关键词： Ebola virus   entropy   enthalpy   temperature   species barrier  

摘要： The host reservoir of Zaire ebolavirus (EBOV) remains elusive. One suggestion is that EBOV emerges in mammals when the precursor virus jumps from mayflies (or other riverine insects) to insectivorous bats. However, this does not fit with the current view that filoviruses cannot infect arthropods. Here, it is first argued that the evidence that arthropods are refractory is not definitive. Second, it is proposed that a combination of filovirus filament length and the high temperature (similar to 42 degrees C) experienced by an insect virus ingested by a flying bat, together with the large number of insects eaten by bats (e.g. during an ephemeral mass emergence of mayflies), facilitate jumping the species barrier. The length of a filovirus filament is related to the number of genome copies (GC). Predictions from a preliminary thermodynamic model developed here suggest that filament length could greatly affect EBOV infectivity to mammalian cells with infectivity peaking for filaments of a certain length. Importantly, the infectivity to mammals of even short filaments may be more than one million-fold higher than that for the single GC virion. Third, it is proposed that at the high temperature within the bat, the phospholipid phosphatidylserine in the virus envelope promotes filament formation through fusion of single GC particles within the ingested insect, thus hugely increasing their infectivity to bats. Forth, according to the thermodynamic model, increasing the temperature from 27 degrees C (insect cell temperature at average air temperature in Guinea, West Africa) to 42 degrees C (bat) could increase the affinity of the filaments for bat cells by 1-2 orders of magnitude, while having no effect on the binding affinity of the single GC virions. The thermodynamic model developed here is supported by the counterintuitive observation that high glycoprotein densities on the EBOV surface reduce its infectivity in contrast to other viruses such as HIV.

关键词： Ebola   Eidolon helvum   knowledge   risk   zoonotic disease  

摘要： A large population of straw-coloured fruit bats (Eidolon helvum) colonizes a prime area in the city of Accra where several public amenities are located. Although the colony is positive to several zoonotic viruses including the Ebola virus, there is limited information on the social dimensions of the existence of the bats. As a step towards effective response to health risk and conservation of the bats, this study assessed the knowledge and attitude of the community living around the bats and determined their level of environmental and public health consciousness. The community generally lacks interest in bat bushmeat consumption but had low knowledge and disease risk perception of the bats. Despite major campaigns during the recent Ebola outbreak in West Africa, elements of risky behaviour including disbelief and disregard for some preventive measures and lack of interest in post-bat exposure prophylaxis were recorded among a limited proportion of the community. There was the need to focus public health education on the community and possibly others that may have *** colonies in West Africa.

关键词： Chiroptera   Contact-rate   Mating systems   Sociality   Viral transmission  

摘要： Characterizing host traits that influence viral richness and diversification is important for understanding wildlife pathogens affecting conservation and/or human health. Behaviors that affect contact rates among hosts could be important for viral diversification because more frequent intra- and inter-specific contacts among hosts should increase the potential for viral diversification within host populations. We used published data on bats to test the contact-rate hypothesis. We predicted that species forming large conspecific groups, that share their range with more heterospecifics (i.e., sympatry), and with mating systems characterized by high contact rates (polygynandry: multi-male/multi-female), would host higher viral richness than species with small group sizes, lower sympatry, or low contact-rate mating systems (polygyny: single male/multi-female). Consistent with our hypothesis and previous research, viral richness was positively correlated with conspecific group size although the relationship plateaued at group sizes of approximately several hundred thousand bats. This pattern supports epidemiological theory that, up to a point, larger groups have higher contact rates, greater likelihood of acquiring and transmitting viruses, and ultimately greater potential for viral diversification. However, contrary to our hypothesis, there was no effect of sympatry on viral richness and no difference in viral richness between mating systems. We also found no residual effect of host phylogeny on viral richness, suggesting that closely related species do not necessarily host similar numbers of viruses. Our results support the contact-rate hypothesis that intra-specific viral transmission can enhance viral diversification within species and highlight the influence of host group size on the potential of viruses to propagate within host populations.

摘要： Besides these species, Rufous horseshoe bats (Rhinolophus rouxii) have also been spotted in small numbers [5]. Among all the participants, only three persons had a history of epistaxis. Besides these, three persons had a history of fever. Though all human samples collected from Malusar wadi, Malusar village and Chikhali villages were found to be negative for Malsoor virus-specific IgG antibodies, there could be antibodies present in the samples but remained undetected by ELISA. [...]the negative results do not rule out the possibility of occasional spill over to humans.

