关键词： Chiroptera   mitochondrial DNA   immune factors   body temperature   Spleen   Retina   ELISA   YOKV  

摘要： Many investigators focused on bats (Chiroptera) for their specific character, i.e. echolocation system, phylogenic tree, food practice and unique reproduction. However, most of basic information about the vital functions related to anti-viral activity has been unclear. For evaluating some animals as a natural reservoir or host of infectious pathogens, it is necessary that not only their immune system but also their biology, the environment of their living, food habits and physiological features should be clarified and they should be analyzed from these multi-view points. The majority of current studies on infectious diseases have been conducted for the elucidation of viral virulence using experimental animals or viral gene function in vitro, but in a few case, researchers focused on wild animal itself. In this paper, we described basic information about bats as follows;genetic background, character of the immunological factors, histological character of immune organs, the physiological function and sensitivity of bat cells to viral infection. (C) 2007 Published by Elsevier Ltd.

关键词： .phylogenetic   newly   emerging infectious   Severe Acute Respiratory   group coronaviruses   emerged   SARS-CoV   Geological Survey   Rocky Mountain   COVs   Bats in North   coronavirus RNA   Myotis   occultus   bat coronaviruses   Asian bats  

摘要： The epidemic of severe acute respiratory syndrome (SARS) was caused by a newly emerged coronavirus (SARS-CoV). Bats of several species in southern People's Republic of China harbor SARS-like CoVs and may be reservoir hosts for them. To determine whether bats in North America also harbor coronaviruses, we used reverse transcription-PCR to detect coronavirus RNA in bats. We found coronavirus RNA in 6 of 28 fecal specimens from bats of 2 of 7 species tested. The prevalence of viral RNA shedding was high: 17% in Eptesicus fuscus and 50% in Myotis occultus. Sequence analysis of a 440-bp amplicon in gene 1b showed that these Rocky Mountain bat coronaviruses formed 3 clusters in phylogenetic group 1 that were distinct from group 1 coronaviruses of Asian bats. Because of the potential for bat coronaviruses to cause disease in humans and animals, further surveillance and characterization of bat coronaviruses in North America are needed.

关键词： RABIES virus   VIRUS diseases   BLOOD-brain barrier   HYPOTHALAMIC-pituitary-adrenal axis   STEROID hormones   DEHYDROEPIANDROSTERONE   CENTRAL nervous system   MICE as laboratory animals  

摘要： Silver-haired bat rabies virus (SHBRV) infection induces a strong virus-specific immune response in the periphery of the host, but death is common due to the failure to open the blood-brain barrier (BBB) and deliver immune effectors to central nervous system (CNS) tissues. Mice with an SJL background are less susceptible to lethal infection with rabies viruses. In addition, these animals are known to have reduced hypothalamus-pituitary-adrenal (HPA) axis activity and an elevated capacity to mediate CNS inflammatory responses. We show here that approximately one-half of PLSJL mice survive an SHBRV infection that is invariably lethal for 129/SvEv mice. This difference is associated with the elevated capacity of PLSJL mice to mediate BBB permeability changes in response to the infection. The induction of more extensive BBB permeability and CNS inflammation in these animals results in greater virus clearance and improved survival. On the other hand, treatment of SHBRV-infected PLSJL mice with the steroid hormone dehydroepiandrosterone reduced BBB permeability changes and caused greater mortality. We conclude that the infiltration of immune effectors across the BBB is critical to surviving a rabies virus infection and that HPA axis activity may influence this process.

