Prevalence of canine coronavirus (CCoV) in dog in Japan: detection of CCoV RNA and retrospective serological analysis

We collected rectal swabs from dogs in Japan during 2011 to 2014, and canine coronavirus (CCoV) nucleocapsid gene was detected by RT-PCR. The relationship between CCoV infection and the manifestation of diarrhea symptoms was investigated, and a correlation was noted (df=1, χ²=8.90, P<0.005). The types of CCoV detected in samples from CCoV-infected dogs were CCoV-I in 88.9% and CCoV-II in 7.4%, respectively. We retrospectively investigated the seroprevalence of CCoV-I in dogs in Japan during 1998 to 2006. The sera were tested with a neutralizing antibody test. In the absence of CCoV-I laboratory strain, we used feline coronavirus (FCoV)-I that shares high sequence homology in the S protein with CCoV-I. 77.7% of the sera were positive for neutralizing anti-FCoV-I antibodies.     

犬冠状病毒JS1706和JS1712毒株基因组3'端分子特性分析

为了全面了解犬冠状病毒（CCoV）分离毒株JS1706和JS1712基因组3'端主要结构蛋白基因和非结构蛋白基因的分子特征,本研究设计了8组引物进行RT-PCR扩增,产物经测序和拼接后,获得了约8.7 kb基因组片段,该基因组结构及其编码蛋白顺序为5'-S-3abc-E-M-N-7ab-3'。对CCoV JS1706、JS1712株8.7 kb基因组核苷酸序列与α冠状病毒属参考毒株的相同区域核苷酸序列进行比对,结果表明,2个分离株与CCoV Ⅱ型参考毒株相似性最高（83.4%~93.1%）,其次为FCoV Ⅱ型参考毒株（87.1%~87.9%）、TGEV参考毒株（86.1%~86.8%）、CCoV Ⅰ型参考毒株（72.0%~72.1%）和FCoV Ⅰ型参考毒株（67.5%~69.9%）。JS1706、JS1712毒株与同属冠状病毒参考株的结构蛋白S、E、M和N蛋白氨基酸相似性分别为46.4%~95.2%、75.6%~100%、82.8%~99.2%和78.5%~99.7%。说明同属内冠状病毒的S基因变异度大,E、M、N基因相对保守。根据基因组3'端8.7 kb核苷酸序列和S蛋白氨基酸序列相似性比对结果,JS1706和JS1712毒株均与泛嗜型原型株CB/05相似性最高,分别为93.0%~93.1%、94.8%~95.2%,其他结构蛋白包括E、M和N氨基酸序列比对也发现与CB/05株的相似性较高,分别为97.6%~100%、92.4%~93.1%和97.9%。S蛋白氨基酸序列的进一步分析表明,JS1706和JS1712毒株的S蛋白N端有一些特有氨基酸,S蛋白氨基酸序列中没有明显的S1/S2蛋白酶切位点（RRARR）,但在958—963位氨基酸有S2'裂解位点特征基序（KRKYRS）。基于S蛋白氨基酸序列构建的系统发育进化树分析显示,CCoV JS1706和JS1712株与CCoV Ⅱa亚型参考毒株和FCoV Ⅱ型参考毒株聚集形成一个分枝。CCoV JS1706和JS1712株非结构蛋白的编码基因ORF3abc和ORF7,其结构、大小与经典疫苗株INSAVC-1相似,无明显插入、缺失和移码突变。本研究有助于深入了解国内CCoV流行毒株的分子特性,为后续分子流行病学调查、诊断试剂和疫苗研发奠定了基础。     

2015年-2016年度南宁部分地区猪戊型肝炎病毒基因型分析

为了解广西猪群中戊型肝炎病毒(HEV)基因型,利用套式RT-PCR用对南宁周边猪场采集到的104份新鲜猪粪便进行HEV检测、分离并成功扩增和克隆了11株阳性毒株的ORF2基因部分保守片段.序列测定结果表明,11株HEV ORF2序列自身核苷酸同源性为97.7%~100%,推导编码的氨基酸同源性为97.9%~100%;与4型HEV代表毒株Ch-S-1、Ch-T11、swGX40等的核苷酸同源性为84.6%~90.6%,而与其他各型之间的同源性较低.系统发育进化树结果表明,11株HEV广西株为基因4型,其中,10株HEV为4a亚型,1株毒株为4e亚型.结果表明,广西猪群中流行的HEV均为基因4型,且以4a亚型为优势流行毒株.     

