On June 11, the World Health Organization raised the worldwide pandemic alert level in response to the ongoing global spread of the novel influenza A (H1N1) virus, aka swine flu.
The Phase 6 alert means a global pandemic is under way and there are ongoing community-level outbreaks.
The alert level reflects the spread of the virus, not the severity of illness it causes.
The virus is a combination of genes from pig, bird and human flu viruses.
People who are infected usually have flu-like symptoms, including fever, cough, sore throat, runny or stuffy nose, body aches, headache, chills and fatigue. Some people have also reported diarrhea and vomiting.
Even though some severe illnesses and deaths from novel H1N1 flu have been reported, most cases have been similar to seasonal flu and have not resulted in severe illness.
Most cases have occurred in children and young adults.