绵羊感染牛病毒性腹泻-粘膜病病毒的调查研究

应用双抗体夹心ELISA对长春、内蒙等地区的244只绵羊进行了牛病毒性腹泻-粘膜病病毒(BVD—MDV)感染调查.结果,BVD—MDV的阳性感染率为14.6％～83.3％.应用电镜对部分ELISA阳性和阴性样品进行观察,结果7份阳性样品中均见有BVD—MDV粒子,5份阴性样品均未观察到BVD—MDV粒子.定期采取11只自然感染BVD—MD病毒的绵羊粪便进行检查,结果自然感染BVD—MDV的绵羊,排毒持续时间至少为3个月.本试验表明,羊感染BVD—MDV可长时间排毒,是潜在的危险传染源.     

新疆伊犁地区哈萨克羊与萨福克羊感染支原体肺炎血清学调查与分析

为调查新疆伊犁地区哈萨克羊与萨福克羊感染支原体肺炎的情况，笔者使用绵羊肺炎支原体ELISA检测试剂盒，对新疆伊犁地区部分牧场的哈萨克羊和萨福克羊2个品种羊随机抽查共800份血清样本进行抗原抗体检测。结果显示，新疆伊犁地区的哈萨克羊和萨福克羊2个绵羊品种之间均存在MO感染的现象。哈萨克羊MP-Ab阳性率26.00%，萨福克羊MP-Ag阳性率7.34%；哈萨克羊MP-Ag阳性率22.91%，萨福克羊MP-Ag阳性率19.71%。血清学检测结果表明，新疆本地的绵羊品种（哈萨克羊）抗原抗体的阳性检出率均高于外来引进品种（萨福克羊）。本地绵羊品种抗体阳性率显著高于外来引进品种；不同绵羊品种抗原检测阳性率无显著差异。本试验为探究新疆伊犁地区不同品种绵羊支原体肺炎的诊治方案提供了科学依据。     

锡盟东苏旗绵羊布病血清抗体调查

通过对临床血清样本布鲁氏菌抗体检测,调查锡林浩特地区绵羊布鲁氏菌病发生与流行情况。应用虎红平板凝集试验对1216份绵羊血清进行了布鲁菌血清抗体检测,结果羔羊、基础母羊和商品羊的抗体阳性率分别为5．57％、769％和2．69％,总的抗体阳性率为4．4％。     

检测山羊嵴病毒的实时荧光定量PCR方法的建立和应用

山羊嵴病毒（caprine kobuvirus，CKoV）是国内山羊新发病毒，本试验目的是建立检测CKoV的实时荧光定量PCR方法，并对西南三省腹泻山羊粪样进行该病毒的检测。选择CKoV最保守的3D基因序列，设计3D基因引物，初步设计实时荧光定量PCR，经优化反应条件和反应体系，成功建立了检测CKoV的TB Green染料法实时荧光定量PCR方法。该方法在病毒浓度2.23×10²～2.23×10⁸copies·μL^-1范围内线性关系良好，相关系数为0.999 2，扩增效率为110%；此方法具有良好的特异性和稳定性，最低检测限为2.23×10¹copies·μL^-1。采用所建立的方法对2020年1—4月采集自四川、云南和重庆的共15个场79份山羊腹泻粪样本进行检测，结果CKoV的平均检出率为25.3%，场阳性率为53.3%。并且本试验获得了13个完整的CKoV 3D基因，遗传进化分析表明这13个3D基因具有独特的进化趋势。本研究为CKoV的分子检测提供了一种新的技术手段和基础流行病学数据。     

2017-2021年成都市猫细小病毒的检测及其VP2基因的变异分析

本研究旨在通过对成都地区家养猫细小病毒(feline parvovirus,FPV)的分子检测,了解FPV在成都地区的流行及遗传变异情况.2017-2021年分别从四川成都地区采集168份家养猫的腹泻粪便样本,用PCR方法对168份样本进行FPV检测,并选取13份阳性样本进行VP2基因全长的克隆和测序,用Meg Ali...     

