Biological agents have a ubiquitous presence in the environment and are found in many sectors. As they are rarely visible, the risks they pose are not always appreciated, but exposure may lead to include acute and chronic, sometimes life-threatening, diseases with serious socio-economic consequences. Health effects include infections, zoonotic diseases, symptoms of the upper and lower respiratory tract, occupational asthma, sensitisation, allergic reactions, systemic (multi-organ) effects, poisoning and cancers