Seroprevalence of contagious caprine pleuropneumonia and field performance of inactivated vaccine in Borana pastoral area, southern Ethiopia

摘要

This study was conducted between September 2012 and May 2013 in three Districts of Borana pastoral area to determine seroprevalence of contagious caprine pleuropneumonia (CCPP) and assess field performance of inactivated commercial vaccine, produced by the National Veterinary Institute (NVI) in Ethiopia, against CCPP. Both pre and post vaccination sera samples were tested using competitive enzyme linked immunosorbent assay (cELISA). Out of 510 examined sera, 161 samples were positive for CCPP, giving an overall seroprevalence of 31.6% (95% CI = 27.57-35.64%) in the study area. Seroprevalence of 35.2, 35.1 and 25% were recorded in Arero, Dhas and Yabello districts, respectively. However, there was no significant difference (χ2=5.56, P=0.062) in seropositivity among the three districts and between male and female goats (χ2=0.068, P=0.794) examined in this study. On the other hand, the differences in seroprevalence among the age categories were statistically significant (χ2=24.48, p<0.0001). A rise in antibody (seroconversion) was observed after field vaccination of goats with inactivated CCPP vaccine and a total of 253 of the 414 examined sera samples were positive for Mycoplasma capricolum subsp. capripneumoniae (Mccp) specific antibodies, thus 61.1% of goats seroconverted following vaccination. Comparison of Mccp specific antibodies in the goat population before and after vaccination indicated that the number of positive reactors increased significantly (P<0.0001) following CCPP vaccination. Seropositivity following vaccination was analyzed among the three age groups and statistically significant differences (χ2=45.48, P<0.0001) were recorded. The change in the serum antibody after vaccination was found to be higher in younger and adult aged goats than old aged goats. In conclusion, the present study indicates that CCPP is one of the major goat health problems in Borana pastoral area which warrants appropriate measures to be in place towards the prevention and control of the disease. Moreover, field vaccination of goats by inactivated CCPP vaccine induced seropositivity in majority of the inoculated goats. Future controlled experimental studies with challenge infection after vaccination need to be conducted for further evaluation of the vaccine efficacy.