Apoptosis in fatal Ebola infection. Does the virus toll the bell for immune system?

In fatal Ebola virus hemorrhagic fever massive intravascular apoptosis develops rapidly following infection and progressing relentlessly until death. While data suggest that T lymphocytes are mainly deleted by apoptosis in PBMC of human fatal cases, experimental Ebola infection in animal models have shown some evidence of destruction of lymphocytes in spleen and lymph nodes probably involving both T and B cells. Nevertheless, we are able to conclude from the accumulated evidence that early interactions between Ebola virus and the immune system, probably via macrophages, main targets for viral replication, lead to massive destruction of immune cells in fatal cases.     

Expression of neutralizing epitope of porcine epidemic diarrhea virus in potato plants

Transgenic plants expressing recombinant proteins from pathogenic microorganisms provide an inexpensive edible vaccine for induction of local immunity. A neutralizing epitope of porcine epidemic diarrhea virus (PEDV) gene containing SEKDEL was expressed in potato using Agrobacterium-mediated transformation system. Putative transgenic plants were regenerated, and genomic PCR confirmed the presence of PEDV epitope gene in the potato plants. Based on the ELISA results, epitope of PEDV protein made up approximately 0.1% of the total soluble tuber protein.     

The uniqueness of wave solutions for the deterministic non-reducible n-type epidemic

In a recent paper, [8], we investigated the existence of wave solutions for a model of the deterministic non-reducible n-type epidemic. In this paper we first prove two properties left as an open question in that paper. The uniqueness of the wave solutions at all speeds for which a wave solution exists is then established. Only an exceptional case is not covered.     

中国埃博拉诊疗中心布局流程的设计与思考

为了应对西非埃博拉病毒病疫情,中国人民解放军援利医疗队在利比里亚建立并独立运营了埃博拉诊疗中心。中心严格按照传染病医院的防护要求和标准,设计科学合理的布局流程,实现有效的感染防控。详细说明了中国埃博拉诊疗中心的布局与流程设计,归纳阐述其特点,并对做好布局流程应把握的几个重点问题进行了探讨。     

病例调查与接触追踪上报体系在埃博拉诊疗中心的建设实践

中国援利埃博拉诊疗中心在执行埃博拉收治任务时,积极对接利国疫情防控体系,建设实践了一套病例调查与接触追踪上报体系,包括建立体系组织架构、完善调查上报制度、构建数据链信息平台、建立内部核查机制,其准确性和及时性得到了广泛赞誉。通过实践,我们认为,建立病例调查和接触追踪机制,是传染病疫情控制的关键,未来应不断探索与国际接轨的机制、拓展应用信息化技术,并始终做到持续改进。     

John Montgomery's Legacy: Carbocyclic Adenosine Analogues as Sah Hydrolase Inhibitors with Broad-Spectrum Antiviral Activity

Ever since the S-adenosylhomocysteine (AdoHcy, SAH) hydrolase was recognized as a pharmacological target for antiviral agents (J. A. Montgomery et al., J. Med. Chem. 25:626–629, 1982), an increasing number of adenosine, acyclic adenosine, and carbocyclic adenosine analogues have been described as potent SAH hydrolase inhibitors endowed with broad-spectrum antiviral activity. The antiviral activity spectrum of the SAH hydrolase inhibitors include pox-, rhabdo-, filo-, arena-, paramyxo-, reo-, and retroviruses. Among the most potent SAH hydrolase inhibitors and antiviral agents rank carbocyclic 3-deazaadenosine (C-c³Ado), neplanocin A, 3-deazaneplanocin A, the 5′-nor derivatives of carbocyclic adenosine (C-Ado, aristeromycin), and the 2-halo (i.e., 2-fluoro) and 6′-R-alkyl (i.e., 6′-R-methyl) derivatives of neplanocin A. These compounds are particularly active against poxviruses (i.e., vaccinia virus), and rhabdoviruses (i.e., vesicular stomatitis virus). The in vivo efficacy of C-c³Ado and 3-deazaneplanocin A has been established in mouse models for vaccinia virus, vesicular stomatitis virus, and Ebola virus. SAH hydrolase inhibitors such as C-c³Ado and 3-deazaneplanocin A should in the first place be considered for therapeutic (or prophylactic) use against poxvirus infections, including smallpox, and hemorrhagic fever virus infections such as Ebola.     

Variation in costs of parasite resistance among natural host populations

Organisms that can resist parasitic infection often have lower fitness in the absence of parasites. These costs of resistance can mediate host evolution during parasite epidemics. For example, large epidemics will select for increased host resistance. In contrast, small epidemics (or no disease) can select for increased host susceptibility when costly resistance allows more susceptible hosts to outcompete their resistant counterparts. Despite their importance for evolution in host populations, costs of resistance (which are also known as resistance trade‐offs) have mainly been examined in laboratory‐based host–parasite systems. Very few examples come from field‐collected hosts. Furthermore, little is known about how resistance trade‐offs vary across natural populations. We addressed these gaps using the freshwater crustacean Daphnia dentifera and its natural yeast parasite, Metschnikowia bicuspidata. We found a cost of resistance in two of the five populations we studied – those with the most genetic variation in resistance and the smallest epidemics in the previous year. However, yeast epidemics in the current year did not alter slopes of these trade‐offs before and after epidemics. In contrast, the no‐cost populations showed little variation in resistance, possibly because large yeast epidemics eroded that variation in the previous year. Consequently, our results demonstrate variation in costs of resistance in wild host populations. This variation has important implications for host evolution during epidemics in nature.     

IFITMs Restrict the Replication of Multiple Pathogenic Viruses

The interferon-inducible transmembrane protein (IFITM) family inhibits a growing number of pathogenic viruses, among them influenza A virus, dengue virus, hepatitis C virus, and Ebola virus. This review covers recent developments in our understanding of the IFITM's molecular determinants, potential mechanisms of action, and impact on pathogenesis.     

On the dynamics of SEIRS epidemic model with transport-related infection

Transportation amongst cities is found as one of the main factors which affect the outbreak of diseases. To understand the effect of transport-related infection on disease spread, an SEIRS (Susceptible, Exposed, Infectious, Recovered) epidemic model for two cities is formulated and analyzed. The epidemiological threshold, known as the basic reproduction number, of the model is derived. If the basic reproduction number is below unity, the disease-free equilibrium is locally asymptotically stable. Thus, the disease can be eradicated from the community. There exists an endemic equilibrium which is locally asymptotically stable if the reproduction number is larger than unity. This means that the disease will persist within the community. The results show that transportation among regions will change the disease dynamics and break infection out even if infectious diseases will go to extinction in each isolated region without transport-related infection. In addition, the result shows that transport-related infection intensifies the disease spread if infectious diseases break out to cause an endemic situation in each region, in the sense of that both the absolute and relative size of patients increase. Further, the formulated model is applied to the real data of SARS outbreak in 2003 to study the transmission of disease during the movement between two regions. The results show that the transport-related infection is effected to the number of infected individuals and the duration of outbreak in such the way that the disease becomes more endemic due to the movement between two cities. This study can be helpful in providing the information to public health authorities and policy maker to reduce spreading disease when its occurs.