人类病毒学的展望

以人类为宿主的病毒研究历来是病毒学最活跃的一个领域。人类病毒学是与动物病毒学一起发展的。这不仅是因为人类病毒本来就是动物病毒的组成部分,人畜又有许多共患的疾病,而且还因为人类病毒研究离不开实验动物,许多动物病毒又为人类病毒提供了理想的模型,例如对许多动物肿瘤病毒和慢病毒的研究,就是为了解决人类疾病的目的而进行的。但是人类病毒学又有其本身的特点:首先,它与医学密切相关,因此对人的一生从胎儿到老年的病     

诺如病毒反向遗传系统的研究进展与应用

诺如病毒是导致人类急性胃肠炎的主要食源性致病原,由于变异快且缺乏稳健的体外细胞培养体系及小动物感染模型,限制了我们对该病原体的深入研究.近年来,可培养鼠源诺如病毒的发现、人源诺如病毒肠道细胞培养体系的开发,以及诺如病毒反向遗传操作体系的构建为系统研究该病原提供了有力工具,加深了我们对其复制机制、致病机理、病毒-宿主相互...     

埃博拉出血热及埃博拉病毒的研究进展

埃博拉病毒可以引起一种人畜共患烈性传染病,即埃博拉出血热,此病于1976年始发于埃博拉河流域,并且于该区域严重流行,故而得名。人类一旦感染埃博拉病毒,死亡率可高达88%,从而引起医学界的广泛关注,世界卫生组织已将埃博拉病毒列为对人类危害最为严重的病毒之一。深入地了解埃博拉出血热及埃博拉病毒,及其致病机理,对于埃博拉出血热的预防和控制具有非常重要的意义。     

预防人畜共患病必须确立"人病兽防"观点

人畜共患病(zoonosis)也称人兽共患病,是指脊椎动物与人类之间自然传播的疾病和感染疾病.它是由病毒、细菌、衣原体、立克次体、支原体、螺旋体、真菌、原虫和蠕虫等病原体所引起的各种疾病的总称.     

鸡新城疫病毒抗人肿瘤性疾病的分子机制

新城疫是由鸡新城疫病毒引起的人畜共患病毒病,主要感染禽类,对人可引起发热等轻微症状。鸡新城疫病毒感染后可诱导机体产生干扰素和肿瘤坏死因子等抗肿瘤作用的细胞因子。鸡新城疫病毒的HN蛋白具有增加肿瘤细胞对淋巴细胞的粘附力、刺激淋巴细胞的分化和改变肿瘤细胞免疫原性的作用,在人类肿瘤性疾病生物防控中具有较高的研究和应用价值。     

单核细胞增生李斯特菌的检测技术进展

单核细胞增生李斯特菌（Listeria monocytogenes）是一类人畜共患的食源性致病菌。近年来其检测技术取得了迅猛的发展,本文对目前使用的基于培养、免疫学和分子生物学技术的三大类单核细胞增生李斯特菌检测方法进行了综述,同时对单核细胞增生李斯特菌检测的新策略进行了展望。     

禽流感:一种人畜共患病

禽流感 (AvianInfluenza ,AI)是严重危害畜牧业与人类健康的一种传染性疾病。多年来在世界上许多国家和地区都发生过此病 ,危害严重 ,经济损失巨大。禽流感病毒可感染多种动物 ,包括人、猪、马、鲸、海豹和雪貂。禽流感病毒经变异或基因重组 ,已具备感染人的能力 ,有可能成为人类新型流感流行的潜在病原。本文对与禽流感病毒相关的流感疫情进行历史性的回顾 ,并对其人畜共患机制做了初步探讨     

乙型脑炎病毒及其疫苗的研究进展

流行性乙型脑炎是由乙型脑炎病毒引起的、经蚊虫传播的严重危害中枢神经系统的人畜共患急性传染病,其重症病死率高,易造成永久性的神经系统后遗症,严重威胁着人类的健康。目前尚无特效的治疗流行性乙型脑炎的方法,控制蚊虫传播和免疫接种是当前的主要防御手段。简要综述了乙型脑炎病毒的基因组结构、结构蛋白与非结构蛋白功能、基因分型,以及流行性乙型脑炎疫苗的研究进展。     

