Influenza

Common Cold and Influenza

Fellow travellers on the train cough and sneeze behind their newspapers. At the office, the first empty chairs forewarn of the start of a flu epidemic. Yes, it is winter – the season of coughs, wheezes and sniffs, of common cold and influenza.

Influenza_virusHistorians describe several devastating influenza epidemics. An estimated 20 million people lost their lives during the ‘Spanish flu’ in 1918. Since then, medical advances contained major outbreaks so that today ‘only’ thousands become victims. The US experienced an epidemic in 1957 that killed an estimated 70,000 people, followed by another outbreak in 1968 with 34,000 victims.

Approximately 200 different kinds of viruses cause symptoms of the common cold. Several others lead to influenza. Often, the first signs are sneezing and a sore throat, followed by the inflammation of the sinuses (sinusitis) and the lungs (bronchitis). Fever generally occurs with influenza only. A third kind of virus (Herpes simplex) attacks the weakened body and causes a cold sore.

These illnesses are most frequent during the colder months of the year. However, the lower temperatures alone have nothing to do with the increase in frequency. Just the opposite: viruses and bacteria multiply more readily at milder temperatures. You can’t catch a cold or influenza because the thermometer has plummeted.

The lower temperatures are an indirect cause, though. Whenever the person next to you sneezes or coughs, he or she dislodges tiny droplets that contain a large number of viruses. In summer, the fresh air outdoors rapidly dilutes the density of the viruses and the risk of catching the germ is lower – not so in winter. During the winter months people tend to spend more time indoors with the windows closed to save energy. The virus concentration is high, and with it comes the risk of inhaling a few. Winter’s low level of ultraviolet sunlight also plays a part. Sufficient ultraviolet rays during the summer period help kill the viruses.

Continually changing weather conditions stress the body and weaken the immune system. Viruses and bacteria find ways to get past the defence system. A runny nose, however, is a sign that at least part of the system is working. It is a healthy body reaction to get rid of the intruders. So, don’t stop this reaction by using nasal sprays. Use a handkerchief instead.

With every exposure to any of the viruses’ strains, the body develops immunity and protects the person against that particular germ when it appears the next time. The children’s immune system, however, hasn’t had much experience with viruses. It is still learning how to recognize the different strains. Until their body develops the relevant immunities, they will be sick more often. Vaccines induce the body to produce such immunities.

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