The main symptoms of H1N1 flu are manifested as

Symptoms of H1N1 influenza mainly include fever and systemic infection with signs of toxemia. H1N1 flu develops rapidly, typically causing persistent fever lasting several days, with body temperature reaching as high as 39–40°C. It is also accompanied by systemic toxemic symptoms such as chills, rigors, muscle and joint pain, headache, fatigue, loss of appetite, sore throat, dry cough, nasal congestion, and runny nose. A small number of individuals with weaker constitutions may develop complications, such as viral pneumonia or encephalitis.