The use of three vaccines against Brucella melitensis in sheep

Control of ovine brucellosis in Najdi sheep in Saudi Arabia

A practical programme for control of ovine brucellosis in a Najdi sheep flock at Haradh and protection of sheep handlers from infection was implemented. Haradh sheep were serologically tested three times at six-month intervals. Of 2,721 sheep subjected to the first tests, 387 (14.2%) were positive reactors. At the second test 2,072 sheep were tested and 31 (1.5%) were positive. The third test was performed on 2,963 sheep and only nine (0.3%) positive reactors were found. Of eight sheep handlers six had Malta fever. Positive reactor sheep were slaughtered and buried after each test. Following the third test all negative sheep were vaccinated with inactivated Brucella melitensis vaccine. Infected sheep handlers were treated at the Haradh clinic. One year after completion of the programme abortions and infertility problems had disappeared and the lambing percentage had increased from 0.8 to 1.3 lambs per ewe. In addition all young lambs born to vaccinated ewes were found to be serologically negative. We suggest expansion of the present programme into a national brucellosis control campaign in the kingdom.