Information for students about bacteria and virus

What are viruses?

Viruses are too small to be seen by the naked eye. They can't multiply on their own, so they have to invade a 'host' cell and take over its machinery in order to be able to make more virus particles.

Viruses consist of genetic materials (DNA or RNA) surrounded by a protective coat of protein. They are capable of latching onto cells and getting inside them.

The cells of the mucous membranes, such as those lining the respiratory passages that we breathe through, are particularly open to virus attacks because they are not covered by protective skin.

What are bacteria?

Bacteria are organisms made up of just one cell. They are capable of multiplying by themselves, as they have the power to divide. Their shapes vary, and doctors use these characteristics to separate them into groups.

Bacteria exist everywhere, inside and on our bodies. Most of them are completely harmless and some of them are very useful.

But some bacteria can cause diseases, either because they end up in the wrong place in the body or simply because they are 'designed' to invade us.

How are infections with viruses and bacteria spread?

Viral and bacterial infections are both spread in basically the same ways.

• A person with a cold can spread the infection by coughing and/or sneezing.
• Bacteria or viruses can be passed on by touching or shaking hands with another person.
• Touching food with dirty hands will also allow viruses or bacteria from the intestine to spread.
• Body fluids, such as blood, saliva and semen, can contain the infecting organisms and transmission of such fluids, for example by injection or sexual contact, is important, particularly for viral infections like hepatitis or AIDS.

How to avoid infection

• Wash your hands thoroughly (often one of the best ways to avoid catching a cold).
• Shaking hands with someone who has a cold is risky, so avoid rubbing your eyes or nose afterwards.
• Food should be cooked or cooled down as quickly as possible.
• Vegetables and meat must be stored separately and prepared on separate chopping boards.
• Meat should preferably be served well-done.
• Remember that food with these invisible organisms does not necessarily smell bad.
• Some organisms are killed as the food is cooked, but they can still leave toxic substances that may cause diarrhoea and vomiting.
• The use of condoms during sexual intercourse reduces the likelihood of spreading sexually transmitted diseases.

How can the doctor treat bacterial infections?

Bacterial infections are usually treated with a special antibiotic, which only kills the bacterium that has caused the disease.
To make sure that you get the right treatment, your doctor may take a sample, for example a swab from the throat or a urine sample.