Using cross-sectional data to improve anthrax outbreak response --- republic of Georgia, 2012

Background: Anthrax, a zoonotic disease caused by Bacillus anthracis, results from exposure to infected animals or their products. The Republic of Georgia reported a 77% increase in human cases from 2011 (81 cases) to 2012 (143 cases). We evaluated animal exposure factors associated with an ongoing outbreak to better inform veterinary response. Methods: The Republic of Georgia National Center for Disease Control identified cases from the Electronic Integrated Disease Surveillance System. Two controls were randomly recruited, matched by residence and gender. After completing a case-control questionnaire, 145 respondents owning or working with livestock were asked to participate in a cross-sectional study. Data were analyzed using SAS v9.2. Results: Exposure to sick animals was associated with increased risk for human anthrax (OR=14, 95% CI 3.2-61.5). Of 125 cross-sectional participants, 15 (12.0%) owned sick animals, nine (64.3%) of 14 with anthrax-related symptoms. Eight (80.0%) of 10 owners had sick animal deaths, and two (20.0%) of 10 slaughtered the animal for consumption. 11 (8.6%) of 128 owners found animals suddenly dead and two (25.0%) of eight owners processed the carcass. Conclusions: Human anthrax was strongly associated with exposure to sick animals. Around one-fifth of owners processed sick or dead animals for consumption. Improving control of animal disease through such measures as vaccination and education are part of an integrated approach that will reduce the human health impact of anthrax in Georgia.