旋毛虫感染与肠黏膜免疫应答作用的研究进展

旋毛虫病是一种常见的人兽共患寄生虫病,也是一种重要的食源性寄生虫病,严重危害着人类的健康。肠黏膜是肠道寄生虫（包括旋毛虫等）进入宿主的重要门户,即机体非特异性抗感染的第一道防线,也是宿主抵御肠道寄生虫入侵的重要固有屏障,后者发挥着固有性免疫和适应性免疫功能的作用。宿主的肠黏膜免疫应答反应决定旋毛虫与宿主相互作用和适应关系。本研究就目前国内外学者研究旋毛虫感染与宿主免疫的现状,分别从肠道黏膜组织学结构、免疫细胞、细胞因子和小肠上皮细胞4个方面,综述一下肠黏膜对旋毛虫感染的免疫应答作用,目的在于揭示宿主肠黏膜对旋毛虫感染的免疫应答机制。     

人工模拟胃肠道模型在食源性致病菌耐受及致病机理中的应用

人工模拟胃肠道模型是研究食源性致病菌耐受及致病机理的一种重要工具,其本质是在实验室模拟的条件下,重现人体消化过程中的化学、物理及生物作用,以研究食源性致病菌的耐受性、致病机理、肠道菌群互作及疫苗开发,对食源性致病菌的控制和治疗具有十分重要的意义。文中综述了人工模拟胃肠道模型在食源性致病菌研究中的应用,将现有胃肠道模型系统地划分为体外静态模型、体外动态模型、普通动物模型及人源化动物模型,并详细介绍了各类模型的概念及特性。在此基础之上,进一步分析了现有模型的不足,并对未来人工模拟胃肠道模型的研究方向进行了展望,以期为食源性致病菌耐受及致病机理的研究奠定扎实的研究基础。     

Foodborne viruses

Foodborne and waterborne viral infections are increasingly recognized as causes of illness in humans. This increase is partly explained by changes in food processing and consumption patterns that lead to the worldwide availability of high-risk food. As a result, vast outbreaks may occur due to contamination of food by a single foodhandler or at a single source. Although there are numerous fecal-orally transmitted viruses, most reports of foodborne transmission describe infections with Norwalk-like caliciviruses (NLV) and hepatitis A virus (HAV), suggesting that these viruses are associated with the greatest risk of foodborne transmission. NLV and HAV can be transmitted from person to person, or indirectly via food, water, or fomites contaminated with virus-containing feces or vomit. People can be infected without showing symptoms. The high frequency of secondary cases of NLV illness and - to a lesser extent - of hepatitis A following a foodborne outbreak results in amplification of the problem. The burden of illness is highest in the elderly, and therefore is likely to increase due to the aging population. For HAV, the burden of illness may increase following hygienic control measures, due to a decreasing population of naturally immune individuals and a concurrent increase in the population at risk. Recent advances in the research of NLV and HAV have led to the development of molecular methods which can be used for molecular tracing of virus strains. These methods can be and have been used for the detection of common source outbreaks. While traditionally certain foods have been implicated in virus outbreaks, it is clear that almost any food item can be involved, provided it has been handled by an infected person. There are no established methods for detection of viruses in foods other than shellfish. Little information is available on disinfection and preventive measures specifically for these viruses. Studies addressing this issue are hampered by the lack of culture systems. As currently available routine monitoring systems exclusively focus on bacterial pathogens, efforts should be made to combine epidemiological and virological information for a combined laboratory-based rapid detection system for foodborne viruses. With better surveillance, including typing information, outbreaks of foodborne infections could be reported faster to prevent further spread.     

Risk factors for human disease emergence

A comprehensive literature review identifies 1415 species of infectious organism known to be pathogenic to humans, including 217 viruses and prions, 538 bacteria and rickettsia, 307 fungi, 66 protozoa and 287 helminths. Out of these, 868 (61%) are zoonotic, that is, they can be transmitted between humans and animals, and 175 pathogenic species are associated with diseases considered to be 'emerging'. We test the hypothesis that zoonotic pathogens are more likely to be associated with emerging diseases than non-emerging ones. Out of the emerging pathogens, 132 (75%) are zoonotic, and overall, zoonotic pathogens are twice as likely to be associated with emerging diseases than non-zoonotic pathogens. However, the result varies among taxa, with protozoa and viruses particularly likely to emerge, and helminths particularly unlikely to do so, irrespective of their zoonotic status. No association between transmission route and emergence was found. This study represents the first quantitative analysis identifying risk factors for human disease emergence.     

