Neisseria meningitidis

About

Neisseria meningitidis is a bacterium hosted only by humans and is a leading cause of bacterial meningitis in the United States. This pathogen may also cause overwhelming sepsis, purpura fulminans, or (rarely) benign meningococcemia.

Meningitis (inflammation of the membranes surrounding the brain and spinal cord) is a common form of meningococcal disease and is characterized by fever, severe headache, and stiff neck. Patients with meningococcal sepsis (severe illness caused by bacteria or their toxins in the blood) may present with high fever, hypotension (low blood pressure), and profound weakness. In either case, patients may develop a characteristic rash including petechiae (pinpoint red spots that do not blanch with pressure) or purpura (purple areas similar to bruises) that are caused by bleeding into the skin. Purpura fulminans (hemorrhagic condition resulting in tissue necrosis and small vessel thrombosis) can result in scarring or limb amputations. Approximately 10-14% of cases of meningococcal disease are fatal. Of patients who recover, 11-19% have permanent hearing loss, mental retardation, loss of limbs or other severe sequelae.

Five serotypes of meningococcal bacteria cause most disease worldwide: serotypes circulating in the U.S. are likely to be B, C, or Y. Serotypes A and W-135 meningococci are potential risks for travelers.

Meningococci are spread through respiratory droplets, normally requiring close and prolonged exposure or direct contact with saliva and respiratory secretions. Spread can occur from an asymptomatic carrier or from a patient who is ill.

Risks for meningococcal disease include age, exposure to meningococcal bacteria, crowding, smoking, and specific immune defects. Risk groups for meningococcal disease include household contacts of case patients, military recruits, college freshmen living in dormitories, microbiologists who work with Neisseria meningitides isolates, patients without a functional spleen or with terminal complement component deficiencies (a specific immune defect), and people exposed to tobacco smoke, including passive smoking.

Prevention

General
Meningococcal disease prevention advice includes maintaining good overall health, avoiding first and second-hand tobacco smoke, using cough etiquette, and minimizing shared saliva.

Vaccination
The Advisory Committee on Immunization Practices (ACIP) recommends routine vaccination of all persons aged 11 to 18 years with 1 dose of Meningococcal conjugate vaccine (MCV4 or Menactra®) at the earliest opportunity, because the incidence of meningococcal disease increases during adolescence. Other persons at risk for meningococcal disease should also be vaccinated; for a detailed schedule of vaccination recommendations, refer to recommendations published by the Advisory Committee on Immunization Practices (ACIP) or consult the Georgia Immunization Program.

Currently (2009), there are two vaccines against N. meningitidis available in the U.S. Meningococcal polysaccharide vaccine (MPSV4 or Menomune®) has been available since 1981 for persons aged at least 2 years. MCV4 (Menactra®) was licensed in 2005, and is available for ages 11 to 55 years. Both vaccines are designed to prevent serogroups A, C, Y, and W-135 meningococcal disease, but are lacking serogroup B antigen. Serogroup B meningococcal disease is not vaccine preventable in the U.S. at this time. MCV4 is generally preferred over MPSV4 because it is likely to trigger a more robust and long-term immune response.

Although large epidemics of meningococcal disease have not occurred in the United States for many years, some countries experience large, periodic epidemics. Overseas travelers should check to see if meningococcal vaccine is recommended for their destination. Travelers should receive the vaccine at least 1 week before departure, if possible. Information on areas for which meningococcal vaccine is recommended can be obtained by calling the Centers for Disease Control and Prevention at 800-CDC-INFO (800-232-4636).

Prophylaxis
Antibiotic prophylaxis is recommended for certain close contacts exposed to a meningococcal disease case, in order to prevent secondary cases. Close contacts include household members, child-care center contacts, and persons directly exposed to the patient's oral secretions (e.g. by kissing, mouth-to-mouth resuscitation, endotracheal intubation, or endotracheal tube management). Because transmission requires close contact, persons who share only a workspace or classroom are not at increased risk.

Resources & Procedures for District Epidemiologists

All district epidemiologists are encouraged to utilize the following resources in the investigation of bacterial meningitis in the state of Georgia:

Bacterial Meningitis & Sepsis Investigation & Control Manual : This manual includes worksheets to aid in case investigation, disease prevention, and obtaining contact exposure information.

Neisseria meningitidis is under statewide active surveillance through the Emerging Infections Program (EIP) and a case report form is required for each case. This form may be completed by district epidemiologists or by EIP personnel.

Isolates
All hospitals and labs are encouraged to promptly submit* isolates of Neisseria meningitidis to:

Georgia Public Health Laboratory
Bacteriology Unit
1749 Clairmont Road
Decatur, GA 30033

The following form is to be used when submitting isolates:

Bacteriology Submission Form