Detection and genotyping of canine coronavirus RNA in diarrheic dogs in Japan

To clarify the prevalence of canine coronavirus (CCoV) infection in Japan, faecal samples from 109 dogs with diarrhoea were examined for CCoV RNA together with canine parvovirus type 2 (CPV-2) DNA. The detection rates of CCoV and CPV-2 for dogs aged less than 1 year were 66.3% and 43.8%, while those for dogs aged 1 year or older were 6.9% and 10.3%, respectively, which were significantly different (p < 0.0001 and p = 0.0003, respectively), indicating not CPV-2 but CCoV is an important diarrhoea-causing organism in juvenile dogs. Among the CCoV-positive dogs, 65.5% and 72.7% showed to be positive for CCoV types I and II, respectively, and simultaneous detection rate of both types was high at 40.0%. Furthermore, transmissible gastroenteritis virus (TGEV)-like CCoV RNA was detected from 8 dogs. These findings indicate that CCoV type I and TGEV-like CCoV are already circulating in Japan, though no reports have been presented to date.     

Clinical,hematological, and biochemical findings in puppies with coronavirus and parvovirus enteritis

The clinical and laboratory findings in puppies naturally infected with canine coronavirus (CCoV) and/or canine parvovirus (CPV) were compared with findings in uninfected puppies. Lymphopenia was the only parameter related to CCoV infection that was statistically significant; vomiting, anorexia, lethargy, hemorrhagic fluid diarrhea, leukopenia, lymphopenia, thrombocytopenia, hypoglycemia, and hypoproteinemia were correlated with CPV infection.     

First description of group A rotavirus from fecal samples of ostriches (Struthio camelus)

This study investigated the occurrence of rotavirus infections in ostriches (Struthio camelus) reared in Northern Paraná, Brazil. Fecal (n=66) and serum (n=182) samples from nine farms located in four different cities were analyzed by silver stained-polyacrylamide gel electrophoresis (ss-PAGE), RT-PCR assay, virus isolation, and counterimmunoelectroosmophoresis (CIE). Rotavirus group A seropositivity occurred in 5.49% (10/182) of serum samples of ostriches originated from two farms. Only 9.09% (6/66) of fecal samples from ostriches with diarrhea maintained in one farm were positive by ss-PAGE, RT-PCR, and virus isolation. The G (VP7) and P (VP4) genotypes of rotavirus wild strains isolated in cell culture were determined by multiplex-nested PCR. The genotyping identified two rotavirus strains: G6P[1] and G10P[1]. In three rotavirus strains it was only possible to identify the P type; one strain being P[1] and two strains that presented the combination of P[1]+P[7]. These findings might represent the first characterization of rotavirus in ostriches, and the finding of porcine and bovine-like rotavirus genotypes in ostriches might suggest virus reassortment and possible interspecies transmission.     

Hepatitis E virus in swine and effluent samples from slaughterhouses in Brazil

Hepatitis E is an infectious disease which virus (HEV) is highly disseminated in swine herd populations. Sporadic acute human hepatitis E cases have been associated to genotype 3 and 4 strains of HEV also reported in swine populations of endemic and non-endemic areas. With the aim to evaluate the incidence of animals with current infection of HEV, 115 bile samples were collected from three slaughterhouses under inspection by Animal Sanitary Protection Agency of Rio de Janeiro, Brazil. In parallel, effluent samples were collected from six sewage pipe exit sites of two slaughterhouses. HEV RNA was detected in 11 out of 115 (9.6%) bile samples collected and three waste samples from one slaughterhouse. Viral loads observed for bile samples varied from 10(1)-10(5) genome copies/mL and for effluent samples mean load was 10(2) genome copies/mL. Sequencing and phylogenetic analysis classified samples within genotype 3 subtype 3b closely related to the sample obtained from the first reported autochthonous human case and samples from swine of commercial herds in Brazil. Our data demonstrates that although most animals achieve slaughter age (around 20 weeks old) already immune to HEV, a significant number of animals are with current infection at commercial age. Further studies should be addressed to consider risk analysis and possible evaluation of inspection regulations considering food safety measures regarding hepatitis E zoonotic aspect in Brazil.     

