Measles

About Measles

Measles rubeola is one of the most contagious human diseases, with an R0 of 12 to 18. Before vaccination, measles infected virtually every child. The disease begins with a prodrome of fever, cough, coryza runny nose, and conjunctivitis the three Cs, lasting 2 to 4 days. Koplik spots, small white lesions on the buccal mucosa inside the cheek, appear during the prodrome and are pathognomonic. The characteristic rash appears 3 to 5 days after symptom onset, starting at the hairline and behind the ears, spreading downward to cover the entire body. The rash is maculopapular and eventually becomes confluent. The child appears uniformly ill. Complications include otitis media, pneumonia the most common cause of death in developing countries, encephalitis approximately 1 in 1,000, subacute sclerosing panencephalitis SSPE a fatal degenerative disease occurring years later, estimated at roughly 1 in 10,000 cases and more often after infection in infancy, and immune amnesia erasing existing immunity to other diseases. Vitamin A deficiency worsens measles outcomes, and WHO recommends vitamin A supplementation for children with measles. Diagnosis is clinical, confirmed by IgM serology or PCR. No specific antiviral treatment exists. Prevention through MMR vaccination is highly effective. One dose is approximately 93 percent effective and two doses approximately 97 percent. Measles was declared eliminated from the US in 2000, but outbreaks linked to imported cases continue to occur in under vaccinated communities.