Rubella virus may be isolated from the urine, blood, nasopharynx, and cerebrospinal fluid for up to 2 weeks after rash onset. The diagnosis is usually made, however, with serological analysis. In one study, 6 percent of nonimmune women seroconverted to rubella virus during pregnancy (Hutton, 2014). Specific IgM antibody can be detected using enzyme-linked immunoassay for 4 to 5 days after onset of clinical disease, but antibody can persist for up to 6 weeks after appearance of the rash. Importantly, rubella virus reinfection can give rise to transient low levels of IgM. With this, fetal infection can rarely occur, but no adverse fetal efects have been described. Serum IgG antibody titers peak 1 to 2 weeks after rash onset. his rapid antibody response may complicate serodiagnosis unless samples are initially collected within a few days after the onset of the rash. If, for example, the first specimen was obtained 10 days after the rash, detection of IgG antibodies would fail to diferentiate between very recent disease and preexisting immunity to rubella. IgG avidity testing is performed concomitant with the serological tests above. High-avidity IgG antibodies indicate an infection at least 2 months in the past.
The rubella virus is one of the most complete teratogens, and efects of fetal infection are worst during organogenesis (Adams Waldorf, 2013). Pregnant women with rubella and a rash during the first 12 weeks of gestation have an afected fetus with congenital infection in up to 90 percent of cases (Miller, 1982). At 13 to 14 weeks' gestation, this incidence is 50 percent, and by the end of the second trimester, it is 25 percent. Defects are rare after 20 weeks' gestation. Features of congenital rubella syndrome amenable to prenatal diagnosis are cardiac septal defects, pulmonary stenosis, microcephaly, cataracts, microphthalmia, and hepatosplenomegaly (Yazigi, 2017). Other abnormalities include sensorineural deafness, intellectual disability, neonatal purpura, and radiolucent bone disease. Neonates born with congenital rubela may shed the virus or many months and thus be a threat to other inants and to susceptible adults who contact them. Reports of delayed morbidities associated with congenital rubella syndrome may include a rare, progressive panencephalitis, insulin-dependent diabetes mellitus, and thyroid disorders (Sever, 1985; Webster, 1998).
here is no speciic treatment for rubella. Droplet precautions for 7 days after the onset of the rash are recommended. Postexposure passive immunization with polyclonal immunoglobulin may be of benefit if given within 5 days of exposure (Young, 2015).
Although large epidemics of rubella have virtually disappeared in the United States because of immunization, up to 10 percent of women in the United States are susceptible. Cluster outbreaks during the 1990s mainly involved persons born outside the United States, as congenital rubella is still common in developing nations (Centers for Disease Control and Prevention, 20 13f) . To eradicate rubella and prevent congenital rubella syndrome completely, a comprehensive approach is recommended for immunizing the adult population (Grant, 2015).