Genetic distance of SARS coronavirus from the recent natural case

Phylogenetic analysis of SARS coronavirus isolates based on the spike gene and protein sequence using Neighbor-Joining, maximum likelihood and Bayesian inference methods indicated that a recent human SARS-CoV isolate was closer to some human SARS-CoV isolates from earlier epidemic phase than to the SARS-CoV-like viruses isolated from wild animals during previous epidemic phase. A reasonable judgment based on phylogenetic relationship and sequence variations it is likely that the recent human SARS-CoV isolate is closer to an unknown SARS-CoV predecessor.     

Swine coronaviruses (SCoVs) and their emerging threats to swine population,inter-species transmission,exploring the susceptibility of pigs for SARS-CoV-2 and zoonotic concerns

Swine coronaviruses (SCoVs) are one of the most devastating pathogens affecting the livelihoods of farmers and swine industry across the world. These include transmissible gastroenteritis virus (TGEV), porcine epidemic diarrhea virus (PEDV), porcine respiratory coronavirus (PRCV), porcine hemagglutinating encephalomyelitis virus (PHEV), swine acute diarrhea syndrome coronavirus (SADS-CoV), and porcine delta coronavirus (PDCoV). Coronaviruses infect a wide variety of animal species and humans because these are having single stranded-RNA that accounts for high mutation rates and thus could break the species barrier. The gastrointestinal, cardiovascular, and nervous systems are the primary organ systems affected by SCoVs. Infection is very common in piglets compared to adult swine causing high mortality in the former. Bat is implicated to be the origin of all CoVs affecting animals and humans. Since pig is the only domestic animal in which CoVs cause a wide range of diseases; new coronaviruses with high zoonotic potential could likely emerge in the future as observed in the past. The recently emerged severe acute respiratory syndrome coronavirus virus-2 (SARS-CoV-2), causing COVID-19 pandemic in humans, has been implicated to have animal origin, also reported from few animal species, though its zoonotic concerns are still under investigation. This review discusses SCoVs and their epidemiology, virology, evolution, pathology, wildlife reservoirs, interspecies transmission, spill-over events and highlighting their emerging threats to swine population. The role of pigs amid ongoing SARS-CoV-2 pandemic will also be discussed. A thorough investigation should be conducted to rule out zoonotic potential of SCoVs and to design appropriate strategies for their prevention and control.     

犬猫冠状病毒研究进展

犬冠状病毒（canine coronavirus,CCoV）与猫冠状病毒（feline coronavirus,FCoV）同属于冠状病毒科冠状病毒属α属,与其同属的病毒还有猪传染性胃肠炎病毒（porcine transmissible gastroenteritis virus,TGEV）、猪流行性腹泻病毒（porcine epidemic diarrhea virus,PEDV）等。遗传进化分析表明,该种属不同基因型病毒通过基因重组能产生新型变异毒株,为疾病的诊断与防控造成了很大的阻碍。β属冠状病毒包括牛冠状病毒（bovine coronavirus,BCoV）、犬呼吸道冠状病毒（canine respiratory coronavirus,CRCoV）、严重急性呼吸综合征冠状病毒（severe acute respiratory syndrome coronavirus,SARS-CoV）等,其中CRCoV与BCoV同源性较高,该类病毒与α属冠状病毒在基因组结构、致病机制、感染症状等方面差异较大。CCoV与FCoV在全球范围内广泛传播,具有发病率高、死亡率低的特点。由于RNA病毒本身的特点和环境选择压力的影响,这两种病毒不断变异进化,新的强致病力毒株相继出现。经FCoV基因突变演化而来的猫传染性腹膜炎病毒（feline infectious peritonitis virus,FIPV）毒力大大增强,病毒基因组中某些特异性的点突变使得针对宿主的细胞嗜性发生改变,该病毒的致病机制主要依赖于病毒感染后诱导机体产生的抗体依赖性增强作用（ADE）。针对犬猫冠状病毒的流行病学调查及防控不能仅依赖于疫苗免疫单一因素,还应综合考虑病毒毒力、环境条件、宠物自身免疫抵抗力状态等。针对犬猫冠状病毒的诊断应根据临床症状,结合常规血液学检查、血清生化检查和实验室诊断技术来进行全面的鉴定,防止出现假阳性及假阴性结果。     

