5 - Rubella infection in pregnancy

Summary

Introduction

Rubella virus belongs to the rubivirus genus of the family Togaviridae, for which humans are apparently the only host. Rubella is an enveloped single-stranded RNA virus which is relatively fragile, multiplies in and is transmitted from the respiratory tract of infected individuals. The virus gains access to the bloodstream resulting in widespread dissemination throughout the body. In pregnant women, rubella can infect the placenta leading to fetal infection with varying degrees of fetal damage. Attention was first drawn to the association between rubella and fetal damage when Gregg, an Australian ophthalmologist noted an epidemic of congenital cataracts following a large outbreak of rubella (Gregg, 1941). Similar reports followed from Sweden, the US and the UK and the role of rubella in congenital cataracts was confirmed. The coincidence of heart disease and deafness was also noted (Plotkin & Mortimer, 1994). Rubella infection is often asymptomatic or causes only mild disease, and the importance is confined to infection during pregnancy and its possible effects on the fetus, referred to as the congenital rubella syndrome (CRS).

Rubella infection is readily prevented by a highly effective and safe live attenuated vaccine which when given to all infants and susceptible adults, as is the case in much of the developed world, has virtually eliminated cases of the congenital rubella syndrome. However, rubella can still be prevalent in immigrant populations from countries where vaccination is not common (Tookey & Peckham, 1999).

Clinical features of rubella

In children rubella infection is usually either asymptomatic or with mild constitutional symptoms accompanied by an evanescent rash, which is often missed. In adults, infection is generally accompanied by an illness although this is likely to be mild.