associated with a fever lasting more than 2 days after the onset of rash (Strebel et al., 2008). Measles-related mortality is highest for infants, young children, and adults with decreased risk in older children and adolescents (CDC, 1998). Other complications include acute otitis media, appendicitis, hepatitis, myocarditis, and thrombocytopenia (Kempe and Fulginiti, 1965).
Although recognized as a disease for approximately 2,000 years, the first major advance in the study of measles was in 1846 when Parnum observed measles cases in the Faroe Islands. Parnum confirmed the infectious nature of measles, defined the 2-week incubation period, and noted that individuals infected with measles did not become ill after subsequent exposure to the virus (Strebel et al., 2008). In 1954, Enders and Peebles propagated measles virus in human renal tissues (Enders and Peebles, 1954). Nine years later, in 1963, the first live, attenuated vaccine was licensed for use in the United States (Enders, 1962). The Edmonston B virus strain that was passaged at 35–36°C through primary renal cells, primary human amnion cells, and embryonic chicken cells a total of 59 times was used in many vaccines (Strebel et al., 2008). In 1965 and 1968, the Schwarz and Moraten (more attenuated strain derived from Ender’s attenuated Edmonston measles virus) strains were also licensed in the United States. These strains were developed from the Edmonston B strain and were passaged at 32°C an additional 85 and 40 times, respectively (Strebel et al., 2008). The Schwarz and Moraten strains were shown to cause less severe and less frequent side effects (Andelman et al., 1963; Hilleman et al., 1968; Schwarz, 1964; Schwarz and Anderson, 1965; Schwarz et al., 1967; Strebel et al., 2008). Today, the only strain licensed in the United States is the more attenuated, live Ender’s Edmonston strain (Moraten strain) (CDC, 1998).
Prior to the licensure of a measles vaccine, an average of 400,000 measles cases were reported each year, although the actual incidence was estimated to be 3.5 million based on the size of the annual birth cohort, and the fact that nearly 100 percent of the population was infected during childhood (CDC, 1998). With the licensure of the vaccine, the measles burden has been reduced by more than 99 percent, and in 1998, the Centers for Disease Control and Prevention (CDC) indicated that 95 and 98 percent of children vaccinated at age 12 and 15 months, respectively, developed measles antibodies (CDC, 1998).
Mumps is an acute viral infection caused by an enveloped, negative-sense RNA virus of the genus Rubulavirus (Litman and Baum, 2010). The virus is composed of 15,384 nucleotides that encode seven genes, one of which is the SH protein that has been used to identify at least 12 mumps virus strains (Jin et al., 2000; Plotkin and Rubin, 2008). Mumps is transmit-