Brucellosis: A menace in livestock production

The causal organism of brucellosis in the various species is Brucella abortus in cattle, Brucella melitensis (Ovis) in sheep and Brucella suis in pigs.
The brucella organisms are very small bacteria which can survive in protein containing animal tissue, e.g. the remains of the after birth, for a long time - up- to 1-2 years on a pasture. Cold acts as a preservative.
The main sources of infection are afterbirths, foetal fluids, aborted foetuses (calves, lambs etc.), post paturient vaginal discharges  and milk. Infection takes place through mucous membranes (conjunctiva and mouth or through the apparently intact skin (very small wounds or erosions, not visible to the naked eye). Practically all animals including man are susceptible. Wild animals (wild ruminants, hares) are important transmitters and reservoirs of infection.
Brucellosis is a disease of the reproductive system (uterus, foetus, foetal membranes, udder, testicles) and f the reticulo- endothelial system (spleen, lymph-node etc.). Except for the obvious act of abortion and the retention of the afterbirth, acute manifestations of the disease are only rarely shown in the female. The disease tends to spread rapidly to other animals in the herd. The first abortion usually occurs in cattle between 6th and 8th month of pregnancy. After several abortions have occurred, infected animals may produce living but weak calves which fail to survive.

Symptoms
Symptoms of the disease are seen mainly in rams. Occasionally, aborting ewes may be encountered but this is an exception. Infected rams (of any age) rapidly develop symptoms. At first, a marked swelling and inflammation of the scrotum and its contents accompanied by loss of appetite and fever is noticed. Often this stage is absent or non apparent. Semen examination at this stage usually reveals a large number of neutrophils (pus cells).
Diagnosis can initially be made by palpation but confirmation depends on serological blood examinations as well as semen examinations.
It is strongly recommended that all rams be regularly palpated every year and that semen be examined of all suspected cases as well as a certain percentage of healthy rams.

Treatment
Treatment is not recommended but a vaccine is available which is an all excellent preventative.