An update on aspects of viral gastrointestinal diseases of dogs and cats

Viruses commonly cause gastrointestinal illnesses in dogs and cats that range in severity from mild diarrhoea to malignant neoplasia. Perpetual evolution of viruses is reflected in changing disease patterns, so that familiar viruses are sometimes discovered to cause new or unexpected diseases. For example, canine parvovirus (CPV) has regained the ability to infect felids and cause a panleucopenia-like illness. Feline panleucopenia virus (FPV) has been shown to cause fading in young kittens and has recently been implicated as a possible cause of feline idiopathic cardiomyopathy. Molecular scrutiny of viral diseases sometimes permits deeper understanding of pathogenesis and epizootiology. Feline gastrointestinal lymphomas have not, in the past, been strongly associated with retroviral infections, yet some of these tumours harbour retroviral proviruses. Feline leukaemia virus (FeLV) may play a role in lymphomagenesis, even in cats diagnosed as uninfected using conventional criteria. There is strong evidence that feline immunodeficiency virus (FIV) can also be oncogenic. The variant feline coronaviruses that cause invariably-fatal feline infectious peritonitis (FIP) arise by sporadic mutation of an ubiquitous and only mildly pathogenic feline enteric coronavirus (FECV); a finding that has substantial management implications for cat breeders and veterinarians. Conversely, canine enteric coronavirus (CECV) shows considerable genetic and antigenic diversity but causes only mild, self-limiting diarrhoea in puppies. Routine vaccination against this virus is not recommended. Although parvoviruses, coronaviruses and retroviruses are the most important known viral causes of canine and feline gastrointestinal disease, other viruses play a role. Feline and canine rotaviruses have combined with human rotaviruses to produce new, reassortant, zoonotic viruses. Some companion animal rotaviruses can infect humans directly. Undoubtedly, further viral causes of canine and feline gastrointestinal disease await discovery.     

Research Progress of Canine Coronavirus and Feline Coronavirus

Canine coronavirus (CCoV) and feline coronavirus (FCoV) belong to α-genus coronavirus of coronavirus family,porcine transmissible gastroenteritis virus (TGEV),porcine epidemic diarrhea virus (PEDV) also belong to the same genus.Genetic evolution analysis showed that different genotype of the virus could produce new variant strains through gene recombination,which caused great obstacles to the diagnosis and control of the disease.β-genus coronaviruses include bovine coronavirus (BCoV),canine respiratory coronavirus (CRCoV) and severe acute respiratory syndrome coronavirus (SARS-CoV).Among them,CRCoV has the highest homology with BCoV,but there are great differences in genomic structure,pathogenic mechanism and infection symptoms between this kind of coronavirus and α-coronavirus.CCoV and FCoV are widely spreading around the world,characterized by high morbidity and low mortality.Due to the characteristics of RNA virus and the influence of environmental selection pressure,the viruses continue to mutate and evolve,and new virulent strains appear one after another.The virulence of feline infectious peritonitis virus (FIPV) is greatly enhanced,some specific point mutations in the virus genome change the cellular tropism against the host.The pathogenesis of the virus mainly depends on the antibody-dependent enhancement (ADE) induced by virus infection.The epidemiological investigation and prevention and control of CCoV and FCoV should not only rely on the single factor of vaccine immunity,but also comprehensively consider the virulence of the virus,environmental conditions,pet self-immune resistance, and so on.The identification of CCoV and FCoV should be based on clinical symptoms,combined with routine hematological examination,serum biochemical examination and laboratory diagnosis techniques to prevent false positive and false negative results.     

猪冠状病毒的起源与遗传演化

冠状病毒变异率高,宿主广泛,主要感染哺乳动物和禽类,严重威胁公共卫生安全与养殖业发展.生猪养殖业中,冠状病毒也是危害猪只健康的重要病原.本研究对4种代表性猪冠状病毒:猪传染性胃肠炎病毒(transmissible gastroenteritis virus,TGEV)、猪流行性腹泻病毒(porcine epidemic...     

