Meningococcal Meningitis

By Alison Cabral

Disease Name: Meningococcal meningitis

• An infection of the cerebrospinal fluid and the meninges, the tissue that covers the brain and spinal cord (1, 2).
• Risk of dying from infection, even with treatment, is 10-15% (3).
• An estimated 3,000 cases occur per year in the United States (4).
• Incidence of the disease is highest among children three to twelve months (4).

Etiologic Agent: Neisseria meningitidis (also referred to as meningococcus) (5)

• General Characteristics
  • Gram-negative diplococci bacteria; aerobic; oxidative metabolism; fastidious (5).
  • Several serogroups are recognized to cause the disease (A, B, C, 29E, W-135, and Y, based on capsular polysaccharides) (5).
  • From 1995-1998 in the United States, serogroup Y was responsible for 34% of cases; serogroup B, 33%, and serogroup C, 28% (14).
• Key Tests for Identification
  • Bacteria can be cultured after extraction via spinal tap (1) and Gram stain can be performed (7). Spinal tap should not be performed if there is a lesion in the nervous system (8).
  • May be cultured on Thayer-Martin agar with incubation at 10% CO2 (5).
  • Oxidase positive (5).
  • Serologic latex agglutination tests for antigens (8)
• Historical Information &endash; Albrecht and Gohn, 1901; Murray, 1929 (9).

Usual Reservoirs:

• Humans only, in the nasopharynx. The bacteria do not survive outside the human host (10).
• At any given time, three to thirty percent of the population may be in a normal carrier or colonization state, which can last days to months (5).
• In carriers, anti-capsular antibodies may be produced, and acquired immunity develops (5, 7).

Means of Transmission:

• Direct contact of respiratory and throat secretions, such as coughing (airborne droplets), kissing, and sharing unwashed eating utensils (1,2).
• "Close and prolonged contact" is required for transmission (7). Incubation of the disease is between two to ten days, typically three to four days (10)
• If a person is in the early stages of colonization, the risk of developing the disease is greatest because the body has not had enough time to produce specific antibodies (11)
• Once in a person's respiratory tract, the bacteria are spread to the meninges "hemotogenously" (through the blood) (7). In the blood, prior to reaching the meninges, the disease is meningigoccemia (11).
• Infection can also occur by CSF contact with the exterior or as an extension of nearby infections (8).

Signs and Symptoms:

• High fever, headache, stiff neck, nausea, vomiting, chills, confusion, sleepiness, seizures, shock, and coma in persons over two years of age (1, 2, 7).
• Some of the above symptoms may be hard to detect in babies &endash; slowness, inactivity, and poor feeding may indicate the disease (1).
• Sepsis and petechial rash may be indicative of the disease (3,12).
• Those with symptoms should go or be taken to the doctor immediately (1).
• Can result in brain damage, deafness, learning disability, amputations, or death (1, 2).

Microbial Virulence Mechanisms Contributing to Disease Process:

• Antiphagocytic capsule, lipo-oligosaccharide endotoxin, pili, IgA protease (7)
• CSF has low levels of antibodies, white blood cells, and complement. Due to this, the disease can flourish in the body (8).

Control:

• This disease can be very deadly - if left untreated, the mortality rate is approximately 85% (5).
• Contact with infected persons should be avoided. (5).
• Vaccination is not recommended for most people (13).
• Vaccinations can be used for populations in which an epidemic is present (8).
• Who should be vaccinated:
  • Members of the military
  • Travelers to or residents of West Africa
  • Individuals who might be infected during an outbreak
  • Individuals without spleens (or a damaged spleen)
  • Anyone with a terminal complement component disorder (13)
• College students living in dormitories may consider vaccination, due to close living quarters (13).

