Seroprevalence of brucellosis in cattle, buffalo and human being in central Gujarat
Varasada, Rupushkumar N. (2003) Seroprevalence of brucellosis in cattle, buffalo and human being in central Gujarat. Masters thesis, College of Veterinary Science and Animal Husbandry, Anand Agricultural University, Anand, Gujarat, INDIA.
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A study was undertaken at the Department of Veterinary Public Health, College of Veterinary Science and Animal Husbandry, Gujarat Agricultural University, Anand Campus,Anand for a period of one year from 1st January to 31s" December, 2002 to assess the seroprevalence of brucellosis in cattle, buffaloes, and human beings of Anand, Kaira, Vadodara and Ahmedabad districts of the Central Gujarat region. Serological tests viz., Rose Bengal Plate Test (RBPT), Standard Tube Agglutination Test (STAT) and indirect enzyme linked immunosorbent assay (i-ELISA) were employed for detecting the Brucella antibodies from animals. RBPT and STAT for serology while PCR was employed for screening of peripheral blood samples of human beings for screening of Brucellosis. They were also compared in terms of their sensitivity and specificity. A total of 682 sera samples including 344 from cattle, 251 from buffaloes, and 87 from human beings collected from the Central Gujarat region were subjected to RBPT, STAT, and i-ELISA for detecting Brucella antibodies from serum while PCR was employed for screening of peripheral blood samples of human being. Rose Bengal Plate Test was carried out by using rose bengal plate test antigen. Using Brucella abortus agglutinating antigen carried out standard tube agglutination test. Both antigens were procured from Indian Veterinary Research Institute, Izatnagar. Indirect enzyme linked immunosorbent assay was carried out by using the smooth lipopolysaccharide (S-LPS) based Avidin-Biotin ELISA kits (for bovine sera as well as milk) supplied by All Indian Co-ordinated Research Project on Animal Disease monitoring and surveillance (ADMAS), Bangalore. The overall seroprevalence of brucellosis in animals (cattle and buffaloes) was 22.11 percent while species wise incidence was found to be 24.12 and 19.12 percent in cattle and buffaloes respectively by i-ELISA. By using RBPT, seropositivity among the cattle, buffaloes, and human beings were found to be 19.75, 12.75 and 8.04 percent respectively. The seroprevalence of brucellosis in districts of Anand, Vadodara, Ahmedabad, and Kaira was observed 25.66 percent, 19.19 percent, 22.48 percent and 19.26 percent respectively. In Anand, incidence in cattle and buffaloes were 31.08 and 20.51 percent respectively while in Vadodara 23.61 and 7.4 percent. In Ahmedabad 21.95 and 232.26 percent respectively while in Kaira seroprevalence of cattle and buffaloes was 21.33 and16.67 percent respectively. In cattle the sexwise seroprevalence among cow was 24.10, and 25.00%.in cow and bulls respectively. In she buffaloes the prevalence was 18.70% while in buffalo bulls it was 23.81, giving overall prevalence of 22.30% in female and 24.13% prevalence in male. Seropositivity among the cattle, buffaloes and human beings by STAT was found to be 16.57, 11.16, and 4.59 percent respectively. In Bovine the relative sensitivity and specificity of the RBPT and STAT tests vis-à-vis i-ELISA was assessed and it was observed that the relative sensitivity of RBPT was 68.70 percent and 63.36 percent of STAT. In cattle the relative sensitivity of RBPT was 79.51 percent, and 67.47 percent of STAT while in buffalo the relative sensitivity of RBPT was 64.58 percent, and 56.25 percent of STAT The relative specificity was observed more than 99.00 percent in all above case. In case of human brucellosis, in comparison to RBPT, STAT showed 57.14 percent sensitivity and 100 percent specificity. The concordance between the results of i-ELISA-RBPT was 92.60 percent, between STAT – i-ELISA was 91.09 percent and between RBPTSTAT was 97.98 percent for the diagnosis of brucellosis. In human being the concordance between the results of RBPT-STAT was 96.55 percent. PCR had detected 25.97% prevalence in human being. In professionally exposed group, in veterinarian 12% prevalence, in farmers 20% prevalence, animal handlers 13% prevalence and hence the overall prevalence in professional group was 14%. While in pyrexia of unknown origin group PCR gave 48% prevalence. The sensitivity of RBPT and STAT for detection of brucellosis in human being was observed 30 percent and 15 percent respectively in comparision with PCR while the specificity was observed 100 percent. Fingerprinting of Brucella isolates with BOX PCR , ERIC PCR and REP PCR generated distinct amplification bands ranging from 1-6, 1-6 and 2-10 respectively. With frequency ranging from 0.10-0.85, 0.05-0.80, 0.05-60 respectively with 85.78%, 83.34% and 100% polymorphic bands respectively. Dendogram observed by popgene analysis results of BOX PCR, ERIC PCR ERIC PCR showed that all isolates were divided in to four major clusters by BOX PCR and REP PCR while in five major clusters by ERIC PCR according to simple similarity coefficient. Over all analysis divided all isolates in to four major clusters. Network analysis of BOX PCR, ERIC PCR, REP PCR divides all isolates in to 5, 8 and 8 clusters respectively according to the mutation present in between various groups. Network graph of pulled analysis showed that only Brucella-15 & Brucella-27, Brucella-59 & Brucella-63, Brucella-69 & Brucella-71 were 100% similar to each other while rest of isolates appeared different from each other with minimum one to maximum 16 mutation in between. In this study no grouping or specific pattern was observed according to professional group or source of infection or exposure. In a survey of Vadodara district 4.15 percent prevalence was observed in cow herds where as in buffalo herds it was 0.46 percent while the incidence among villages was 3.53 percent. CONCLUSIONS : Following conclusions could be drawn from the present study. 