Human seroprevalence of brucellosis in three regions of northern Azerbaijan

Background: Public health surveillance in Azerbaijan currently relies primarily on passive disease reporting from health care providers. Public health officials suspect that brucellosis is underreported, due to low healthcare utilization and the non-specific clinical presentation of the infection. The true prevalence of antibodies to brucellosis is unknown, but suspected to be high in rural areas due to the close proximity to livestock, as well as prevalence of antibodies to brucellosis in proximal geographic areas. This study was conducted in support of the Biological Threat Reduction Program (BTRP), and will provide information that can be used to evaluate the passive disease surveillance system implemented by this program.

Methods: A two-stage, probability-proportional to size sampling design was used to select 40 villages in northern Azerbaijan with populations less than 500 people. Informed consent was provided, and samples were obtained and tested for IgG antibodies against Brucella. Volunteers completed a questionnaire identifying their demographics, history of clinical symptoms, and potential exposures.

Results: Out of 463 samples tested, 78 volunteers were antibody positive (16.8%). Risk factor analysis is ongoing. The prevalence of brucellosis detected in this study is higher than expected; public health officials cite the northeastern part of Azerbaijan as an area of low brucellosis prevalence.

Conclusion: Determination of the background prevalence of brucellosis will provide useful information to clinicians determining the etiology of febrile illness in Northern Azerbaijan, and provide guidance regarding public health measures to address infectious diseases in Azerbaijan. In particular, public health officials will have a better understanding of the disease prevalence in rural populations, which will guide disease surveillance efforts and help improve the Threat Agent Detection and Response (TADR) system.