关键词： 蝙蝠   病毒   新发病毒   储存宿主  

摘要： 蝙蝠是一些重要病毒的自然储存宿主。2010-2015年调查研究表明,云南省蝙蝠中广泛存在SARS样冠状病毒(SARS-like CoV)和其它多种类型冠状病毒(α-CoV和β-CoV)的自然感染,还从蝙蝠中分离或检测到新的呼肠孤病毒(Reovirus)、轮状病毒(Rotavirus)、肝炎病毒(Orthohepadnavirus)、丝状病毒(Filovirus)、副粘病毒(Paramyxovirus)、腺病毒(Adenovirus)、博卡病毒(Bocavirus)和圆形病毒(Circovirus)。本文对云南省自然界蝙蝠携带重要人兽共患病相关病毒病原的研究进展及其公共卫生意义做一综述。

关键词： Nipah virus   NiV   viruses   infections   case-control study   human behavior   humans   bats   trees   culture   virus transmission   epidemiology   convergence   date palm sap   vector-borne infections   zoonoses   Bangladesh  

摘要： Preventing emergence of new zoonotic viruses depends on understanding determinants for human risk. Nipah virus (NiV) is a lethal zoonotic pathogen that has spilled over from bats into human populations, with limited person-to-person transmission. We examined ecologic and human behavioral drivers of geographic variation for risk of NiV infection in Bangladesh. We visited 60 villages during 2011-2013 where cases of infection with NiV were identified and 147 control villages. We compared case villages with control villages for most likely drivers for risk of infection, including number of bats, persons, and date palm sap trees, and human date palm sap consumption behavior. Case villages were similar to control villages in many ways, including number of bats, persons, and date palm sap trees, but had a higher proportion of households in which someone drank sap. Reducing human consumption of sap could reduce virus transmission and risk for emergence of a more highly transmissible NiV strain.

摘要： 在世界范围内,蝙蝠是冠状病毒的主要宿主,这是对非洲、亚洲和美洲的数千种动物进行的一项调查得出的结论.动物被认为与之前由冠状病毒引起的严重急性呼吸系统综合征(SARS)疫情和中东呼吸道综合征(MERS)疫情的暴发有着直接关系,然而直到现在,研究人员并不确定这仅是一个巧合还是表明了一种更大的趋势.

关键词： 冠状病毒   蝙蝠   病毒传播  

摘要： 严重性急性呼吸系统综合症(severe acute respiratory syndrome,SARS),又名非典型性肺炎,虽爆发已经10年过去了,恐惧依旧笼罩在人们心中,近日,中东呼吸系统综合症(middle east respiratory syndrome,MERS)又强势来袭,再次引发了人们对冠状病毒的强烈关注。近年来研究证明,蝙蝠在冠状病毒的传播中具有重要作用。本文对冠状病毒的多样性和蝙蝠在冠状病毒传播中作用进行了比较系统综述。

关键词： Mx protein   bat   bunyavirus   Ebola virus   influenza   interferons   orthomyxovirus   vesicular stomatitis virus  

摘要： Bats serve as a reservoir for various, often zoonotic viruses, including significant human pathogens such as Ebola and influenza viruses. However, for unknown reasons, viral infections rarely cause clinical symptoms in bats. A tight control of viral replication by the host innate immune defense might contribute to this phenomenon. Transcriptomic studies revealed the presence of the interferon-induced antiviral myxovirus resistance (Mx) proteins in bats, but detailed functional aspects have not been assessed. To provide evidence that bat Mx proteins might act as key factors to control viral replication we cloned Mx1 cDNAs from three bat families, Pteropodidae, Phyllostomidae, and Vespertilionidae. Phylogenetically these bat Mx1 genes cluster closely with their human ortholog MxA. Using transfected cell cultures, minireplicon systems, virus-like particles, and virus infections, we determined the antiviral potential of the bat Mx1 proteins. Bat Mx1 significantly reduced the polymerase activity of viruses circulating in bats, including Ebola and influenza A-like viruses. The related Thogoto virus, however, which is not known to infect bats, was not inhibited by bat Mx1. Further, we provide evidence for positive selection in bat Mx1 genes that might explain species-specific antiviral activities of these proteins. Together, our data suggest a role for Mx1 in controlling these viruses in their bat hosts. IMPORTANCE Bats are a natural reservoir for various viruses that rarely cause clinical symptoms in bats but are dangerous zoonotic pathogens, like Ebola or rabies virus. It has been hypothesized that the interferon system might play a key role in controlling viral replication in bats. We speculate that the interferon-induced Mx proteins might be key antiviral factors of bats and have coevolved with bat-borne viruses. This study evaluated for the first time a large set of bat Mx1 proteins spanning three major bat families for their antiviral potential, including activity ag

关键词： Hipposideridae   Guano   ssDNA   CRESS DNA virus   Nucleotide composition analysis  

摘要： Members of the viral family Circoviridae are increasingly recognized worldwide. Bats seem to be natural reservoirs or dietary-related dispensers of these viruses. Here, we report a distantly related member of the genus Cyclovirus detected in the faeces of a great roundleaf bat (Hipposideros armiger). Interestingly, the novel virus lacks a Circoviridae-specific stem-loop structure, although a Geminiviridae-like nonamer sequence was detected in the large intergenic region. Based on these differences and its phylogenetic position, we propose that our new virus represents a distant and highly divergent member of the genus Cyclovirus. However it is lacking several characteristics of members of the genus, which raises a challenge in its taxonomic classification.