Welcome to the Invasive Meningococcal Outbreak toolbox

Key reference documents

Meningococcus: Surveillance standards for vaccine-preventable diseases (Geneva: World Health Organization; 2018).
Meningococcal meningitis (Brazzaville: WHO Regional Office for Africa).
Meningitis information page (Geneva: World Health Organization).
Meningitis fact sheet (Geneva: World Health Organization; 2021).

Suspected case

any person with sudden onset of fever (>38.5°C rectal or 38.0°C axillary), neck stiffness, OR other meningeal signs (including bulging fontanelle in infants).

Probable case

macroscopic aspect of cerebrospinal fluid (CSF) turbid, cloudy or purulent; or
a CSF leukocyte count >10 cells/mm3; or
bacteria identified by Gram stain in CSF; or
positive Neisseria meningitidis antigen detection (e.g. by latex agglutination testing).

Confirmed case

any suspected case that is laboratory confirmed by culture or polymerase chain reaction (PCR) detection of Neisseria meningitidis in the CSF or blood.

Excluded case

Suspected IMD case

Probable IMD case

any person with clinical diagnosis of meningitis or septicaemia AND at least one of the following:
- purpuric rash where IMD is considered the most likely cause (linked to confirmed cases with other causes of haemorrhagic rash excluded or considered less likely); or
- gram-negative diplococci identified from normally sterile site1 or from a purpuric skin lesion; or
- positive Neisseria meningitidis antigen detection (e.g., by latex agglutination testing) from any normally sterile site1 or purpuric skin lesion.

Confirmed IMD case

Neisseria meningitidis is identified via culture or PCR from a purpuric skin lesion or any normally sterile site¹.

any person:
- living in the same household or who has an equivalent level of contact; or
- in the same childcare or pre-school setting; or
- sitting next to IMD case on a long flight (travel contact); or
- directly exposed to respiratory or oral secretions of a case in the seven days before disease onset.

_{1. A normally sterile fluid is defined as blood, cerebrospinal fluid, joint fluid or other sterile site.}

Case investigation form: PDF | Word
Line list:
- Annex 6: WHO generic line list for reporting from health facility to district (during outbreak) Standard operating procedures for surveillance of meningitis, preparedness and response to epidemics in Africa: Merged standard operating procedures (Geneva: World Health Organization; 2018) Page 48-49.
- Annex 7: Standardized excel data collection tool for enhanced surveillance of Meningitis Standard operating procedures for surveillance of meningitis, preparedness and response to epidemics in Africa: Merged standard operating procedures (Geneva: World Health Organization; 2018) Page 50.
Electronic tools: Not available.