The prevalence of a group 2 coronavirus in dogs in Japan

Canine coronavirus (CCoV) has been reported to cause acute diarrhea mainly in young pups. CCoV and feline coronavirus are classified as group 1 coronaviruses. However, it has recently been reported in the United Kingdom that the group 2 coronavirus gene, which is more closely related to the bovine coronavirus (BCoV) and human coronavirus strain OC43, has been detected in respiratory tract tissue samples from dogs with respiratory disease. In this study, we examined the prevalence of antibodies to group 2 coronaviruses in domestic dogs and cats in Japan by a neutralization test using BCoV. All 104 feline serum samples were negative (<1:5) for anti-BCoV antibodies. In contrast, of the 898 canine serum samples, 160 (17.8%) were positive for anti-BCoV antibodies, and the antibody titers ranged from 1:5 to more than 1:640, with 1:160 being the most frequent. No correlation was found between the titers of the anti-BCoV and anti-CCoV antibodies in the 198 serum samples of dogs with a known history of CCoV vaccination. We amplified, by RT-PCR, group 2 coronavirus-specific hemagglutination/esterase genes in the oral swabs of a total of 10 young pups presenting with or having recovered from respiratory signs, or having anti-BCoV antibodies, with the result that 2 pups were positive for the hemagglutination/esterase genes. These results strongly suggest that an unknown group 2 coronavirus as well as the known enteritis-causing CCoV (group 1 coronavirus) is prevalent among domestic dogs in Japan.     

Genetic diversity of porcine sapoviruses

Sapoviruses (SaVs) within the Caliciviridae family are an important cause of gastroenteritis in both humans and animals. Although the widespread occurrence of divergent human SaV strains has been reported, there have only been a few studies of porcine SaVs examining their genetic diversity. The aim of this study was to assess the genetic diversity of porcine SaVs in piglets with diarrhea in South Korea. Two hundred and thirty-seven fecal specimens from piglets with diarrhea were examined from 78 farms over a 2-year period from six provinces in South Korea. Overall, 69 (29.1%) of the samples from five provinces tested positive for porcine SaVs by either RT-PCR or nested PCR with the primer pairs specific to porcine SaVs. An analysis of the partial capsid gene (757bp) of 12 porcine SaVs detected from fecal samples showed genetic divergence, not only among the Korean porcine SaVs (67.7-99.1%), but also between Korean and American porcine SaVs (69.1-90.2%). Interestingly, one strain (Po/SaV/JN-MA113/05/Korea), formed a second porcine SaV/GIII genotype, and is tentatively called GIII/2. This strain had a 0.236-0.405 inter-cluster distance with the other strains in the same genogroup, which is comparable to the distances between the established GI and GII SaVs. Furthermore, two potential recombinant porcine SaVs were identified. In conclusion, porcine SaV infections are common in diarrheic piglets in South Korea. The infecting strains are genetically diverse, and include a newly recognized genotype and recombinant viruses within genogroup III.     

Genetic evolution of canine coronavirus and recent advances in prophylaxis

Since the first identification of the virus in 1971, the disease caused by canine coronavirus (CCoV) has not been adequately investigated and the role that the virus plays in canine enteric illness has still not been well established. In the last decade, as a consequence of the relatively high mutation frequency of RNA positive stranded viruses, CCoV has evolved and a new genotype has been identified in the faeces of infected dogs. The several studies carried out by different researchers have focused upon the epidemiological relevance of these viruses and, considering the wide diffusion of CCoV infections among dog populations, the author underlines the need for further investigation on the biology of CCoV and on the pathogenetic role of their infections.     