请勿谈“冠”色变——人和动物冠状病毒的那些事

新型冠状病毒疫情的爆发和持续扩散已经对我国经济、社会和人民生活产生了一定的影响。本文就人们关心的几个问题进行了探讨和澄清,如:冠状病毒家族有哪些成员,目前流行新型冠状病毒与已知人和动物冠状病毒间有什么关系,新型冠状病毒可能的来源,养殖场在当前新冠疫情下如何维持生产和降低损失等,以期增加人们对新型冠状病毒的认识,重视当前疫情,同时减少不必要的"新冠"恐惧。     

SARS冠状病毒的流行演化分析

严重急性呼吸综合症(Severe acute respiratory syndrome,SARS)是21世纪初暴发的一种重症病毒感染疾病.病原体为一种以前未在人类或动物中发现过的新的冠状病毒--SARS相关冠状病毒(SARS-CoV).尽管SARS-CoV基因组结构与其他的冠状病毒相似,但SARS-CoV与其他冠状病毒的潜在关系仍未明确.文章简要地介绍了其生物学特性,回顾了SARS发生和发展过程,并根据SARS的流行传播特点和SARS-CoV的进化分析,推测了SARS-CoV可能的发源和衍变.     

大熊猫犬冠状病毒的分离与鉴定

以犬肾传代细胞(MDCK)从1只病死大熊猫肝脏中分离到1株病毒,命名为DXMV。电镜观察磷钨酸负染的病毒细胞培养物，发现冠状病毒样粒子，超薄切片上可见细胞浆内病毒包涵体。理化学和生物学鉴定结果表明，DXMV核酸类型为RNA，对氯仿、乙醚敏感，可耐受1％胰蛋白酶的作用，具有一定的耐酸性和耐热性，可在MDCK、FCWF、F81细胞中增殖，无血凝性和血吸附特性。血清中和试验结果表明，DXMV可被犬冠状病毒阳性血清中和。采用犬冠状病毒间接荧光抗体法染色DXMV细胞飞片，可在细胞浆内见到特异性荧光。以冠状病毒通用引物和犬冠状病毒特异性引物，可从大熊猫肝脏和不同代次的病毒细胞培养物中扩增出与预期值251bp和515bp大小相同的核苷酸片段。由此说明，该病毒为犬冠状病毒，大熊猫可被犬冠状病毒感染。     

SARS,possible zoonosis in the area of conflict of pathogenic coronaviruses of animals

Severe acute respiratory syndrome (SARS) is an emerging disease, which was first recognized in Guangdong Province, China, in November 2002. In the meantime, SARS has been recognized in patients on all five continents. A novel coronavirus, which is not related to the hitherto known coronaviruses, has been proven to be associated with the disease. Our genomic analyses strongly suggest that the new SARS-coronavirus did not emerge through mutation or recombination and that it has probably been transmitted from a so far not identified animal species to humans. Therefore, it is most likely that SARS virus is a zoonotic agent. A broad body of knowledge originating from research in veterinary medicine indicates that development of vaccines against the SARS-coronavirus may be problematic. The potential danger of such vaccines should not be neglected during the process of vaccine development.     

(Highly pathogenic) avian influenza as a zoonotic agent

Zoonotic agents challenging the world every year afresh are influenza A viruses. In the past, human pandemics caused by influenza A viruses had been occurring periodically. Wild aquatic birds are carriers of the full variety of influenza virus A subtypes, and thus, most probably constitute the natural reservoir of all influenza A viruses. Whereas avian influenza viruses in their natural avian reservoir are generally of low pathogenicity (LPAIV), some have gained virulence by mutation after transmission and adaptation to susceptible gallinaceous poultry. Those so-called highly pathogenic avian influenza viruses (HPAIV) then cause mass die-offs in susceptible birds and lead to tremendous economical losses when poultry is affected. Besides a number of avian influenza virus subtypes that have sporadically infected mammals, the HPAIV H5N1 Asia shows strong zoonotic characteristics and it was transmitted from birds to different mammalian species including humans. Theoretically, pandemic viruses might derive directly from avian influenza viruses or arise after genetic reassortment between viruses of avian and mammalian origin. So far, HPAIV H5N1 already meets two conditions for a pandemic virus: as a new subtype it has been hitherto unseen in the human population and it has infected at least 438 people, and caused severe illness and high lethality in 262 humans to date (August 2009). The acquisition of efficient human-to-human transmission would complete the emergence of a new pandemic virus. Therefore, fighting H5N1 at its source is the prerequisite to reduce pandemic risks posed by this virus. Other influenza viruses regarded as pandemic candidates derive from subtypes H2, H7, and H9 all of which have infected humans in the past. Here, we will give a comprehensive overview on avian influenza viruses in concern to their zoonotic potential.     

