| evolutionary relationships and systematics of the alphaviruses. | partial e1 envelope glycoprotein gene sequences and complete structural polyprotein sequences were used to compare divergence and construct phylogenetic trees for the genus alphavirus. tree topologies indicated that the mosquito-borne alphaviruses could have arisen in either the old or the new world, with at least two transoceanic introductions to account for their current distribution. the time frame for alphavirus diversification could not be estimated because maximum-likelihood analyses indic ... | 2001 | 11581380 |
| a conserved histidine in the ij loop of the semliki forest virus e1 protein plays an important role in membrane fusion. | the enveloped alphavirus semliki forest virus (sfv) infects cells via a low ph-triggered membrane fusion reaction mediated by the e1 protein. e1 is a class ii fusion protein that contains the hydrophobic fusion peptide loop and converts to a stable homotrimer during the fusion reaction. intriguingly, the fusion loop is closely associated with a loop connecting the i and j beta-strands. this ij loop plays a role in the cholesterol dependence of membrane fusion and is specifically susceptible to p ... | 2004 | 15564465 |
| phylogenetic analysis of buggy creek virus: evidence for multiple clades in the western great plains, united states of america. | we present the first detailed phylogenetic analysis of buggy creek virus (bcrv), a poorly known alphavirus with transmission cycles involving a cimicid swallow bug (oeciacus vicarius) vector and cliff swallows (petrochelidon pyrrhonota) and house sparrows (passer domesticus) as the principal avian hosts. nucleotide sequences of a 2,075-bp viral envelope glycoprotein-coding region, covering the entire pe2 gene, were determined for 33 bcrv isolates taken from swallow bugs at cliff swallow colonies ... | 2006 | 16936062 |
| functions of the stem region of the semliki forest virus fusion protein during virus fusion and assembly. | membrane fusion of the alphaviruses is mediated by the e1 protein, a class ii virus membrane fusion protein. during fusion, e1 dissociates from its heterodimer interaction with the e2 protein and forms a target membrane-inserted e1 homotrimer. the structure of the homotrimer is that of a trimeric hairpin in which e1 domain iii and the stem region fold back toward the target membrane-inserted fusion peptide loop. the e1 stem region has a strictly conserved length and several highly conserved resi ... | 2006 | 16971447 |
| discovery of frameshifting in alphavirus 6k resolves a 20-year enigma. | the genus alphavirus includes several potentially lethal human viruses. additionally, species such as sindbis virus and semliki forest virus are important vectors for gene therapy, vaccination and cancer research, and important models for virion assembly and structural analyses. the genome encodes nine known proteins, including the small '6k' protein. 6k appears to be involved in envelope protein processing, membrane permeabilization, virion assembly and virus budding. in protein gels, 6k migrat ... | 2008 | 18822126 |
| e1 mutants identify a critical region in the trimer interface of the semliki forest virus fusion protein. | the alphavirus semliki forest virus (sfv) uses a membrane fusion reaction to infect host cells. fusion of the virus and cell membranes is triggered by low ph in the endosome and is mediated by the viral membrane protein e1. during fusion, e1 inserts into the target membrane, trimerizes, and refolds into a hairpin conformation. formation of the e1 homotrimer is critical to membrane fusion, but the mechanism of trimerization is not understood. the crystal structure of the postfusion e1 trimer show ... | 2009 | 19692469 |
| Genome scale phylogeny of the Alphavirus genus suggests a marine origin. | The genus Alphavirus comprises a diverse group of viruses, including some that cause severe disease. Using full-length sequences of all known alphaviruses, we produced a robust and comprehensive phylogeny of the Alphavirus genus, presenting a more complete evolutionary history of these viruses compared to previous studies based on partial sequences. Our phylogeny suggests the origin of the alphaviruses occurred in the southern oceans and spread equally through the Old and New World. Since lice a ... | 2011 | 22190718 |
| tick cell lines for study of crimean-congo hemorrhagic fever virus and other arboviruses. | abstract continuous cell lines derived from many of the vectors of tick-borne arboviruses of medical and veterinary importance are now available. their role as tools in arbovirus research to date is reviewed and their potential application in studies of tick cell responses to virus infection is explored, by comparison with recent progress in understanding mosquito immunity to arbovirus infection. a preliminary study of propagation of the human pathogen crimean-congo hemorrhagic fever virus (cc ... | 2011 | 21955214 |
| a field-deployable reverse transcription recombinase polymerase amplification assay for rapid detection of the chikungunya virus. | chikungunya virus (chikv) is a mosquito-borne virus currently transmitted in about 60 countries. chikv causes acute flu-like symptoms and in many cases prolonged musculoskeletal and joint pain. detection of the infection is mostly done using rt-rcr or elisa, which are not suitable for point-of-care diagnosis. | 2016 | 27685649 |
