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Colds and Flu:
UNDERSTANDING INFLUENZA - a public health service. (Part 3)
Influenza is best known by its short form – the flu. It is a contagious disease caused by a virus that spreads from one person to another. (Click the Respiratory System image on the left to enlarge.)
The spreading is from hand-to-hand contact, shaking hands for example, and from the spray from coughs and sneezes which can stay for hours in the air on or the hands. The virus enters the upper part of the respiratory tract through the mouth or nose. Symptoms appear after an incubation period of 1 to 4 days. Influenza usually occur in winter or early spring.
Influenza Epidemics
Epidemics of influenza spread rapidly around the world. They occur at unpredictable intervals. One winter may pass without an epidemic, whilst another winter may see 2 or 3 epidemics.
Epidemics die out when everyone who has been infected by a particular strain or type of flu virus becomes immune or resistant to further attacks by that virus. There are several strains of influenza virus. The most common strains are:
- Influenza A viruses are known to infect humans, other mammals and birds (including Avian (bird) influenza)
- Influenza B viruses are known to infect humans and seals
- Influenza C viruses – less common but known to infect humans and pigs.
The A type of influenza virus is the most likely to cause epidemics and pandemics as they can quickly mutate.
The H and the N
Influenza viruses are named by two surface proteins, H (hemagglutinin) or N (neuraminidase). The H is the safecracker which gets the virus into the cell and the N gets the virus back out (the exit side) of the cell after it is affected to move on. The exit side is what Tamiflu and other anti-virals work to resist.
Influenza symptoms
Early symptoms of flu can include chills, fever, sneezing, headache, muscle pain and a sore throat. These are usually followed by a dry, hacking cough and, often, chest pains. The fever generally lasts for 3 to 5 days but leaves you feeling weak. If there are no complications, you should recover within 1 or 2 weeks although you may feel weak for a few weeks to come.
Dangers of influenza
Sometimes flu symptoms are confined mainly to the upper respiratory tract. But if you have a bacterial infection complicating the flu, it could spread from the upper respiratory tract down into the lungs and cause bronchitis or pneumonia. This usually occurs in very young children, elderly folk or those with diabetes, chronic chest disorders and chronic heart disease.
What to do?
If you seem to be the only person in your area with the flu-like symptoms, you may have a different viral disease. Influenza spreads quickly and others will have it too. Here is some advice:
- Go to bed.
- Drink plenty of fluids.
- If your fever persists more than 3 or 4 days or if you have difficulty breathing while resting, call your physician.
- If you sneeze or cough, cover your mouth with a tissue.
- Do not shake hands with anyone and frequently wash your hands. When you sneeze or cough, the virus “cloud” can last for hours on our hand and even in the air.
- In general, stay clear of antibiotics – viruses do not respond to them anyway.
Vaccinations and Immunizations
It is possible and in many cases recommended to get vaccinated against influenza with a flu vaccine. However, due to the high mutability of the virus, a particular flu vaccine formulation usually only works for about a year. The World Health Organization co-ordinates the contents of the vaccine each year, to contain the most likely strains of the virus which probably will attack the next year. The flu vaccine is usually recommended for anyone in a high-risk group, who would be likely to suffer complications from influenza. Flu vaccine is available as nasal spray vaccine (recommended for all healthy people ages 5 to 49) and as injectable vaccine.
* REMEMBER: Antiviral drugs can be taken but are only effective if started just as the symptoms develop!!
Sources
* Some of this article was originally from the public domain CDC
publication www.cdc.gov/
* World Health Organization Fact Sheet Overview of influenza.
Next: » Part 4: Flu Vaccinations, Immunization and Bird Flu Vaccine Facts
Related Articles:
» Is mine a Cold or Influenza?
» Part 2: What is a common Cold? -
facts and tips.
» What is Influenza? - differences
between colds and flu.
» Flu Vaccines and Vaccinations -
preventative measures.
» Anti-viral drugs and
immunization facts and links.
(the Treating Pneumonia article is here »)
Video
Presentation: (A three minute YouTube.com video)
A flu vaccination can greatly reduce your chances of getting flu. A new
flu vaccination is needed each year. Please take the threat of Flu
seriously this year. A 'Family
Doctor Advice' video on YouTube (opens in a new window)