RESUMO
The production of an agricultural commodity involves a sequence of processes: planting/growing, harvesting, sorting/grading, postharvest treatment, packing, and exporting. A Bayesian network has been developed to represent the level of potential infestation of an agricultural commodity by a specified pest along an agricultural production chain. It reflects the dependency of this infestation on the predicted level of pest challenge, the anticipated susceptibility of the commodity to the pest, the level of impact from pest control measures as designed, and any variation from that due to uncertainty in measure efficacy. The objective of this Bayesian network is to facilitate agreement between national governments of the exporters and importers on a set of phytosanitary measures to meet specific phytosanitary measure requirements to achieve target levels of protection against regulated pests. The model can be used to compare the performance of different combinations of measures under different scenarios of pest challenge, making use of available measure performance data. A case study is presented using a model developed for a fruit fly pest on dragon fruit in Vietnam; the model parameters and results are illustrative and do not imply a particular level of fruit fly infestation of these exports; rather, they provide the most likely, alternative, or worst-case scenarios of the impact of measures. As a means to facilitate agreement for trade, the model provides a framework to support communication between exporters and importers about any differences in perceptions of the risk reduction achieved by pest control measures deployed during the commodity production chain.
RESUMO
INTRODUCTION: No data has been reported on the prevalence of asthma in highland rural areas of Vietnam. We attempt to determine the prevalence of asthma and asthma-like symptoms in Dalat, a Vietnamese city at 1,500 m altitude, and to learn about environmental influences, patient attitudes toward diagnosis and treatment, and the prevalent general knowledge about asthma. METHODS: Investigators were trained in the use of formal questionnaires. After an extensive publicity campaign by local television, the investigators randomly selected homes for interviews in 12 districts. When physician-diagnosed asthma or asthma-like symptoms were identified, all parts of the questionnaire were completed and a more detailed visit was arranged with the patients, for clinical examination, spirometry and skin tests for important allergens. RESULTS: 9,984 individuals were interviewed, of whom 243 were identified as having asthma or asthma-like symptoms, giving a prevalence of 2.4 percent. Average age was 48 +/- 27 years, age at onset of asthma was 25 +/- 22 years. Hospitalisation had been required in 18.3 percent of patients during 2003. Daily asthma treatment was used by only 17 percent of patients. 34 percent used inhalers and 6 percent used nebulisation. 52.3 percent had associated atopic features. Polyvalent positive prick tests were prevalent, but no one reacted to a pollen mixture. General knowledge about asthma was lacking. CONCLUSION: The prevalence of asthma and asthma-like symptoms in Dalat is low. Allergic cutaneous reactions to house mites predominate. Diagnosis and treatment of those afflicted with asthma appears to be suboptimal. The study highlights the need for further patient education and for preventative interventions for asthma sufferers in this region.
