Clinical Information

Measles is a highly contagious, acute, exanthematous disease. It is generally self-limiting and without serious consequences, although complications such as bronchopneumonia and otitis media do occur. The most serious consequence, encephalomyelitis, is fortunately rare (about 1 in 10,000 cases). Natural infection with measles virus confers permanent immunity.

Prior to the advent of vaccines, measles was an almost universally acquired disease of childhood. With the widespread introduction of vaccines, however, the incidence of measles has been dramatically reduced, and physicians have become increasingly less familiar with this disease. Populations vaccinated in childhood with attenuated measles vaccines have presented atypical forms of measles; and children vaccinated before 15 months of age may be susceptible to measles infection despite being vaccinated. Finally, measles infection poses a serious threat to immunosuppressed or immunocompromised patients. For these reasons, the laboratory diagnosis of measles has become increasingly important, notwithstanding the reduction in the incidence due to the introduction of vaccines.

The usual means of laboratory diagnosis of acute measles is serologic, either by the demonstration of a four-fold or greater rise in virus-specific IgG antibody in acute/convalescent serum pairs, or by the detection of virus-specific IgM antibody in a single, early serum specimen. The traditional serologic test, hemagglutination-inhibition, has been replaced by enzyme-linked immunosorbent assays (ELISA) for practical reasons.