Rubella virus

From IDWiki
  • Also known as German measles
  • Causes fever, rash, ± arthritis
  • Congenital syndrome: deafness, cataracts, and CHD

Background

Microbiology

  • RNA virus in the Matonaviridae family, genus Rubivirus
    • Previously in the Togaviridae family

Epidemiology

  • Seasonal, in spring, if no vaccine
  • Less contaggious than measles, spread by respiratory droplets
    • Most contagious while the rash is erupting, but ranges from 10 days prior to 15 days after
    • Infants with congenital rubella can shed it in body fluids for months
  • Epidemics happened every 6 to 9 years, with larger epidemics every 30 years
  • Worldwide, until it was eliminated in the Americas in 2009
    • All cases are imported

Clinical Manifestations

  • Incubation period 18 days (range 12 to 23 days)
  • Benign after birth (postnatal rubella)
  • In adults, prodrome of fever, malaise, and anorexia, followed by the rash
  • Rash appears along with development of immunity
    • Rash starts at the head and moves down
    • Maculopapular
    • May desquamate during healing
    • May be absent
    • Can have Forschheimer's spots (petechial lesions on the soft palate), but not pathognomonic
  • Adenopathy can last weeks, primarily posterior auricular, posterior cervical, and suboccipital
  • Can develop arthritis in a third, usually fingers, wrists, and knees
    • Onset soon after the rash, can take up to a month to resolve
  • Hemorrhage from thrombocytopenia and vascular damage, more commonly in children
  • Encephalitis is rare

Congenital rubella syndrome

Diagnosis

  • Acute and convalescent ELISA serology, or single IgM titre
  • Can do PCR for viral RNA on throat swabs, CSF, or amniotic fluid

Management

  • First trimester infection is more likely to have congenital rubella, rare in third trimester
  • Confirm vaccination status of the exposed individual, in which case they will be very low risk

Prevention

  • Live attenuated vaccine is included in MMR at 12-15 months and 4-6 years
  • Vaccine is 95% effective
  • Should revaccinate most young women