biosafety level(redirected from biosafety level 4)
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Related to biosafety level 4: biosafety level 2
biosafety level(1) The degree of caution required when working with specific groups of pathogens
(2) A specific combination of work practices, safety equipment, and facilities, intended to minimise exposure of workers and environment to certain classes of pathogens.
BL 1—Organisms are relatively innocuous and are not known to cause infection in healthy human adult—e.g., Bacillus subtilis and Naegleria gruberi.
BL 21—Organisms are “moderate risk” agents that may cause human disease of varying severity, potentially affecting healthy adults; often good microbiologic technique, such as minimising exposure to aerosols, is a sufficient precaution for these agents—e.g., C difficile, hepatitis A, B and C, influenza A, Lyme disease, dengue fever, Salmonella; mumps, measles, HIV, scrapie, MRSA and VRSA.
BL 32—Organisms are indigenous or exotic and may infect personnel by aerosols, autoinoculation or ingestion, resulting in potentially serious or lethal consequences—e.g., Mycobacterium tuberculosis, Bacillus anthracis, West Nile virus, Venezuelan equine encephalitis virus, Eastern equine encephalitis virus, Hendra virus, SARS coronavirus, Salmonella typhi, Coxiella burnetii, Rift Valley fever virus, Rickettsia rickettsii and yellow fever virus.
BL 4—Organisms are dangerous and exotic, require a maximum containment facility and pose a high individual risk of exposure and risk to laboratory personnel—e.g., Bolivian and Argentine hemorrhagic fevers, Marburg virus, Ebola virus, Lassa fever, Crimean-Congo hemorrhagic fever and other various hemorrhagic diseases. BSL 4 agents may be transmitted by aerosol; there is no vaccine or therapy.
biosafety levelEpidemiology A classification for the degree of caution required when working with specific groups of pathogens. See Maximum containment facility.
A classification system to indicate the safety precautions required when investigating microorganisms, esp. viruses known to be dangerous or lethal to those exposed to them. There are four BSLs, with BSL-4 requiring the highest level of security.