ABSTRACT
Brucella abortus vaccines play a central role in bovine brucellosis control with tremendous success worldwide for decades. The study was aimed to evaluate the efficacy of reduced dose (5.0 × 10 9 cfu) of S19 vaccine in adult cattle and its shedding in the milk of vaccinated cattle using molecular techniques. The OIE recommended tests (RBPT, SAT, and iELISA) for brucellosis screening in cattle were used. Seronegative cattle (n = 90) of different age groups (young, old heifers & milking cows, n = 30 each) were selected for the vaccine trials. Antibody titers were recorded at 7th, 21st, 30th, 60th, 90th and 120th days post-vaccination (DPV) to monitor the immune responses following vaccination and at 150th, 180th, 210th and 240th DPB following booster-dose to an intraocular group. The humoral immune responses observed by RBPT and ELISA, proved that antibody titers persisted in s/c group compared to the i/o group in all categories. The IFN-γ stimulation (CMI) due to reduced dose vaccination was noticed early as 30th in all groups and declined after 90th DPV, with higher IFN-γ stimulation among the s/c group. The Bcsp31 and IS711 targeted PCR detected the presence of Brucella DNA in milk samples (n = 120) from the vaccinated cows (n = 30) and confirmed by qPCR (TaqMan assay) at 30th, 60th, 90th and 120th DPV. A Significant number, 70% (7/10) was detected in s/c by qPCR. BCSP31 sequence was deposited at NCBI GenBank (accession no. MK881173-6). PCR and qPCR techniques could provide a reliable diagnosis of brucellosis from milk. The intraocular route remains the safer route for vaccinating adult cattle than subcutaneous.
ABSTRACT
We evaluated livestock owners' knowledge, attitudes, and practices regarding brucellosis in Jordan. A questionnaire was administered and biological samples were examined to verify the serological status of animals. Seroprevalence estimates indicated that 18.1% (95% CI: 11-25.3) of cattle herds and 34.3% (95% CI: 28.4-40.4) of small ruminant flocks were seropositive. The results showed that 100% of the interviewed livestock keepers were aware of brucellosis: 87% indicated a high risk of infection if unpasteurized milk is consumed and 75% indicated a high risk if unpasteurized dairy products are consumed. Awareness of the risk of infection through direct contact with fetal membranes or via physical contact with infected livestock is considerably lower, 19% and 13%, respectively. These knowledge gaps manifest in a high frequency of high-risk practices such as assisting in animal parturition (62%), disposing aborted fetuses without protective gloves (71.2%) or masks (65%), and not boiling milk before preparation of dairy products (60%). When brucellosis is suspected, basic hygiene practices are often disregarded and suspect animals are freely traded. Public health education should be enhanced as the disease is likely to remain endemic in the ruminant reservoir as long as a suitable compensation program is not established and trust on available vaccines is regained.
