ORIGINAL PAPER
Seroprevalence of anti-HAV total antibodies among workers in wastewater treatment plants
 
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1
Medical University of Plovdiv, Plovdiv, Bulgaria (Faculty of Public Health, Department of Hygiene and Ecomedicine)
2
Medical University of Plovdiv, Plovdiv, Bulgaria (Faculty of Pharmacy, Department of Microbiology and Immunology)
CORRESPONDING AUTHOR
Elka Ilieva Toseva   

Medical University of Plovdiv, Faculty of Public Health, Department of Hygiene and Ecomedicine, Bul. Vasil Aprilov 15-A, Plovdiv-4002, Bulgaria
 
Int J Occup Med Environ Health 2018;31(3):307–315
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ABSTRACT
Objectives: Data on high frequency of hepatitis A virus (HAV) antibodies for wastewater treatment staff is contradictory. Literature lacks data on the seroprevalence of antibodies to HAV (anti-HAV) among workers in wastewater treatment plants (WWTPs) in Bulgaria. The aim of this study is to establish a specific humoral immune response to hepatitis A virus – anti-HAV total antibodies among staff in WWTPs. Material and Methods: A complex study of health and working conditions included 110 subjects working in 3 WWTPs in Bulgaria (74% of all workers in the 3 studied WWTPs and 20% of all employees in Bulgaria registered in 2014 under the wastewater collection, discharge and treatment code of economic activity). Workers had been differentiated in 3 groups on the basis of their occupational work: operators, support staff and other workers exposed to biological agents. Venous blood from all 110 subjects was tested once for carriers of HAV antibodies. Results: Anti-HAV total antibodies were found for 52.7% of workers in WWTPs. There is a positive association between activity performed in WWTPs (operators, maintenance personnel and others exposed) and a positive one for the presence of anti-HAV (Chi2 = 6.882, df = 2, p = 0.032). Odds ratio (OR) for hepatitis A increases 2.9 times in the group of operators vs. others exposed to biological agents in WWTPs (OR = 2.914, 95% confidence interval (CI): 1.149–7.393, Fisher’s p = 0.039). Odds ratio for hepatitis A increases 4.3 times in the group of support staff from WWTPs vs. others exposed to biological agents in WWTP (OR = 4.295, 95% CI: 1.075–17.167, Fisher’s p = 0.049). Conclusions: Higher frequency of anti-HAV antibodies among operators and maintenance personnel at WWTPs has been established as compared to other workers exposed to biological agents in WWTPs. There is a positive association between increasing age of the workers and the presence of anti-HAV. Int J Occup Med Environ Health 2018;31(3):307–315
eISSN:1896-494X
ISSN:1232-1087