牦牛源牛冠状病毒部分基因的扩增、序列分析及病毒分离鉴定

本试验的目的是对青藏高原地区牦牛进行牛冠状病毒(bovine coronavirus,BCoV)的分子流行病学调查,并分离牦牛源BCoV。采用RT-PCR方法检测西藏、青海、四川、云南的犊牦牛腹泻粪便中BCoV,并扩增其S、HE及N基因片段;选取阳性样本进行BCoV分离。结果显示:从336份犊牦牛腹泻粪便中检出232份BCoV阳性,检出率为69.05%。序列分析和系统发育分析显示,本试验克隆的32个BCoV阳性样本中的S1亚基序列、HE基因片段和N基因片段均有独特的遗传进化趋势;首次成功分离到1株牦牛源BCoV,蚀斑纯化后病毒TCID50为10-7.17·0.1mL-1,鉴定结果显示该毒株S基因发生了重组事件。本试验结果表明青藏高原牦牛源BCoV感染率很高,且有独特的遗传进化趋势。     

部分地区奶牛腹泻粪便样中诺如病毒的检测和演化分析

牛诺如病毒(bovine norovirus,BNoV)是一种引起犊牛腹泻的病原,目前已在19个国家检出。本研究旨在调查该病毒在国内部分地区的流行情况及分子特征。采用RT-PCR方法检测了5个省12个奶牛场的93份腹泻粪便样本和54份健康粪便样本。结果显示:腹泻样本中BNoV检出率为25.81%,极显著高于健康粪便样本中9.26%的检出率(P<0.01),证明该病毒与犊牛腹泻具有相关性;基于29个RdRp序列的遗传进化分析显示,5份样本为GIII.1型,24份样本为GIII.2型。对获得的18个VP1和13个VP2基因片段的遗传进化分析发现,中国的BNoV毒株具有独特的演化趋势。本研究证明BNoV已在国内的奶牛中广泛流行,是国内犊牛腹泻的新发病原,且国内的BNoV毒株具有独特的演化趋势,为犊牛腹泻的防控提供了重要参考。     

四川省甘孜州藏绵羊梨形虫感染情况的调查

梨形虫病是严重危害牛羊养殖业的寄生虫病之一,本试验的目的是对四川省甘孜州藏绵羊主产区开展梨形虫感染情况调查。2018年6月—2019年5月,采集了甘孜州泸定、丹巴等9县主要藏绵羊养殖区临床健康藏绵羊全血352份,采用靶向18S rRNA的巢氏PCR进行梨形虫核酸检测,挑选阳性样本的PCR产物测序用于虫种的鉴定。结果表明,352份藏绵羊全血样本中梨形虫核酸阳性样本147份,平均阳性率为41.76%(147/352),其中半农半牧业县平均阳性率为48.25%(124/257),纯牧业县平均阳性率为24.21%(23/95);藏绵羊感染的虫种有吕氏泰勒虫(46/68)、绵羊泰勒虫(14/68)和奥氏巴贝斯虫(3/68)。本试验结果表明,甘孜州藏绵羊梨形虫感染率较高,优势虫种为吕氏泰勒虫,为甘孜州藏绵羊梨形虫病防控提供了重要参考。     

贵阳市某猪场病毒性腹泻的诊断与防控对策

贵阳市某猪场发生了一起不明原因的猪腹泻,经采集132份猪腹泻样本(粪便、胃和肠内容物),分别用猪流行性腹泻病毒(PEDV)、猪轮状病毒(Po RV)、猪传染性胃肠炎病毒(TGEV)RTPCR实时荧光进行病毒核酸分析鉴定,结果猪流行性腹泻病毒阳性率22.7%(30/132)、猪轮状病毒阳性率2.3%(3/132)、猪传染性胃肠炎病毒阳性率9.8%(13/132)。确诊此次疫病系流行性腹泻病毒、轮状病毒、传染性胃肠炎病毒单独或混合感染所致。     

