Measles, Mumps & Rubella

Question 1

Transmission of measles

Answer 1

Aerosol, respiratory route, extremely contagious

Question 2

Epidemiology of measles

Answer 2

• ubiquitous infection of early childhood

- without vaccination, infection acquired by age 5

Question 3

Incubation period of measles

Answer 3

10-14 days

Question 4

Symptoms of measles (4)

Answer 4

1. Viremia, virus replication in respiratory epithelium & skin
2. Fever, conjunctivitis, rhinorrhea, cough
3. Koplik’s spots around parotid duct orifices herald onset (salt & pepper)
   4, Few days later, typical maculopapular rash from face spreads to body

Question 5

Complications of measles (4)

Answer 5

1. Mucosal infections - conjunctivitis, otitis media
2. Respiratory - bronchopneumonia, giant cell pneumonia
3. GIT - diarrhea (measles/sec bact inf)
4. Neurological
   - post infectious demyelinating encephalitis
   - subacute sclerosing panencephalitis - develops long period after apparent recovery, myoclonic seizures, intellectual deterioration, cytoplasmic inclusions in neuronal cells, rapidly fatal

Question 6

Diagnosis of measles (2)

Answer 6

1. Tissue culture
   - virus isolated from pharynx, conjunctiva, urine
   - infected monkey kidney cells - multinucleated giant cells
2. Serology
   - IgM assay for recent infection
   - IgG for retrospective diagnosis

Question 7

Treatment of measles

Answer 7

1. Live attenuated vaccine (MMR) at age 1
   - effective & long lasting immunity
   - mild pyrexia, serious complications are rare
   - contraindications: severely malnourished & immunocompromised children, pregnant women
   - passive immunisation with immune gammaglobulin for contacts with immunodeficiency
   - new MMRV vaccine includes VZV antigen

Question 8

Incubation period of mumps

Answer 8

2-3 weeks

Question 9

Symptoms of mumps

Answer 9

• fever, malaise, tender cervical lymphadenopathy (+/-)
• salivary gland enlargement, pain aggravated by eating esp parotid gland
• most infections between age 5-15

Question 10

Complications of mumps (3)

Answer 10

1. Aseptic meningitis - relatively common but mild
2. Orchitis - pain & swelling, usually unilateral
3. more frequent in adults, pancreatitis 10%

Question 11

Diagnosis of mumps (4)

Answer 11

1. Specimens - saliva, throat washings, urine, CSF
2. Tissue culture
3. CPE - rounding of cells, multinucleated syncytial formation, eosinophilic inclusions
4. Serology - IgM, IgG

Question 12

Treatment of mumps

Answer 12

Live attenuated vaccine at age 1, recommended for unimmunized pre-adolescents who have not had mumps parotitis

Question 13

Symptoms of rubella

Answer 13

• often subclinical esp in children
• constitutional symptoms - mild but variable
• prodrome of malaise, headache, fever, conjunctivitis, coryza, cough, lymphadenopathy
• occasionally discrete rose spots on palate (Forschheimer’s spots)
• typically rubella rash - small maculopapular lesion from face to trunk to extremities (~3d)
• tender lymphadenopathy, freq suboccipital, post auricular & cervical nodes

Question 14

Complications of rubella (4)

Answer 14

1. Arthralgia & arthritis - affects 1 or more joints when rash subsides
2. Encephalitis - uncommon, more in adults, occassionally fatal
3. Purpura - thrombocytopaenia & haemorrhage (+/-)
4. Congenital rubella sydrome
   - teratogenic to fetus (esp intrauterine inf in 1st trimester) - virus crosses placenta to invade & damage fetal organ - esp severe during earlier periods of organogenesis - stillbirth, spontaneous abortions
   - permanent defects - ocular lesions (cataract, retinopathy, microphthalmia), ear (sensorineural deafness), CNS (microcephaly, mental retardation, spasticity), heart malformations, interstitial pneumonitis, DM, hepatosplenomegaly, thrombocytopaenia, bone

Question 15

Epidemiology of rubella

Answer 15

• worldwide distribution, recurrent spring endemics
• moderately infectious & transmitted via resp route
• viral replication in respiratory epithelium & lymph nodes followed by viremia

Question 16

Diagnosis of rubella (2)

Answer 16

1. Tissue culture (but viral isolation is time consuming)

2. Serology - detection of significant rise in antibody titre and/or IgM for up to one month after rash

Question 17

Treatment of rubella (5)

Answer 17

1. Live attenuated rubella vaccine - children aged 12 & women of childbearing age
   - adverse effects - fever, rash, lymphadenopathy, arthralgia, arthritis, polyneuropathy
   - advise against pregnancy within 3m after vaccination
2. Quarantine infected individual
3. Specific immunoglobulin may be protective if given early after exposure
4. Screen all surrounding family members, exposed contacts & hospital personnel
5. Screen all pregnant mothers antenatally for rubella antibodies