Rubella virus, a togavirus of the genus Rubivirus.
Rubella virus is transmitted by the respiratory route and the virus replicates in the nasopharyngeal mucosa and local lymph nodes. Humans are the only known host.
Nature of the disease
Acquired rubella is characterized by a transient, erythematous rash, conjunctivitis, coryza, postauricular and suboccipital lymphadenopathy, low fever and nausea. Arthralgia and arthritis rarely occur in children but may affect up to 70% of adults, particularly women. Haemorrhagic manifestations, Guillain-Barré syndrome and encephalitis are reported rarely. Serological studies have shown that 20-50% of all rubella infections are subclinical. Congenital rubella infection and congenital rubella syndrome (CRS) are caused by infection in early pregnancy. From just before conception and during the first 8-10 weeks of gestation, rubella infection may result in multiple fetal defects in up to 90% of cases and often causes miscarriage or stillbirth. Although the worldwide burden of CRS is not well characterized, it is estimated that more than 100 000 cases occur each year in developing countries alone.
Risk for travellers
Travellers who are not immunized against rubella may be at risk when visiting countries where the vaccine coverage is suboptimal. Particular attention should be paid to ensuring protection of women who may become pregnant during the period of travel.