Bovine brucellosis in relation to public health

Abstract

A serological survey was undertaken to assess the extent of brucellosis in bovines and humans. Serum samples from 1233 bovines and 747 human were collected. These samples were screened by Rose Bengal Plate Test (RBPT) and Standard Tube Agglutination Test (STAT). The samples which showed a positive reaction, either by RBPT or STAT or both were subjected to Heat inactivation test (HIT), 2- Mercaptoethanol test (MET) and EDTA agglutination test (EAT). Of the 610 slaughtered male bovine serum samples screened, 41 (6.72 per cent) was found positive by RBPT and 37 (6.07 per cent) by STAT. HIT, MET and EAT detected positive reaction in 32 (5.25 per cent), 26 (4.26 per cent) and 27 (4.43 per cent) samples respectively. A total of 23 samples were positive by all the above tests. Among the 518 slaughtered female bovine serum samples, RBPT detected 41 (7.92 per cent) samples as positive while only 38 (7.34 per cent) samples were found positive by STAT. HIT, MET and EAT detected positive reaction in 31 (5.98 per cent), 26 (5.02 per cent) and 28 (5.4 per cent) samples respectively. Twenty four serum samples were found positive for the disease by all the above tests. None of the serological test employed could detect a statistically significant difference in the seroprevalence of disease between males and females. Of the serum samples collected from 105 farm fed cows, six (5.7 per cent) samples were found positive for brucellosis by both RBPT and STAT. The number of samples found positive by HIT, MET and EAT were three (2.86 per cent), one

(0.95 per cent) and two (1.9 per cent) respectively. Only one sample revealed a positive reaction for the disease by all the above serological tests. Among the 406 human male serum samples collected, six (1.47 per cent) revealed an agglutination reaction positive for the disease by RBPT while only four. (0.99 per cent) showed an agglutination titre positive for the disease by STAT. HIT, MET and EAT detected three (0.74 per cent) samples each as positive for the disease. Three samples revealed a positive reaction in all the above serological tests. Of the 327 human female serum samples screened, RBPT and STAT recorded a positive reaction in five (1.53 per cent) and four (1.22 per cent) samples, respectively. Three samples (0.92 per cent) each were found positive by HIT, and MET and EAT. Only three samples were found positive for all the serological tests used in this study. It was observed that serological tests employed in this study could not detect a statistically significant difference in the seroprevalence of disease between males and females. None of the serum samples collected from veterinary surgeons (10), animal attendants (two), and slaughter house workers (two) were positive for the disease. Of the serological tests employed in this study, RBPT detected the highest number of samples as positive followed by STAT, HIT, EAT and MET. It was also observed that, of the RBPT and STAT positive cases, HIT recorded maximum number of positive cases followed by EAT and MET. The reason for difference observed in the agglutination titre of the serum samples by the above tests were discussed.