Avian (bird) flu

The highly pathogenic avian influenza (HPAI) H5N1 virus, which is panzootic in poultry, can infect humans (1):

• since pandemic influenza virus has its origins in avian influenza viruses, HPAI H5N1 virus has to be considered a potentially serious pandemic threat
• infection with bird flu is widespread among wild birds and poultry (2)
  • mammals such as dairy cows may also become infected
  • bird flu can be transmitted to humans when viral particles from fluids and secretions of infected animals (saliva, mucus, faeces, milk) are inhaled or get into a person’s eyes, nose, or mouth
  • multiple subtypes of bird flu have been linked to sporadic outbreaks of infections among humans, with the H5N1 and H7N9 subtypes the most common causes

Infection in humans

• symptoms of bird flu, which typically develop 2 to 7 days after exposure to the virus, are often similar to seasonal influenza and may include:
  • fever
  • cough
  • sore throat
  • coryza
  • conjunctivitis
  • myalgia
  • headache
  • fatigue
• complications of severe avian influenza include:
  • pneumonia
  • respiratory failure
  • meningoencephalitis

Treatment with oseltamivir, twice daily for 5 days, is recommended for all patients with bird flu (2).

Reference:

1. Peiris JS, de Jong MD, Guan Y. Avian influenza virus (H5N1): a threat to human health. Clin Microbiol Rev. 2007 Apr;20(2):243-67.
2. Saravolatz LD, Malani PN. What Is Bird Flu? JAMA. Published online January 10, 2025.