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african swine fever: pathogenicity and immunogenicity of two non-haemadsorbing viruses.the virulence of 2 non-haemadsorbing african swine fever virus isolates were compared with 2 haemodsorbing viruses. while 3 of these isolates usually produced acute death in pigs, 1 non-haemadsorbing virus caused either a fatal infection with an extended course, or few or no obvious signs of infection. pigs that survived infection with the latter virus were resistant to the lethal effects of the other 3 strains as well as to a pool of 7 isolates made from ornithodorus porcinus porcinus (senus wa ...1979551362
experimental studies on the replication and transmission of crimean-congo hemorrhagic fever virus in some african tick species.seven african tick species were studied as potential vectors of crimean-congo hemorrhagic fever (cchf) virus. engorged nymphae of 4 ixodid species, hyalomma marginatum rufipes, h. truncatum, rhipicephalus evertsi mimeticus, and amblyomma hebraeum, were inoculated intracoelomically with cchf virus and assayed for virus content at varying times post-inoculation. the virus replicated in all 4 species, reaching maximum titers of 4.6-5.5(10) fluorescence focus units per ml on days 5-9 post-inoculatio ...19892494900
african swine fever virus infection in the argasid host, ornithodoros porcinus porcinus.the pathogenesis of african swine fever virus (asfv) infection in ornithodoros porcinus porcinus was examined in nymphal ticks infected with the asfv isolate chiredzi/83/1. at times postinfection (p.i.) ranging from 6 h to 290 days, ticks or dissected tick tissues were titrated for virus and examined ultrastructurally for evidence of virus replication. the asfv infection rate in ticks was 100% in these experiments, and virus infection was not associated with a significant increase in tick mortal ...19989499019
functionality and cell anchorage dependence of the african swine fever virus gene a179l, a viral bcl-2 homolog, in insect cells.the african swine fever virus gene a179l has been shown to be a functional member of the ced9/bcl-2 family of apoptosis inhibitors in mammalian cell lines. in this work we have expressed the a179l gene product (p21) under the control of the baculovirus polyhedrin promoter using a baculovirus system. expression of the a179l gene neither altered the baculovirus replication phenotype nor delayed the shutoff of cellular protein synthesis, but it extended the survival of the infected insect cells to ...19989811766
african swine fever virus replication in the midgut epithelium is required for infection of ornithodoros ticks.although the malawi lil20/1 (mal) strain of african swine fever virus (asfv) was isolated from ornithodoros sp. ticks, our attempts to experimentally infect ticks by feeding them this strain failed. ten different collections of ornithodorus porcinus porcinus ticks and one collection of o. porcinus domesticus ticks were orally exposed to a high titer of mal. at 3 weeks postinoculation (p.i.), <25% of the ticks contained detectable virus, with viral titers of <4 log(10) 50% hemadsorbing doses/ml. ...199910482612
an african swine fever virus erv1-alr homologue, 9gl, affects virion maturation and viral growth in macrophages and viral virulence in swine.the african swine fever virus (asfv) genome contains a gene, 9gl, with similarity to yeast erv1 and alr genes. erv1 has been shown to function in oxidative phosphorylation and in cell growth, while alr has hepatotrophic activity. 9gl encodes a protein of 119 amino acids and was highly conserved at both nucleotide and amino acid levels among all asfv field isolates examined. monospecific rabbit polyclonal antibody produced to a glutathione s-transferase-9gl fusion protein specifically immunopreci ...200010627538
african swine fever virus multigene family 360 and 530 genes are novel macrophage host range determinants.pathogenic african swine fever virus (asfv) isolates primarily target cells of the mononuclear-phagocytic system in infected swine and replicate efficiently in primary macrophage cell cultures in vitro. asfvs can, however, be adapted to grow in monkey cell lines. characterization of two cell culture-adapted viruses, ms16 and ba71v, revealed that neither virus replicated in macrophage cell cultures. cell viability experiments and ultrastructural analysis showed that infection with these viruses r ...200111238833
ornithodoros porcinus ticks, bushpigs, and african swine fever in madagascar.african swine fever (asf) has recently made its appearance in madagascar. ticks of the ornithodoros moubata group, considered to be o. porcinus walton, 1962 were formerly known to occur in western madagascar, but seem to have disappeared from that region. however, three new sites where they occur were found in the humid and cool central highlands of anatananarivo province. these ticks are known to be efficient reservoirs and vectors of asf and constitute a considerable complication to the contro ...200111523921
pathogenesis of african swine fever virus in ornithodoros ticks.african swine fever virus (asfv) is the only known dna arbovirus and the sole member of the family asfarviridae. it causes a lethal, hemorrhagic disease in domestic pigs. asfv is enzootic in sub-saharan africa and is maintained in a sylvatic cycle by infecting both wild members of the suidae (e.g. warthogs) and the argasid tick ornithodoros porcinus porcinus. the pathogenesis of asfv in o. porcinus porcinus ticks is characterized by a low infectious dose, lifelong infection, efficient transmissi ...200111831434
