Guidelines for the Prevention and Control
of Meningococcal Disease
6.0 Surveillance of Invasive Meningococcal Disease in
Canada
IMD is reportable in all provinces and territories and is
nationally notifiable. Each province or territory has procedures in
place for the rapid notification of cases to medical officers of
health and timely reporting to the appropriate provincial or
territorial public health official.
Both confirmed and probable cases of IMD are notifiable at the
national level. Provinces and territories report case-by-case data
with basic core variables on a weekly basis to the Notifiable
Diseases Reporting System. In addition, the Immunization and
Respiratory Infections Division (IRID), Centre for Infectious
Disease Prevention and Control, Public Health Agency of Canada,
conducts enhanced surveillance for IMD. Provinces and territories
report more detailed epidemiologic and laboratory data for each
case to the IRID. Detailed surveillance reports are published
periodically in the CCDR; the most recent report was
published in February 2004(2).
Most jurisdictions rely on passive surveillance for
identification of cases. When an increase in the incidence of IMD
is suspected in a particular region, there should be heightened
surveillance for cases and the collection of more detailed
epidemiologic and microbiologic information.
The following steps should be taken:
- The provincial or territorial epidemiologist or medical health
officer should be consulted immediately to decide whether the
increased incidence constitutes an outbreak.
- Active surveillance should be initiated. Epidemiologic
information should be obtained on each case, with the objective of
identifying high-risk groups and determining associations that will
permit targeted control interventions. The data collected should
include age; sex; place of residence; vaccination status, including
the type of meningococcal vaccine, the number of doses and age at
vaccine administration; recent travel; attendance or employment at
a day care centre or school; and participation in recent athletic
or recreational events and gatherings. Other information relevant
to the outbreak should also be collected (e.g. social or cultural
setting).
- Basic epidemiologic analysis should include age-group-specific
attack rates (calculated for 5-year age groups), serogroup-specific
rates and case fatality ratios. Techniques such as historical
modeling can be used to determine whether the current incidence is
greater than in previous years; this is particularly important in
light of the seasonality of the disease.
- The province or territory should notify the IRID of the
increase in IMD incidence, and the IRID will relay the information
to the other provinces and territories.
- When an outbreak is suspected, serogroup determination becomes
critical for appropriate decisions regarding control measures.
Provincial and territorial public health laboratories, in
collaboration with the NML, may conduct typing, subtyping and other
genotyping tests (e.g. PFGE) that have proven helpful in
characterizing outbreaks and determining disease trends.
- During outbreaks or whenever there is failure to isolate or
determine the serogroup of an organism, clinical specimens should
immediately be forwarded by the provincial laboratory to the NML,
Public Health Agency of Canada, for molecular diagnostic testing
and further strain identification.
At this time conjunctivitis and pneumonia cases due to N.
meningitidis are not nationally notifiable and reported to the
Public Health Agency of Canada. However the following definitions
and suggested treatments have been made. A conjunctivitis case
requires isolation of N. meningitidis from the eye or the
conjunctival sac in association with purulent conjunctivitis. A
pneumonia case is one with a Gram strain (if done) showing
Gram-negative diplococci and a polymorphonuclear cell response from
sputum or respiratory aspirate, isolation with heavy growth of N. meningitidis and clinical or radiological evidence of
pneumonia. Patients with N. meningitidis conjunctivitis or
pneumonia should be treated with appropriate systemic
antibiotics(28).
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