新疆部分地区绵羊包虫病的血清学调查

为了解新疆部分地区绵羊包虫病流行情况,笔者采用ELISA法检测新疆35个县（市、区）共计1450份绵羊血清样本。结果显示：新疆部分地区绵羊包虫病血清阳性率为11.66%(169/1450),以铁门关市绵羊包虫病血清阳性率较高,为23.08%;不同调查点绵羊包虫病血清阳性率统计学差异显著（P<0.05）。规模化场和散养绵羊包虫病血清阳性率分别为10.89%(33/303)和11.86%(33/303),无统计学差异（P>0.05）。新疆南疆地区、北疆地区和东疆地区绵羊包虫病血清阳性率分别为13.16%(139/1056)、6.54%(17/260)和9.70%(13/134),不同区系绵羊包虫病血清阳性率不具有统计学差异（P>0.05）。调查结果表明,新疆地区绵羊包虫病感染仍较为普遍,应持续加强犬的管理和驱虫,并给农牧民普及包虫病防治知识。     

Detection of Escherichia coli Shiga toxin (stx) and enterotoxin (estA and elt) genes in fecal samples from non-diarrheic and diarrheic greyhounds

Virulence factors responsible for acute diarrhea in greyhounds have not been well established. The objective of this study was to determine if a correlation exists between disease and the presence of the Escherichia coli toxin genes in non-diarrheic and diarrheic greyhound feces. DNA extracted from broth cultures was evaluated for the presence of Shiga toxin and enterotoxin genes and broth samples were evaluated for Shiga toxin and heat-labile enterotoxin. Shiga toxin (stx1 and stx2) and enterotoxin (et and estA) genes were identified in both non-diarrheic and diarrheic samples after in vitro cultured of swabs at 37 degrees C for 16-24h. The stx1 gene was present in 3% of non-diarrheic and 15% diarrheic samples and the stx2 gene was identified in 36 and 23%, non-diarrheic and diarrheic samples, respectively. Shiga toxin was present in 48% diarrheic and 25% of the non-diarrheic in vitro cultured samples. The elt gene was detected in vitro cultured swabs in 12% of the non-diarrheic and 7% of the diarrheic samples. Labile toxin was present in the feces of small numbers of both groups of dogs. A significant correlation existed between the presence of both stx1 genes and Shiga toxin in feces, and lack of disease in non-diarrheic (P=0.01) and presence of disease in diarrheic (P=0.024) greyhounds. Correlation between production of Shiga toxin and detection of stx1 or stx2 was significant in both the diarrheic and non-diarrheic feces (P=0.03); however, only the presence of stx1 correlated with diarrhea in both groups of samples (P<0.008). The incidence of toxigenic E. coli in both non-diarrheic and diarrheic greyhounds indicates a zoonotic potential from dogs to humans and requires further study.     

Prevalence of Cryptosporidium parvum infection in Punjab (India) and its association with diarrhea in neonatal dairy calves

A prevalence study was contemplated to determine the prevalence of Cryptosporidium spp. in dairy farms in Punjab, India. The cryptosporidium oocysts were detected from 50 and 25.68% from 80 diarrheic and 74 non-diarrheic animals, respectively. Both shedding and intensity of shedding were significant in calves with diarrhea. The Cryptosporidium spp. appears to be common in dairy calves and an important contributor of calf diarrhea in the Punjab province. The prevalence of the infection peaked in young calves between 0 and 30 days in both the diarrheic and non-diarrheic groups (86.4 and 66.6%, respectively). The percentage distribution of positive samples, with reference to age groups of diarrheic and non-diarrheic animals was negatively correlated with increase in age. High mortality rate and case fatality rate of 35.2 and 44.4% were observed in young calves between 0 and 30 days of age.     

