الملخص الإنجليزي
ABSTRACT
A cluster of 75 human Brucellosis cases was identified during the period of May to July 2016 from the coastal area in the north of Oman mainly in Saham in the North Batinah Governorate. During the period of the outbreak the seroprevalence was 1.95%, 4.47%, 1.06% and 18.18% in goat, sheep, cattle and camels respectively which was determined based on an animal being positive in Rose Bengal test LPS-ELISA. Test-and-slaughter and quarantine of suspected animal were implemented in the area by the Ministry of Agriculture and Fisheries. A proportional allocation method was used to determine the sample size from six randomly selected villages from Saham. A total of 399 animals were selected; goats (n=100), sheep (n=99), cattle (n=99) and camels (n=101) and tested using RBT and LPS-ELISA. The results showed a drop in the sero-positivity to 0% in goats and camel and to 1.01% in sheep and cattle which indicated the effectiveness of the test-and-slaughter strategy for the control and eradication of Brucellosis. SS Bp26 is a conserved protein among all members of the genus Brucella that is believed to not cross-react with other Gram negative organism.
To assess a diagnostic potential of Bp26, the recombinant protein was cloned, expressed in E. coli, purified and used as an antigen in an indirect ELISA (Bp26-iELISA). Four groups of sera from naturally B. melitensis-infected goats were tested. Group A were serologically positive animals in three tests (RBT, LPS-ELISA and CFT tests). Group B were serologically positive animals in two tests (RBT and LPS-ELISA) or (LPS-ELISA and CFT). Group C were serologically positive animals in one test only (RBT, IELISA or CFT). Group D were sera from 10 healthy goats used to determine the cutoff and the specificity of the ELISA. A cutoff value of(0.42) corresponding to a 99% confidence interval was employed to determine a true positive. Group A and group B has values of 1.79 and 0.93 respectively and were considered significantly above the denoted cutoff value. Group C satisfied a positive value if a 95% CI was used. In addition, one Brucella melitensis was isolatesd from a bronchial lymph node. It was cultured in Farrell's medium and identified using Vitek 2 system. The Multiplex PCR also clearly demonstrated bands characteristic of Brucella melitensis. Furthermore, an anti Bp26 mouse serum was used in an immunohistochemical study to localize Bp26 in a variety of tissue sections. Positive staining was found on the spleen and mesenteric lymph nodes. Based on the results of the study Bp26 is potential diagnostic antigen for the serodiagnosis of Brucella in goats