| sindbis and middelburg old world alphaviruses associated with neurologic disease in horses, south africa. | old world alphaviruses were identified in 52 of 623 horses with febrile or neurologic disease in south africa. five of 8 sindbis virus infections were mild; 2 of 3 fatal cases involved co-infections. of 44 middelburg virus infections, 28 caused neurologic disease; 12 were fatal. middelburg virus likely has zoonotic potential. | 0 | 26583836 |
| evolutionary genetics and vector adaptation of recombinant viruses of the western equine encephalitis antigenic complex provides new insights into alphavirus diversity and host switching. | western equine encephalitis virus (weev), highlands j virus (hjv), and fort morgan virus (fmv) are the sole representatives of the wee antigenic complex of the genus alphavirus, family togaviridae, that are endemic to north america. all three viruses have their ancestry in a recombination event involving eastern equine encephalitis virus (eeev) and a sindbis (sin)-like virus that gave rise to a chimeric alphavirus that subsequently diversified into the present-day weev, hjv, and fmv. here, we pr ... | 2014 | 25463613 |
| in- silico exploration of thirty alphavirus genomes for analysis of the simple sequence repeats. | the compilation of simple sequence repeats (ssrs) in viruses and its analysis with reference to incidence, distribution and variation would be instrumental in understanding the functional and evolutionary aspects of repeat sequences. present study encompasses the analysis of ssrs across 30 species of alphaviruses. the full length genome sequences, assessed from ncbi were used for extraction and analysis of repeat sequences using imex software. the repeats of different motif sizes (mono- to penta ... | 2014 | 25606453 |
| a genome-wide analysis of rna pseudoknots that stimulate efficient -1 ribosomal frameshifting or readthrough in animal viruses. | programmed -1 ribosomal frameshifting (prf) and stop codon readthrough are two translational recoding mechanisms utilized by some rna viruses to express their structural and enzymatic proteins at a defined ratio. efficient recoding usually requires an rna pseudoknot located several nucleotides downstream from the recoding site. to assess the strategic importance of the recoding pseudoknots, we have carried out a large scale genome-wide analysis in which we used an in-house developed program to d ... | 2013 | 24298557 |
| a tyrosine-to-histidine switch at position 18 of the ross river virus e2 glycoprotein is a determinant of virus fitness in disparate hosts. | arthritogenic alphaviruses are human pathogens maintained in nature through alternating replication in vertebrates and mosquitoes. using chimeric viruses, we previously reported that replacement of the pe2 coding region of the t48 strain of ross river virus (rrv-t48) with that from the attenuated dc5692 strain, which differ by 7 amino acids, resulted in an attenuated disease phenotype in a mouse model of rrv-induced rheumatic disease. here, we demonstrate that introduction of one of these amino ... | 2013 | 23514884 |
| adaptive changes in alphavirus mrna translation allowed colonization of vertebrate hosts. | members of the alphavirus genus are arboviruses that alternate replication in mosquitoes and vertebrate hosts. in vertebrate cells, the alphavirus resists the activation of antiviral rna-activated protein kinase (pkr) by the presence of a prominent rna structure (downstream loop [dlp]) located in viral 26s transcripts, which allows an eif2-independent translation initiation of these mrnas. this article shows that dlp structure is essential for replication of sindbis virus (sinv) in vertebrate ce ... | 2012 | 22761388 |
| cell-based analysis of chikungunya virus e1 protein in membrane fusion. | chikungunya fever is a pandemic disease caused by the mosquito-borne chikungunya virus (chikv). e1 glycoprotein mediation of viral membrane fusion during chikv infection is a crucial step in the release of viral genome into the host cytoplasm for replication. how the e1 structure determines membrane fusion and whether other chikv structural proteins participate in e1 fusion activity remain largely unexplored. | 2012 | 22520648 |
| alphaviruses: population genetics and determinants of emergence. | alphaviruses are responsible for several medically important emerging diseases and are also significant veterinary pathogens. due to the aerosol infectivity of some alphaviruses and their ability to cause severe, sometimes fatal neurologic diseases, they are also of biodefense importance. this review discusses the ecology, epidemiology and molecular virology of the alphaviruses, then focuses on three of the most important members of the genus: venezuelan and eastern equine encephalitis and chiku ... | 2012 | 22522323 |
| an updated checklist of mosquito species (diptera: culicidae) from madagascar. | an updated checklist of 235 mosquito species from madagascar is presented. the number of species has increased considerably compared to previous checklists, particularly the last published in 2003 (178 species). this annotated checklist provides concise information on endemism, taxonomic position, developmental stages, larval habitats, distribution, behavior, and vector-borne diseases potentially transmitted. the 235 species belong to 14 genera: aedeomyia (3 species), aedes (35 species), anophel ... | 2016 | 27101839 |
| viral metagenomics on animals as a tool for the detection of zoonoses prior to human infection? | many human viral infections have a zoonotic, i.e., wild or domestic animal, origin. several zoonotic viruses are transmitted to humans directly via contact with an animal or indirectly via exposure to the urine or feces of infected animals or the bite of a bloodsucking arthropod. if a virus is able to adapt and replicate in its new human host, human-to-human transmissions may occur, possibly resulting in an epidemic, such as the a/h1n1 flu pandemic in 2009. thus, predicting emerging zoonotic inf ... | 2014 | 24918293 |