Occurrence and characteristics of enterohemorrhagic Escherichia coli O26 and O111 in calves associated with diarrhea

The aims of this study were: (1) to examine whether or not enterohemorrhagic Escherichia coli O26 and O111 (EHEC O26 and O111) are involved in neonatal calf diarrhea; (2) to determine the specific age periods at which the calves are vulnerable to these organisms, and (3) to reveal the biochemical, genetic and cytotoxic characteristics of the isolates. The study investigated the occurrence of EHEC O26 and O111 in calves associated with or without diarrhea. A total of 442 diarrheic and non-diarrheic young calves from 115 different farms were examined. Of the 257 calves with diarrhea, 37 (14.4%) and 32 (12.5%) tested positive for EHEC O26 and EHEC O111, respectively. Of the 185 non-diarrheic calves, 14 (7.6%) and 11 (5.9%) tested positive for EHEC O26 and EHEC O111, respectively. EHEC O26 and O111 were recovered from 14/69 (20%) and 11/69 (16%) diarrheic calves <2-weeks-old, respectively, and no EHEC O26 and O111 were detected in the non-diarrheic claves of this age group, suggesting that EHEC O26 and O111 are possible causes of the disease in infected neonatal calves. However, there were similar rates of occurrence in the diarrheic and non-diarrheic calves in the older animals (particularly, aged >10 weeks). PCR analysis showed that the isolates carried various virulence genes such as Ehly, eae, stx1 and stx2, which highlight the potential importance of these attributes for the infection, colonization and the possible pathogenesis of calf diarrhea. Cytotoxicity analysis revealed that many of the EHEC isolates showed high cytotoxicity to Vero cells, re-emphasizing the potential for cattle being a direct source of EHEC infections in humans.     

Detection of the saa gene in verotoxin-producing Escherichia coli from ruminants.

A total of 163 verotoxin-producing Escherichia coli (VTEC) strains isolated from diarrheic and healthy cattle, sheep, and goats were analyzed for the presence of the saa gene by polymerase chain reaction. Seventeen (45.9%) and 5 (29.4%) of the VTEC isolated from healthy cattle and diarrheic calves, respectively, had the saa gene. None of the saa-positive strains carried the eae gene, but 20 of the 22 saa positive were ehxA positive. In contrast with cattle VTEC, none of the VTEC isolated from small ruminants were saa positive. These results show that the saa gene is commonly associated with bovine eae-negative VTEC strains but not with ovine or caprine VTEC strains.     

Pathogenic characteristics of Escherichia coli strains isolated from newborn piglets with diarrhea in Brazil

Ninety-one Escherichia coli isolates obtained from diarrheic and normal feces of newborn piglets (0-11 days of age) from three states of Brazil were assessed for phenotypic and genotypic characteristics associated with pathogenic processes. These isolates expressed fimbriae F18ac and type 1, but not fimbriae K88, K99, 987P or F41. Genes for toxins (LT-I, STa, SLT-I, SLT-II, SLT-IIv) either individually or combined were found to be present in most of the diarrheic strains (65.7%) and in 42.8% of the non-diarrheic ones. The eaeA gene was present in 25.7% of the diarrheic isolates and in 9.5% of the non-diarrheic ones. Colicin, hemolysin and aerobactin were also found to be produced by some strains from both sources. Because of the great variety of biological characteristics associated with different illness processes, we suggest that, in Brazil, pigs may act as a reservoir for transmission of Escherichia coli strains to other animals.     

Genotype identification and prevalence of Giardia duodenalis in pet dogs of Guangzhou, Southern China

Giardia duodenalis is a flagellated parasite and is considered one of the most common causes of protozoal diarrhea in both humans and animals worldwide. This paper represents the first study of the prevalence of G. duodenalis in pet dogs in Guangzhou, China. Faecal samples (209 specimens) were obtained from young (<6 months old), adult (6 months to 3 years) and elder dogs (>3 years old). 8.61% (18/209) faecal samples were recorded positive using microscopy examination, and 11.00% (23/209) using PCR. The prevalence was significantly higher in diarrheic dogs (26.31%) compared with non-diarrheic dogs (5.10%), while it was higher in young (25.58%) than both adult (7.37%) and elder (7.04%) dogs and the difference was statistically significant (P<0.05). The prevalence in male dogs 11.30% (13/115) was higher than females 10.87% (10/92), and in suburban dogs (12.15%) higher than urban 9.80%, but the difference was not statistically significant (P>0.05). Sequence analysis of the 23 PCR-positive samples revealed the presence of Assemblage D (18/23), and zoonotic Assemblage A (5/23). The present investigation reported a high infection rate of G. duodenalis in pet dogs, especially in young dogs. Genotypic characterization demonstrated that the zoonotic Assemblage A was found, a fact that poses a potential risk of G. duodenalis transmission from pet dogs to humans. It is suggested that pet owners should take appropriate hygiene measures to prevent and control giardiasis in this region.     