Optimization of a Novel Non-invasive Oral Sampling Technique for Zoonotic Pathogen Surveillance in Nonhuman Primates

Free-ranging nonhuman primates are frequent sources of zoonotic pathogens due to their physiologic similarity and in many tropical regions, close contact with humans. Many high-risk disease transmission interfaces have not been monitored for zoonotic pathogens due to difficulties inherent to invasive sampling of free-ranging wildlife. Non-invasive surveillance of nonhuman primates for pathogens with high potential for spillover into humans is therefore critical for understanding disease ecology of existing zoonotic pathogen burdens and identifying communities where zoonotic diseases are likely to emerge in the future. We developed a non-invasive oral sampling technique using ropes distributed to nonhuman primates to target viruses shed in the oral cavity, which through bite wounds and discarded food, could be transmitted to people. Optimization was performed by testing paired rope and oral swabs from laboratory colony rhesus macaques for rhesus cytomegalovirus (RhCMV) and simian foamy virus (SFV) and implementing the technique with free-ranging terrestrial and arboreal nonhuman primate species in Uganda and Nepal. Both ubiquitous DNA and RNA viruses, RhCMV and SFV, were detected in oral samples collected from ropes distributed to laboratory colony macaques and SFV was detected in free-ranging macaques and olive baboons. Our study describes a technique that can be used for disease surveillance in free-ranging nonhuman primates and, potentially, other wildlife species when invasive sampling techniques may not be feasible.     

Survival of human enteric viruses in the environment and food

Human enteric pathogenic viruses can enter the environment through discharge of waste materials from infected persons, and be transmitted back to susceptible persons to continue the cycle of disease. Contamination of food with viruses may also promote disease outbreaks. A number of studies have investigated the survival characteristics of several enteric viruses in various environments and foodstuffs, to help explain the transmissibility of these pathogens. This review deals with published work on enteric virus survival on fomites, and in waters, soil, and foods; the results of these studies have illustrated the robust survival of viruses in these environments. Much information is lacking, however, especially for foodstuffs and soils, and no detailed information is available concerning the survival of noroviruses, the most significant foodborne type.     

Key characteristics of foods with an elevated risk for viral enteropathogen contamination

Viral enteropathogens are one of the leading causative agents of foodborne illnesses in both the United States and the European Union. While human noroviruses and hepatitis A virus cause the vast majority of outbreaks and illnesses, there are handful of human enteric viruses that contribute to sporadic outbreaks worldwide including astrovirus, sapovirus, rotavirus, enterovirus and Aichi virus. In addition, hepatitis E virus is increasingly being recognized as an emerging zoonotic threat within the food supply. This review aims to briefly describe the primary human enteric viruses of concern with respect to foodborne transmission. Next, we focus on the contamination and persistence of these viruses within three high-risk food commodities—leafy greens, soft red fruits and bivalve mollusks. As opposed to detailing the specific routes by which these foods can be contaminated with enteric viruses, we have chosen to focus on their persistence and specific interactions within the food itself. Therefore, the processes of attachment and internalization of the viruses in foods have been emphasized. Looking forward, the implications of these specific interactions of human enteric viruses with leafy greens, soft red fruits and bivalve mollusks are briefly considered within the context of future prevention and control strategies.     

Classification of viral zoonosis through receptor pattern analysis

Background  

Viral zoonosis, the transmission of a virus from its primary vertebrate reservoir species to humans, requires ubiquitous cellular proteins known as receptor proteins. Zoonosis can occur not only through direct transmission from vertebrates to humans, but also through intermediate reservoirs or other environmental factors. Viruses can be categorized according to genotype (ssDNA, dsDNA, ssRNA and dsRNA viruses). Among them, the RNA viruses exhibit particularly high mutation rates and are especially problematic for this reason. Most zoonotic viruses are RNA viruses that change their envelope proteins to facilitate binding to various receptors of host species. In this study, we sought to predict zoonotic propensity through the analysis of receptor characteristics. We hypothesized that the major barrier to interspecies virus transmission is that receptor sequences vary among species--in other words, that the specific amino acid sequence of the receptor determines the ability of the viral envelope protein to attach to the cell.     

