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illnesses and conditions

Viruses

IT'S that time of year again when many of us develop cold and flu symptoms which make us feel under the weather and send us off to our GPs in search of a cure.

Instead we are often told we have a virus which cannot be treated with antibiotics and we leave the surgery empty handed and non the wiser.

So what exactly is a virus?

Viruses are the smallest type of infectious agent, so minute they cannot be viewed without the help of an electron microscope.

Viruses are about one hundredth the size of the smallest bacteria and, because of their incredibly small size, they are extremely hard to study and understand.

They have a much simpler structure than bacteria and a simpler method of multiplication but while antibiotics can zap bacteria quickly and effectively it has no effect on a virus.

Viruses are strictly parasites. They cannot survive outside a living cell or a group of host cells. The host provides the virus with all the conditions it needs to survive and reproduce.

You might think of viruses as sophisticated computers that need to take over a factory to make more of themselves. Without that back-up, viruses can lie dormant within any host or environment until the proper conditions for their activity are provided.

For example the herpes virus - once you have it you will always have it, but you will not always have an outward sign.

That is why we sometimes say that viruses have incubation periods of certain lengths of time, like chicken pox.

And there are hundreds of thousands of different types of virus. In fact their number probably exceeds the different varieties of all other organisms.

Viral infections range from the trivial, such as warts and the common cold, to extremely serious diseases such as rabies and lassa fever.

How do we catch a virus?

Viruses gain access to the body by all possible entry routes. They are inhaled in fine droplets, swallowed in food and fluid, through punctures in the skin and directly through mucous membranes during sexual intercourse.

The body reacts to a virus in the same way as to any infection. The immune system deals fairly rapidly with most viral infections leading to recovery within a few days or weeks.

Furthermore, the immune system is sometimes sufficiently sensitized by the infection to make a second illness with the same virus rare (as in the case of measles).

With the flu virus however, there are so many different types that immunity to one will not protect you from another.

And with other viruses serious damage may occur before the immune system can adequately respond (as in the case of Rabies).

How can we prevent infection?

Medical researchers are constantly working toward a better understanding of viruses. But research and testing costs millions of pounds, which is limiting the type of viral diseases being studied.

Nevertheless, there has been progress in the development of anti-viral agents, especially against the Herpes group of viruses.

Such drugs help prevent viruses by preventing them from entering cells or by interfering with their replication. But they don't come close to being as effective as antibiotics are against bacteria.

Treatment of viral infections depends largely on relieving unpleasant symptoms through rest, plenty of fluids and paracetamol to relieve pain, trusting the body's immune system to bring about a cure.

A much more fruitful area in the fight against viruses is active immunization (vaccination) which induces immunity. Vaccines against a whole range of viruses are now available including Whooping Cough, German Measles and Tuberculosis.

The good news however is that the most effective preventive measures are not related to medicine at all!

For example, the best way to prevent blood-related viruses such as HIV is to practice safe sex and not be involved in sharing needles.

But perhaps the biggest advancement we have in fighting disease includes the toilet!

Good sanitation and hygiene is the best method we have of protecting ourselves. Cleanliness is the best weapon, be it in the kitchen, in the bathroom or personal. So don't forget to wash your hands after using the toilet and before handling food.

Protect yourself and your family.