detection of borrelia duttonii, a tick-borne relapsing fever agent in central tanzania, within ticks by flagellin gene-based nested polymerase chain reaction.argasid ticks collected in the site near mvumi hospital, dodoma, tanzania, were subjected to flagellin gene-based nested polymerase chain reaction (pcr) amplification for examination of borrelial infections. eight of 13 ticks gave a strong 350-bp signal; three had a weak signal at the same size, and the rest were negative. sequence determination of eight of the positive samples resulted in three types of flagellin gene sequences. the first type of sequence (shown by three individuals) was identi ...200112653131
african swine fever virus multigene family 360 genes affect virus replication and generalization of infection in ornithodoros porcinus ticks.recently, we reported that african swine fever virus (asfv) multigene family (mgf) 360 and 530 genes are significant swine macrophage host range determinants that function by promoting infected-cell survival. to examine the function of these genes in asfv's arthropod host, ornithodoros porcinus porcinus, an mgf360/530 gene deletion mutant (pr4delta35) was constructed from an asfv isolate of tick origin, pr4. pr4delta35 exhibited a significant growth defect in ticks. the deletion of six mgf360 an ...200414963141
phylogenetic analysis of the francisella-like endosymbionts of dermacentor ticks.bacterial endosymbionts with significant homology to francisella tularensis (gamma-proteobacteria) have been described from at least five species of ticks in three different genera, including two north american dermacentor species [d. andersoni stiles and d. variabilis (say)]. the evolutionary relationships among the francisella-like endosymbionts (fle) from different hosts and between fle and the arthropod-borne pathogen f. tularensis are not known. a 1,169-base fragment of the 16s rdna and a 7 ...200415185926
new world relapsing fever borrelia found in ornithodoros porcinus ticks in central tanzania.ticks were collected from 8 houses in mvumi mission village, near dodoma, tanzania. all ticks were examined for borrelia infestation by flagellin gene-based nested polymerase chain reaction. all houses were highly infested with ticks, and all ticks collected were of the ornithodoros porcinus species. fifty-one out of 120 ticks were infected with spirochetes, and a flagellin gene sequence comparison showed that most of the spirochetes belonged to borrelia duttonii, which is the causative agent of ...200415272195
preclinical diagnosis of african swine fever in contact-exposed swine by a real-time pcr assay.a fluorogenic probe hydrolysis (taqman) pcr assay for african swine fever virus (asfv) was developed and evaluated in experimentally infected swine. this sensitive and specific one-step single-tube assay, which can be performed in 2 h or less, detected viral dna in tonsil scraping samples 2 to 4 days prior to onset of clinical disease. thus, the assay would have application for preclinical diagnosis of african swine fever and surveillance and/or emergency management of a disease outbreak.200515634958
discrimination between francisella tularensis and francisella-like endosymbionts when screening ticks by pcr.the presence of francisella-like endosymbionts in tick species known to transmit tularemia poses a potential diagnostic problem for laboratories that screen tick samples by pcr for francisella tularensis. tick samples initially considered positive for f. tularensis based on standard 16s rrna gene pcr were found to be positive only for francisella-like endosymbionts using a multitarget f. tularensis taqman assay (isftu2, tul4, and iglc) and 16s rrna gene sequencing. specificity of pcr-based diagn ...200516269811
african swine fever virus isolate, georgia, 2007.african swine fever (asf) is widespread in africa but is rarely introduced to other continents. in june 2007, asf was confirmed in the caucasus region of georgia, and it has since spread to neighboring countries. dna fragments amplified from the genome of the isolates from domestic pigs in georgia in 2007 were sequenced and compared with other asf virus (asfv) isolates to establish the genotype of the virus. sequences were obtained from 4 genome regions, including part of the gene b646l that enc ...200819046509
a host species-informative internal control for molecular assessment of african swine fever virus infection rates in the african sylvatic cycle ornithodoros vector.african swine fever virus (asfv) infection in adult ornithodoros porcinus (murry 1877, sensuwalton 1979) ticks collected from warthog burrows in southern and east africa was assessed using a duplex genomic amplification approach that is informative with respect to the invertebrate host species and infecting sylvatic cycle virus. dna extracted from individual ticks was used as template for the simultaneous amplification of a c-terminal 478-bp asfv p72 gene region and a approximately 313-bp fragme ...200919941606
african swine fever viruses with two different genotypes, both of which occur in domestic pigs, are associated with ticks and adult warthogs, respectively, at a single geographical site.the role of the ancestral sylvatic cycle of the african swine fever virus (asfv) is not well understood in the endemic areas of eastern africa. we therefore analysed the asf infection status on samples collected from 51 free-ranging warthogs (phacocherus africanus) and 1576 ornithodorus porcinus ticks from 26 independent warthog burrows at a single ranch in kenya. abattoir samples from 83 domestic pigs without clinical symptoms, originating from specific locations with no recent reported asf out ...201020965989
