For the purpose of this Directive:
'biological agents' shall mean micro-organisms, including those which have been genetically modified, cell cultures and human endoparasites, which may be able to provoke any infection, allergy or toxicity;
'micro-organism' shall mean a microbiological entity, cellular or non-cellular, capable of replication or of transferring genetic material;
'cell culture' shall mean the in-vitro growth of cells derived from multicellular organisms.
'Biological agents' shall be classified into four risk groups, according to their level of risk of infection:
group 1 biological agent means one that is unlikely to cause human disease:
group 2 biological agent means one that can cause human disease and might be a hazard to workers; it is unlikely to spread to the community; there is usually effective prophylaxis or treatment available;
group 3 biological agent means one that can cause severe human disease and present a serious hazard to workers; it may present a risk of spreading to the community, but there is usually effective prophylaxis or treatment available;
group 4 biological agent means one that causes severe human disease and is a serious hazard to workers; it may present a high risk of spreading to the community; there is usually no effective prophylaxis or treatment available.