Signs and Symptoms of Avian Influenza A Virus Infections in Humans
The reported signs and symptoms of low pathogenic avian influenza* (LPAI) A virus infections in humans have ranged from conjunctivitis to influenza-like illness (e.g., fever, cough, sore throat, muscle aches) to lower respiratory disease (pneumonia) requiring hospitalization.
Highly pathogenic avian influenza (HPAI) A virus infections in people have been associated with a wide range of illness from conjunctivitis only, to influenza-like illness, to severe respiratory illness (e.g. shortness of breath, difficulty breathing, pneumonia, acute respiratory distress, viral pneumonia, respiratory failure) with multi-organ disease, sometimes accompanied by nausea, abdominal pain, diarrhea, vomiting and sometimes neurologic changes (altered mental status, seizures).
LPAI H7N9 and HPAI Asian H5N1 have been responsible for most human illness worldwide to date, including the most serious illnesses and deaths.