Individuals who have or may have IMD shall be reported to the local Health Unit.
Neisseria meningitidis, (meningococcus) is a Gram-negative diplococcus bacterium with multiple serogroups; serogroups A, B, C, Y, and W-135 are most commonly known to cause invasive disease.
Clinical illness usually manifests as meningitis, meningococcemia or both. Less common presentations are pneumonia with bacteremia, septic arthritis and pericarditis.
Meningococcal meningitis presents as sudden onset of fever, headache, stiff neck, nausea and often vomiting, photophobia, and an altered mental state. In infants, clinical findings include fever, irritability, difficulty waking, difficulty feeding, vomiting, stiff neck, and bulging fontanelle.
Meningococcemia (meningococcal sepsis or bloodstream infection) is the most severe form of infection characterized by sudden onset of fever, chills, malaise, myalgia, limb pain, prostration, and a macular, maculopapular, petechial, or purpuric rash.
Modes of Transmission
Person-to-person by respiratory droplets or direct contact with secretions of the nose and throat, and often with an asymptomatic carrier. Direct contact includes activities such as kissing or sharing drinking bottles.
Variable; 2–10 days, commonly 3–4 days.
Period of Communicability
Usually 7 days prior to onset of symptoms to 24 hours after the initiation of appropriate antibiotic therapy. A person who is untreated or a carrier can spread the bacteria until meningococci are no longer present in discharge from the nose and mouth.
Susceptibility decreases with age; incidences are highest in infants, adolescence and young adults. There is an increased risk of secondary infections in close contacts of cases, particularly in household contacts.
Other risk factors include:
- Communal residency
- Inhalation/injection drug use
- Receipt of cochlear implant
- Recent upper respiratory tract infection (<2 weeks)
Diagnosis and Laboratory Testing
Isolation of Neisseria meningitidis from a normally sterile site (blood, cerebrospinal fluid, joint, pleural or pericardial fluid). The following will constitute a confirmed case:
- Positive culture
- Positive NAAT for N. meningitidis
Treatment and Case Management
Treatment with antibiotics and follow up is under the direction of the attending health care provider. To ensure eradication of N. meningitidis nasopharyngeal carriage, cases who did not receive treatment using ceftriaxone or other third-generation cephalosporins should also receive chemoprophylactic antibiotics prior to discharge from hospital. Chemoprophylaxis using rifampin, ciprofloxacin, or ceftriaxone is between 90–95% effective in decreasing nasopharyngeal carriage.
Hospitalized persons should be placed on droplet precautions for 24 hours after initiation of antibiotic therapy.
Close contacts of an IMD case will be followed by Public Health staff to determine eligibility for chemoprophylaxis. If eligible, this should be given within 24 hours of the case being identified. Household contacts are at particularly high risk of secondary transmission. All identified contacts should be alerted to signs and symptoms of IMD and advised to seek medical attention immediately should they develop a fever or other symptoms of IMD. See Recommended chemoprophylaxis for Invasive Meningococcal Disease, page 7, MOHLTC.
Chemoprophylaxis is not recommended for casual contacts such as school, work or transportation contacts, social contacts, persons without direct contact with the case, and HCWs without direct exposure to a case’s nasal/oral secretions. In addition to chemoprophylaxis, close contacts having ongoing exposure to a case should also receive immunization with a serogroup-specific meningococcal vaccine where indicated (i.e. if the case is caused by a vaccine-preventable serogroup).