Seroprevalence of brucellosis in humans with non-specific clinical symptoms in Punjab, India

Abstract

Background and aim: Brucellosis is a zoonotic disease that remains underdiagnosed in humans due to its non-specific clinical presentations. Punjab, India, is particularly vulnerable to brucellosis due to its high-density livestock farming. This study aimed to estimate the seroprevalence of brucellosis in individuals presenting with non-specific clinical symptoms.

Materials and methods: A cross-sectional study was conducted at the Centre for One Health, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, from January 2021 to December 2021. A total of 137 serum samples were collected from individuals either self-referred or physician-referred for brucellosis testing. The samples were screened using the rose Bengal plate test (RBPT) and confirmed with the standard tube agglutination test (STAT). Data on demographics, symptoms, and occupational exposure were analyzed using SPSS version 26.0, with statistical significance set at p < 0.05.

Results: Overall, 17.52% (24/137) of individuals tested positive using STAT, with antibody titers ranging from 80 IU/mL to >2560 IU/mL. Seropositivity was higher in males (20.83%) than in females (9.77%). The highest seropositivity (42.9%) was observed in individuals aged 71-80 years. Among symptomatic individuals (n = 92), fever was the most common symptom (n = 79), followed by joint pain (n = 13). However, 15.6% of asymptomatic individuals also tested positive. No significant association was found between symptoms and seropositivity (p > 0.05). In addition, self-referred individuals (24.1%) had a higher seropositivity rate compared to physician-referred cases (12.7%). Among occupationally exposed individuals, veterinary officers showed the highest seropositivity.

Conclusion: The study highlights a considerable seroprevalence of brucellosis among various symptomatic and among asymptomatic individuals. Given its non-specific clinical manifestations, routine serological screening is recommended, especially for high-risk groups. A One Health approach integrating human and animal health surveillance is crucial for effective disease control.

Keywords: India; Punjab; brucellosis; non-specific symptoms; rose bengal plate test; seroprevalence; standard tube agglutination test; zoonosis.