H1N1 influenza, also known as swine flu, is a subtype of influenza A virus that caused a global pandemic in 2009-2010. It was first identified in April 2009 in Mexico and quickly spread to other countries, leading to significant public health concerns. Symptoms of H1N1 influenza are similar to seasonal flu and can include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills, fatigue, and sometimes diarrhea and vomiting. Diagnosis is typically based on clinical symptoms and may be confirmed through specific tests like rapid influenza diagnostic tests (RIDTs) or PCR testing to detect the influenza virus.
