Objective: Anthrax, is a lethal bacterial zoonosis transmitted through skin, inhalation or gastrointestinal tract, and spread by herbivorous animals particularly with cattle and sheep. One of the fundamental virulence factors of Bacillus anthracis is its toxins consisting of protective antigen (PA), edema factor and lethal factor. The protective antigen is especially responsible for intracellular entrance of the other two factors. The aim of the present study is to investigate the protective antigen in blood samples of patients who applied to the hospitals in our region with a suspected anthrax infection, and to determine the prevalence in the region.

Material and Methods: ELISA (Enzyme Linked Immunosorbent Assay, Biosource, USA) method was used in the study in order to detect the presence of the protective antigen IgG antibody.

Results: We determined 35 Bacillus anthracis protective antigen IgG positive results out of 47 samples taken from patients suspected of anthrax in Ataturk University Yakutiye Training and Research Hospital and Erzurum Regional Training and Research Hospital. Thirty-five (6 female: 17%, and 29 male:82.8%) patients had positive results. Out of 35 patients 27 (77.1%) were into animal husbandry, 8 patients (22.8%) were not involved in animal husbandry but had a history of contact with animal flesh.

Conclusion: We have attributed the results obtained from the samples taken from patients, who had clinical findings of anthrax but without protective antigens in their blood to medical treatments they received in various health institutes before they applied to our hospital, to random use of antibiotics relying on the common tendency that antibiotics can cure any disease, impairment of toxin-producing ability of the bacteria, drawal of blood samples when protective antigen levels in the circulation decreased to undetectible levels.