What is H1N1?
According to the Centers for Disease Control and Prevention (CDC), novel H1N1 (often referred to as "swine flu") is a new influenza virus causing illness in people. This new virus was first detected in people in the United States in April 2009. This virus is spreading from person-to-person worldwide, probably in much the same way that regular seasonal influenza viruses spread. On June 11, 2009, the World Health Organization (WHO) signaled that a pandemic of novel H1N1 flu was underway.
This virus was originally referred to as "swine flu" because laboratory testing showed that many of the genes in this new virus were very similar to influenza viruses that normally occur in pigs (swine) in North America. But further study has shown that this new virus is very different from what normally circulates in North American pigs. It has two genes from flu viruses that normally circulate in pigs in Europe and Asia and bird (avian) genes and human genes. Scientists call this a "quadruple reassortant" virus.
The novel H1N1 virus is spread mainly from person to person through coughing or sneezing by people with influenza. Sometimes people may become infected by touching something - such as a surface or object - with flu viruses on it and then touching their mouth or nose.
The symptoms of novel H1N1 flu virus in people include fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills and fatigue. A significant number of people who have been infected with this virus also have reported diarrhea and vomiting.
Illness with the new H1N1 virus has ranged from mild to severe. While most people who have been sick have recovered without needing medical treatment, hospitalizations and deaths from infection with this virus have occurred.
People infected with seasonal and novel H1N1 flu shed virus and may be able to infect others from one day before getting sick to five to seven days after. This can be longer in some people, especially children and people with weakened immune systems and in people infected with the new H1N1 virus.
For more information on H1N1, please refer to the CDC web site.