The Chikungunya threat: an ecological and evolutionary perspective

Chikungunya virus (CHIKV) is an emerging mosquito-borne alphavirus. Although primarily African and zoonotic, it is known chiefly for its non-African large urban outbreaks during which it is transmitted by the same vectors as those of Dengue viruses. Unlike Dengue viruses, CHIKV displays a re-emergence pattern that closely depends on long-distance migrations including recent re-immigrations from African (putatively zoonotic) sources. Genus-based differences also emerged when comparing the evolution of Dengue-related (Flaviviruses) and of CHIKV-related (Alphaviruses) arboviruses. In this review, we discuss current information on CHIKV genetics, ecology and human infection. Further investigations on African CHIKV ecology and the differences between Flavivirus and Alphavirus members in adaptive changes and evolutionary constraints are likely to help delineate the potential of further CHIKV (re-)emergence.     

Diagnosis of influenza viruses with special reference to novel H1N1 2009 influenza virus

On 15 April and 17 April 2009, novel swineorigin influenza A (H1N1) virus was identifi ed in specimens obtained from two epidemiologically unlinked patients in the United States. The ongoing outbreak of novel H1N1 2009 influenza (swine influenza) has caused more than 3,99,232 laboratory confi rmed cases of pandemic influenza H1N1 and over 4735 deaths globally. This novel 2009 influenza virus designated as H1N1 A/swine/California/04/2009 virus is not zoonotic swine flu and is transmitted from person to person and has higher transmissibility then that of seasonal influenza viruses. In India the novel H1N1 virus infection has been reported from all over the country. A total of 68,919 samples from clinically suspected persons have been tested for influenza A H1N1 across the country and 13,330 (18.9%) of them have been found positive with 427 deaths. At the All India Institute of Medical Sciences, New Delhi India, we tested 1096 clinical samples for the presence of novel H1N1 influenza virus and seasonal influenza viruses. Of these 1096 samples, 194 samples (17.7%) were positive for novel H1N1 influenza virus and 197 samples (18%) were positive for seasonal influenza viruses. During outbreaks of emerging infectious diseases accurate and rapid diagnosis is critical for minimizing further spread through timely implementation of appropriate vaccines and antiviral treatment. Since the symptoms of novel H1N1 influenza infection are not specifi c, laboratory confi rmation of suspected cases is of prime importance.     

Rapid evolution of H5N1 influenza viruses in chickens in Hong Kong

The H5N1 avian influenza virus that killed 6 of 18 persons infected in Hong Kong in 1997 was transmitted directly from poultry to humans. Viral isolates from this outbreak may provide molecular clues to zoonotic transfer. Here we demonstrate that the H5N1 viruses circulating in poultry comprised two distinguishable phylogenetic lineages in all genes that were in very rapid evolution. When introduced into new hosts, influenza viruses usually undergo rapid alteration of their surface glycoproteins, especially in the hemagglutinin (HA). Surprisingly, these H5N1 isolates had a large proportion of amino acid changes in all gene products except in the HA. These viruses maybe reassortants each of whose HA gene is well adapted to domestic poultry while the rest of the genome arises from a different source. The consensus amino acid sequences of "internal" virion proteins reveal amino acids previously found in human strains. These human-specific amino acids may be important factors in zoonotic transmission.     

云南蛋鸡源肠炎沙门氏菌的分离鉴定及生物学特性

[背景]肠炎沙门氏菌(Salmonella enteritidis)是一种重要的人畜共患病原菌,禽类的肉制品及蛋类是其重要的传播途径.[目的]确诊云南某蛋鸡场疑似沙门氏菌感染病原情况.[方法]无菌采集发病蛋鸡肝脏组织进行细菌分离培养鉴定,对获得的菌株进行耐药性分析、致病性实验及毒力基因的检测.[结果]鉴定该分离菌为肠炎...