2016-2017年江西地区猪繁殖与呼吸综合征病毒分子流行病学调查及ORF5基因变异分析

为了解近年来江西地区猪繁殖与呼吸综合征病毒（porcine reproductive and respiratory syndrome virus,PRRSV）分子流行病学和其遗传变异情况,本次调查于2016-2017年从江西省各地区规模化猪场采集453份疑似猪繁殖与呼吸综合征（PRRS）的病料,采用RT-PCR方法对所有病料进行检测。结果发现,其中321份病料为PRRSV阳性,阳性率为70.86%,各地区的阳性率在19.15%~84.85%之间。挑选14份阳性样品测序后,经ORF5基因序列分析,江西地区各PRRSV毒株ORF5基因的核苷酸同源性为83%~100%,PRRSV流行毒株与参考毒株的同源性在59.9%~98.5%之间。基于ORF5基因的进化树分析表明,14个测序毒株均为美洲型毒株,其中有4株为基因亚型Ⅰ,即高致病性毒株（HP-PRRSV）;3株为基因亚型Ⅱ,即经典毒株;3株为基因亚型Ⅲ,即NADC30-like毒株;4株为新出现的基因亚型Ⅳ。氨基酸序列比对分析表明,基因亚型Ⅰ、Ⅱ、Ⅲ和Ⅳ毒株ORF5基因编码的GP5蛋白氨基酸在3个表位及2个重要的抗原相关区域存在较大变异,其中以NADC30毒株为代表的基因亚型Ⅲ毒株和以GD1404毒株为代表的基因亚型Ⅳ毒株均表现出独有的氨基酸变异,这些变异可能会影响GP5蛋白的免疫原性。本次调查结果表明,2016-2017年江西地区PRRSV流行出现了新形势,美洲型毒株出现了多基因亚型共同存在的局面,以高致病性毒株（HP-PRRSV）为主,NADC30-like毒株和新基因亚型等新毒株的比例较高,同时还存在经典毒株;持续实时监测PRRSV的毒株流行和变异情况,可为临床诊断、药物和疫苗开发及PRRS的科学防控提供依据。     

C基因型牛副流感3型病毒的分离鉴定

为了对宁夏地区患有呼吸系统疾病的舍饲牛进行病原鉴定,试验主要利用RT-PCR方法对样品进行牛副流感3型病毒(BPIV3)M基因序列扩增,将扩增产物连接在pMD18-T载体后转化到大肠杆菌DH5α感受态细胞中进行亚克隆。通过氨苄青霉素平板筛选,将鉴定为阳性的克隆菌进行核苷酸序列测定并利用分子生物学软件与GenBank上参考序列进行同源性比对。测序结果表明,从样品中分离到了1株BPIV3,并命名为NX49,其M基因全长为1056bp;进化分析表明,NX49隶属于BPIV3C基因型,其M基因与中国山东C型分离株SD0835具有较高同源性,核苷酸同源性为99.4%;理化分析表明,该毒株对温度、酸及有机物均敏感,高温孵育下Mg²⁺对该病毒无保护力;血凝试验表明,NX49对豚鼠红细胞凝集效价仅为1∶4,且仅在4℃孵育时出现凝集反应。本研究成功分离得到一株BPIV3C型毒株,这将有助于中国BPIV3分子进化规律及病毒流行特点的进一步研究。     

Characterization of Onthophagus sellatus as the major intermediate host of the dog esophageal worm Spirocerca lupi in Israel

A total of 750 faecal samples of dairy calves at up to 2 months of age kept in various housing systems were screened for Cryptosporidium spp. infection using the aniline-carbol-methyl violet staining method. DNA was extracted from Cryptosporidium positive samples and from 150 randomly selected microscopically negative samples. Nested PCR was performed to amplify the partial SSU rRNA gene of Cryptosporidium that was subsequently digested by SspI, VspI and MboII restriction enzymes to determine the present Cryptosporidium species and genotype. In addition, the samples characterized as Cryptosporidium parvum were subsequently analyzed at the GP60 gene to determine the distribution of zoonotic subtypes. Sequence analyses and RFLP identified C. parvum in 137, Cryptosporidium andersoni in 21 and Cryptosporidium bovis in 3 samples. Neither mixed infections nor Cryptosporidium ryanae was detected. Sequencing of the GP60 gene from C. parvum-positive samples revealed all five subtypes of family IIa (A15G2R1, A16G1R1, A22G1R1, A18G1R1, and A15G1R1). The obvious management-associated distribution of Cryptosporidium spp. was demonstrated. Direct contact with adult animals was found to be a risky factor for C. andersoni and C. bovis infection. IIaA15G2R1 and IIaA16G1R1 were detected as major subtypes, whereas only the IIaA16G1R1 subtype was found in animals kept in boxes. Three of the five detected subtypes were previously associated with human cryptosporidiosis, and moreover, the IIaA15G1R1 subtype, previously reported in humans only, was detected in calves for the first time.     