新疆绵羊及其环境中李氏杆菌的生态分布多样性调查

对新疆健康绵羊及其相关环境如青贮饲料、饮水、土壤、鸟粪中李氏杆菌(Listeria)种群采用改良国标法(4789.30-2010)进行生态分布多样性调查,并对分离的单核细胞增多性李氏杆菌(L.monocytogenes)采用PCR方法进行溶血素基因(hly)和血清型检测。结果:514份样本中,共检出阳性样本26份,平均阳性率为5.1%,其中羊体分离率为6.2%(22/353),饮水分离率为33%(2/6),鸟粪分离率为3.0%(2/67),其余样本均为阴性;26份阳性样品中,检出单核细胞增多性李氏杆菌5株,塞氏李氏杆菌(L.seeligeries)21株,且5株单核细胞增多性李氏杆菌均检出溶血素基因,血清型为1/2a。     

A preliminary serological survey of viral antibodies in Peruvian sheep

This study reports the sero-prevalence of viral infections in sheep in Peru. Serum samples were collected from 34 mature healthy rams located in 3 different geographic regions of the country (north, central and south). The sera were tested for antibodies to the following viruses: respiratory syncytial virus (RSV); parainfluenza 3 (PI-3) virus; bovine viral diarrhea/border disease (BVD/BD) virus; bovine herpesvirus 1 (BHV-1); bluetongue (BT) virus; ovine progressive pneumoniae (OPP) virus; bovine leukosis virus (BLV). The serological studies showed that 47% were positive for RSV; 82% for PI-3; 3% for BVD/BD virus; 49% for BT virus; 13% for OPP virus. Antibodies were not detected to bovine herpesvirus 1 or to bovine leukosis virus.     

Characterization of atypical Enteropathogenic Escherichia coli (aEPEC) isolated from dogs

Enteropathogenic Escherichia coli (EPEC), an important human pathogen has the ability to form attaching and effacing lesions on the intestinal epithelium and has been isolated from a wide range of species. Two EPEC subgroups are recognized: typical (tEPEC) and atypical (aEPEC) strains, differing by the presence of EAF plasmid and bundle-forming pilus (BFP) in typical strains and their absence in atypical strains. This study searched the presence of EPEC strains in 101 fecal samples of diarrheic (n=65) and non-diarrheic (n=36) dogs from two cities in Rio de Janeiro State, Brazil. The isolates were evaluated for the presence of eae, tir, espA, espB and bfpA genes, EAF plasmid, and for the insertion site of the LEE locus. Cell-adherence assays, fluorescent actin staining (FAS) test, hemolysin production and serotyping were also performed. Twenty eight aEPEC isolates were recovered from 48 eae-positive fecal samples, 24 from diarrheic animals and 4 from non-diarrheic ones. PCR showed that most isolates was positive for β or γ intimin, and for β or α subtypes of tir, espA and espB. Six isolates showed a selC insertion of locus LEE. Only two isolates from the same diarrheic animal harbored the bfpA gene, and none presented the EAF plasmid. Most isolates was FAS-positive and showed a localized adherence-like (LAL) in a 6h HeLa cell-adherence assay. A wide diversity of serotypes was detected including O4:H16 and O51:H40, previously described in human disease. The phenotypic and genotypic markers of aEPEC isolated from diarrheic and non-diarrheic dogs were similar to those found in isolates recovered from human disease.