Meningococcal Infection

Table of Contents

Disease Information

Invasive meningococcal infections are caused by the bacterium Neisseria meningitidis (meningococcus), a gram-negative diplococcus.

Overview

Report Immediately by Phone

Also known as: Spinal or bacterial Meningitis, Meningococcemia

Responsibilities

  • Hospital/Infection Preventionist: Report by phone immediately
  • Lab: Report by phone immediately; send all isolates from invasive sites to SHL for testing and serogrouping
  • Physician: Report by phone immediately
  • Local Public Health Agency (LPHA): Follow-up required

Iowa Department of Public Health
Disease Reporting Hotline: (800) 362-2736
Secure Fax: (515) 281-5698

A. Agent

Invasive meningococcal infections are caused by the bacterium Neisseria meningitidis (meningococcus), a gram-negative diplococcus. There are 13 serogroups of N. meningitidis; nine of these serogroups are known to cause invasive disease (A, B, C1+, C1-, L, X, Y, W-135, and Z) in humans.

Note: Other organisms, including several viruses, can cause meningitis. This chapter is only referring to meningitis caused by N. meningitidis.

B. Clinical Description

Symptoms: Invasive infection with N. meningitidis may cause several clinical syndromes, including meningitis, bacteremia, sepsis or pneumonia. Symptoms of meningitis (infection of the meninges, the membrane covering the brain and spinal cord) typically include the sudden onset of a stiff neck, high fever and headache. A petechial rash (small red pinpoints that do not blanch when compressed) may also be present. Nausea, vomiting and mental confusion are often also present. Meningococcemia (infection of the blood) typically presents with the abrupt onset of fever, chills, malaise, prostration and rash (urticarial, maculopapular, purpuric or petechial).

Onset is usually abrupt.

Complications: Fulminant cases who present with purpura (large areas of subdermal bleeds), disseminated intravascular coagulation, shock, and/or coma and may lead to death within hours, despite appropriate therapy. The case-fatality rate for meningococcal meningitis and meningococcemia is about 5% - 15%, even with appropriate antibiotic treatment. Persons with certain complement deficiencies (blood disorders that cause immunosuppression) are more susceptible, as are persons without a spleen or a functioning spleen.

C. Reservoirs

Humans are the only known reservoir of N. meningitidis.  Approximately 5 to 10% of the population may carry this bacteria in the nasopharynx at any given time.

D. Modes of Transmission

The principal mode of transmission of N. meningitidis is person-to-person through direct contact with a case’s oral or nasal secretions. The bacteria may also be spread through droplets or via an inanimate vehicle contaminated with saliva (e.g., a cigarette, baby’s toy or water bottle).

E. Incubation period

The incubation period ranges from 2 - 10 days, with an average incubation period of 3 - 4 days.  Due to the asymptomatic carrier state, it is usually difficult to determine when exposure occurs.

F. Period of Communicability or Infectious period

Cases remain infectious as long as meningococci are present in oral secretions or until 24 hours after initiation of treatment with the appropriate antibiotic.  Most carriers do not easily spread the organism.

G. Epidemiology

Sporadic cases and occasional outbreaks of invasive meningococcal disease occur worldwide. A “meningitis belt” extends from sub-Saharan Africa into India/Nepal, and invasive meningococcal disease due to N. meningitidis serogroup A is considered endemic in these areas. Epidemics of meningococcal meningitis also occur in this meningitis belt every 8 - 12 years and last from 2 - 4 years. Seasonal variations occur in these epidemics.  Highest rates usually occur in dry, hot seasons, (December through June). The prevalent serotypes of N. meningitidis in other parts of the world may vary over time and by geography.

In the United States, the largest number of cases of invasive meningococcal disease usually occurs during the winter and early spring, coincident with an increase in the occurrence of acute respiratory infections. Historically in the U.S., cases of invasive meningococcal disease were most commonly seen in children <11 years old. Sporadic cases of meningococcal disease account for more than 98% of cases. Meningococcal pneumonia is more commonly seen in older patients. In the U.S., outbreaks of invasive meningococcal disease occur most frequently in crowded conditions (i.e., military bases, college dormitories). Cases of invasive meningococcal disease in the U.S. are most often caused by serogroups B, C and Y (each accounting for approximately 30% of reported cases), although other serogroups are also seen sporadically. Epidemics of invasive disease are most commonly associated with serogroups C and Y. Serogroup A is seen rarely in the U.S.

Since the 1990s, meningococcal diseases has been declining in the US, with 550 cases reported in 2013.  In 2011, Iowa reported 12 cases; 6 were group B, 4 were group Y, 2 were group W-135, and 2 were undetermined, whereas in 2013 only one case was reported, and it was serogroup C.

Meningococcal carriage: N. meningitidis typically colonizes the nose and throat of 5-10% of the general population at any given time. These carriers are generally asymptomatic, and carriage of the bacteria may act as an immunizing exposure. By young adulthood, the majority of people in the United States have measurable antibody to the pathogenic serogroups of N. meningitidis.  Carriers can spread the bacteria to others through saliva and respiratory secretions. Factors that increase colonization are antecedent upper respiratory tract infection, household crowding and both active and passive smoking.

H. Bioterrorism Potential

None.

I. Additional Information

The Council of State and Territorial Epidemiologists (CSTE) surveillance case definitions should not affect the investigation or reporting of a case that fulfills the criteria in this chapter. (CSTE case definitions are used by the state health department and the CDC to maintain uniform standards for national reporting.)

Fact Sheets and Forms

Comment

  • Positive antigen test results from urine or serum samples are unreliable for diagnosing meningococcal disease, but can be used to assist in diagnosis if a positive result is obtained.

References

American Academy of Pediatrics. 2015 Red Book: Report of the Committee on Infectious Diseases, 30th Edition. Illinois, American Academy of Pediatrics, 2015.

Heymann, D.L., ed. Control of Communicable Diseases Manual, 20th Edition. Washington, DC, American Public Health Association, 2015.

CDC, Laboratory-Acquired Meningococcal Disease – United States, 2000, MMWR, February 22, 2002; 51:7

Gardner, P., Prevention of Meningococcal Disease, The New England Journal of Medicine, October 5, 2006

Raghuanthan, P. L., Bernhardt, S. A., Rosenstein, N. E., Opportunities for control of meningococcal disease in the United States. Annu. Rev. Med. 2004. 55:333–53

Sejvar, James J., et al., Assessing the Risk of Laboratory-Acquired Meningococcal Disease, Journal of Clinical Microbiology, September 2005 4811-4814

Additional Resources

CDC. Epidemiology and Prevention of Vaccine-Preventable Diseases. (The Pink Book), 12th ed. Washington DC: Public Health Foundation, April, 2011.

National Foundation for Infectious Diseases, The Changing Epidemiology of Meningococcal Disease Among U.S. Children, Adolescents and Young Adults, November, 2004
CDC. Meningitis vaccination website.