Swine flu virus (H1N1)
The World Health Organisation has declared swine flu a global pandemic. In this medical guide you can find out more about diagnosis, medicines and treatment.
Swine flu has been declared a global pandemic after the World Health Organisation raised the alert status of the H1N1 virus to the highest level on its six-phase scale. Click here to get the latest news and find out more about the WHO pandemic alert status.
What is a flu pandemic?
A pandemic is a global outbreak of a disease that affects numerous populations or countries. A flu pandemic happens when a new version of the flu virus emerges and spreads easily and quickly across the world.
A flu pandemic can be caused by a dramatic change to the flu virus, or a change to the virus that occurs when two strains of flu from different species combine. This mix of genes can make a new, unique virus to which most people will have little or no immunity.
What is swine flu?
Swine influenza - or Influenza A (H1N1) - is a contagious respiratory disease found in pigs that is caused by type A influenza viruses. The virus often causes outbreaks in pigs, and many countries regularly vaccinate their pigs against the virus. Swine flu doesn’t usually affect humans, but there have been a small number of cases in the past. These were mostly in people who had been in direct contact with infected pigs.
What type of swine flu has been detected in people?
Flu is caused by three groups of viruses – influenza A, B and C. The influenza viruses in groups B and C affect only humans. The influenza A group can affect birds, pigs and horses as well as humans, and these viruses may be able to transfer from one species to another.
All of the recently identified cases of swine flu are a new form of influenza A/H1N1. This new sub-type hasn’t been seen in either pigs or humans before. Viruses in the influenza A group may have caused flu pandemics in the past when they have crossed to people and created a unique virus.
Can it spread from pigs to people?
Yes. The A/H1N1 strain of swine flu has already passed to people. Close contact with an infected pig is thought to be responsible for the transfer of the virus to people.
Can it spread between people?
Yes. It appears that the A/H1N1 virus is contagious and that it can spread from person to person. However, it isn’t yet known how easily this happens.
What are the symptoms of swine flu in people?
The symptoms of swine influenza are similar to ordinary flu and include fever, a cough, a sore throat, a headache, chills and tiredness. The Centers for Disease Control and Prevention (CDC) currently recommends antiviral drugs to treat swine influenza. Symptoms have been mild among those affected in the USA, with only one person requiring hospitalization.
Who is most at risk?
A flu pandemic could affect anyone, even if they are fit and healthy.
How is swine flu diagnosed?
Swine flu can be diagnosed in a lab by analysing a respiratory specimen taken from a person within the first four to five days of the illness. This is the best time to diagnose it although in some people, especially children, they can be diagnosed up to 10 days after the start of their symptoms.
Is there a vaccine to prevent it?
No. Currently available influenza vaccines will not protect against infection with A/H1N1 in people. At the moment, it isn’t known whether current flu vaccines will help to minimise the spread of swine influenza. The WHO is trying to find out as much information as possible, in order to make a vaccine that is specifically directed at this strain of influenza A/H1N1.
Are there any specific medicines to prevent or treat swine flu?
In the USA the CDC are recommending the use of oseltamivir (Tamiflu) or zanamavir (Relenza) to prevent and treat swine flu in people. These medicines will work better if taken in the first two days after symptoms start.
These drugs can help to reduce symptoms, but are more effective if treatment is given within two days of your symptoms starting.
If you have flu symptoms, you shouldn’t visit your GP or family doctor. There are a number of things you can do at home to help.
- Drink enough fluids to prevent dehydration.
- Stay at home and rest.
- Take over-the-counter medicines such as paracetamol, aspirin or ibuprofen to help with symptoms.
Always read the patient information leaflet that comes with your medicine and if you have any questions, ask your pharmacist for advice. Children under 16 years old should not be given aspirin or any medicines containing aspirin.
What can people do to reduce their risk of catching it?
If you do have flu-like symptoms, you should stay off work or school and minimise contact with other people.
To help reduce the chance of getting or spreading flu of all types, you should:
- maintain basic hygiene, such as hand-washing
- cover your nose and mouth when coughing or sneezing
- avoid crowds whenever possible
You do not need to alter your diet. Swine influenza can’t be transferred through pork or pork products as long as they are properly prepared and cooked to over 70°C throughout. If a pandemic is confirmed by the WHO, further advice will be issued at the time.
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