Serodiagnosis of Brucellosis in Patients with Fever of Unknown Origin at a Tertiary Care Hospital in Bangalore: A Cross-sectional Study

Abstract

Introduction: Brucellosis is a zoonotic disease caused by bacteria of the genus Brucella. Although it is not commonly transmitted between humans, it can be transmitted through direct handling of cattle or their products, such as raw milk, unevenly heated milk, clotted cream, and cheese, for varying periods. Brucellosis is considered as one of the neglected zoonotic diseases worldwide, as it can cause debilitating acute infections and later become chronic with numerous complications. Aim: To determine the prevalence of brucellosis among patients with Pyrexia of Unknown Origin (PUO). Materials and Methods: This cross-sectional study was conducted in the Department of Microbiology at Ramaiah Medical College and Teaching Hospital in Bangalore, Karnataka, India, over a period of two years, from December 2019 to December 2021. The study included patients who visited the Outpatient Department (OPD) and those admitted to the hospital with fever persisting for more than 5-7 days and Fever of Unknown Origin (FUO). The total sample size was 180, and 5-10 ml of blood was collected from each patient under aseptic precautions from the median cubital vein for serological tests. The blood samples were stored at 2-8°C for the Rose Bengal Test (RBT) assay and Enzyme-Linked Immunosorbent Assay (ELISA). The demographic parameters considered included clinical history, age, gender, residency, and history of animal exposure. Data analysis was performed using the statistical software Statistical Package for the Social Sciences (SPSS) version 18.0, employing the Chi-Square test, Fisher’s-Exact test, and descriptive statistics. The significance level employed was set at p-value <0.05. Results: Among 180 samples, six (i.e., 3.3%) were positive for the Brucella RBT (BRBT), while 11 (i.e., 6.1%) were positive for the (ELISA IgM), and 17 (i.e., 9.4%) were positive for the (ELISA IgG). Additionally, 22 samples (i.e., 12.22%) tested positive for either ELISA of IgG or IgM (ELISA IgG/IgM). Conclusion: The present study identified 22 patients (12.22%) with Brucella-positive cases who presented with various clinical signs and symptoms, originating from different geographical locations and regardless of gender. These findings suggest that all cases of FUO presented to a clinician should be evaluated for Brucella infection.

Keywords

• enzyme linked immunosorbent assay
• immunoglobulin m and g
• pyrexia
• rose bengal test
• zoonosis