Isolation and characterization of a coronavirus from pigeons with pancreatitis

OBJECTIVE: To identify and partially characterize a coronaviruslike virus isolated from naturally infected pigeons. ANIMALS: 50 specific pathogen-free (SPF) embryonated chicken eggs, 30 White Leghorn SPF chickens, and 12 clinically normal pigeons. PROCEDURES: Pancreatic tissue specimens from sick pigeons were inoculated into SPF embryonated chicken eggs for viral isolation and investigation of morphologic and hemagglutinating properties of the isolate, called PSH050513. Furthermore, virulence studies in SPF chickens and experimental pigeons were performed. The spike (S) glycoprotein gene of PSH050513 was further sequenced and analyzed. RESULTS: PSH050513 was isolated and identified from the experimentally infected pigeons by a routine method, which was in accordance with Koch's postulates. The complete S protein (1,167 amino acids) was compared with published S protein sequences of other avian and mammalian coronaviruses. A high degree of sequence identity (79.3% to 99.6%) was observed between the S protein sequence of PSH050513 and published sequences of avian infectious bronchitis virus (IBV); only limited identity (< 37.8%) was observed with turkey coronavirus and mammalian coronaviruses. Furthermore, when the virus was inoculated into SPF chickens, pancreatitis developed. CONCLUSIONS AND CLINICAL RELEVANCE: PSH050513 has been tentatively identified as a novel member of group 3 coronaviruses that have close genetic relationships with IBV strains.     

PEDV编码蛋白拮抗宿主天然免疫的研究进展

猪流行性腹泻病毒(PEDV)属于冠状病毒家族成员,是近年来引起新生仔猪水样腹泻致死的主要病原之一,给养殖业带来了巨大威胁.病毒感染后,宿主细胞通过模式识别受体(PRRs)识别病原相关分子模式(PAMPs),促进I型干扰素等细胞因子的产生,进而抑制病毒的增殖.近年来的研究表明,PEDV能够通过其编码蛋白对宿主的抗病毒天然...     

Detection of potentially novel paramyxovirus and coronavirus viral RNA in bats and rats in the Mekong Delta region of southern Viet Nam

Bats and rodents are being increasingly recognized as reservoirs of emerging zoonotic viruses. Various studies have investigated bat viruses in tropical regions, but to date there are no data regarding viruses with zoonotic potential that circulate in bat and rat populations in Viet Nam. To address this paucity of data, we sampled three bat farms and three wet markets trading in rat meat in the Mekong Delta region of southern Viet Nam. Faecal and urine samples were screened for the presence of RNA from paramyxoviruses, coronaviruses and filoviruses. Paramyxovirus RNA was detected in 4 of 248 (1%) and 11 of 222 (4.9%) bat faecal and urine samples, respectively. Coronavirus RNA was detected in 55 of 248 (22%) of bat faecal samples; filovirus RNA was not detected in any of the bat samples. Further, coronavirus RNA was detected in 12 of 270 (4.4%) of rat faecal samples; all samples tested negative for paramyxovirus. Phylogenetic analysis revealed that the bat paramyxoviruses and bat and rat coronaviruses were related to viruses circulating in bat and rodent populations globally, but showed no cross‐species mixing of viruses between bat and rat populations within Viet Nam. Our study shows that potentially novel variants of paramyxoviruses and coronaviruses commonly circulate in bat and rat populations in Viet Nam. Further characterization of the viruses and additional human and animal surveillance is required to evaluate the likelihood of viral spillover and to assess whether these viruses pose a risk to human health.     

SARS冠状病毒与动物冠状病毒的分子生物学研究进展

冠状病毒是一类有囊膜的单股正链RNA病毒,经常引起动物和人群的感染。2003年,全世界多个国家和地区暴发了重症急性呼吸系统综合征,这也使冠状病毒的研究成为病毒学领域中最为关注的问题。文章主要叙述了动物冠状病毒和SARS冠状病毒的分子生物学特性及其最新研究进展。同时,也对SARS冠状病毒和其他冠状病毒的相关性进行了比较分析。     

Dynamics of avian coronavirus circulation in commercial and non-commercial birds in Asia – a review

It is essential to understand the latest situation regarding avian coronaviruses (ACoVs), commonly referred to as the well-known avian infectious bronchitis virus (IBV), given that new and diverse types of IBV are continually being identified worldwide, particularly ones that are isolated from commercial poultry and associated with a wide range of disease conditions. The existing IBVs continue to evolve in various geographic areas in Asia, which results in the recombination and co-circulation between IBV types. This makes it increasingly difficult to prevent and control IBV infections, despite routine vaccination. Some ACoVs have also been identified in other avian species and they may pose a threat of cross-transmission to commercial sectors. The present review provides an overview of IBV circulation and the dynamic emergence of new variants found throughout Asia via the recombination of IBV strains. In addition to commercial poultry, backyard poultry and free-ranging birds may serve as a ‘hub’ for ACoV transmission within a particular area. These birds may be capable of spreading viruses, either to areas of close proximity, or to remote places via migration and trade.     

