RUBELLA

Rubella

Rubella

Introduction

Rubella (previously known as German measles) is a disease caused by the rubella virus (Rubivirus rubella). The rubella virus belongs to the Togaviridae family of viruses, whose only hosts are humans. Rubella occurs worldwide, with periodic epidemics occurring every 4-7 years in countries whose population is unvaccinated. Rubella rarely occurs in countries that have a wide-reaching vaccination program (e.g., the United States and Scandinavian countries).

Rubella is transmitted by exposure to respiratory droplets (i.e., wet secretions of an infected person) that contain the virus; these can spread through the air or can be carried to the mouth, nose, or eyes by hands contaminated with nasopharyngeal secretions, urine, stool, blood, or skin. Contaminated surfaces can also harbor the virus in droplet form. The virus replicates in the nasopharynx and nearby lymph nodes, spreads to the skin, causing a rash, and can spread to other organs. The classic sign of infection is a maculopapular rash, which usually lasts about 1-3 days. Symptoms in children are usually mild or subclinical, but in adults can be severe. In pregnant women, the virus passes through the chorion membrane and is transported into the fetal circulation. Viral exposure occurring in utero can result in congenital abnormalities; the highest risk of teratogenic effects is during the first trimester, when exposure carries an 80% risk of developing congenital abnormalities. Antiviral medications are ineffective in reducing replication and growth of the rubella virus, so treatment is focused on alleviating symptoms of infection with antipyretics and analgesics. There is no treatment for the fetus exposed in utero. Children born with congenital abnormalities are treated for the specific abnormality (e.g., heart defects, cataracts). Prevention strategies (e.g., vaccination) are a key focus in preventing the spread of the disease.

Facts and Figures

Viral dispersion occurs more often in late winter and spring. Rubella is predominantly found in children aged 5-9, in adolescents, and in young adults. Males and females are affected equally, but complications of arthralgia and arthritis are more common in post-pubertal females. The average incubation period is 16-18 days; persons with rubella are communicable 10 days before signs and symptoms present to 5 days after the rash disappears (Knuf, 20082, 79).

Epidemiology of rubella

One of the original aims of the introduction of the combined MMR vaccine was to eliminate rubella circulating in the community. This was largely successful in the first few years of the vaccine's use. However, public and parental fears following the Wakefield controversy led to immunization rates falling, allowing rubella once again to circulate within the community. In the mid 1990s confirmed cases of rubella increased substantially (Figure). However, despite the number of notifications of suspected cases remaining relatively constant over the last 10 years, numbers of confirmed cases have fortunately fallen, with very few cases being laboratory confirmed.

The impact of rubella virus infection and the progress made toward controlling congenital rubella infection have been well chronicled. Rubella was first recognized in the mid-18th century as a clinical entity by German researchers, who called it ...