Influenza porcina is one of the common names for the novel H1N1 influenza virus. According to the World Health Organization (WHO), there were cases identified in more than 200 countries and influenza porcina was linked to more than 15,000 deaths as of January 2010. Compared to seasonal influenza, the WHO warns that younger people--ages 10 to 45--have been the hardest hit by influenza porcina, also as of January 2010. For people who contract influenza porcina, the effects are generally symptoms similar to seasonal flu.
Systemic Effects
Systemic effects of influenza porcina reflect the response of the immune system to the infection. Common systemic effects include fever, headache and muscle or joint pain. According to a June 18, 2009 report by Novel Swine-Origin Influenza A (H1N1) Virus Investigation Team, fever greater than 101.3 degrees F is the single most common effect of the influenza porcina, seen in 94 percent of laboratory-confirmed cases. In adults, the first effects of influenza porcina may be headache or muscle/joint pain, followed a few days later by fever.
Respiratory Effects
Influenza porcina affects both the upper and lower respiratory tracts. Lower respiratory effects include cough and breathing problems, reported in 92 and 22 percent of people, respectively, according to a 2009 study published in the "Journal of Clinical Microbiology and Infections." Upper respiratory tract effects include sore throat (64 percent of people), runny nose (56 percent) and nasal congestion (43 percent). According to a 2009 report in the "New England Journal of Medicine," cough may precede fever by one or two days, or they may begin around the same time. Upper respiratory tract effects tend to start a few days after and end a few days before other kinds of symptoms. Cough is often the most persistent effect of the swine influenza, lasting longer than 10 days in about 10 percent of infected people.
Gastrointestinal Effects
In contrast to seasonal influenza, the influenza porcina frequently affects the gastrointestinal tract. According to the Novel Swine-Origin Influenza A (H1N1) Virus Investigation Team, vomiting, diarrhea or both were reported by nearly 40 percent of outpatients with a laboratory-confirmed swine virus. In the investigation, diarrhea and vomiting were equally prevalent, reported by 25 percent of patients each (13 percent of patients experienced both vomiting and diarrhea). However, a subsequent investigation reported in the "Journal of Clinical Microbiology and Infections" found that diarrhea was more common--31 percent of patients compared to 15 percent of patients for vomiting. On average, vomiting lasted for 2 days and diarrhea lasted for 4 days. Both symptoms were rated as mild compared to other symptoms of influenza porcina.
References
- WHO: Pandemic (H1N1) 2009 - Update 86
- "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); C.S. Lee and J.H. Lee; Nov. 13, 2009