关键词： Australian bat lyssavirus   dogs   cats   susceptibility   lyssavirus   rabies virus   genotypes  

摘要： The susceptibility of cats and dogs to Australian bat lyssavirus (ABLV;genotype VII) was investigated by intramuscular (IM) inoculation of 10(3.7)-10(5) 50% tissue culture infective doses (TCID50) of virus followed by observation of experimental animals for up to 3 months post-inoculation (pi). Each experiment also included positive and negative controls, animals inoculated with a bat variant of rabies virus (Eptesicus 1, genotype 1), or a 10% suspension of uninfected mouse brain, respectively. Each of the ABLV-inoculated cats showed occasional abnormal clinical signs, but none died. Necropsies performed at 3 months pi revealed no lesions, and no viral antigen, in the central nervous system of any cat. ABLV could not be recovered from any cats. However, rabies virus-neutralizing antibodies were detected between 4 and 14 weeks pi in the sera of all three ABLV-inoculated cats. At 23 weeks pi, three of the five ABLV-inoculated dogs showed very mild abnormal clinical signs that persisted for 1-2 days, after which the dogs recovered. At 3 months pi, when all dogs were necropsied, neither lesions nor ABLV antigen were detected in, and virus was not isolated from, any dog. No ABLV RNA was detected by polymerase chain reaction (PCR) in clinical or necropsy samples from the three ABLV-affected dogs. However, all ABLV-inoculated dogs seroconverted by 2 weeks pi, and serum antibody titres were higher than those observed in cats. CSF, collected at 3 months pi, was positive for rabies virus-neutralizing antibody in two ABLV-inoculated dogs. Crown Copyright (C) 2007 Published by Elsevier B.V. All rights reserved.

关键词： Nipah virus   experimental infection   fruit bat   guinea-pig  

摘要： Seventeen grey-headed fruit bats (Pteropus poliocephalus) were inoculated subcutaneously with an isolate of Nipah virus derived from a fatally infected human. A control group of eight guinea-pigs was inoculated intraperitoneally with the same isolate in order to confirm virulence. Three of eight infected guinea-pigs developed clinical signs 7-9 days post-inoculation. Infected fruit bats developed a subclinical. infection characterized by the transient presence of virus within selected viscera, episodic viral excretion and seroconversion. A range of histopathological changes was observed within the tissues of infected bats. Nipah virus was excreted in bat urine while neutralizing antibody was present in serum. This intermittent, low-level excretion of Nipah virus in the urine of bats may be sufficient to sustain the net reproductive value of the virus in a species where there is regular urine contamination of the fur, mutual grooming, and where urine droplets are a feature of the environment. Crown Copyright (C) 2007 Published by Elsevier Ltd. All rights reserved.

关键词： Chiroptera   Rabies   Rabies virus   翼手目   狂犬病   Rabies virus   Chiroptera   Hydrophobia   Neutralizing Antibodies  

摘要： Between 1956 and 1977, 4 human cases of rabies virus infection were attributed to aerosolized rabies virus;however, little work has been done to address this topic since the late 1960s. Employing modern nebulization equipment coupled with serologic, cell culture, and molecular technology, we have continued the investigation into aerosolized rabies virus as a potential route of transmission. Laboratory mice and 2 species of bats were exposed, through aerosol, to 3 variants of rabies virus. All bats survived exposure to aerosolized rabies virus and produced rabies neutralizing antibody. Several mice died of rabies as a result of aerosol exposure. Antibody response was followed for 6 months before animals were given an intramuscular challenge of rabies virus. Poor protection from challenge was afforded in bats, despite the presence of neutralizing antibodies.

关键词： immune system   epizootic model   viral infection   rabies  

摘要： Bats are natural reservoirs of rabies. We address the maintenance of the disease in bat colonies by developing individual and population models that generate indicators of risk of rabies to bats, that provide dynamic estimates of effects of rabies on population densities, and that suggest consequences of viral exposures and infections in bats relative to physiological and ecological characteristics of bats in different habitats. We present individual models (within host) for the immune responses to a rabies virus challenge, an immunotypic disease model that describes the evolution of the disease and a disease demographics model, which is structured by immunotypic response governed by immune system efficiency. Model simulations are consistent with available data, characterized by relatively low prevalence of the virus in colonies and much higher prevalence of rabies virus-neutralizing antibodies. Under model conditions, there is a robust non-clinical state that can be attained by the exposed individual that allows persistence of the disease in the population. (c) 2006 Elsevier Ltd. All rights reserved.

