Seroprevalence of Brucella among Camels in Upper Egypt

The objective of this work was to determine the seroprevalence of brucellosis among camel obtained from El Shalateen area, Red Sea governorate.  Identification of   Brucella isolates, from naturally infected slaughtered camel, using bacteriological and molecular methods to identify the prevalent field strain in camels. This investigation was carried out on 470 camels during the period from July 2020 to June 2021 in El Shalateen area, Red Sea governorate, Egypt using Modified Rose Bengal plate test (mRBPT), Immunochromatographic Assay (ICA) and further confirmation by complement fixation test (CFT) for evaluation of the seroprevalence of camel brucellosis and characterization of Brucella microorganism on bacteriological and molecular basis. The results revealed that the seroprevalence was 10.9%, 8.9%, and 8.5% using mRBPT, ICA and CFT, respectively. The results revealed that there is a highly significant association between brucellosis diagnosed by mRBPT and CFT and the age of the camel. The highest percentage of seropositivity was recorded in older camels > 6y, (p-value < 0.0001). While brucellosis by ICA showed a significant relationship with age (P < 0.05). But there was a non-significant association between brucellosis diagnosed by mRBPT, ICA, and CFT and the sex of the camel, (P > 0.05). The results also revealed that the sensitivity was 100% for mRBPT and ICA While the specificity was 97.44% and 99.53% for mRBPT and ICA, respectively using CFT as the gold standard test. Brucella isolation was 6.7% isolated from costocervical and precrural lymph nodes, liver spleen, and testicles which were identified biochemically as Brucella melitensis biovar 3. DNA extraction and PCR amplification from isolates revealed 5 out of 5 isolates with a molecular size of 282 bp identified as Br. melitensis DNA. In conclusion, ICA can be used as a rapid screening and confirmatory test for the diagnosis of camel brucellosis. Besides, CFT is still a gold standard test because of its balance between sensitivity and specificity.