Factbox: swine flu outbreak
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The H1N1 flu strain is a heretofore unknown mixture of viruses from swine, birds and humans, with early symptoms similar to those of the common flu. Here are a few facts about the nature and spread of swine flu.
What is swine flu?
Swine flu, short for swine influenza virus, is a respiratory disease caused by Orthomyxoviruses endemic to pig populations (type A flu strains H1N1, H1N2, H3N1, H3N2).
According to the World Health Organization, the current epidemic may stem from a new strain, apparently born when human and avian flu viruses infected pigs and mixed together.
What are the symptoms?
The symptoms typically include fever, coughing, sore throat, body aches, headache, chills and general fatigue. Unlike the common flu, swine flu's symptoms appear brutally and all at once. Symptoms of diarrhea and vomiting have also been reported.
Because they are similar to those of the common flu, cases are sometimes not detected early enough. If left untreated, infection from the virus can lead to pneumonia and respiratory failure, and even death.
How does the virus spread?
Swine flu is believed to be transmitted through air and saliva. Before recent outbreaks, most people who contracted swine flu were infected through contact with sick pigs. Person-to-person transmission is likely to happen through coughing, sneezing, kissing or contact with contaminated surfaces.
Experts think that the virus cannot be caught by eating cooked pork or pork products.
How do you treat and prevent the virus?
Isolating infected people during their illness, wearing a face mask in crowded places or around infected people and thoroughly washing hands before eating and several times a day are effective preventive measures.
For treatment, antiviral drugs (prescription medicines that prevent flu viruses from reproducing in the body) work best if started within two days of the first symptom’s appearance.
What are the WHO’s pandemic alert levels?
Phase 1 – Low risk of human infection.
Phase 2 – Higher risk of human infection.
Phase 3 - Sporadic cases in people, but very little human-to-human transmission.
Phase 4 – Human-to-human transmission able to sustain community-level outbreaks.
Phase 5 – Widespread human infection, with the virus spreading among humans in at least two countries in the same region.
Phase 6 - Sustained community-level outbreaks in more than one region.
Sources: World Heath Organization, Mexican health ministry