Treatment:

• Antibiotic treatment (chemoprophylaxis) should begin immediately, even prior to official diagnosis, due to the disease's swiftness (8).
• Patient should be isolated for 24 hours in the hospital (8).
• Antibiotics - Penicillin G, cephalosporins (ceftriaxone and cefuroxime), cefotaxime, doxycycline (7). Treatment with antibiotics should last for at least one week after body temperature goes back to normal (8).
• Corticosteroids can be used to reduce inflammation (8).
• People in contact with the infected person should be put on antibiotics, such as rifampin, for two days (2).

Prevention:

• Vaccines exist for serogroups A, C, Y, and W-135, but not for serogroup B.
• The killed vaccines are "chemically defined antigens consisting of purified bacterial capsular polysaccharides."
• Serogroup A vaccine is not effective in infants younger than three months; Serogroup C vaccine is not effective in those younger than two years.
• Bad reactions to vaccines are "infrequent and mild."
• Travelers to sub-Saharan Africa are advised to receive vaccination.
• Vaccination is not required for entry into any country, except for Mecca, Saudi Arabia during the annual Hajj (12).

References:

1. Center for Disease Control and Prevention. "Meningococcal Disease: General Information." June 20, 2001. URL: http://www.cdc.gov/ncidod/dbmd/ diseaseinfo/meningococcal_g.htm accessed on April 23, 2002.

2. Texas Department of Health. "Facts about Meningococcal Meningitis." January 2001. URL: http://www.tdh.state.tx.us/ideas/factsht/mengitis.htm accessed on April 23, 2002.

3. Center for Disease Control and Prevention. "Meningococcal Disease: Technical Information." March 9, 2001. URL: http://www.cdc.gov/ncidod/dbmd/ diseaseinfo/meningococcal_t.htm accessed on April 23, 2002.

4. Pickering, Larry K. and William J. Martone. "What is Meningococcal Disease?" May 18, 2000. URL: http://www.nfid.org/library/meningococcal/fs_what_is.html accessed on April 30, 2002.

5. Fix, Douglas F. "Neisseria." 2002. URL:http://www.cehs.siu.edu/fix/medmicro/ neiss.htm accessed on April 30, 2002.

6. Pickering, Larry K. and William J. Martone. "Preventing Meningococcal Disease." May 18, 2000. URL: http://www.nfid.org/library/meningococcal/fs_prevent.html accessed on April 30, 2002.

7. Duckworth, Donna. "'BUGS' Index - Neisseria meningitidis." May 12,1999. URL: http://www.medinfo.ufl.edu/year2/mmid/bms5300/bugs/neimeni.html accessed on April 23, 2002.

8. The Merck Manual of Diagnosis and Therapy. "Acute Bacterial Meningitis." 2002. URL: http://www.merck.com/pubs/mmanual/section14/chapter176/176b.htm accessed on April 25, 2002.

9. Euzeby, J.P. "List of Bacterial names with Standing in Nomenclature &endash; Genus Neisseria." 2002. URL: http://www.bacterio.cict.fr/n/neisseria.html accessed on April 30, 2002.

10. Health Canada. "Material Safety Data Sheets (MSDS) &endash; Neisseria meningitidis." March 2001. URL: http://www.hc-sc.gc.ca/pphb-dgspsp/msds-ftss/msds109e.html accessed on April 30, 2002.

11. Pickering, Larry K. and William J. Martone. "What You Should Know." May 18, 2000. URL: http://www.nfid.org/library/meningococcal/fs_should_know.html accessed on April 30, 2002.

12. Center for Disease Control and Prevention. "Travelers' Health Information on Meningococcal Disease." February 25, 2002. URL:http://www.cdc.gov/travel/ diseases/menin.htm accessed on April 30, 2002.

13. National Immunization Program. "Mennigococcal Vaccine: What You Need to Know." March 31, 2000. URL: http://www.immunize.org/vis/menin00.pdf accessed on April 30, 2002.

14. Pickering, Larry K. and William J. Martone. "The Meningococcal Bacterium." May 18, 2000. URL: http://www.nfid.org/library/meningococcal/fs_bacterium.html accessed on April 30, 2002.