Measles is one of the most contagious viral infections we know, where 90% of non-protected individuals will contract the disease after they have been exposed to it. It is transmitted by "droplet spread", ie. by secretions from the respiratory tract, or coughing and sneezing onto others if you like. It only exists in man, and the average age of onset, since the introduction of vaccination, is above five years.
The infection begins in the nose and throat, and there the virus incubates for 10-14 days. After this, signs and symptoms of measles start to develop. The onset of these is gradual, starting with fever and cold-like symptoms within the first 24 hours. These are followed by cough and conjunctivitis, and this whole phase - known as the "prodromal" phase - lasts three to four days. Within three days of onset of these symptoms, and 24 hours before the onset of the typical measles rash, spots appear on the lining of the mouth known as Koplik spots. These are blobs of bright red with a small bluish/white centre. Usually by the time the rash appears these spots have gone, but they are important in establishing the clinical diagnosis of measles.
As mentioned before the measles rash appears 24 hours after the Koplik spots have appeared. It begins in the forehead and neck, spreading over the trunk over three to four days. The rash is red, blanching (i.e. goes away when you press it with a glass, unlike the infamous Meningococcal rash which does not) and raised. It later becomes darker, nearly brown, and in dark skin may appear very different by becoming a deep red or purple rash. Between two and four days after the spreading of the rash, the skin may become very dry and start to peel away. The most startling aspect of measles though is quite how miserable the child is.
Very rarely the rash can become haemorrhagic, i.e. there is bleeding in to the skin (this is when it will look like a Meningococcal rash) - this carries a high mortality rate.
Measles is contagious mainly during the early stages, from about four to five days before the onset of the rash until two to three days after the rash has appeared. Once a child has been infected and has recovered, he or she is immune for life.
During an episode of measles, many of the body's systems can become involved: the initial conjunctivitis may become severe; the mouth can become very sore and may interfere with eating and drinking. Laryngitis may occur as may bronchopneumonia (these particularly if the child's nutrition is poor), as well as diarrhoea.
Another vulnerable system is the central nervous system, the brain. The most commonly (which isn't very common overall) seen event is a short generalised seizure from which complete recovery is made.
More rarely one may see measles encephalitis - where the measles virus actually infects the brain matter itself. The prognosis for this is pretty poor, with a death rate of 10-15% and a quarter of affected children being left with some permanent form of neurological disability. Another rare neurological condition is a bit of a mouthful and is known as Subacute Sclerosing Panencephalitis. This is caused by a persistent viral infection of the brain and usually comes to the fore about five to ten years after the original infection, with gradual personality changes and signs of mental deterioration, leading eventually to death.
Diagnosis is made on clinical grounds and can be confirmed by a blood test looking for antibodies or, more commonly now, a mouth swab looking for the measles virus itself. There is no treatment for measles other that a supportive one: this includes plenty of fluid and nutrition, as well as help with pain and fever. Should there be any suspicion of bacterial infection on top of the measles then it is very important to begin antibiotics (measles is known to make the immune system less efficient).
Measles can be a devastating infection. The only way to protect your child and to control measles is to VACCINATE your child against it.
