Measles

Summary of measles virus

Measles is a highly contagious viral infection characterized by a fever and a red, bumpy rash.

What is going on in the body? Measles is acquired by coming into contact with infected respiratory secretions and droplets. Infected people can spread it when they cough, sneeze or wipe their noses. Over the last four decades, widespread use of a highly effective measles vaccine and aggressive outbreak control have resulted in the elimination of measles virus circulation in the United States. However, measles is imported into this country periodically by travelers, visitors, and immigrants.

What are the signs and symptoms of the infection? Symptoms usually begin about 1 to 1-1/2 weeks after acquiring the virus. The symptoms can include: • A fever, usually 39-40 degrees C or higher (103 -104 degree F) • A red, slightly bumpy rash. • cough. • Tiny white spots inside the mouth (known as "Koplik's spots") • Runny nose (Coryza) • Conjunctivitis, also known as pink or red eye. Conjunctivitis is an inflammation of the mucous membrane that lines the inner part of the eyelid.

• Sometimes, measles cases can be complicated by ear infections, croup, or pneumonia. About 0.1% of patients can contract encephalitis, an infection of the brain after becoming infected with measles. Encephalitis can result in brain damage and, sometimes, death.

What are the causes and risks of the infection? Measles is caused by the measles virus, which belongs to the Paramyxovirus family of viruses. Anyone who has not had measles before, and has not been immunized, is at risk for measles. Measles is so highly communicable by airborne spread that cases have been shown to result from sitting in a waiting room occupied by a measles case hours before.

What can be done to prevent the infection? The measles vaccine is very effective at preventing measles in immunized people. The vaccine is usually combined with the rubella, mumps, and chickenpox vaccines and given as one shot, called the MMRV vaccine. Side effects of the MMRV vaccine can include: • fever and rash • joint pain • allergic reactions Other side effects are rare. The vaccine should not be given to pregnant women or to women who are planning on getting pregnant in the 3 months following immunization. Another way to prevent the spread of infection is to isolate the infected person. An infected person with a normal immune system should stay home from school or work for 4 days after the rash appears. An infected person with autoimmune problems, where the body attacks its own tissues, may be contagious for even longer. In some circumstances, susceptible individuals who have been exposed to measles are also isolated, until it is determined whether they will come down with the infection. Some people with autoimmune problems or other immune system disorders should not have the measles vaccine. If these unprotected people are exposed to an infected person, they should receive immune globulin prophylaxis, an injection of disease-fighting proteins.

How is the infection diagnosed? A measles case is usually confirmed with a blood test for measles antibodies, though if a person with symptoms is a known contact of a confirmed case, a clinical diagnosis is sufficient. The measles virus can be cultured from infected respiratory secretions, the eye, the blood, or the urine during the acute phase of the illness. The usual reason to recover measles virus from a person is to identify the viral strain in order to trace the source of an importation.