1.The overall seroprevalence of brucellosis in animals (cattle and buffaloes) was 22.11 percent by indirect-ELISA test. 2. Specieswise, maximum seroprevalence of brucellosis was found in cattle (24.12 percent) followed by buffaloes (19.12 percent) 3. District wise overall maximum seroprevalance was observed in Anand i.e. 25.66 percent followed by Ahemdabad 22.48 percent, Kaira 19.26 percent and Vadodara 19.19 percent. 4. In cattle, district wise maximum seroprevalance was observed in Anand i.e. 31.08 percent followed by Vadodara 23.61 percent, Ahemdabad 21.95 percent, and Kaira 21.33 percent. 5. In buffalo, district wise maximum seroprevalance was observed in Ahemdabad i.e. 21.95 percent, followed by Anand 20.51 percent, Kaira 16.67 percent, and Vadodara 7.40 percent. 6. By RBPT District wise overall maximum seroprevalance was observed in Anand i.e. 19.08 percent followed by Vadodara 16.16 percent, Kaira 15.55 percent and Ahemdabad 12.92 percent. 7. In cattle, district wise maximum seroprevalance by RBPT was observed in Anand i.e. 24.32 percent followed by Kaira 20.11 percent, Vadodara 19.44 percent, and Ahemdabad 17.07 percent. 8. In buffalo, district wise maximum seroprevalance by RBPT was observed in Ahemdabad i.e. 15.11 percent, followed by Anand 14.10 percent, Kaira 10.00 percent, and Vadodara 7.40 percent. 9. By STAT district wise overall maximum seroprevalance was observed in Anand i.e. 15.18 percent followed by Ahemdabad 14.83 percent, Vadodara 14.14 percent, and Kaira 12.59 percent. 10. In cattle, district wise maximum seroprevalance by STAT was observed in Anand i.e. 18.91 percent followed by Vadodara 16.67 percent, Kaira 16.00 percent, and Ahemdabad 15.44 percent. 11. In buffalo, district wise maximum seroprevalance by STAT was observed in Ahemdabad i.e. 13.95 percent, followed by Anand 11.53 percent, Kaira 8.34 percent, and Vadodara 7.40 percent. 12. Sexwise overall maximum seroprevalence was observed 24.03 percent in male while 22.30 percent in female. 13. In cattle sexwise maximum seroprevalence was observed in male i.e. 25.00 percent while 24.10 percent in female. 14. In buffalo sexwise maximum seroprevalence was observed in male i.e. 23.81 percent while 18.70 percent in female. 15. Sexwise overall maximum seroprevalence by RBPT was observed 17.27 percent in female while 13.79 percent in male. 16. In cattle sexwise overall maximum seroprevalence by RBPT was observed 19.94 percent in female while 12.50 percent in male. 17. In buffalo sexwise overall maximum seroprevalence by RBPT was observed 12.61 percent in female while 14.29 percent in male. 18. Sexwise overall maximum seroprevalence by STAT was observed 14.57 percent in female while 13.79 percent in male. 19. In cattle sexwise overall maximum seroprevalence by RBPT was observed 16.67 percent in female while 12.50 percent in male. 20. In buffalo sexwise overall maximum seroprevalence by RBPT was observed 10.87 percent in female while 14.29 percent in male. 21 All the three serological tests used in the present study i.e. RBPT, STAT and i-ELISA showed the highest seropositivity in cattle followed by buffaloes. 22. In human sera samples, RBPT gave more positivity (8.04 percent) than STAT (4.60 percent). 23 Seroseroprevalence of brucellosis was found to be higher in slaughterhouse worker than animal handlers and veterinarians as compared to farmers. 24 Seroseroprevalence in the group of pyrexia of unknown origin was 14.81 percent by RBPT and 4.60 percent by STAT. 25 Compared to i-ELISA, RBPT showed sensitivity of 79.51 and 64.58 percent, while STAT showed 67.47 and 56.25 percent in cattle, buffaloes respectively. 26 i-ELISA test in conjunction with other serological tests can give more reliable diagnosis. 27 i-ELISA was found to be very reliable and efficacious test. 28 PCR is more sensitive test than conventional serological tests. 29 Milk based i-ELISA detected 3.53 percent villages of Vadodara district positive for brucellosis. 30 Milk based i-ELISA had the added advantage of being very practicable for large scale brucellosis screening programme under field condition specially in the “Anand Pattern” village milk co-operative societies. 31 Analysis of rep-PCR suggested intense genetic diversity among Brucella strains 32 rep-PCR fingerprinting can be used for strain differentiation of Brucella spp. 33 Analysis of PCR-SSCP suggested that there was no variation among PCR amplicons.
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