Brucellosis in pastoral and confined livestock: prevention and vaccination.

ABSTRACT

The traditional lifestyle and beliefs of pastoralists and small-scale farmers with confined livestock, together with certain farming environments, create favourable conditions for the spread and transmission of brucellosis. The risks associated with these practices are difficult to control because of a lack of alternatives and simple and/or affordable solutions. Brucellosis affects the health and productivity of livestock as well as that of their owners and caretakers and can have a deep economic impact. The control of brucellosis is likely to be cost effective. Good quantitative information on brucellosis in livestock and the human population is essential for demonstrating the benefits of intervention. Effective vaccines for the control of brucellosis in cattle and small ruminants are available and cheap, and in high-risk areas there is an urgent need to start large-scale vaccination programmes. Risks for the spread and transmission of brucellosis, such as the migration of herds with frequent contacts with other herds at common feeding grounds and near water sources, are inherent in the way of life of pastoralists. Such risks may need to be accepted when developing a control programme. Thus, the control of brucellosis by vaccination is expected to be more effective for confined livestock. Essential to the success of mass vaccination in controlling brucellosis is achieving a high degree of protection of adult livestock in a very short period and vaccinating young stock before natural infection can occur. To reduce the risk of transmission of infection from neighbouring areas where animals are not vaccinated, a region-wide approach is important. Because shepherds and farmers may have very little knowledge of infectious diseases and the consequences of infection, providing disease information and education is important to help them understand the need for control measures. Public health services can also assist in encouraging acceptance of control programmes in livestock by creating awareness of brucellosis as a human disease. To reduce costs, brucellosis control programmes can be combined with other veterinary or public health activities or interventions. An up-to-date livestock census and an effective surveillance system are crucial for the control of brucellosis, as the disease may quickly re-emerge from remaining foci of infection. Although test and slaughter may be an option for the management of remaining or re-emerging foci of infection, such a strategy is frequently not an option because of the cost.