Influenza
is a highly contagious virus infection that affects the respiratory
tract. It is spread by the aerosol effect of coughing and sneezing
or, simply, if in close contact, by talking. It can be a very
serious illness indeed. In the 1919 influenza pandemic more
people died than were killed in the First World War. Because
it is highly infectious, and because immunity in the population
is rather poor, it tends to occur in epidemics. The reason for
poor immunity is that there are many strains of the virus, new
ones are always mutating, and immunity to one strain may give
no protection against the others. The disease starts one to
four days after initial contact and the symptoms include feeling
weak and ill, generalised aches and pains, headache, fever and
shivering, loss of appetite, unproductive cough and a sore throat.
It is very difficult for the patient to get comfortable and
sleep may be very poor. The symptoms usually last a week or
so. People often have difficulty even in getting out of bed
and those who say they “worked through the ‘flu” probably did not. ( see Common Cold) Some of the epidemics bring a more virulent type of infection than others, generally of the Influenza A variety. A particularly severe complication is pneumonia, which may be due to the virus itself or secondary bacterial infection. Influenza is can be very dangerous to those with debilitating illness, the elderly and those with respiratory problems.
Prevention is better than cure. All people considered at particular risk from influenza should be vaccinated against the most common, and most recent, strains of the disease. Unfortunately, new strains can, and do, appear against which even the immunised person has no protection. Neither does ‘flu vaccine stop people getting the common cold. Generally, the treatment of influenza is symptomatic and supportive – bed rest, plenty of fluids, simple analgesics, proprietary cough medicines if needed (see. Common Cold for warnings on accidental paracetamol overdosage). Anti-viral drugs against influenza are beginning to appear but, so far, only seem to modify the course of the disease to a certain extent. It is vital that someone who is ill, particularly with fever, headache and vomiting should not be deemed, automatically, to have influenza even in the middle of an epidemic. Those cases in which there is concern, or in which the diagnosis of influenza may be in doubt, should be seen by a doctor. This is particularly true when a diagnosis of influenza is made in isolation from any other evidence of influenza in the area. |
