Dejyong Tosapol, Chanachai Karoon, Prarakamawongsa Tippawon, Kongkaew Wandee, Thiptara Anyarat, Songserm Taweesak, Rukkwamsuk Theera, TagoPacheco Damian, Phimpraphai Waraphon
Food and Agriculture Organization of the United Nations, Regional Office for Asia and the Pacific, Phranakorn, Bangkok, Thailand, 10200.
Graduate Student, Bio-Veterinary Science Program (International), Faculty of Veterinary Medicine, Kasetsart University, Bangkok, Thailand, 10900.
Vet World. 2023 Jan;16(1):35-45. doi: 10.14202/vetworld.2023.35-45. Epub 2023 Jan 9.
Marek's disease (MD) is a common lymphoproliferative disease affecting chickens and causing economic losses in commercial poultry. The MD outbreak was noticed in the southern part of Thailand in 2019. The suspected cases were found with an abnormal number of cases of layers dying with clinical signs, for example, weakness and emaciation, with evidence of MD gross lesions. This study aimed to raise awareness of the MD outbreak through value chain analysis (VCA), identifying associated possible risk factors, and estimating the associated economic impact.
Value chain analysis, including seasonal calendar, value chain diagram, and layer movement mapping of the layer industry, was conducted. High-risk stakeholders were identified on the basis of risk practices and interactions between stakeholders. A case-control study was conducted to determine risk factors associated with the MD outbreak on layer farms, and partial budget analysis was used to estimate economic losses associated with MD.
The value chain diagram showed the linkages between stakeholders, including estimation of the percentage of products moved from one stakeholder group to another and the negotiated price. Fourteen out of 35 layer farms were case farms. Farm size and source of birds were significantly associated with the MD outbreak. The MD outbreak caused total economic losses of 295,823 USD. Farms that slaughtered infected birds with additional revenues incurred losses of 140,930 USD, whereas farms that culled infected birds without additional revenue returned incurred losses of 1995 USD.
The VCA provided a better understanding of the layer and egg businesses in South Thailand and guided the development of questionnaires for outbreak investigation. The potential risk factor findings suggested the need for further exploration of the source of the MD outbreak.
马立克氏病（MD）是一种常见的影响鸡群的淋巴增生性疾病，会给商业家禽业造成经济损失。2019年在泰国南部发现了马立克氏病疫情。疑似病例表现为蛋鸡出现异常数量的伴有临床症状（如虚弱和消瘦）死亡的情况，且有马立克氏病肉眼可见病变的证据。本研究旨在通过价值链分析（VCA）提高对马立克氏病疫情的认识，识别相关的潜在风险因素，并估算相关的经济影响。
进行了价值链分析，包括季节日历、价值链图以及蛋鸡产业的蛋鸡流动映射。根据风险实践和利益相关者之间的互动确定了高风险利益相关者。开展了一项病例对照研究以确定蛋鸡养殖场马立克氏病疫情的相关风险因素，并使用部分预算分析来估算与马立克氏病相关的经济损失。
价值链图展示了利益相关者之间的联系，包括从一个利益相关者群体转移到另一个群体的产品百分比估算以及协商价格。35个蛋鸡养殖场中有14个是病例养殖场。养殖场规模和鸡苗来源与马立克氏病疫情显著相关。马立克氏病疫情造成的总经济损失为295,823美元。宰杀感染鸡并获得额外收入的养殖场损失了140,930美元，而扑杀感染鸡且无额外收入回报的养殖场损失了1995美元。
价值链分析有助于更好地了解泰国南部的蛋鸡和鸡蛋业务，并指导了疫情调查问卷的制定。潜在风险因素的发现表明需要进一步探究马立克氏病疫情的源头。
