Biological risk and occupational health.

Many work activities include hazards to workers, and among these biological risk is particularly important, mostly because of different types of exposure, contact with highly dangerous agents, lack of limit values able to compare all exposures, presence of workers with defective immune systems and therefore more susceptible to the risk. Bioaerosols and dust are considered important vehicles of microganisms at workplaces and interaction with other occupational agents is assumed. Moreover, biological risk can be significant in countries with increasing economic development or particular habits and some biological agents are also classified as carcinogenic to human.