Diagnosis and control of brucellosis in small ruminants

Abstract

Brucellosis is a communicable disease which may seriously endanger the efforts for increasing and improving the production of small ruminants, particularly in developing countries which have problems with ensuring the necessary animal protein for rapidly growing human populations. Brucellosis of goats and sheep is caused by Brucella melitensis and is an important public health problem. Infected goats and sheep are the source of a serious and often prolonged incapacitating illness of humans. The diagnosis of caprine and ovine brucellosis is based largely upon serologic tests. Simple tests are available which can be used directly in the field on hundreds of animals. However, all tests have limited reliability and the results of testing should be interpreted on a flock basis. Some characteristics of the most often used tests such as the card test, milk ring test, and the serum agglutination tube test have been discussed with regard to their diagnostic value and practical application. Special attention was given to the allergic skin test which is very useful in large-scale tests. The control of caprine and ovine brucellosis is discussed with particular emphasis on the conditions that prevail in developing countries. The classical principles of prevention are often not feasible and the only practical way of control is vaccination. B. melitensis Rev 1 vaccine has proven to be superior to all other vaccines in small ruminants. The extensive use of this vaccine is a milestone in brucellosis control. The main characteristics of the vaccine along with practical suggestions for vaccination programs are given. Experiences with a large-scale program using Rev 1 vaccine in Mongolia are presented. A critical part of any control program should be supporting measures. Particular attention should be paid to organizational measures in the veterinary services, legislative and financial support, health education, and collaboration between veterinary and health services.