Rubella

Question 1

What is the family?

Answer 1

Togavirus

Question 2

What is the genus?

Answer 2

Rubivirus

Question 3

Characteristics

Size, genome etc

Answer 3

Small RNA non-arthropod-borne virus

Question 4

How many serotypes?

Answer 4

1

Question 5

What “measles” is it known as?

Answer 5

German measles

Question 6

How long is the incubation period?

Answer 6

2-3 weeks

Question 7

What are the clinical presentations?

Answer 7

• Prodrome of maliase, headache, fever, conjunctivitis, coryza, cough
• Ocasionally discrete rose spots (Forschheimer’s spots) on palate herald onset of skin rash
• Typically rubella rash (small maculopapular lesions from face to trunk and extremities, lasting about 3 days)
• Tender lymphadenopathy (frequently suboccipital, postauricular and cervical nodes)

Question 8

What are the complications?

Answer 8

1. Arthralgia, arthritis (affects one or more large and small joints when rash subsides)
2. Fever
3. Encephalitis (uncommon, adults>children, fatal)
4. Purpura, thrombocytopaenia and haemorrhage
5. Congenital rubella syndrome

Question 9

How does Congenital Rubella Syndrome affect foetus?

Answer 9

• Teratogenic to foetus particularly if intrauterine infection of mother during first trimester of pregnancy
• Virus crosses placenta to invade and damage practically any foetal organ
• Stillbirth, spontaneous abortion
• Permanent defects: ocular lesions (cataract, retinopathy, microphthalmia), ear (sensorineural deafness), CNS (microcephaly, mental retardation, spasticity)
• Cardiorespiratory (heart malformations, interstitial pneumonitis)
• Diabetes mellitus (insulin dependent)
• Hepatosplenomegaly
• Thrombocytopenia
• Metaphyseal osteitis

Question 10

Describe how the pathogenesis

Answer 10

Viral replication in respiratory epithelium and lymph nodes followed by viraemia

Question 11

How to diagnose?

Answer 11

• Cell culture (virus isolation is time-consuming)
• RT-PCR
• Serology (one month after rash to detect significant rise in antibody titre, part of TORCHES IgG panel)

Question 12

How to manage and prevent?

Answer 12

• Quarantine infected individual
• Specific immunoglobulin may be protective if given early after exposure
• Screen all surrounding family members, exposed contacts and hospital personnel
• Screen all pregnant mothers antenatlly for rubella antibodies
• Live attenuated rubella vaccine (current strain developed in human cells)
• Vaccination programme targeted for both sexes (vaccinate women of childbearing age)

Question 13

What are the adverse effects of vaccine?

Answer 13

Fever, rash, lymphadenopathy, arthralgia, arthritis, rarely polyneuropathy