5N1 viruses have been reported since 2003 worldwide.
• However, the predominant H5N1 viruses now circulating among birds globally are different from earlier H5N1 viruses.