Human anthrax outbreak and associated factors in the horrific siege of Tigray, Ethiopia

Objectives To investigate the magnitude of the anthrax outbreak and its associated factors during the war and the de facto siege of Tigray, Ethiopia. Design or methods A case-control study design was applied after an initial descriptive cross-sectional study. Multiple logistic regression was used to identify factors associated with the outbreak. Results A total of 339 participants (113 cases and 226 controls) were enrolled with a mean age of 22 ( ± 17) and 35 ( ± 16) years for cases and control groups, respectively. Human anthrax attack and case fatality rates in selected districts of Tigray were estimated at 42.3 per 100,000 population and 5.4%, respectively. Cutaneous anthrax was identified as the most common case of anthrax, accounting for 141/149 total cases (94.6%). Age, consumption of raw meat of diseased animals, sharing of meat, presence of a diseased person among household members, disposal of diseased/dead animals, and contact with products of diseased/dead animals were associated with the outbreak. Conclusion A high rate of human anthrax attacks and fatal cases was recorded during the Tigray defacto blockade, with an epidemic curve. The defacto blockade of Tigray complicated the investigation and management of the outbreak.