Infections are universal phenomena affecting all ages and sexes. The symptoms are fever, pain, cold, cough, diarrhoea, vomiting and cramps. Infections are caused by external organisms, usually bacteria or viruses, entering the body.

Bacteria have been in existence for billions of years and predates even dinosaurs. Single-celled organisms very much like a plant cell, they have a rigid outer wall supporting a thin, flexible membrane that surrounds fluid cytoplasm and a nucleus. Bacteria are able to survive extreme heat, freezing cold and even radioactivity. They go into a dormant state or mutate so that they can change their structure to withstand adverse

conditions. Many bacteria live harmlessly in the environment and the human body. Some are beneficial and can help in digestion, produce micronutrients and vitamins, and even attack cancer cells.

Only one per cent of bacteria is harmful and causes disease. The infections have to be treated with antibiotics. This medication either kills the bacteria outright or prevents them from reproducing until the population superannuates and dies.

Sometimes, it is impossible to clinically distinguish between bacterial and viral infections. Antibiotics may then be prescribed because of pressure from patients or bought over the counter.

But antibiotics are ineffective against viral infections.

Their misuse has lead to a global problem of superbugs — bacteria that are resistant to available antibiotics and which can eventually cause death.

Viruses are tinier than bacteria and can only be seen under an electron microscope. They contain genetic material in the form of DNA or RNA in a protein coat. They are incapable of independent existence and have to enter a living cell to survive. Once inside, they reprogramme the cell nucleus and multiply rapidly. Finally, the cell bursts and the viruses are released into the immediate environment and the bloodstream. When they invade, they can transform a normal cell into a malignant one.

Anti-viral medication is available against a few viral infections such as hepatitis B and C, herpes and influenza. They are not as effective as immunisation, which programmes the body’s own cells to produce antibodies against the virus. This remains in the memory of the cell. Although the antibody level falls over a period of time, in the event of an infection, the cells can make antibodies rapidly. Immunisation is available against viral infections such as hepatitis A and B, chicken pox, measles, mumps, German measles, polio, diarrhoea due to rotavirus, seasonal flu, Japanese B encephalitis and HPV (human papilloma virus) which causes 97 per cent of the cervical cancers.

Some bacterial infections such as diphtheria, tetanus, pneumonia, ear infections, and typhoid can also be prevented with immunisation.

Unfortunately, there is a great deal of unscientific negative publicity on social media about the perceived undocumented and unproven side effects of vaccines. As a result, many children are being denied protection by guardians.

Bacterial infections for which there is no treatment or immunisation have to be treated with appropriate antibiotics in the correct dose for a sufficient duration. Viral infections such as bronchitis and otitis do not have any specific treatment. General measures like antipyretics for fever and cough suppressants can be used for symptomatic relief. Recovery from viral infections may take 10 days to two weeks.

Infections are less frequent and recovery is more rapid in those children and adults who exercise regularly because it gives their immune systems a boost.

• The writer is a paediatrician with a family practice at Vellore and the author of Staying Healthy in Modern India. If you have any questions on health issues, please write to yourhealthgm@yahoo.co.in