Swine flu is the common name for the novel strain of influenza now known as H1N1. Antiviral therapy administered within 48 hours of the onset of symptoms may reduce the risk of serious complications, including death. People with classic symptoms of swine flu should seek medical attention promptly.
Systemic
Systemic symptoms are so named because they reflect evidence of system-wide infection. Classic systemic symptoms of swine flu include fever, headache, muscle pain and fatigue. In a June 2009 article in the New England Journal of Medicine, fever over 101.3 degrees F (38 degrees C) was the most common symptom of swine flu, present in 94 percent of patients. Systemic symptoms typically peaked two to three days after onset and resolved completely within eight days in 95 percent of patients.
Respiratory
Classic swine flu is associated with upper respiratory symptoms, including sore throat, congestion, runny nose, cough and difficulty breathing. Not all patients exhibit each symptom. According to an article in the November 13, 2009 edition of Clinical Microbiology and Infections, 92 percent of confirmed H1N1 patients reported a cough, followed by sore throat (69.8 percent), runny nose (64 percent), nasal congestion (55.8 percent) and mild breathing problems (22 percent). A cough usually appeared one to two days before a fever and took longer to resolve than any of the other symptoms (an average of 12 days).
Gastrointestinal
Gastrointestinal symptoms of swine flu include nausea, vomiting and diarrhea. The CDC says these symptoms are less common than respiratory and systemic symptoms. According to the article in Clinical Microbiology and Infections, just over 30 percent of patients complained of diarrhea, followed by approximately 25 percent for nausea and 15 percent for vomiting. These symptoms are usually mild and resolve before other symptoms. In 90 percent of patients, vomiting, nausea and diarrhea resolved within five, six and eight days, respectively.
References
- Centers for Disease Control and Prevention H1N1 Flu
- New England Journal of Medicine.Emergence of a Novel Swine-Origin Influenza A (H1N1) Virus in Humans. Novel Swine-Origin Influenza A (H1N1) Virus Investigation Team. June 18, 2009.
- Clinical Microbiology and Infections. Dynamics of Clinical Symptoms in a Case with Pandemic Influenza A (H1N1). Lee CS, Lee JH. November 13, 2009.
