Abstract
            Background: Brucellosis is recognized as one of the most prevalent diseases among humans and animals.  This study investigated and followed up brucellosis in seropositive participants in the Famenin (Hamadan  province, Iran) cohort of brucellosis and their families by culture and serology methods.  
  Methods: Blood samples were taken from 66 subjects, including 18 subjects in the Famenin brucellosis  cohort study with antibody titers≥1:180 and 36 subjects from their families and 12 subjects in the Famenin  brucellosis cohort study with antibody titers<1:80. In the serological method, standard tube agglutination  test (STAT positive with≥1:80) and 2-mercaptoethanol (2-ME) test (positive with≥1:40) were performed  using the patient serum. Finally, 8 cc of the blood of all subjects was used for culture in the BACTEC  culture medium.  
  Results: Of the 66 serum samples, 20 (30.3%) samples, including 5, 4, and 10 samples at 1:20, 1:40,  and 1:80 dilution, respectively, and 1 sample at 1:160 dilution were positive by the STAT, of which 13  (65%) samples belonged to patients’ family members. Using the 2-ME test, 10 (15.2%) serum samples  were positive, of which 5 (50%) cases were related to patients’ family members. Eventually, no growth of  Brucella was observed in 66 flasks of the BACTEC culture medium.  
  Conclusion: Considering that a definite diagnostic method is not yet accessible, a combination of methods  must be applied to diagnose the disease.