The swine flu is a pandemic with laboratory-confirmed cases identified in more than 200 countries, according to the World Health Organization. Swine flu, also known as H1N1 flu, produces a spectrum of symptoms ranging from mild upper respiratory tract illness to fatal pneumonia. Although the symptoms vary from person to person, symptoms do tend to follow a certain chronology.
Systemic Symptoms
Systemic symptoms reflect the response of the immune system to infection. Common systemic symptoms of swine flu include fever, headache,and muscle or joint pain. According to the findings of the Novel Swine-Origin Influenza A (H1N1) Virus Investigation Team, fever greater than 101.3 degrees F (38 degrees C) is the most common symptom of swine flu, appearing in 94 percent of patients. In some cases, particularly among children, fever is also the first symptom of swine flu. In adults, headache or muscle/joint pain may precede the onset of fever by one to two days.
Respiratory Symptoms
Swine flu is associated with both lower-respiratory symptoms such as cough and breathing problems and upper-respiratory symptoms such as sore throat, runny nose and nasal congestion. According to a 2009 article in the "New England Journal of Medicine," cough is the second most common symptoms of swine flu, present in 92 percent of adults. It may precede fever by one or two days or onset around the same time.
Upper-respiratory symptoms are not reported by all patients: sore throat (64 percent), runny nose (56 percent) and nasal congestion (43 percent). When present, they tend to appear a few days after other symptoms are established and are characteristically mild. Breathing problems are least common (22 percent). When present, they vary significantly in both onset and severity.
Gastrointestinal Symptoms
Nearly 40 percent of people with swine flu reported diarrhea, vomiting or both, according to the a report by the Novel Swine-Origin Influenza A (H1N1) Virus Investigation Team. Gastrointestinal symptoms of swine flu tend to begin after other kinds of symptoms, often coinciding with the peak of fever. In contrast to symptoms produced by rotovirus and other more traditional gastrointestinal viral infections, gastrointestinal symptoms of swine flu tend to be short-lived and relatively mild.
References
- World Health Organization
- 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); CS Lee and JH Lee; November 13 2009
