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Rubella was first clinically differentiated from other exanthematous illnesses by German physicians in the late eighteenth century, hence its popular name, German measles. The Latin term rubella, or ''little red," was coined by a British physician who reported on an epidemic of the disease among schoolboys in India in 1841 (Veale, 1866). Rubella subsequently evoked little interest in the medical community until 1941, when a report appeared associating congenital cataracts with maternal exposure to the disease during pregnancy (Gregg, 1941). A flurry of subsequent reports confirmed this association and further noted increased risks of congenital heart disease and deafness following maternal exposure to the disease, thus establishing the classical congenital rubella triad (Greenberg et al., 1957; Lundstrom, 1962; Manson et al., 1960; Pitt and Keir, 1965). Intrauterine rubella exposure is now known to be associated with a wide variety of abnormalities, including, for example, encephalitis, mental retardation, glaucoma, thrombocytopenic purpura, hypoplastic right heart, and diabetes (Alford and Griffiths, 1983; Cooper et al., 1969; Plotkin et al., 1965b).

The incubation period of rubella is 14 to 21 days, with the characteristic rash appearing within 14 to 17 days after exposure. The patient is usually asymptomatic in the first week after exposure.  By early in the second week, lymphadenopathy becomes apparent and rubella virus can usually be cultured from nasopharyngeal secretions. By the end of the second week, virus is detectable in the blood. After the 14- to 21-day incubation period, a 1- to 5-day prodromal illness consisting of malaise, low-grade fever, mild conjunctivitis, and, occasionally, arthralgia can occur, but it may be minimal or absent. The rash, in most cases, appears at this time, beginning on the face and neck and spreading quickly to the trunk and extremities. It usually lasts for about 5 days (Cherry et al., 1988; Plotkin, 1988).

Diagnosis

Diagnosis of rubella can be made in several ways. Virus can be most consistently isolated by inoculation of appropriate tissue culture media with nasal secretions. Virus can also be isolated from the throat, blood, urine, and cerebrospinal fluid, particularly in congenitally infected infants. Serologic testing of acute- and convalescent-phase serum is also useful in diagnosis, with seroconversion indicating infection. Diagnosis based on history of German measles or on clinical findings is unreliable without laboratory confirmation, because other viral exanthems mimic rubella.

Complications

Although a number of acute, transient sequelae of postnatal rubella, including polyarthralgia, polyarthritis, and testicular pain, have been noted