Invasive Meningococcal Disease Flashcards
Is IMD nationally notifiable?
Yes - urgent.
Which organism causes IMD?
Neisseria meningitidis (bacteria) – key serogroups A, B, C, W and Y
How is IMD transmitted?
Respiratory droplets – close/prolonged contact required.
Most cases sporadic. Transmission from symptomatic case uncommon.
What are the clinical features of IMD?
- Commensal – carried in throat of 3-25% of population; asymptomatic
- Invasive disease – acute onset meningitis or septicaemia (fever, headache, N&V, neck stiffness, petechial/purpuric rash). Mortality 5-10%.
Which groups are at high risk for IMD?
- Under 5 and age 15-19 years
- Indigenous people
- Immunocompromised
- HH contacts 500-800x risk
Bimodal incidence - childhood and early adolescence/adulthood
Vaping is a RF.
What is the case definition for IMD?
- Confirmed - lab definitive or lab suggestive + clinical
- Probable - clinical only
How is IMD diagnosed?
- PCR and culture (blood/CSF/other sterile site)
- Gram stain CSF
- Cultures from invasive cases to MDU for serogroup and susceptibility.
What is the incubation period for IMD?
Average 3-4 days
(range 1-10 days)
What is the infectious period for IMD?
Whilst organisms present in nose/throat discharge.
Generally not infectious after 24 hours of appropriate antibiotics
What is the definition of an organisational IMD outbreak?
≥2 cases in 4 weeks of same strain in a CCC/school/uni.
What is the definition of a community IMD outbreak?
≥3 cases with no epi link within 3 months in same area with attack rate of at least 10 per 100,000
What is the disease status of IMD in Australia?
Endemic.
Low incidence, seasonal outbreaks (winter, spring).
Which is the most dominant strain of IMD in Australia?
MenB has become dominant since MenACWY introduced via NIP.
How is IMD prevented?
Vaccination.
What is the NIP vaccination schedule for IMD?
MenACWY (Nimenrix) - 12mo and 14-16 years
MenB (Bexsero) - First Nations infants 2, 4, 12 months
Both vaccines - asplenia/hyposplenia/complement deficiency or on eculizumab
In what other scenarios is IMD vaccination recommended?
- MenB for all children and adolescents (not on NIP)
- MenACWY - overseas travel to high-risk countries
- Both - adolescents/young adults living in “close quarters” or who are smokers
Need to check this slide.
What is the aim of the public health response to IMD?
Prevent transmission of potentially more virulent strain.
How are cases of IMD managed?
- Call clinician - suspicion level, illness, exposures
- Interview case / NOK - Sx, vax, RF, Ex 1-7d prior to sx, contacts
- Respiratory isolation for 24hr post ABx
SRVECT - for case interview: Sx, Rx, Vx, Ex, Cx, Tx
Symptoms, Risk factors, Vaccinations, Exposures, Contacts, Travel hx
What is the definition of an IMD contact?
Contacts are those exposed to a case 7 days prior to symptom onset:
- HH/HH-like
- Intimate kissing/sexual
- CC with specific amount of exposure
- Flight passengers immediately adjacent >8hrs
- HCW unprotected exposure to airway
How are contacts for IMD managed?
- Education
- Clearance ABx (cipro/rif/ceftriaxone)
- Vaccination if Men A/C/W/Y; MenB only if 2 cases in HH.
Should cases of IMD be excluded?
Yes from school / CC / work until 24 hours after ABx.
Should contacts of IMD be excluded?
Depends on if receiving clearance ABx or not.
- Clearance Abx - no exclusion/restriction
- VIC only: if no clearance Abx - exclude from primary school/childcare for 7 days from exposure
SoNG says isolation and restriction of contacts is not required.
What is the environmental management of IMD?
Nil routine.
Disinfection of articles with nose/throat discharge.
Why do IMD outbreaks create community concern?
- Cases often reported in media
- Significant community anxiety - disease severity, affects children
When was a recent outbreak of IMD that created community concern?
Splendour in the Grass 2022 - 3 cases and 1 death.