| multi-gene detection and identification of mosquito-borne rna viruses using an oligonucleotide microarray. | arthropod-borne viruses are important emerging pathogens world-wide. viruses transmitted by mosquitoes, such as dengue, yellow fever, and japanese encephalitis viruses, infect hundreds of millions of people and animals each year. global surveillance of these viruses in mosquito vectors using molecular based assays is critical for prevention and control of the associated diseases. here, we report an oligonucleotide dna microarray design, termed arbochip5.1, for multi-gene detection and identifica ... | 2013 | 23967358 |
| isolation of tick and mosquito-borne arboviruses from ticks sampled from livestock and wild animal hosts in ijara district, kenya. | tick-borne viruses infect humans through the bite of infected ticks during opportunistic feeding or through crushing of ticks by hand and, in some instances, through contact with infected viremic animals. the ijara district, an arid to semiarid region in northern kenya, is home to a pastoralist community for whom livestock keeping is a way of life. part of the ijara district lies within the boundaries of a kenya wildlife service-protected conservation area. arbovirus activity among mosquitoes, a ... | 2013 | 23805790 |
| viral metagenomics demonstrates that domestic pigs are a potential reservoir for ndumu virus. | the rising demand for pork has resulted in a massive expansion of pig production in uganda. this has resulted in increased contact between humans and pigs. pigs can act as reservoirs for emerging infectious diseases. therefore identification of potential zoonotic pathogens is important for public health surveillance. in this study, during a routine general surveillance for african swine fever, domestic pigs from uganda were screened for the presence of rna and dna viruses using a high-throughput ... | 2012 | 23006778 |
| mosquito-borne arbovirus surveillance at selected sites in diverse ecological zones of kenya; 2007 - 2012. | increased frequency of arbovirus outbreaks in east africa necessitated the determination of distribution of risk by entomologic arbovirus surveillance. a systematic vector surveillance programme spanning 5 years and covering 11 sites representing seven of the eight provinces in kenya and located in diverse ecological zones was carried out. | 2013 | 23663381 |
| detection of persistent chikungunya virus rna but not infectious virus in experimental vertical transmission in aedes aegypti from malaysia. | vertical transmission may contribute to the maintenance of arthropod-borne viruses, but its existence in chikungunya virus (chikv) is unclear. experimental vertical transmission of infectious clones of chikv in aedes aegypti mosquitoes from malaysia was investigated. eggs and adult progeny from the second gonotrophic cycles of infected parental mosquitoes were tested. using polymerase chain reaction (pcr), 56.3% of pooled eggs and 10% of adult progeny had detectable chikv rna, but no samples had ... | 2015 | 26598564 |
| molecular detection of torque teno sus virus and coinfection with african swine fever virus in blood samples of pigs from some slaughterhouses in nigeria. | torque teno sus virus 1 (ttsuv1a/ttsuv1b) infection is present in pig herds worldwide. this study investigated the prevalence of ttsuv1a/ttsuv1b infections in domestic pigs from some slaughterhouses in nigeria as well as coinfection with african swine fever virus (asfv) and described the phylogeny in relation to global strains. one hundred and eighty-one (181) blood samples from four slaughterhouses were used for the study and viral nucleic acid detection was carried out by pcr. comparative sequ ... | 2016 | 27833640 |
| blood meal analysis and virus detection in blood-fed mosquitoes collected during the 2006-2007 rift valley fever outbreak in kenya. | rift valley fever (rvf) is a zoonosis of domestic ruminants in africa. blood-fed mosquitoes collected during the 2006-2007 rvf outbreak in kenya were analyzed to determine the virus infection status and animal source of the blood meals. | 0 | 25229704 |
| natural vertical transmission of ndumu virus in culex pipiens (diptera: culicidae) mosquitoes collected as larvae. | ndumu virus (nduv) is a member of the family togaviridae and genus alphavirus. in kenya, the virus has been isolated from a range of mosquito species but has not been associated with human or animal morbidity. little is know about the transmission dynamics or vertebrate reservoirs of this virus. nduv was isolated from two pools of female culex pipiens mosquitoes, ijr37 (n = 18) and ijr73 (n = 3), which were collected as larvae on 15 april 2013 from two dambos near the village of marey, ijara dis ... | 2014 | 25276943 |
| ndumu virus, a hitherto unknown agent, isolated from culicine mosouitoes collected in northern natal. union of south africa. | | 1961 | 13757662 |
| arboviruses isolated from the barkedji mosquito-based surveillance system, 2012-2013. | a mosquito-based arbovirus surveillance system was set up at barkedji, senegal after the first outbreak of rift valley fever in west africa in 1988. this system was recently updated using more sampling methods and collecting in greater number of ponds and villages sites. | 2018 | 30541472 |