2018-2020年中国部分省市猪流行性腹泻病毒S1基因的监测及遗传变异分析

【目的】 调查中国规模化猪场猪流行性腹泻病毒(Porcine epidemic diarrhea virus,PEDV)的流行情况。【方法】 利用RT-PCR检测方法对2018-2020年采集于全国11个省市318个规模化猪场的2 391份样品进行PEDV核酸检测,对30份阳性样品进行S1全基因扩增与测序,并利用MegAlign、Mega 7.0等软件进行分析。【结果】 2018-2020年,猪场PEDV核酸阳性率分别为48.57%、10.96%和4.72%,样品PEDV核酸阳性率分别为28.97%、8.27%和7.50%,猪场和样品PEDV核酸阳性率呈现逐年下降的趋势。S1基因相似性分析显示,获得的30株毒株全部为GⅡ基因型,其中17株毒株为GⅡa基因亚型、5株毒株为GⅡb亚型、8株毒株为GⅡc亚型,GⅡa基因亚型毒株为2018-2020年流行的主要毒株类型;30株毒株S1基因序列之间核苷酸相似性为93.0%~99.5%, 氨基酸相似性为91.7%~100%,其中22株毒株与2017-2018年流行的GⅡ基因型毒株相比S1氨基酸序列表现出特征性插入和缺失。【结论】 本研究结果为监测和分析中国PEDV的变异和演化提供了临床数据,为猪流行性腹泻防控和疫苗研制提供了参考。     

M gene evolution of canine coronavirus in naturally infected dogs

Two stray pups (A and B), three and five months old, respectively, both naturally infected with canine coronavirus (CCoV), were studied for 180 days. The virus was detected intermittently in the pups' faeces by PCR for periods of 156 and 146 days, respectively. Sequence analysis of a fragment of the gene encoding the M protein revealed that the viruses detected at the onset of the infection were very similar to typical strains of CCoV, whereas from 42 days after infection in pup A and 40 days after infection in pup B the viruses had nucleotide and amino acid mutations resembling sequences in feline coronavirus.     

Development of a nanoparticle-assisted PCR assay to distinguish canine coronaviruses I and II

Nanoparticle-assisted PCR (nanoPCR) is a novel method for the simple, rapid, and specific detection of viruses. We developed a nanoPCR method to detect and differentiate canine coronavirus I (CCoV I) and II (CCoV II). Primer pairs were designed against the M gene conserved region of CCoV I and CCoV II, producing specific fragments of 239 bp (CCoV I) and 105 bp (CCoV II). We optimized the annealing temperature and primer concentrations for the CCoV nanoPCR assay and assessed its sensitivity and specificity. Under optimized nanoPCR reaction conditions, the detection limits were 6.47 × 10¹ copies/μL for CCoV I and 6.91 × 10² copies/μL for CCoV II. No fragments were amplified using other canine viruses as templates. The sensitivity of the nanoPCR assay was 100-fold higher than that of a conventional RT-PCR assay. Among 60 clinical samples collected from Beijing, China, the assay detected 12% positive for CCoV I and 48% positive for CCoV II. Our nanoPCR method is an effective method to rapidly detect CCoV I and CCoV II alone, or as a mixed infection, in dogs.     

猪流行性腹泻病毒变异株XP2018的分离及S基因序列分析

本研究旨在从临床仔猪腹泻样品中分离猪流行性腹泻病毒(PEDV),并对其S基因进行测序分析.对腹泻仔猪小肠样品进行RT-PCR检测、病毒的分离培养、RT-PCR和间接免疫荧光鉴定、S基因测序及遗传演化分析.结果显示:仔猪腹泻由流行性腹泻病毒引起;在Vero细胞上成功分离流行性腹泻病毒,命名为XP2018,该毒株细胞病变明...