Università degli Studi di Milano, 2013-02-07

Objectives: Animal breeding is associated with exposure to a wide variety of risk factors including zoonotic agents, organic dusts, endotoxins, allergens and other chemicals. This PhD project has been addressed at characterizing, at different levels, exposure to biological risks of farmers and animal breeders in the Region of Lombardy. The project has been developed in three main studies, as follows: 1. characterization of biological risks in animal breeders, with a particular focus on selected virus and bacteria; 2. Definition of the anti-tetanus coverage among agricultural workers of the Region in selected population subgroups; 3. study of the immune system function in these workers, through the determination of the serum concentrations of specific cytokines. Methods: Two groups of farmers and animal breeders were included in the studies. Blood samples were collected from all the subjects and analysed for the presence of the following antibodies against zoonotic agents: Hepatitis E Virus (HEV), Salmonella, Brucella, Coxiella, Leptospira and Borrelia. In addition, selected serum parameters were measured, including cytokines IL-6, IL-8, IL-10, IFN-gamma and TNF-alpha, immunoglobulins and proteins, and total and differential white blood cell counts. In addition, level of Immunity to tetanus was investigated. Lung function was measured using a spirometer. Data was analysed using SPSS (version 19) and STATA (version 11) softwares. Results: Prevalences of antibodies against HEV, Leptospira spp., Coxiella spp. and Borrelia spp., were 1.0, 54.7, 44.2 and 9.4%, respectively. Animal breeder workers had higher rates of IgG antibodies against Coxiella (51.6% vs 28.1%, P-value: 0.09) and Leptospira (59.4% vs. 43.7%, P-Value: 0.39) than farmers. None of the subjects showed antibodies against Salmonella spp and Brucella spp. Italian and other European workers had higher immunity to tetanus (93%) in comparison with non-EU workers (77.8%, P<0.01). There was a significant increase of TNF-alpha, IL-8 and IL-10 in animal breeders, and pig breeders had the highest values. Linear regression analysis revealed that there was a statistically difference between EU and Non-EU workers for some spirometry parameters. Conclusion: Higher titers of antibodies to zoonotic agents in animal breeders indicates that they are probably more exposed to biological agents than other workers who are not involved in animal breeding activities. There must be more attention to the immunity status of tetanus among agricultural workers and in particular migrant workers and occupational health physicians should investigate about the history of immunization during health surveillance activities. The findings of the present study suggest a condition of immune system activation in animal breeders, with the highest levels observed in pig breeders. These changes may be attributable to exposure to organic dusts, endotoxins, or to the different biological agents present in the rural environment. In the curent study we did not point out any significant alteration in the values of spirometry tests between animal breeders and farmers. This data might suggest that, in the conditions of exposure of these workers, only slight sublclinical and adaptive changes are anticipated, but not conditions of overt disease. Further studies with larger sample size are needed to better understand the mechanisms for transmission of zoonotic infections and their potential reservoirs in northern Italy.

diritti: info:eu-repo/semantics/openAccess
supervisor: C. Colosio ; co-supervisor: F. Vellere ; coordinator: G. Costa
Settore MED/44 - - Medicina del Lavoro

Tesi di dottorato. | Lingua: Inglese. | Paese: | BID: TD16001054