Brucellosis is one of the most important reemerging zoonoses in many countries. 
Brucellosis is caused by Gram-negative coccobacillus belonging to genus 
Brucella. Human brucellosis often makes the diagnosis difficult. The symptoms 
and clinical signs most commonly reported are fever, fatigue, malaise, chills, 
sweats headaches, myalgia, arthralgia, and weight loss. Some cases have been 
presented with only joint pain, lower backache, and involuntary limb movement, 
burning feet, or ischemic heart attacks. The focus of this work was to develop a 
highly sensitive and specific indirect ELISA by using smooth lipopolysaccharide 
antigen of Brucella abortus 99 to detect anti-Brucella antibodies at Project 
Directorate on Animal Disease Monitoring and Surveillance. Serum samples 
collected from 652 individuals in whom fever was not the major symptom but the 
complaint was of joint pain, headache, lower backache, and so forth, were 
screened by Rose Bengal plate agglutination test (RBPT) and standard tube 
agglutination test (STAT). Subsequent testing of sera by indigenous indirect 
ELISA detected 20 samples positive (3.6% seroprevalence), and indirect ELISA was 
found to be more sensitive than RBPT and STAT. The seroprevalence in South 
Karnataka was 2.14%, and in North Karnataka it was 0.92%.