Swine flu is the common name for the novel influenza strain H1N1. According to the World Health Organization, the swine flu is a pandemic with laboratory-confirmed cases identified in more than 200 countries and linked to more than 12,000 deaths. Swine flu produces a spectrum of disease ranging from mild upper respiratory tract illness to fatal pneumonia. Although the spectrum of disease varies from person to person, some signs seem to appear earlier than others.
Fever
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 many cases, particularly children, fever is also the first symptom of swine flu. In 50 percent of people treated with oseltamivir (Tamiflu), fever peaked two days after treatment and resolved within three.
Headache and Muscle Pain
In a 2009 report in the Journal of Clinical Microbiology and Infections, headache and muscle pain were reported by 61 and 43 percent of patients, respectively. In adults, headache and muscle pain--particularly in the lower extremities--may begin one to two days before fever, or they may present at the same time. Muscle pain is often one of the most persistent symptoms of swine flu, lasting longer than eight days in up to 10 percent of patients, even those treated with antiviral drugs.
Altered Mental Status
In some individuals, especially very young infants and the elderly, a period of unusual agitation, irritability or mental confusion precedes the development of other symptoms of swine flu. However, this is not a specific sign of infection with swine flu. According to a 2006 study published in the Journal of the American Geriatric Society, mental status changes typically began a few days before the onset of other symptoms in a variety of illnesses, including urinary tract infection, respiratory tract infection and influenza.
References
- 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
- Journal of the American Geriatric Society; Agitated Behavior as a Prodromal Symptom of Influenza; DL Mentes and JH Woods; December 2006
