Comparative Clinical Pathology

, Volume 18, Issue 4, pp 439–442 | Cite as

Post vaccination follow-up of Brucella melitensis in blood stream of sheep by PCR assay

  • Gholam Ali KojouriEmail author
  • Masood Gholami
Original Article


Brucella melitensis is the causative agent of brucellosis in sheep and goats. While there is no treatment of choice for brucellosis, vaccination with Rev1 vaccine in sheep is the only effective procedure to reduce the incidence of brucellosis in many countries. As it has been shown earlier, in cases with brucellosis, the agent enters into the blood stream at first and then localises in the reticuloendothelial system and reproduction organs. For this reason, and in order to determine the duration of presence of bacteria in blood, this research was carried out on 15 female sheep 3 months of age. Ten sheep were vaccinated with Rev1 vaccine and five were used as control (unvaccinated) group. Polymerase chain reaction (PCR) was used for amplification of the 720-bp sequence of immunogenic outer membrane protein gene specific to B. melitensis. Blood samples were taken before the beginning of the experiment and on the first, 7th, 14th, 21st, 28th and 60th days after that. PCR results showed that all animals were negative before the beginning of experiment, but on the first, 7th, 14th, 21st, 28th and 60th days after that, a positive reaction was observed in 50%, 100%, 100%, 90%, 70% and 50% of vaccinated animals, respectively. Also, 40% of the control group showed positive results only on the 14th day after vaccination. Some serological tests such as Rose Bengal test (RBT), serum agglutination test (SAT) and 2-mercapto-ethanol (2ME) were performed on samples which showed that both vaccinated and unvaccinated animals had titres for Brucella antibody in their sera on the 7th day with relative frequency of 70 and 20%, respectively. These findings show that bacteraemia may occur on the first day and prolongs until the end of experimentation with maximum presence on the 7th and 14th days after vaccination. Conversely, this can explain the B. melitensis dissemination ability from vaccinated animals to healthy ones.


PCR Brucellosis Rev1 Vaccination Sheep 


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Copyright information

© Springer-Verlag London Limited 2009

Authors and Affiliations

  1. 1.Department of Clinical Sciences, School of Veterinary MedicineShahrekord UniversityShahrekordIran
  2. 2.School of Veterinary MedicineShahrekord UniversityShahrekordIran

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