Sydney School of Veterinary Science, The University of Sydney, Sydney, New South Wales, Australia.
Transbound Emerg Dis. 2022 Sep;69(5):e1289-e1298. doi: 10.1111/tbed.14573. Epub 2022 May 11.
African Swine Fever Virus (ASFV) is a contagious pathogen that can cause severe acute haemorrhagic fever in pigs. The first occurrence of an ASF outbreak in Asia was reported in China in August 2018. The devastating impacts caused by ASF on the pig industry have strongly focused research on risk factors for the spread of ASFV. The purpose of this systematic review was to identify the potential knowledge gap in the English literature on risk factors for the spread of ASFV in outbreaks that occurred in China, 2018-2020. China National Knowledge Infrastructure (CNKI) was searched as the primary database. Sixty-four records were screened, and 31 (48%) records were included in data extraction. These records were also assessed for quality of evidence. Frequency tables for reported risks were created, considering quality of evidence. A narrative summary of mortality rate and case fatality rate reported in a small number of records was made. Mortality rate was reported in seven studies, ranging from 3.7% to 84.0% (median 11.9%). Case fatality rate was reported in six studies, ranging from 20.6% to 100% (median 63.3%). Based on 31 reviewed records, live pig transport, swill feeding and vehicles were the three most important risks for spread contributing to the ASF epidemic in China. Bites of infected Ornithodoros ticks was stated in 12 low level of evidence records but only 1 high level of evidence record as a risk factor for transmission. Direct contact with wild pigs was reported to be a risk factor in 8 records with low level of evidence, and 1 record from the high level of evidence group. However, limited evidence was provided to support the tick-domestic pig or wild pig-domestic pig transmission routes in China. Lack of resources to obtain veterinary assistance and to improve husbandry and biosecurity was mentioned four times in the 31 records, especially in remote rural areas. In conclusion, to effectively control the spread of ASF, it is very important to reduce mechanical dissemination of ASFV by vehicles and live pig transport involved in the production cycle and to ensure that transported pigs are always subject to inspection and quarantine. Additionally, despite strict implementation of prohibition on swill feeding often being impractical or nearly impossible, ensuring the safety of pig feed can greatly contribute to disease prevention. Improvement in biosecurity management, specifically environment disinfection, carcass disposal, and decontamination of vehicles and personnel will be most effective in reducing the risk of infection in small-scale pig farms.
非洲猪瘟病毒（ASFV）是一种传染性病原体，可导致猪发生严重急性出血性发热。2018 年 8 月，亚洲首次报告发生 ASF 疫情。ASF 对养猪业造成的破坏性影响使人们强烈关注 ASFV 传播的风险因素。本系统评价的目的是确定 2018-2020 年中国暴发疫情中 ASFV 传播的英文文献中潜在的知识空白。中国国家知识基础设施（CNKI）被作为主要数据库进行检索。筛选了 64 份记录，其中 31 份（48%）记录被纳入数据提取。这些记录也被评估了证据质量。考虑到证据质量，为报告的风险创建了频率表。对少数记录报告的死亡率和病死率进行了叙述性总结。有 7 项研究报告了死亡率，范围从 3.7%到 84.0%（中位数为 11.9%）。有 6 项研究报告了病死率，范围从 20.6%到 100%（中位数为 63.3%）。基于 31 份综述记录，生猪运输、泔水喂养和车辆是导致 ASF 在中国流行的三个最重要的传播风险因素。12 份低水平证据记录中提到了受感染的钝缘蜱的叮咬，但仅有 1 份高水平证据记录将其作为传播的风险因素。8 份低水平证据记录报告了野猪的直接接触是风险因素，而 1 份高水平证据记录组也报告了这一风险因素。然而，在中国，支持蜱-家猪或野猪-家猪传播途径的证据有限。31 份记录中有 4 次提到缺乏资源获得兽医援助以及改善畜牧业和生物安全，尤其是在偏远的农村地区。总之，为了有效控制 ASF 的传播，减少车辆和参与生产周期的生猪运输过程中 ASFV 的机械传播非常重要，同时确保运输的猪始终受到检查和检疫。此外，尽管严格实施禁止泔水喂养往往不切实际或几乎不可能，但确保猪饲料的安全对疾病预防有很大帮助。改善生物安全管理，特别是环境消毒、尸体处理、车辆和人员的消毒，将是减少小型养猪场感染风险的最有效方法。
