Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, 751 89, Uppsala, Sweden.
Department of Disease Control and Epidemiology, National Veterinary Institute, 751 89, Uppsala, Sweden.
Acta Vet Scand. 2023 Sep 14;65(1):39. doi: 10.1186/s13028-023-00703-z.
A growing number of people in western countries keep small chicken flocks. In Sweden, respiratory disease is a common necropsy finding in chickens from such flocks. A respiratory real-time polymerase chain reaction (PCR) panel was applied to detect infectious laryngotracheitis virus (ILTV), Avibacterium paragallinarum (A. paragallinarum) and Mycoplasma gallisepticum (M. gallisepticum) in chickens from small flocks which underwent necropsy in 2017-2019 and had respiratory lesions. Owners (N = 100) of PCR-positive flocks were invited to reply to a web-based questionnaire about husbandry, outbreak characteristics and management.
Response rate was 61.0%. The flocks were from 18 out of Sweden's 21 counties indicating that respiratory infections in small chicken flocks are geographically widespread in Sweden. Among participating flocks, 77.0% were coinfected by 2-3 pathogens; 91.8% tested positive for A. paragallinarum, 57.4% for M. gallisepticum and 50.8% for ILTV. Larger flock size and mixed-species flock structure were associated with PCR detection of M. gallisepticum (P = 0.00 and P = 0.02, respectively). Up to 50% mortality was reported by 63.9% of respondents. Euthanasia of some chickens was carried out in 86.9% of the flocks as a result of the outbreaks. Full clinical recovery was reported by 39.3% of owners suggesting chronic infection is a major challenge in infected flocks. Live birds had been introduced in many flocks prior to outbreaks, which suggested these as an important source of infection. Following the outbreaks, 36.1% replaced their flocks with new birds and 9.8% ceased keeping chickens.
This study highlights the severity of respiratory outbreaks in small non-commercial chicken flocks and points to the need for more research and veterinary assistance to prevent and manage respiratory infections in small chicken flocks.
西方国家越来越多的人饲养小型鸡群。在瑞典，这种鸡群的鸡剖检时常见的呼吸道疾病。2017-2019 年间，对剖检时发现有呼吸道病变的小型鸡群进行了呼吸道实时聚合酶链反应（PCR）检测，以检测传染性喉气管炎病毒（ILTV）、禽传染性鼻炎病原体（A. paragallinarum）和鸡败血支原体（M. gallisepticum）。我们邀请了 PCR 阳性鸡群的主人（N=100）回答一个关于饲养、暴发特征和管理的网络问卷。
回复率为 61.0%。这些鸡群来自瑞典 21 个郡中的 18 个，表明呼吸道感染在瑞典的小型鸡群中具有广泛的地理分布。在参与调查的鸡群中，77.0%的鸡群混合感染了 2-3 种病原体；91.8%的鸡群检测到 A. paragallinarum 阳性，57.4%的鸡群检测到 M. gallisepticum 阳性，50.8%的鸡群检测到 ILTV 阳性。较大的鸡群规模和混合物种鸡群结构与 M. gallisepticum 的 PCR 检测呈正相关（P=0.00 和 P=0.02）。63.9%的受访者报告死亡率高达 50%。86.9%的鸡群因暴发而对部分鸡只实施了安乐死。39.3%的鸡主报告称鸡群完全康复，这表明慢性感染是感染鸡群的主要挑战。在暴发前，许多鸡群中都引入了活禽，这表明这些鸡群是感染的重要来源。暴发后，36.1%的鸡群用新鸡取代了原来的鸡群，9.8%的鸡群停止饲养鸡。
本研究强调了小型非商业鸡群中呼吸道暴发的严重性，并指出需要更多的研究和兽医援助，以预防和管理小型鸡群的呼吸道感染。
