Biological risks considered are: viruses, bacteria, parasites, protozoa, fungi and bacilli.

Biological risks occur through microorganisms that, in contact with man, can cause numerous diseases. Many professional activities favor contact with such risks. This is the case of the food industries, hospitals, public cleaning (garbage collection), laboratories, etc.

Among the many occupational diseases caused by microorganisms are: tuberculosis, brucellosis, malaria, yellow fever.

In order for these diseases to be considered occupational diseases, the employee must be exposed to these microorganisms.

Preventive measures are necessary so that the conditions of hygiene and safety in the various sectors of work are adequate.

The biological risks in laboratories can be related to the manipulation of:

• Wild pathogens;
• Attenuated pathogens;
• Pathogens that have undergone a recombination process;
• Biological samples;
• Cell cultures and manipulations (transfection, infection);
• Animals.

All of the items mentioned above can become a source of contamination for handlers. The main pathways involved in a biological contamination process are the coetaneous or percutaneous pathway (with or without injuries – by accident with needles and glassware, in animal experimentation – scratches and bites), the respiratory pathway (aerosols), the conjunctive pathway and the pathway oral.

There is a classification of wild pathogens that takes into account the risks to the handler, the community and the environment. These risks are assessed according to the pathogenic power of the infectious agent, its resistance in the environment, the mode of contamination, the importance of the contamination (dose), the immunity status of the handler and the possibility of effective preventive and curative treatment.

The existing classifications (WHO, EEC, CDC-NIH) are quite similar, dividing the agents into four classes:

Class 1 – where the agents that do not present risks to the handler or to the community (eg E. coli, B. subtilis) are classified;

Classes 2 – present a moderate risk for the handler and weak for the community and there is always a preventive treatment (eg: bacteria – Clostridium tetani, Klebsiella pneumoniae, Staphylococcus aureus; virus – EBV, herpes; fungi – Candida albicans; parasites – Plasmodium, Schistosoma);

Class 3 – are the agents that present a serious risk for the handler and moderate for the community, and the lesions or clinical signs are severe and there is not always treatment (eg: bacteria – Bacillus anthracis, Brucella, Chlamydia psittaci, Mycobacterium tuberculosis; viruses – hepatitis B and C, HTLV 1 and 2, HIV, yellow fever, dengue; fungi – Blastomyces dermatiolis, Histoplasma; parasites – Echinococcus, Leishmania, Toxoplasma gondii, Trypanosoma cruzi);

Class 4 – agents of this class present a serious risk to the handler and the community, there is no treatment and the risks in case of spread are very serious (eg, hemorrhagic fever virus).

Regarding genetic manipulations, there are no predetermined rules, but it is known that researchers were able to induce the production of antibodies against the simian immunodeficiency virus in monkeys that were inoculated with the proviral DNA inserted in a bacteriophage. Thus, it is important that general safety measures are adopted in the manipulation of recombinant DNA, especially when dealing with viral vectors (adenovirus, retrovirus, vaccinia). Bacterial plasmids present a lower risk than viral vectors, although it is important to consider the genes inserted in these vectors (especially when manipulating oncogenes).

In general, safety measures for biological risks involve:

Knowledge of the Brazilian Biosafety Legislation, especially the Biosafety Standards issued by the National Technical Biosafety Commission;

The knowledge of the risks by the handler;

The training and information of the people involved, especially with regard to the way in which this contamination can occur, which implies a broad knowledge of the microorganism or vector with which it works;

Respect for the General Safety Rules and also the implementation of individual protection measures;

Use of apron, disposable gloves (and / or hand washing before and after handling), mask and goggles (to avoid aerosols or projections in the eyes) and other necessary Personal Protective Equipment,

Use of the laminar flow hood correctly, keeping it clean after use;

Autoclaving of pathogenic biological material, before disposing of it in common waste;

Use of an appropriate disinfectant to inactivate a specific agent.