Book 4: General biohazards - an introducton

Biosafety is concerned with the containment methods required when managing parasites, infectious agents and infected or potentially infected animals, tissues or other materials, as well as radiation. Biological fluids such as blood, and even cell lines (particularly primary cell cultures), may harbour a variety of pathogenic organisms, such as HIV, hepatitis viruses or prions, and thus are a biohazard risk.

The purpose of biosafety is to reduce exposure of persons, animals and the outside environment to potentially hazardous agents. Unnecessary or avoidable exposure to such hazards is ethically unacceptable. Organisms have traditionally been classified according to their characteristics, such as pathogenicity, infectious dose required for disease, mode of transmission, hosts and availability of preventive measures and treatment. Although organisms have been classified according to risk groups in the past, it is arguably more appropriate to consider the handling and containment requirements, as outlined below.

Samples obtained, whether of prokaryotic origin or from human or animal subjects, must be obtained with the consent of the agency or subject, and the material is subject to the ethical and other considerations of the provider. Care must be exercised to prevent the importation of potentially biohazardous materials into a facility currently not involved with that material.

The Directorate: Genetic Resources of the National Department of Agriculture, Private Bag X973, Pretoria, 0001, must be consulted about pilot experiments, trials or the release into the environment of genetically modified organisms in South Africa, except where this involves only basic research in a contained environment.

Reasonable precautions must be taken with any work involving biological material or radiation. The difficulty lies in defining reasonable or absolute requirements. It is unlikely that we will be able to ensure a situation of no risk, as there may be unknown agents or effects still to be defined. It should be noted that the risk to, or exposure of, laboratory workers or researchers is often less than in the case of health care workers such as nurses or clinicians, who have regular and frequent contact with patients or body fluids harbouring a variety of infectious agents. In all cases however, one attempts to minimise exposure and risk.

The recommendations that follow apply essentially to immunocompetent individuals. Immunocompromised individuals are at increased risk and should be advised to avoid additional risk. Persons who believe they may be immunocompromised should inform their supervisory authority, and their case should be carefully considered before exposure occurs. In any deliberation, perhaps the most important safety consideration is 'distance'. Distance is not simply geographical location, but implies barriers, whether these are full-body protective clothing for avoidance of pathogenic organisms, or lead screens to confine radiation exposure.

In a broad context, work should not contravene other general ethical considerations, such as those approved in the MRC Guidelines on Ethics for Medical Research, the Declaration of Helsinki, the Cartagena Protocol on Biosafety or the Convention on Biological Diversity.

Detailed laboratory biosafety guidelines are beyond the scope of this document, but are available in publications dealing with various pathogens or from the Internet, such as the Canadian Guidelines.