ABC of Safety in the Biological Sciences




Micro­organisms and viruses are classified into four groups according to the level of hazard they present and the minimal safety conditions for handling them.

Category A includes organisms, viruses and materials that are extremely hazardous to laboratory workers and which may cause serious epidemic disease. These are not normally encountered in routine clinical laboratories but if so they require the most stringent of containment measures.

The human pathogens currently listed as Category A are:

  • Simian herpes (BO) virus
  • Lassa Fever virus
  • Marburg virus
  • Rabies virus
  • Smallpox virus
  • Crimea (Congo) Haemorrhagic fever (HF) virus
  • Machupo (HF) virus
  • Junin (HF) virus
  • Venezuelan equine encephalitis virus
  • Ebola virus

If specimens received in the laboratory are suspected of containing any of the above, or are subsequently shown to contain any of the above, then they must be removed to a quarantine area designed for handling highly infectious material. Under no circumstances should material containing any of the above be handled in a routine laboratory.

Department of Health and Social Security (1980)
Code of Practice for Prevention of Infection in Clinical Laboratories and P.M. Rooms.
H.M. Stationery Office, London, England.

Miller, B.M. et al. (1986)
Laboratory Safety: Principles and Practices.
American Society for Microbiology, Washington DC, U.S.A.



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