Seroprevalence of caprine brucellosis in district Dir of Northwest Frontier Province of Pakistan

During present survey, 150 goats of both sexes and different ages were examined by various conventional techniques, i.e. Rose Bengal Plate Test (RBPT), Serum Agglutination Test (SAT) and Milk Ring Test (MRT). The overall prevalence of brucellosis was recorded to be 4%, 4.67% and 10% by RBPT, SAT and MRT respectively. 75 male goats were examined by RBPT and SAT while similar number of female goats were also investigated by RBPT and SAT techniques. However, 60 milk samples from female goats were also examined by MRT. The prevalence of brucellosis in females was recorded as 5.33%, 6.67% and 10% by RBPT, SAT and MRT respectively while in males it was observed as 2.67% and - 2.67% by RBPT and SAT respectively. 120 adult goats (above 9 months) were examined by RBPT and SAT and 60 adult female goats by MRT while 30 young goats (up to 9 months) by RBPT and SAT. The positive cases of brucellosis in adult goats were recorded as 5.0%, 5.83% and 10% by RBPT, SAT and MRT respectively while all young goats were found to be negative. A total of 60 adult female goats were analyzed, through Rose Bengal, Serum Agglutination and Milk Ring Tests which detected 6.67, 8.33 and 10% brucellosis in adult female goats respectively while remaining were recorded as negative or free from any brucellosis. During present investigation, 15 young females were examined through RBPT and SAT, both techniques were failed to detect any positive cases from young females and considered to be negative. On the other hand, similar number of adult and young RBPT and SAT methods examined males, detected the same prevalence. The seroprevalence of brucellosis was recorded as 3.33% by RBPT and SAT in adult males. Whereas no any single from young male goat was found positive for brucellosis. The serum samples of 75 females were titrated. Five sera from 75 female goats interaction and showed 1:40 and 1:80 titers while no any positive interacted was observed beyond the above dilutions. From these five positive cases, only 4 animal sera interacted and showed 1:40 antibody titer whereas 1 serum sample from female goat showed antibody titer, which was recorded as 1:80. On the other hand, similar number of serum samples from 75 male goats were obtained and tested by the Tube Agglutination, 2 positive samples were detected and both samples interacted at dilution 1:40 with antigen and recognized as positive for brucellosis. However, no any interaction between antigen and serum antibodies was recorded in the other serum dilutions. Brucella abortus antigen interacted with 5 serum samples contained the antibodies of Brucella abortus species while with sample modification in the procedure where two drops of sera were added to antigen showed the characteristics of melitensis and recorded as positive for melitensis. During study 6 sera showed the presence of melitensis antibodies. Serologically, the incidence of Brucella abortus and melitensis was recorded as 3.33 and 4% in goats respectively. It is concluded that the brucellosis is prevailing in the area. It was relatively higher in females as compared to males. Further, higher prevalence of brucellosis was present in adult female than in male goats. However, no brucellosis was detected in young goats of both sexes. The higher incidence (4%) of Brucella melitensis was recorded as compared to Brucella abortus (3.33%) in goats. The serum antibody titers of Brucella abortus and melitensis were also determined which interacted with antigen at dilutions of 1:40 and 1:80, however, beyond these dilutions no interactions between antigen and serum antibody were observed. It was also concluded that the Serum Agglutination Test (SAT) technique is highly specific, sensitive and relatively more accurate in determining brucellosis in animals as compared to Rose Bengal Plate Test and Milk Ring Test which sometimes produced false results.