Exposure Response Plan for the Laboratory Handling Neisseria meningitidis
Humans are the only reservoir and host of N. meningitidis, a gram negative coccus. N. meningitidis is responsible for considerable morbidity and mortality throughout the world. The most serious sequelae of infection are meningitis and septicemia. Healthy humans harbor bacteria in the intact upper respiratory tract. Sources disagree on the percentage of persons who are carriers. The widest range is 5-30%. Strains are based on capsular variation; carriers tend to harbor nonencapsulated strains. Carrier rates appear higher during epidemics and when people are living in military and college housing.
Infections occur when organisms penetrate the respiratory mucosa and enter the circulatory system. Known virulence factors include encapsulation by an antiphagocytic polysaccharide capsule and release of lipooligosaccharide. Infections range from subclinical to fatal. Current research includes developing a vaccine for serotype B, improved drug treatment and more in depth understanding of virulence factors.
Although infectious dose is unknown, Swain and Martin noted that coughing and sneezing deliver between 10-1000 c.f.u/cm3. Natural transmission is person-to-person through mucous membrane contact with respiratory droplets or oral secretions. Swain and Martin found that glass fomites and group B strains correlated with survival outside a host. At least 17 cases of lab acquired infections have been identified with approximately 50% case fatality. About 60% were due to serotype B and 40% due to serotype C.
Reporting Exposure Incidents:
Report all exposures to the Principal Investigator or lab supervisor and seek immediate medical evaluation as this is a significant occupational hazard. Bacterial meningitis can be effectively treated with antibiotics when treatment is started as soon as possible. A researcher infected in 2012 died 17 hours after his symptoms first appeared. If help is needed with injuries or clean up, members of the University will contact the police at 6-6911 and members of the Medical Center will contact security at 6-5100.
Pre-exposure Health Screening: Prior to beginning work with or around N. meningitidis, the PI or an Employee Health Professional will inform each person of the risks s/he takes and of the symptoms s/he may experience following exposure. All persons working with this agent must be screened by Occupational Health.
Before an Exposure Incident Occurs: FDA licensed vaccines are available. US vaccines are quadrivalent targeting serogroups A, C, W-135 and Y. The vaccines are not 100% effective and are licensed for specific
age groups. A licensed vaccine against serotype B is not available. Persons at higher risk of disease include:
- Those without a spleen
- Those whose spleen has been effected by sickle cell disease
- Those with acquired or inherited terminal complement component deficiencies (e.g. autoimmune disorders)
- Those exposed to first or second hand smoke
Participate in a risk assessment discussion during your Occ Health visit.
After an Exposure Incident Occurs: Immediate Action by Route of Exposure:
Inhalation: If contaminated materials are aerosolized outside of primary containment and potentially inhaled, rinse mouth twice expelling the rinsate. Do not swallow. Evacuate area. Exposure due to droplets or aerosols is correlated with lab and naturally acquired infections.
Mucous membranes (eye, nose, mouth): If contaminated material is splashed or sprayed contaminating the eyes, nose or mouth: Flush the eyes for 10-15 minutes. Rinse mouth out with clean water and do not swallow.
Needlestick, Animal Bite or Laceration: Wash the area with soap and running water.
After an Exposure Incident Occurs: Medical Evaluation and Follow-up:
Following immediate post exposure actions, contact the TMC Employee Health Clinic (Boston), TCSVM Occupational Medical Clinic (Grafton) or the Mt. Auburn Occupational Health Services (Medford) and arrange for medical evaluation, diagnosis and treatment. Meningoccoccal disease is potentially fatal despite prompt antibiotic treatment. Exposure should be viewed as a medical emergency.
During this appointment, the exposed individual will be informed of the signs and symptoms of N. meningitidis, and will be instructed to watch for the development of meningitis and septicemia. Blood and/or CSF may be collected. Depending upon the signs and symptoms, hospitalization is a possibility. The incubation period is generally 2-10 days with an average of 2-4. From exposure to rash onset averages 14 days.
Signs and Symptoms:
- Severe headache
- High fever
- Neck stiffness and pain
- Sensitivity to light (photophobia)
Signs & Symptoms for Meningococcemia (septicemia)
- High fever
- Blood flow problems resulting in dark red or purple splotches all over (DIC – disseminated intravascular coagulation)
- Septic shock (multiorgan dysfunction)
Complications upon recovery:
- Limb loss
- Brain damage
Immediate hospitalization may be needed. Chemoprophylaxis may be indicated for close contacts (generally not workplace) of those with meningococcal disease.
Suspected and/or confirmed disease must be reported immediately to the Massachusetts Department of Public Health by telephone. A graduate student in Boston recovered from a lab acquired meningococcemia in 2009.
If an employee develops signs and symptoms associated with N. meningitidis in the absence of an exposure incident, the PI and Biosafety Officer shall be notified immediately. In the absence of relevant information, the infection will be considered laboratory-acquired.
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