Brucella infections in high-risk population and in patients hospitalized for fever: A serological study at Kolar, Karnataka

Abstract

Background: Brucellosis, one of the world's major zoonoses, is endemic in many parts of India. It is an occupational hazard for veterinary employees, butchers, dairy personnel, and laboratory workers. There is no information available on human brucellosis from Kolar region of southern India. Methods and Materials: Serum samples from 154 adults, at high risk for brucellosis and residing in and around Kolar, Karnataka, India, were screened for antibodies to brucella by the Rose Bengal plate agglutination test and immunoglobulin (Ig)G Enzyme-linked immunosorbent assay (ELISA). Sera detected to be positive by these screening tests were further tested by standard tube agglutination test (SAT), SAT with 2 Mercaptoethanol, and IgM ELISA. In addition, serum samples from 100 hospitalized patients with prolonged fever were also subjected to the above tests to detect acute brucella infections among patients. Results: Among the 154 individuals at high-risk screened, brucella antibodies were detected in 15 (9.74%) of the subjects. The seropositivity rate was 30.76% among veterinarians, 14.28 among cattle businessmen, 9.67% among butchers, and 3.79% among animal owners. Seropositivity was associated with drawing blood and exposure to animals during parturition. Symptoms such as myalgia, low back ache, and joint pains were significantly more among seropositives. When the results of all the tests were taken together, 33.3% seropositives could be classified as past brucella infections and 66.6% as possible chronic brucella infections. Among the 100 hospitalized patients with prolonged fever acute brucellosis was diagnosed in one patient. Conclusion: Brucellosis is an important zoonosis in Kolar region. Among individuals at high risk many have serological profile of possible chronic brucellosis; such individuals may need treatment and follow-up.