Measles (sometimes known as rubeola) is a highly infectious viral illness. It causes a range of symptoms including fever, coughing and distinctive red-brown spots on the skin.
The measles virus is contained in the millions of tiny droplets that come out of the nose and mouth when an infected person coughs or sneezes.
You can catch measles by breathing in these droplets or, if the droplets have settled on a surface, by touching the surface and then placing your hands near your nose or mouth.
The most effective way of preventing measles is the measles, mumps and rubella (MMR) vaccine.
How common is measles?
The success of the MMR vaccine means that in Ireland, cases of measles are less common. Before the vaccine was introduced in Ireland it was common for thousands of cases to be reported each year.
Outbreaks still occur in Ireland. During the large measles outbreak in Ireland in 2011 nearly 300 cases were reported.The number of cases reported in 2010 was 405 compared with 162 in 2009 and 55 in 2008. The largest outbreak in recent years occurred in 2000, when more than 1600 cases were reported.
It is thought that the rise in the number of cases of measles is due to parents not getting their child vaccinated with the MMR vaccine.
Publicity in 1998 highlighted a report claiming a link between the MMR jab and autism. However, numerous studies that were undertaken to investigate this claim found no link between the MMR vaccine and autism.
Who is affected?
Measles is most common among children aged 1-4 years old, although anyone who has not been vaccinated against measles can catch it.
Treatment for measles is normally not necessary as the body's immune system can usually fight off infection in a couple of weeks. Typically, once you have fought off the measles infection, you develop immunity (resistance) to it.
However, possible complications of measles include pneumonia, ear and eye infections and croup (an infection of the lungs and throat).
More serious complications, such as inflammation of the brain (encephalitis), are rarer but can be fatal. There are hundreds of thousands of deaths worldwide from measles every year. Three children died in Ireland of measles following the outbreak in 2000.