Occupational brucellosis among veterinarians in Minas Gerais state, Brazil

Abstract

Brucellosis is a zoonotic disease of remarkable importance worldwide, with a strong occupational chacter that affects mainly farmers, abattoir workers, microbiologists, hunters and veterinarians. The focus of this dissertation was to conduct a systematic review and metaanalysis about occupational exposure to Brucella and identify the main risks factors in each group exposed to the pathogen, as well as to determine the prevalence and risk factors of occupational brucellosis and accidental exposure to S19 and RB51 vaccine strains among veterinarians registered to perform brucellosis vaccination in cattle in Minas Gerais, Brazil. The systematic review was conducted based on PRISMA recommended guidelines. The metaanalysis was performed using three case controls studies. Data from epidemiological survey was collected by means of an online questionnaire. Three hundred and twenty nine veterinarians were included in the analyzes, using a stratified random sampling. A multivariable logistic regression analysis was used to evaluate the predictors of accidental exposure to bovine brucellosis vaccines. The main risk factors and exposure sources involved in the occupational infection were not use of personal protective equipment (PPE), direct contact with animal fluids and accidental exposure to live attenuated Brucella vaccines. The meta-analysis demonstrated that laboratory workers, animal breeders and abattoir workers had 3.47 [95% confidence interval (CI); 1.47 - 8.18] times more chance to become infected by Brucella than other professionals that have no contact with the possible sources of infection. In the cross sectional study, it was identified that 32.83% (108/329) [95% confidence interval (CI): 27.78 to 38.19%] of the veterinarians reported having been accidentally exposed to S19 or RB51 strains. The risk associated with this outcome included score of PPE use during work [odds ratio (OR), 0.94; 95% CI: 0.89 to 0.98] and score of knowledge about brucellosis symptoms, classified in mean (OR, 0.26; 95% CI: 0.07 to 0.87) or good (OR, 0.22; 95% CI: 0.07 a 0.62) compared to poor knowlegde. In addition, 4.56% (15/329) (95% CI: 2.57 to 7.41%) of veterinarians self reported brucellosis, of which 46.67% (7/15) considered that the disease was due to accidental exposure to S19 or RB51 strains. Hence, it was concluded that the lack of knowledge about brucellosis among exposed professionals, added to some behaviors such as negligence in the use of PPE, increases the probability of infection with Brucella spp.