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Livestock owners, especially traditional farmers, are a valuable source of epidemiological intelligence |
Backyard swine rearing is an important livelihood strategy for many small farmers in South America. Disease is a major limiting factor in pig production throughout the region. Many small producers do not have access to regular veterinary services and are beyond the reach of state animal health services and surveillance systems. As a result, the extent and impact of infectious diseases in smallholder systems are often poorly understood within veterinary services, especially at the central decision-making levels. Lack of representative information leads to a tendency towards policies poorly adapted to the needs of small producers and leads to further marginalization of the poor.
Livestock owners, especially traditional farmers, are a valuable source of epidemiological intelligence for the detection and control of infectious disease often overlooked by conventional disease surveillance systems. Livestock owners are often well aware of the clinical presentation, main pathological lesions and epidemiological patterns of diseases that are important to their livelihood. They can describe how disease affects the benefits they derive from livestock and contributes to the risks and vulnerability associated with their livelihood strategies. Participatory epidemiology is the use of participatory rural appraisal methods that directly involve farmers in disease surveillance to collect information on the incidence, impact and dynamics of diseases of local importance. Participatory disease searching (PDS) was developed as one method of participatory epidemiology that hunts for outbreaks of a specific disease as part of a control programme. This approach was developed as part of the Global Rinderpest Eradication Programme (GREP), and it has increased the sensitivity of rinderpest surveillance programmes. PDS has been essential to the successes achieved in the global eradication of rinderpest and has been proven effective in diverse countries in Africa and Asia.
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J. MARINER |
At the request of FAO, Bolivian and international practitioners of participatory epidemiology recently evaluated and adapted the techniques used in participatory disease surveillance to the classical swine fever (CSF) situation in Bolivian smallholder systems. One month was spent interviewing swine farmers in six different communities in remote areas of the Tarija and Chuquisaca Provinces. The core of the approach was the use of open-ended interview techniques to encourage farmers to identify and describe disease problems in their own words. As problems were identified by the farmers, they were asked to describe the nature of the disease in detail and to talk about its history and importance on their farm and in the area. Interviewers never introduced disease names into the discussion; the farmers controlled the direction of the interview. In this way, the interview data were more likely to reflect the experience and priorities of the farmer rather than biases on the part of the study team.
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J. MARINER |
In the areas studied, CSF was frequently the first or only disease problem mentioned by swine owners. Livestock owners used the terms cólera, peste or peste porcina to refer to CSF. When the owners were asked to describe the disease, fever, diarrhoea, vomiting, neurological signs (trembling, staggering gait, convulsions, etc.) and death were the principal signs they mentioned. The course of the disease was reported to last from one day to several weeks. These descriptions were consistent with acute and subacute CSF. Abortion and weak piglets were not described as problems associated with CSF. This observation indicates either that chronic forms of CSF are not common or that farmers do not recognize chronic CSF. Peracute death syndromes were reported from areas apparently affected by CSF and were sometimes referred to as peste by respondents. The clinical course was so short and devoid of signs that it was not possible to validate these reports in the absence of laboratory support. Acute and subacute CSF were endemic or periodic problems in five of the six communities visited.
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Small farmers who practised extensive production identified CSF as the most important infectious disease affecting swine |
Overall, small farmers who practised extensive production identified CSF as the most important infectious disease affecting swine. However, some non-infectious disease problems such as internal parasites were given greater importance. Intensive periurban producers were largely able to control CSF through vaccination and limitation of contact with other herds. Classical swine fever losses caused some small farmers to drop swine rearing from their mix of livelihood activities. In general, swine production was seen as a profitable but high-risk activity that supplemented more secure activities. It was concluded that CSF was primarily present in the extensive production systems and that control programmes should prioritize backyard swine production.
Farmers had access to CSF vaccine through private veterinary pharmacies. Because of the high cost of professional travel relative to the value of animals, veterinarians rarely diagnosed or treated cases in the field. Primarily, farmers travelled to pharmacies and provided case descriptions, and veterinarians arrived at a presumptive diagnosis. Veterinarians could provide information that allowed general cross-checking of farmers’ reports, but veterinarians could not provide first-hand, eyewitness accounts with specific names, dates and locations. In some areas, community animal health workers (CAHWs), or promotores de salud animal, acted as important intermediaries between urban veterinarians and rural farmers. The CAHWs were the best source of CSF surveillance intelligence encountered in this study. Their reports were highly detailed and specific and could be fully cross-checked against independent sources.
The conclusions of the study were that:
Jeffrey C. Mariner, RDP Livestock Services, and Erick Eulert, Consultant, FAO
FAO. 2000. Manual on participatory epidemiology: methods for the collection of action-oriented epidemiological intelligence. FAO animal health manual 10. Rome (also available at http://www.fao.org/documents/show_cdr.asp?url_file=//DOCREP/003/X8833E/X8833E00.htm).
