Influenza, otherwise known as the flu, is a viral infection caused by one of the many strains of the influenza virus. It is a virus spread through aerosol droplets from coughs or sneezes and by touching surfaces such as door handles, bank notes, computer keyboards etc. The virus can survive on some surfaces for several days but is killed by detergents and disinfectants. A person is infective prior to them showing symptoms, and infectivity lasts 5 to 7 days, though children and those with poor immune systems can be infectious for longer. Flu can be caught at any time of the year, but is more common in the winter months.
Different Strains
There are three strains of the influenza virus:
- Type A. The most common and severe strain and can infect a number of species such as pigs and birds. A number of serotypes have been determined, which includes the serotypes associated with a number of pandemics.
- Type B. Occurs almost exclusively in humans and is less severe. This type appears to mutate slowly and therefore some immunity is acquired at an early age though life long immunity does not occur.
- Type C. Appears to be the mildest form, often occuring in children.
Symptoms
Flu symptoms can appear between 1 and 3 days after being in infected with the virus. Symptoms can include a high temperature, cough, sneezes, chills, headaches, muscle aches, sore throat, fatigue, nausea and vomiting. Flu symptoms usually last for 3 to 5 days though the tiredness can last longer.
Treatment and Prevention
Treatment is rest, plenty of fluids and medications such as paracetamol to reduce aches and the high temperature, though care should be taken that the recommended dose of medications is not exceeded as many medications contain paracetamol.
The best prevention is annual vaccination and those in high-risk groups such as the elderly (over 65 years), those with chronic medical conditions (e.g. asthma, kidney, heart, liver or lung problems, diabetes, cancer, MS patients) and pregnant women should be vaccinated. Good general hygiene such as washing hands regularly, cleaning surfaces especially communal surfaces (e.g. telephones, door handles, computer keyboards) can reduce the spread. Using tissues to catch aerosols from sneezing and coughing and immediately disposing of the tissue in a bin can also help prevent the spread.
Those in high-risk groups who have been in contact with someone with the flu or have flu-like symptoms should consult their GP (by telephone) for advice, as they may be prescribed antiviral medications which shorten and reduces the symptoms and may prevent complications. GP’s should also be contacted if anyone with flu-like symptoms has any of the following symptoms: coughing up blood, yellow-green phlegm, have a rash, sensitive to light, stiff neck, drowsiness or there is difficulty in breathing.
Resources
NHS Choices - Flu last accessed 1st December 2011
Kerstin Rolfe - Kerstin Rolfe is a research scientist who writes in her free time because she loves writing. She was awarded a PhD from the University of ...
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