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Efficacy of Brucella melitensis Rev. 1 vaccine against Brucella ovis infection in rams
Abstract:
The efficacy of Brucella melitensis strain Rev. 1 vaccine against a Brucella ovis experimental infection was judged on 30 rams, 15 of which had received 8.5 X 10(8) Rev. 1 at the age of 4 months. All were challenged 9 months later by conjunctival route with 5 X 10(8) B. ovis. The 30 rams were killed three months after challenge and were autopsied. Genital and other organs and lymph-nodes were searched for B. ovis. Only a few organs and lymph-nodes of three vaccinated rams shed B. ovis, contrary to controls which were all heavily infected. The distribution of infection indicated that the most frequently infected organs are the vesicular glands which, more than epididymes, seem to be the target organs of the infection. These results show that immunization with strain Rev. 1 is very effective against B. ovis infection. It is recommended to vaccinate rams of four to six months in an area where B. ovis or B. melitensis infection, or both, are prevalent.
Insights
The Brucella melitensis strain Rev. 1 vaccine effectively protected rams against Brucella ovis infection. Vaccination significantly reduced B. ovis shedding and organ infection in rams.
Area of Science:
- Veterinary Immunology
- Bacteriology
- Vaccinology
Background:
- Brucella ovis causes significant economic losses in sheep farming.
- Brucella melitensis strain Rev. 1 is a live vaccine commonly used against brucellosis in small ruminants.
Purpose of the Study:
- To evaluate the efficacy of Brucella melitensis strain Rev. 1 vaccine against experimental Brucella ovis infection in rams.
Main Methods:
- Thirty rams were divided into two groups: 15 vaccinated with B. melitensis Rev. 1 and 15 unvaccinated controls.
- All rams were challenged conjunctivally with B. ovis 9 months post-vaccination.
- Post-challenge, rams were euthanized and necropsied to detect B. ovis in genital organs and lymph nodes.
Main Results:
- Only three vaccinated rams shed B. ovis, while all control rams showed heavy infection.
- Vesicular glands were identified as the primary target organs for B. ovis infection.
- Vaccination significantly reduced the prevalence and shedding of B. ovis.
Conclusions:
- Brucella melitensis strain Rev. 1 vaccination is highly effective in preventing Brucella ovis infection in rams.
- Vaccination of rams aged 4-6 months is recommended in areas endemic for B. ovis or B. melitensis.