湖南省一起非洲猪瘟疫情的暴发调查

An Outbreak Investigation on African Swine Fever in Hunan Province

2018年11月21日,农业农村部通报湖南省怀化市鹤城区排查出非洲猪瘟疫情。为追溯这起非洲猪瘟疫情的来源,怀化市动物疫病预防控制中心开展了流行病学调查,从生猪调运、饲料、泔水、生物安全等风险因素入手,结合流行病学关联养殖场血清以及饲料、泔水、关联屠宰场环境及冻库冷冻猪肉产品等样品的实验室检测,综合分析非洲猪瘟传播的可能途径。调查结果显示:疫情猪场2018年10月曾使用收购的泔水喂养生猪;泔水、冷冻猪肉产品非洲猪瘟病毒(ASFV)核酸阳性检出率分别为0.9%(3/348)、25.6%(10/39),而血清和饲料样品全为阴性;在冻库、餐饮机构和销售终端检出ASFV核酸阳性样品,阳性检出率分别为16.7%、1.8%、7.7%。调查分析显示,该疫情猪场的泔水饲喂时间、发病时间与ASFV自然感染的潜伏期相符,且与泔水有关联的某物流公司冻库猪肉被产品检测出ASFV核酸阳性。综上表明,泔水喂养引起该非洲猪瘟疫情的可能性最大。依据调查结果,采取严格生猪及其产品移动监管,强化落实禁止泔水饲喂政策,加强生物安全管理等一系列防控措施,使疫情得到了有效控制。

On November 21,2018,an outbreak of African swine fever(ASF)was reported in Hecheng District,Huaihua City of Hunan Province by Ministry of Agriculture and Rural Affairs.In order to find out the sources of the outbreak,an epidemiological investigation was carried out by Huaihua Animal Disease Prevention and Control Center.Based on the risk factors including live pig transportation,feed,swill and bio-safety,and according to laboratory detection results of serum,feed and swill from farms related to epidemiology,associated slaughterhouses and frozen pork products from freezers,the possible pathways of ASF spreading were comprehensively analyzed.The results showed that pigs in the affected farm were fed with purchased swill in October 2018;the positive rates of ASF virus(ASFV)nucleic acid in swill and frozen pork products were 0.9%(3/348)and 25.6%(10/39)respectively,while all the serum and feed samples were negative;samples from freezers,restaurants and sale markets were detected ASFV-positive,with the positive rate of 16.7%,1.8%and 7.7%respectively.As it was investigated that the period of feeding with swill and the date of outbreak were consistent with the incubation period of ASF,and positive ASFV nucleic acid was detected in pork products that were stored in the freezer of a transportation company related to swill.In conclusion,the ASF outbreak was possibly caused by feeding with swill.Based on the above investigation results,the outbreak was effectively controlled by a series of control measures,including strict supervision over the movement of live pigs and their products,implementing the ban of feeding with swill,and strengthening management on bio-safety.