Rubella
by Halley Dawe
Rubella: aka “German Measles,” “three-day measles”
Transmission: It is spread by direct contact with nasal or throat secretions, such as coughing or sneezing, of infected individuals (2). It can also be spread to a fetus by an infected mother (3).
Reservoirs: People, typically children in unvaccinated populations and typically adolescents and adults in well immunized populations
Etiologic Agent: Rubivirus
General Characteristics: This virus is of the family togavirus. It is an enveloped RNA virus with a single antigenic type that does not cross-react with other members of the togavirus group. This virus is relatively unstable and is inactivated with the use of lipid solvents, trypsin, formalin, low pH, heat, and amantadine (1).
Key tests for isolation: Acute Rubella can be identified by a positive viral culture for rubella. This can be isolated from nasal, throat, blood, urine, and cerebrospinal fluids specimens from the patient. Although viral identification is very specific and accurate, this test is very labor intense and not commonly used for routine identification of the rubella virus. Serology is most commonly used. Acute rubella can be confirmed by a significant rise in IgG antibody from paired acute- and convalescence-phase sera or by the presence of the IgM antibody. Different laboratories vary in which test they use but some common serological tests are: the Enzyme-linked immunosorbent assay (Elisa test), Hemagglutination inhibition (HI test), and the Immunofluorescent antibody assay (IFA test). (1)
History: Rubella was at first considered to be a variant of the measles or scarlet fever and was called 3rd disease. The name Rubella comes from the Latin word meaning “little red.” In 1814, it was first discovered to be a separate disease from the measles in German medical literature thus receiving its nickname the “german measles.” In 1914, Hess postulated a viral etiology, and in 1938, Hiro and Tosaka confirmed his etiology by passing the disease to children with nasal washings from an infected person with an acute case. In 1941, Norman Gregg reported congenital cataracts in 78 infants whose mothers had maternal rubella in early pregnancy. These were the first cases reported of congenital rubella syndrome (CRS) (5). In 1962, rubella was first isolated by Parkman and Weller who then went on to find the general characteristics of the virus.
Signs and Symptoms: The rubella virus is a mild viral disease and often passes through undetected. This can make rubella hard to diagnosis (4). About one half of infected persons go by asymptomatically. The severity of the disease tends to increase with age(6). Typical symptoms include: swollen gland or lymph nodes, fever no higher than 100.4 degrees Fahrenheit, a rash of small red bumps under the skin that appears first on the face and then spreads to trunk and limbs, flaking, dry skin, inflammation of the eyes, nasal congestion, joint pain and swelling, pain in the testicles, loss of appetite, and headache (4). Complications rarely occur but encephalitis occurs in about 1 in 6,000 (7). In 1941, the seriousness of rubella was discovered among the discovery of Congenital Rubella Syndrome. An association was made between severe birth defects and an occurrence of rubella in pregnant mothers during the 1st trimester (7). When a mother is infected with rubella in early gestation, typically before 20 weeks, the fetus may be affected. About 85% of fetuses with mothers who become infected before the 20th week will develop CRS. The infection can affect all organs and may lead to fetal death, spontaneous abortion, or premature delivery. The seriousness of the infection depends on the time in pregnancy when infected. Some symptoms of CRS include deafness, cataracts, heart defects, microcephaly, mental retardation, bone alterations, and liver and spleen damage (1).
Virulence Mechanisms: There are no know virulence factors (8). But not being vaccinated or having no prior contact with the disease may increase the virulence.
Control and Treatment: Rubella is typically a mild disease and no specific treatment has been found. Rest and fluids are typically the treatment for the disease. Pain relievers like acetaminophen and aspirin can be used to reduce fevers and inflammation. People remain contagious for about 7 days after the onset of the rash, and they should be isolated from school, work, and non-immunized people (6). Treatment to CRS depends on the type of defect caused and should be treated according to treatment of specific defects (3).
Prevention: Rubella is most commonly prevented by the rubella vaccine. The widespread use of the vaccine prevents outbreaks and the occurrence of birth defects due to CRS. The vaccine is typically given to children between 12 and 15 months as part of their Measles-Mumps-Rubella shot (MMR). A second dose of the vaccine is given at 4-6 years of age (5). The vaccine provides life-long protection against the disease (4). The vaccine is very safe and only occasionally has complaints of fever, lyphadenopathy, arthralgia, and pain at the injection site. People who have acquired the disease naturally are also immune to infection again. The best way to prevent rubella is by the maintenance of high immunization levels, intense surveillance of rubella cases, and prompt outbreak control.
Current Outbreaks: In 2004, the CDC announced that fewer than 25 cases have been reported annually since 2001, and that there is a 95% vaccination rate among school-aged children and about a 91% vaccination among the entire U.S. population. In contrast, in 2003, there was in increase in rubella cases in England and Wales because of the thought of adverse side-effects of the vaccine (6). Rubella became notified in 1966, and the largest number of cases in the U.S. occurred in 1969. Following the licensure of the vaccine, the amount of cases dropped dramatically. A moderate resurgence of the disease occurred in 1990 due to an outbreak in California. From then to the present the numbers have dropped dramatically, and in 2004 the CDC put together a panel to review available rubella and CRS data. This expert panel declared rubella no longer an endemic in the U.S.
Works Cited
1. Anon. Rubella. 2003
2. Anon. Rubella. 2004.<http://www.health.state.ny.us/nysdoh/communicablediseases/en/rubella.htm>. 4/25/06
3. Goldenring, John. Rubella. 2005. <http://www.nlm.nih.gov/medlineplus/ency/article/001574.htm>. 4/25/06
4. Anon. Rubella- Wikipedia. 2006 < http://en.wikipedia.org/wiki/Rubella >. 4/25/06
5. Ben-Joseph, Elana P. Rubella (German Measles). 2003.<http://kidshealth.org/parent/infections/bacterial_viral/german_measles.html>. 4/25/06
6. Lombardo, Peter. Rubella. 2005. http://www.emedicine.com/derm/topic380.htm. 4/25/06
7. Case, C., Funke, B., Tortora, G. Microbiology: An Introduction. 2004. Pg.604-605.
8. Anon. Rubella Virus. 1999.<http://medinfo.ufl.edu/year2/mmid/bms/5300/bugs/rubella.html 4/25/2006
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