摘要
本试验通过对高发病率、高死亡率的新生仔猪腹泻病例进行诊断与控制,以期为该病的防控提供参考和借鉴。2013年1月初广西玉林某规模猪场发生以2-3日龄仔猪腹泻、呕吐、精神不振为主的疫情,发病率80%,死亡率80%-100%。为确定此次疫病的病因,本研究从发病猪群中采集10份病死猪小肠、脾脏、肺脏、淋巴结等组织进行细菌分离、PCR检测、病毒分离、病毒效价（TCID50）测定、基因测序与分析。检测结果显示猪流行性腹泻病毒（PEDV）和猪繁殖与呼吸综合征病毒（PRRSV）均为阳性,猪瘟病毒（CSFV）、猪伪狂犬病病毒（PRV）、猪传染性胃肠炎病毒（TGEV）和猪轮状病毒（PRoV）均为阴性,未分离到致病菌。克隆测序分离株的ORF7和Nsp2全基因序列,结果显示分离株为美洲型PRRSV,ORF7基因全长为372bp,编码123个氨基酸;Nsp2基因全长为2 850bp,编码950个氨基酸,其中Nsp2基因在第481、532—560位发生了共30个氨基酸的不连续缺失,与高致病性PRRSV（HP-PRRSV）JXA1株Nsp2基因缺失特征一致,属于HP-PRRSV分离株。匀浆病料接种Marc-145细胞,48h开始出现PRRSV特征性病变,TCID50为10-5.75/0.1mL。推测此次新生仔猪大批死亡主要是PEDV感染后继发高致病性猪繁殖与呼吸综合征所致。
The assay was aimed to provide theoretical references for the prevention and control of newborn piglet epidemic diarrhea which was characteristic of high morbidity and mortality.An outbreak of newborn piglet epidemic featuring diarrhea,emesis and lassitude was reported in January 2013 in a large-scale pig farm in Yulin,Guangxi province.The morbidity and mortality in the epidemic were 80% and 80% to 100%,respectively.To identify the causes,ten samples of small intestines,spleens,lungs and lymph glands were collected for the bacterial isolation,PCR,virus isolation,determination of TCID50,gene sequencing and analysis.The detection results showed that PEDV and PRRSV were positive while those of CSFV,PRV,TGEV and PRoV were negative.No pathogenic bacteria were isolated.Clone and sequence results of ORF7 and Nsp2genes of the isolate indicated that the isolate was an American PRRSV,with ORF7 of 372bp（123aminoacids）and Nsp2 of 2 850bp（950amino acids）.There was a discontinuous deletion of 30 amino acids of Nsp2 gene at sites 481 and 532to 560,which was consistent with Nsp2 of highly pathogenic PRRSV JXA1,so the isolate could be determined as a HP-PRRSV strain.48 hafter Marc-145 cells being inoculated by pathological sample,the typical CPE of PRRSV appeared,and TCID50 of PRRSV isolate was 10-5.75/0.1mL.The newborn piglet epidemic diarrhea was caused by PEDV infection and HP-PRRSV subsequent infection.
出处
《中国畜牧兽医》
CAS
北大核心
2016年第2期520-526,共7页
China Animal Husbandry & Veterinary Medicine
基金
广西畜禽疫苗新技术重点实验室系统性研究课题(12-071-28-A-2)
广西自然基金(桂科自0991219)