Antigen selection and presentation to protect against transmissible gastroenteritis coronavirus.

The antigenic structure of the S glycoprotein of transmissible gastroenteritis virus (TGEV) and porcine respiratory coronavirus (PRCV) has been determined and correlated with the physical structure. Four antigenic sites have been defined (A, B, C, and D). The sites involved in the neutralization of TGEV are: A, D, and B, sites A and D being antigenically dominant for TGEV neutralization in vitro. These two sites have specific properties of interest: site A is highly conserved and is present in coronaviruses of three animal species, and site D can be represented by synthetic peptides. Both sites might be relevant in protection in vivo. PRCV does not have sites B and C, due to a genomic deletion. Complex antigenic sites, i.e., conformation and glycosylation dependent sites, have been represented by simple mimotopes selected from a library expressing recombinant peptides with random sequences, or by anti-idiotypic internal image monoclonal antibodies. An epidemiological tree relating the TGEVs and PRCVs has been proposed. The estimated mutation fixation rate of 7 +/- 2 x 10(-4) substitutions per nucleotide and year indicates that TGEV related coronaviruses show similar variability to other RNA viruses. In order to induce secretory immunity, different segments of the S gene have been expressed using a virulent forms of Salmonella typhimurium and adenovirus. These vectors, with a tropism for Peyer's patches may be ideal candidates in protection against TGEV.     

几种常见冠状病毒感染疾病的病理学特征

冠状病毒(coronavirus)属于单股正链RNA病毒,在自然界中广泛存在,根据血清型特点和基因序列可分为α、β、γ和δ4个种属.目前发现,冠状病毒仅感染脊椎动物,且容易引起人畜共患病的发生,对公共卫生安全具有重大隐患.然而,不同种属的冠状病毒对动物的感染性存在差异,导致患病动物出现不同的病理学特征.现综述几种常见冠...     

Inner structures of some coronaviruses.

When treated with formaldehyde, Tween 80, sodium oleate and Nonidet P-40, avian infectious bronchitis virus, porcine transmissible gastroenteritis virus, neonatal calf diarrhea coronavirus, porcine hemagglutinating encephalomyelitis virus as well as the human coronavirus show similar inner structures by negative staining. The first one is an inner membranous bag. This structure could be evaginated following treatments used and does not show the characteristic projections of coronaviruses. Subsequently, the inner fold could be separated from the outer membrane at the point of junction between these two membranes. Each virus does not react in the same way to the action of the different products. The transmissible gastroenteritis virus appears more sensitive to treatments than other viruses. On the other hand, the hemagglutinating encephalomyelitis virus is the most resistant. The variable sensitivities of these viruses are not related to the type of host-cells. Also, a second internal structure, which is more dense than the viral particle, encircles partially the aperture of the internal tongue-shaped structure and seems to emerge from the viral particle through the aperture of the inner bag.     

7种动物冠状病毒特异基因的克隆与序列分析

为了比较冠状病毒基因相关性,获得特异基因克隆制备冠状病毒基因芯片,根据发布的基因序列,每种病毒设计4~17对引物,利用火鸡冠状病毒(TCV)原毒和蔗糖密度梯度离心纯化浓缩的犬冠状病毒(CCV)、猫冠状病毒(FCV)、猫传染性腹膜炎病毒(FIPV)、猪传染性胃肠炎病毒(TGEV)、猪呼吸道冠状病毒(PRCV)、牛冠状病毒(BCV)细胞毒,提取总RNA并反转录和PCR扩增。回收PCR产物连接pGEM-T-easy载体并转化大肠杆菌TGI,经PCR鉴定后测序。将所有基因片段的核苷酸序列和推导的氨基酸序列,分别与GenBank有关病毒相关基因片段的核苷酸序列进行分析比较,确定它们的同源性。通过对不同冠状病毒不同基因片段的克隆和测序,发现同一群冠状病毒核苷酸序列间具有较高的同源性。