The assessment of occupational biological risk is generally limited to the evaluation of a "potential exposure", without any quantitative estimate. The risk assessment output is then usually expressed as a level (low, medium, high) and represented in risk matrices combining magnitude and probability scores. A possible innovative approach for the risk assessment in occupational settings characterized by bioaerosol exposure is to monitor the air for a pathogen that can be further used for QMRA. Adenovirus is the virus that contains the highest amount of features favorable to its use as a virological indicator. This pathogenic virus has a low infectious dose, it is resistant on the environment, abundant, easily detected by molecular methods and is of great importance in public health. In this study, HAdV is used as the reference pathogen to develop a preliminary QMRA model to assess the microbial risk associated with the inhalation of contaminated bioaerosols. This model was then applied to data on air contamination from different settings (wastewater treatment plants, solid waste landfills, toilets in offices and hospitals) and with various exposure times. Air samples (1000 l of air in the indoor workplace and 3000 l of outdoor) were collected using an impactor sampler and the genomic concentration of positive samples was measured by real-time polymerase chain reaction (q-PCR). The virological monitoring showed the presence of HAdVs in all the considered settings, thus confirming their wide diffusion, nevertheless, the average concentrations of HAdV were different. The model estimates show that in the most contaminated settings a stay longer than 3 minutes would lead to a probability of infection of 100%, while for the less contaminated areas even after 15 min the probability of infection remains around 1%. The definition of critical exposure times, using a QMRA model, could be useful to give operational guidance for risk management on the use of respiratory personal protection equipment (RPPE). This approach is new and should be faced with caution. However it is worthy of discussion and further investigation.
Quantitative microbial risk assessment in occupational settings: the airborne infectious biological risk
DONZELLI, GABRIELE;VERANI, MARCO;MASTROENI, GIANDOMENICO;CARDUCCI, ANNALAURA
2015-01-01
Abstract
The assessment of occupational biological risk is generally limited to the evaluation of a "potential exposure", without any quantitative estimate. The risk assessment output is then usually expressed as a level (low, medium, high) and represented in risk matrices combining magnitude and probability scores. A possible innovative approach for the risk assessment in occupational settings characterized by bioaerosol exposure is to monitor the air for a pathogen that can be further used for QMRA. Adenovirus is the virus that contains the highest amount of features favorable to its use as a virological indicator. This pathogenic virus has a low infectious dose, it is resistant on the environment, abundant, easily detected by molecular methods and is of great importance in public health. In this study, HAdV is used as the reference pathogen to develop a preliminary QMRA model to assess the microbial risk associated with the inhalation of contaminated bioaerosols. This model was then applied to data on air contamination from different settings (wastewater treatment plants, solid waste landfills, toilets in offices and hospitals) and with various exposure times. Air samples (1000 l of air in the indoor workplace and 3000 l of outdoor) were collected using an impactor sampler and the genomic concentration of positive samples was measured by real-time polymerase chain reaction (q-PCR). The virological monitoring showed the presence of HAdVs in all the considered settings, thus confirming their wide diffusion, nevertheless, the average concentrations of HAdV were different. The model estimates show that in the most contaminated settings a stay longer than 3 minutes would lead to a probability of infection of 100%, while for the less contaminated areas even after 15 min the probability of infection remains around 1%. The definition of critical exposure times, using a QMRA model, could be useful to give operational guidance for risk management on the use of respiratory personal protection equipment (RPPE). This approach is new and should be faced with caution. However it is worthy of discussion and further investigation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
