Brucella melitensis infection in sheep: present and future

Area of Science:

• Veterinary Medicine
• Microbiology
• Zoonotic Diseases

Background:

• Sheep brucellosis, primarily caused by Brucella melitensis, is a significant zoonotic disease with global prevalence.
• The disease shares pathological and epidemiological similarities with Brucella abortus infection in cattle.

Purpose of the Study:

• To review current strategies for controlling sheep brucellosis.
• To evaluate diagnostic methods and vaccine efficacy for Brucella melitensis.

Main Methods:

• Review of literature on sheep brucellosis control, diagnosis, and vaccination.
• Analysis of diagnostic techniques including culture, PCR, serological tests (Rose Bengal plate agglutination, complement fixation, ELISA), and skin tests.
• Evaluation of the live B. melitensis Rev 1 vaccine efficacy.

Main Results:

• The live B. melitensis Rev 1 strain, administered conjunctivally, is highly effective for whole-flock vaccination, reducing disease prevalence in sheep and humans.
• Bacterial isolation and identification rely on selective media, biochemical tests, phage lysis, and increasingly, PCR-based methods for differentiation.
• Serological tests like Rose Bengal plate agglutination and complement fixation are recommended for screening, despite potential limitations in sensitivity and specificity.

Conclusions:

• Whole-flock vaccination with B. melitensis Rev 1 is a key strategy for sheep brucellosis control.
• A combination of diagnostic methods, including bacterial culture, PCR, and serological tests, is essential for accurate diagnosis and disease management.
• Test-and-slaughter strategies should be reserved for low-prevalence areas due to cost-effectiveness.