MEASLES

also called rubeola contagious disease caused by a virus, with community outbreaks taking place about every two to four years. Measles is commonest in children but may appear in older persons who have escaped it earlier in life. Infants are immune up to four or five months of age if the mother has had the disease. Immunity to measles following an attack is usually lifelong. Measles is so highly communicable that the slightest contact with an active case may infect a susceptible person. Infectivity is greatest just before the eruption appears and subsides as the rash fades. Uncomplicated measles is seldom fatal; deaths attributed to measles usually result from secondary bronchopneumonia caused by bacterial organisms entering the inflamed bronchial tree. After an incubation period of about 10 days, the patient develops fever, redness and watering of the eyes, profuse nasal discharge, and congestion of the mucous membranes of the nose and throatsymptoms often mistaken for those of a severe cold. This period of invasion lasts for 48 to 96 hours. The fever increases with appearance of a blotchy rash, and the temperature may rise as high as 104 to 106 F (about 40 C) when the rash reaches its maximum. Twenty-four to 36 hours before the rash develops, there appear in the mucous membranes of the mouth typical maculae, called Koplik spotsbluish-white specks surrounded by bright red areas about 1/32 inch (0.75 millimetre) in diameter. After a day or two the rash becomes a deeper red and gradually fades, the temperature drops rapidly, and the catarrhal symptoms disappear. Measles must be differentiated from other disorders accompanied by an eruption. In roseola infantum, a disease seen in babies, a measles-like rash appears after the child has had a high temperature for two or three days, but there is no fever at the time of the rash. German measles (rubella) can be superficially differentiated from measles by the shorter course of the disease and mildness of the symptoms. Sometimes the rashes of scarlet fever, serum reactions, and other conditions may, on certain parts of the body, look like measles. Drugs that may produce rashes similar to measles are phenobarbital, diphenylhydantoin, the sulfonamides, phenolphthalein, and penicillin. Mortality caused by measles declined steadily in the 20th century as the health of children and infants improved and effective treatment of complications became possible through the use of sulfonamide and antibiotic drugs. No drug is effective against measles; the only treatment required is rest in bed, protection of the eyes, care of the bowels, and sometimes steam inhalations to relieve irritation of the bronchial tree. The widespread use of measles vaccine, beginning in the late 1960s, raised hopes for the eventual eradication of the disease; but, contrary to expectations, the incidence of measles continued to rise worldwide. One of the great problems with the measles vaccine is that it is a live vaccine that rapidly becomes inert if exposed to warm temperatures; 10 minutes in sunlight is sufficient to kill it. This sensitivity is a great hindrance to its use in tropical areas. Research is currently directed toward development of a more stable vaccine.