A precursor of the measles began causing infections in humans as early as the 4th century BC or as late as after AD 500. The Antonine Plague of AD 165–180 has been speculated to have been measles, but the actual cause of this plague is unknown and smallpox is a more likely cause. The first systematic description of measles, and its distinction from smallpox and chickenpox, is credited to the Persian physician Muhammad ibn Zakariya al-Razi (860–932), who published The Book of Smallpox and Measles. At the time of Razis book, it is believed that outbreaks were still limited and that the virus was not fully adapted to humans. Sometime between AD 1100 and 1200, the measles virus fully diverged from rinderpest, becoming a distinct virus that infects humans. This agrees with the observation that measles requires a susceptible population of >500,000 to sustain an epidemic, a situation that occurred in historic times following the growth of medieval European cities. Measles is an endemic disease, meaning it has been continually present in a community and many people develop resistance. In populations not exposed to measles, exposure to the new disease can be devastating. In 1529, a measles outbreak in Cuba killed two-thirds of those indigenous people who had previously survived smallpox.
However, the effectiveness of passive immunization in comparison to active measles vaccine is not clear.The MMR vaccine is 95% effective for preventing measles after one dose if the vaccine is given to a child who is 12 months or older; if a second dose of the MMR vaccine is given, it will provide immunity in 99% of children.There is no evidence that the measles vaccine virus can be transmitted to other persons. Treatment
There is no specific antiviral treatment if measles develops. Instead the medications are generally aimed at treating superinfections, maintaining good hydration with adequate fluids, and pain relief. Some groups, like young children and the severely malnourished, are also given vitamin A, which acts as an immunomodulator that boosts the antibody responses to measles and decreases the risk of serious complications. Medications
Treatment is supportive, with ibuprofen or paracetamol (acetaminophen) to reduce fever and pain and, if required, a fast-acting medication to dilate the airways for cough. As for aspirin, some research has suggested a correlation between children who take aspirin and the development of Reye syndrome.The use of vitamin A during treatment is recommended to decrease the risk of blindness; however, it does not prevent or cure the disease. A systematic review of trials into its use found no reduction in overall mortality, but two doses (200 000 IU) of vitamin A was shown to reduce mortality for measles in children younger than two years of age.