Why it's deadly, and why it can be prevented
What is measles?
Measles is a highly contagious viral disease, which affects mostly children. It is transmitted via droplets from the nose, mouth or throat of infected persons. Initial symptoms, which usually appear 10–12 days after infection, include high fever, runny nose, bloodshot eyes, and tiny white spots on the inside of the mouth. Several days later, a rash develops, starting on the face and upper neck and gradually spreading downwards. There is no specific treatment for measles and most people recover within 2–3 weeks. However, particularly in malnourished children and people with reduced immunity, measles can cause serious complications, including blindness, encephalitis, severe diarrhoea, ear infection and pneumonia. Measles can be prevented by immunization.
Why should we be worried?
An outbreak of measles recently affected over 140 people in Disneyland CA. The source was traced back to a visitor who had traveled overseas with the disease. The outbreak started just before christmas 2014, and has just last Friday (Apr. 17 2015) been declared over. Analysis by CDC scientists shows that the measles virus type in this outbreak (B3) is identical to the virus type that caused the large measles outbreak in the Philippines in 2014. On January 23, 2015, CDC issued a Health Advisory to notify public health departments and healthcare facilities about this multi-state outbreak and to provide guidance for healthcare providers nationwide. The outbreak sickened 147 people in the U.S., including 131 in California. There were no deaths. Many who fell ill were not immunized against measles. While the Disneyland outbreak is over in the U.S., it's still a problem in the Canadian province of Quebec, where 159 people were sickened after someone visited the theme park and returned home. About 20 percent had to be hospitalized. (Most belong to a tight-knit religious community with a low vaccination rate.)
How do people get infected?
Measles is an endemic disease, meaning it has been continually present in a community, and many people develop resistance. Measles is caused by the measles virus, a single-stranded, negative-sense, enveloped RNA virus of the genus Morbillivirus within the family Paramyxoviridae. The virus was first isolated in 1954 by Nobel Laureate John F. Enders and Thomas Peebles, who were careful to point out that the isolations were made from patients who had Koplik's spots. Humans are the natural hosts of the virus; no other animal reservoirs are known to exist. Measles is thought to have originated in the middle east.
How can we prevent it?
Measles is a preventable disease, but many people are not able to prevent it. Most cases of measles appear in third world countries, where medicine is not as readily available as it is in the US, while even some US citizens are against vaccination. Herd immunization is also possible, where a group of people develop immunity. If you have had measles before, you will most likely not have it again.
How is it dangerous?
Measles itself is usually not dangerous in developed countries, requiring only a week of bed rest, but many cases in third world countries can be fatal, as it weakens the immune system and leads to infections of other sorts. In rare cases, however, measles can lead to brain swelling, at a 15% mortality rate.