MENINGOCOCCAL DISEASE

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MENINGOCOCCAL DISEASE PREVENTION

• Dr Deb Wilson
• Consultant in Communicable Disease Control
• 2001

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Neisseria meningitidis

• gram negative diplococci
• throat carriage - varies with age
• Neisseria lactamica carriage thought to be
  protective
• systemic immunity or invasive disease usually
  develop within a week of acquisition
• the length of carriage after acquiring
  meningococci varies
• transmitted by prolonged person to person spread
  through droplets or respiratory secretions
• serogroups - A, B, C, W135, Y
• no environmental or animal reservoir

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Meningococcal Disease

• Meningitis
• Septicaemia
• Conjunctivitis
• Septic Arthritis
• 10 mortality rate ?20 in septicaemia
• sequelae - amputations, deafness, brain damage,
  fits

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Signs and symptoms
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Pre-admission penicillin

• On suspicion of meningococcal disease give
  pre-admission benzyl penicillin - saves lives
• preferably i.v. but i.m. if access is difficult
• adults and children over 10 1.2 g
• children aged 1 - 9 years 600 mg
• infants 300 mg
• alternatives if history of penicillin allergy are
  chloramphenicol or cefotaxime
• pre-admission treatment pack
• drugs
• information

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Diagnosis

• Clinical
• Microbiological
• blood cultures
• CSF microscopy culture
• throat swab
• PCR on blood or CSF
• serology
• skin scrapings - microscopy culture

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Epidemiology

• approximately 2500 cases and 250 deaths each year
  in England Wales
• seasonal variation
• increase in disease 1995 onwards, especially C
• incidence in County Durham Darlington is
• 10 per 100,000 per year
• incidence highest in under 5s and teenagers
• can occur at any age
• serogroup B causes 70 deaths in under 5s
• serogroup C causes 80 deaths in teenagers

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Incidence in contacts of cases

• Relative Risk in household contacts of cases
  500-1200 X population risk
• RR in school contacts ?30 X population - highest
  RR in nursery schools, lowest RR in secondary
  schools
• secondary cases mainly occur in 7 days following
  the index case

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Roles and responsibilities
Make clinical diagnosis
Recognise symptoms and seek help
Confirm microbiological diagnosis
Deal with worries of contacts public schools,
colleges nurseries workplace media
Treat the case
Monitor who is getting disease, where, trends
etc.
Prevent linked cases
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Confirmed, Probable or Possible

• cannot wait for microbiology before contact
  tracing
• Confirmed case
• microbiological confirmation with clinical
  diagnosis
• Probable case
• signs and symptoms of meningococcal disease and
  this the most likely diagnosis
• Possible cases
• some signs and symptoms of meningococcal disease
  but another diagnosis is as likely or more likely

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Contact Tracing

• Defined by CCDC (or PHN)
• Only contact trace confirmed or probable cases
• Close contacts in 7 days before index case unwell
• usual household members
• stayed under same roof
• boyfriend / girlfriend (intimate kissing)
• Not
• close contacts
• sharing crockery
• social kissing
• contacts of contacts
• healthcare workers (unless mouth to mouth)

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Close contacts need.

• Information about signs and symptoms to increase
  vigilance
• Antibiotic prophylaxis
• a.s.a.p.
• rifampicin or ciprofloxacin (unlicensed)
• Vaccine
• only if case is confirmed serogroup C (or A, W135
  or Y)
• Hospital primary care roles re antibiotic
  prophylaxis

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Clusters in schools, colleges

• Single cases in school/college - offer
  information only to school, no prophylaxis
• Two confirmed or probable cases that are due to
  the same organism (or could be due to the same
  organism)
• offer information
• offer antibiotic prophylaxis /- vaccine to whole
  school - or relevant group

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CONJUGATE VACCINES

• conjugation - coupling of the polysaccharide
  antigen to a conjugate (e.g. protein) can
  overcomes the problem of lack of serological
  response to bacterial capsules
• Hib vaccine was the first conjugate vaccine
  ?dramatic reduction in invasive Hib disease in
  children
• ?pneumococcal conjugate vaccine next

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Bacterial Capsules

• polysaccharide capsule
• helps avoid ingestion of the bacteria by
  phagocytes
• prevents complement system being activated
• young children, the elderly and the
  immunocompromised are unable to mount a
  serological response to the capsule of bacteria -
  including pneumococci, meningococci and
  haemophilus influenzae
• some capsule polysaccharides mimic host
  polysaccharides, thus protecting themselves
• an issue with serogroup B meningococci
• spleen is important with capsulate bacteria -
  intrasplenic phagocytosis