RESUMO
INTRODUCTION: In the present work, we studied the association between multiple exposure of waste water treatment plant workers to infection with existing hepatitis A virus in waste water and development of rheumatoid arthritis, taking in consideration number of working years as an indicator for frequency of exposure to infection, compared to non waste water treatment plant workers. METHODOLOGY: A total of 105 waste water treatment plant workers and 48 NWWTPWs were included in the study. Exclusion criteria were positivity for HBV and/or HCV IgG, negativity to HAV IgG and suffering from rheumatic diseases other than rheumatoid arthritis. RESULTS: 96.2% of waste water treatment plant workers were anti-HAV-IgG positive, of whom 5 had high antibody titer indicating ongoing infection and were anti-HAV-IgM negative excluding primary infection. These 5 samples were further subjected to quantification of liver enzymes, glutamate oxaloacetate trasaminase and glutamate pyruvate transaminase and HAV-RT-PCR to check viremia and results showed increase of glutamate oxaloacetate trasaminase and glutamate pyruvate transaminase as well as viremea in all of them. Rheumatoid arthritis diagnosis was carried out by detection of C-reactive protein, rheumatoid factor and anti-cyclic citrullinated protein. Rheumatoid arthritis development was 19% in the waste water treatment plant workers with >10 working years and 8% for < 10 working years. Also, disease development started earlier (Age 30-40 years) among the waste water treatment plant workers compared to non waste water treatment plant workers (age: 40-50 years). CONCLUSIONS: Multiple exposures of waste water treatment plant workers to HAV might be one of the etiological stimuli of rheumatoid arthritis.