A Stepwise Approach for Progressive Control of Brucellosis in Animals and HumansTuesday, March 05, 2013
A systematic four step process has been outlined by the Food and Agriculture Organisation to assist controlling Brucellosis in human and animal populations.
Despite advances in surveillance and control, the prevalence of brucellosis is increasing in many developing countries because of sanitary, socio-economic and political factors, according to Ahmed El Idrissi in the FAO EMPRES newsletter. Many countries in post-communist transition face a sharp increase in zoonotic diseases resulting from the breakdown of government-run disease surveillance and control and weak private health and veterinary services. Fast-growing demand for milk, the subsequent upsurge in peri-urban dairy production, and a lack of adequate food safety practices have been identified as risk factors for human brucellosis in many developing countries.
With varying degrees of success, most countries have attempted to combat brucellosis, leading to changes in its global distribution over time. At present, a number of developed countries (such as Australia, Canada, Japan, New Zealand and countries in northern and central Europe) have eradicated or significantly reduced the prevalence of B. abortus infections. However, with the exception of some in Western Europe, few countries have successfully eradicated B. melitensis infections, which tend to be associated with more severe human disease than does B. abortus.
Control programmes are planned or ongoing throughout the world, adopting different approaches and targeting different priorities. In some developing countries, however, the implementation of these control programmes is not always based on an epidemiologically sound strategy, and the programmes are not planned and sustained for a sufficiently long term to achieve their initial objectives.
To assist member countries in launching, correcting and pursuing brucellosis control programmes aimed at controlling and eradicating brucellosis in animals and humans, the Food and Agriculture Organization of the United Nations (FAO) has designed a roadmap for stepwise progressive control. The roadmap describes a sequence of activities that reduce brucellosis in livestock and humans, eventually leading to the self-declaration of brucellosis-free status as defined by the World Organisation for Animal Health (OIE) Terrestrial Animal Health Code.
A Stepwise Approach for Progressive Control
The roadmap for progressive control of brucellosis consists of four stages (Box 1), each with key activities and objectives; external influences that affect achievement of the desired outcomes of each stage are also identified.
The roadmap is designed to make brucellosis control a progressive process; each country enters this pathway at the stage that corresponds to its prevailing situation. The roadmap guides countries in decisions regarding whether or not to commence or improve their brucellosis surveillance and control programmes.
A Four-stage Roadmap for Progressive Control of Brucellosis in Animals and Humans
Stage 0: Unknown Situation
Situation: Brucellosis in humans and livestock is suspected to occur more or less frequently, but cases/outbreaks are seldom confirmed and prevalence and distribution have not been determined. Veterinary and medical authorities need to know the Brucella species involved in suspected cases/outbreaks, the prevalence of the disease in various livestock species, the prevalence in various livestock management systems or zones, and information on how new cases/outbreaks occur, how the disease is spread and how it persists.
Expected outcome: Better understanding of the magnitude of brucellosis infection and an agreed control strategy based on sound epidemiological knowledge.
Stage 1: Known Situation with Control Programme
Situation: The veterinary authority is implementing the agreed national brucellosis control programme either in a pilot area or country-wide. Quality control of vaccines and vaccination delivery by field staff, and laboratory diagnosis have become standard operating procedures. Brucellosis epidemiology units in the public health and veterinary services are collaborating in a national intersectoral brucellosis committee to share information, trace back newly diagnosed human cases and issue public communications.
Expected outcome: Decreased brucellosis prevalence in livestock and humans.
Stage 2: Near to Eradication
Situation: Brucellosis sero-prevalence trends are lower in livestock but progress among livestock management systems and districts/zones is uneven. Human incidence is also trending lower. Effective routine surveillance is critical during this stage.
Expected outcome: Brucellosis rates continuing to fall to low levels in livestock and humans.
Stage 3: Self-declared Freedom from Brucellosis
Situation: The national veterinary authority may make a self-declaration of freedom from brucellosis by meeting OIE standards. Requirements for self-declared freedom from brucellosis change over time, so periodic consultation of OIE standards is necessary.
Expected outcome: Self-declaration of freedom from brucellosis made by veterinary authorities according to OIE standards.
A Source of Up-to-date Information on Brucellosis Control
As well as descriptions of the four stages of progressive brucellosis control, the roadmap also provides basic information on control tools and strategies, such as a review of control options, recent practical experiences, accepted international opinions, lessons learned from the field, and innovations from research. Links to technical tools (tool kits) and supporting literature or accepted international opinion give national veterinary authorities additional confidence in undertaking roadmap activities. Major issues are discussed, and the text clearly stipulates instances where information is lacking or data are controversial or contradictory.
Factors Influencing Implementation of the Roadmap
Externalities and enabling factors that might influence the course of progressive brucellosis control are highlighted in the roadmap text. Examples of externalities and the prerequisites for implementing a control option provide national authorities with insights into essential management considerations and recognized best practices. These examples enrich the often apparently simple activities recommended, and provide examples of the magnitude of risks, which can allay fears about the use of certain vaccines, for instance. They emphasize the importance of components such as competent field and laboratory services, enabling legislation, effective animal movement control and a compensation system for test-and-removal of animals, in achieving the goal of self-declaration of brucellosis-freedom under OIE standards.
The stepwise approach is being promoted for the progressive control of major transboundary animal diseases and zoonoses, particularly where control or eradication is deemed to be a global public good or where the disease restrains trade in livestock and livestock products. The roadmap for brucellosis control and elimination is designed to provide easy access to clear information for chief veterinary officers and inspectors and their staff responsible for the control of infectious diseases.
Further ReadingYou can view the full report by clicking here.
Further ReadingYou can view the disease page by clicking here.