Measles

• should not be regarded as a simple mild disease
• Deaths occur mainly in children under 5 years of age, primarily from pneumonia, and occasionally from encephalitis
• Causative Agent
  • Measles virus ( ssRNA paramyxovirus)
• Host:
  • Human
• Invade:
  • Upper respiratory tract, regional LN
• Transmited by :
  • Large respiratory droplets with no fomites (close contact transm.)
•  infectious :
  • from about 5 days before the onset of the rash until about 4 days after the rash appears
• Virus present :
  • Respiratory secretion, blood, urine
• Endemic in regions where measles vaccination is not available
• Young infants – protected by transplacental antibody, but become more susceptible toward the end of the first year.
• Passive immunity may interfere with effective vaccination until 12 to 15 months of age
• Divided into 4 phases :
  • Incubation
    • time from contact with the virus until onset of symptoms is about 10 days but may be from 7 to 18 days.
  • Prodromal (catarrhal)
    • fever
    • tiredness
    • cough – often worse at night
    • runny nose – coryza
    • red inflamed eyes – conjunctivitis (Stimson line)
    • Koplik spots (buccal mucosa) – white spots on a red base in the mouth on the inside of the cheek
  • Exanthematous (rash)
    • accompanied by high grade fever (40-40.5°C)
    • blotchy, dark red rash usually beginning at the hairline
    • spread down to the leg (descending) –> rash spreads over the entire body
    • show severity of illness
    • most unwell during the first couple of days after the rash appears. The rash usually disappears after 6 days.
  • Recovery

• Other manifestations :
  • Cervical lymphadenitis
  • Spleenomegaly
  • Abdominal pain
  • Mesenteric lymphadenopathy
  • Otitis media- common in infants
  • Pneumonia – common in infants
  • Diarrhea- common in infants
  • Liver involvement – common in adults

Investigations

• Serological test
  • IgM antibody
    • appear in 1-2 days of rash
    • persist for 1-2 month
• Chest X-ray
  • interstitial infiltration
  • -ve measle pneumonia vs bacterial superinfection

Complications

• Acute otitis media (10-15%)
• Interstitial pneumonia (50-75% pathological chest XR)
• Myocarditis and pericarditis
• Encephalitis (1/1000 cases) 7-10 days after rash
• Subacute sclerosis panencephalitis
• Mesenteric lymphadenitis

TREATMENT

• There is no specific antiviral treatment for measles infection
• Management of measles is supportive
• maintain adequate hydration
• antipyretics
• IV ribavirin (severe infection)
• Isolation:
  • Infected:
    • NO work/school/childcare centres for at least 4 days after the appearance of the rash
  • Contacts:
    • Non-immune contacts ≥ 6 months age should receive a MMR vaccine within 72 hours of the exposure
      • If receive MMR vaccine within 72 hours, they may return to childcare, school or work
    • Children > 12 months age who have received one dose of measles-containing vaccine may receive their second dose early if at least 4 weeks have passed since their first dose
    • Normal human immunoglobulin (NHIG) may be indicated for post-exposure prophylaxis for immunocompromised or pregnant contacts and infants less than 6 months age

PREVENTION

• MMR
  • Live attenuated measles vaccine
• Side effects
  • usually appear 7 to 10 days after immunisation and last 2 or 3 days
    • fever
    • fine red rash which is not infectious
    • drowsiness
    • tiredness
• Measles-containing vaccine is recommended for:
  • children ≥12 months of age
    • 12 months of age — MMR 
    • 18 months of age — MMRV
  • adolescents and adults born during or since 1966 who have not received 2 doses of measles-containing vaccine, particularly
    • healthcare workers
    • childhood educators and carers
    • people who work in long-term care facilities
    • people who work in correctional facilities
    • travellers
• Pregnancy
  • if planning pregnancy -> check immunity
  • if not vaccinated/immune should be vaccinated with a MMR containing vaccine at least 28 days before becoming pregnant or immediately after the birth of the baby.
• Contraindicated for severe immunosupression patient