关键词： Nipah virus   diagnosis   RT-PCR   bats  

摘要： A method for duplex nested RT-PCR (nRT-PCR) with internal control (IC) for the detection of Nipah virus RNA is described. Incorporation of IC RNA distinguished false and true negative results. The extrinsic RNA was added directly to the PCR master mix and co-amplified with virus specific RNA in a duplex reaction to determine the presence of PCR inhibitor. Limit of detection was affected minimally when IC was added. Of 53 pooled urine samples collected from fruit bats (Pteropus lylei), 16 were validated by the presence of IC band on gel electrophoresis. Seven of these were also Nipah virus RNA positive. The remaining 37 samples were considered invalid. Twenty-two urine samples became valid after dilution of 1:5 and re-examined;two were Nipah virus RNA positive. These nine positive results were confirmed by sequencing of heminested PCR products. The result indicated that at least two different Nipah strains circulated in this bat species from Thailand. This method should be useful for surveillance for Nipah virus infection in animals in a country where a biosecurity level (BSL) 4 laboratory is not available. PCR inhibitors were present in a significant number of bat urine samples. The technique described in this study should improve reliability of surveillance statistics. (c) 2006 Elsevier B.V. All rights reserved.

关键词： .invasion   central nervous   Thomas Jefferson   infected animals   Rabies virus   Immune response   periphery   mice infected   blood-brain   postexposure   immune cells   neurotropic   immune effectors   SHBRV infection   CNS tissues  

摘要： Rabies is a lethal disease caused by neurotropic viruses that are endemic in nature. When exposure to a potentially rabid animal is recognized, prompt administration of virus-neutralizing antibodies, together with active immunization, can prevent development of the disease. However, once the nonspecific clinical symptoms of rabies appear conventional postexposure treatment is unsuccessful. Over the last decade, rabies viruses associated with the silver-haired bat (SHBRV) have emerged as the leading cause of human deaths from rabies in the United States and Canada as a consequence of the fact that exposure to these viruses is often unnoticed. The need to treat SHBRV infection following the development of clinical rabies has lead us to investigate why the immune response to SHBRV fails to protect at a certain stage of infection. We have established that measurements of innate and adaptive immunity are indistinguishable between mice infected with the highly lethal SHBRV and mice infected with an attenuated laboratory rabies virus strain. While a fully functional immune response to SHBRV develops in the periphery of infected animals, the invasion of central nervous system (CNS) tissues by immune cells is reduced and, consequently, the virus is not cleared. Our data indicate that the specific deficit in the SHBRV-infected animal is an inability to enhance blood-brain barrier permeability in the cerebellum and deliver immune effectors to the CNS tissues. Conceivably, at the stage of infection where immune access to the infected CNS tissues is limited, either the provision or the development of antiviral immunity will be ineffective.

关键词： leptin trophoblast invasion   leptin receptor   ObRb   ObRa   little brown myotis  

摘要： In addition to effects on metabolism and appetite, leptin is a reproductive hormone produced and secreted by the placenta of many, but not all mammalian species. In mice, in which the placenta does not secrete leptin, exogenously added leptin stimulates invasiveness of early (but not late)-gestation trophoblast cells. We report a similar phenomenon occurs in Myotis lucifugus (little brown myotis), a species in which the placenta synthesizes and secretes leptin. Immunoneutralization of endogenously secreted leptin from cultured M. lucifugus trophoblast cells inhibited the ability of these cells to invade a matrigel matrix. The effect was not due to an inhibitory effect of the antibody on cell proliferation, nor was it a non-specific effect of antibody administration. Cell invasion was significantly reduced in untreated cells obtained from late-gestation placentas, and the antibody had no effect at that time. This occurred despite continued expression throughout gestation of the long (OBRb) and short (OBRa) isoforms of leptin receptor mRNA. This study suggests that an important function of leptin during pregnancy is an effect on trophoblast cell invasiveness, at a time when the placenta is becoming established. That this occurs in two phylogenetically unrelated and distant species, regardless of whether the placenta is a source of secreted leptin, suggests that this is a highly conserved reproductive action of leptin. (c) 2006 Elsevier Inc. All rights reserved.