the complete mitochondrial genome of the citrus red mite panonychus citri (acari: tetranychidae): high genome rearrangement and extremely truncated trnas.the family tetranychidae (chelicerata: acari) includes ~1200 species, many of which are of agronomic importance. to date, mitochondrial genomes of only two tetranychidae species have been sequenced, and it has been found that these two mitochondrial genomes are characterized by many unusual features in genome organization and structure such as gene order and nucleotide frequency. the scarcity of available sequence data has greatly impeded evolutionary studies in acari (mites and ticks). informat ...201020969792
first detection of african swine fever virus in ornithodoros porcinus in madagascar and new insights into tick distribution and taxonomy.abstract:201021118485
detection of new francisella-like tick endosymbionts in hyalomma spp. and rhipicephalus spp. (acari: ixodidae) from bulgaria.we report on the identification of two new francisella-like endosymbionts (fles) found in three different tick species from bulgaria. the fles were characterized by 16s rrna and tul4 gene sequencing and seem to lack the molecular marker rd1. these two new taxa seem to be facultative secondary endosymbionts of ticks.201121705542
multiplex real-time pcr diagnostic of relapsing fevers in africa.in africa, relapsing fever borreliae are neglected arthropod-borne pathogens causing mild to deadly septicemia and miscarriage. the closely related borrelia crocidurae, borrelia duttonii, borrelia recurrentis and borrelia hispanica are rarely diagnosed at the species level, hampering refined epidemiological and clinical knowledge of the relapsing fevers. it would be hugely beneficial to have simultaneous detection and identification of borrelia to species level directly from clinical samples.201323390560
laboratory diagnosis of tick-borne african relapsing fevers: latest developments.in africa, relapsing fevers caused by ectoparasite-borne borrelia species are transmitted by ticks, with the exception of borrelia recurrentis, which is a louse-borne spirochete. these tropical diseases are responsible for mild to deadly spirochetemia. cultured borrelia crocidurae, borrelia duttonii, and borrelia hispanica circulate alongside at least six species that have not yet been cultured in vectors. direct diagnosis is hindered by the use of non-specific laboratory tools. indeed, microsco ...201526618151
the recent evolution of a maternally-inherited endosymbiont of ticks led to the emergence of the q fever pathogen, coxiella burnetii.q fever is a highly infectious disease with a worldwide distribution. its causative agent, the intracellular bacterium coxiella burnetii, infects a variety of vertebrate species, including humans. its evolutionary origin remains almost entirely unknown and uncertainty persists regarding the identity and lifestyle of its ancestors. a few tick species were recently found to harbor maternally-inherited coxiella-like organisms engaged in symbiotic interactions, but their relationships to the q fever ...201525978383
tick-box for 3'-end formation of mitochondrial transcripts in ixodida, basal chelicerates and drosophila.according to the trna punctuation model, the mitochondrial genome (mtdna) of mammals and arthropods is transcribed as large polycistronic precursors that are maturated by endonucleolytic cleavage at trna borders and rna polyadenylation. starting from the newly sequenced mtdna of ixodes ricinus and using a combination of mitogenomics and transcriptional analyses, we found that in all currently-sequenced tick lineages (prostriata, metastriata and argasidae) the 3'-end of the polyadenylated nad1 an ...201223077630
the complete mitochondrial genome of pseudocellus pearsei (chelicerata: ricinulei) and a comparison of mitochondrial gene rearrangements in arachnida.mitochondrial genomes are widely utilized for phylogenetic and population genetic analyses among animals. in addition to sequence data the mitochondrial gene order and rna secondary structure data are used in phylogenetic analyses. arachnid phylogeny is still highly debated and there is a lack of sufficient sequence data for many taxa. ricinulei (hooded tickspiders) are a morphologically distinct clade of arachnids with uncertain phylogenetic affinities.200717961221
revealing pancrustacean relationships: phylogenetic analysis of ribosomal protein genes places collembola (springtails) in a monophyletic hexapoda and reinforces the discrepancy between mitochondrial and nuclear dna markers.in recent years, several new hypotheses on phylogenetic relations among arthropods have been proposed on the basis of dna sequences. one of the challenged hypotheses is the monophyly of hexapods. this discussion originated from analyses based on mitochondrial dna datasets that, due to an unusual positioning of collembola, suggested that the hexapod body plan evolved at least twice. here, we re-evaluate the position of collembola using ribosomal protein gene sequences.200818366624
the complete mitochondrial genome of the house dust mite dermatophagoides pteronyssinus (trouessart): a novel gene arrangement among arthropods.the apparent scarcity of available sequence data has greatly impeded evolutionary studies in acari (mites and ticks). this subclass encompasses over 48,000 species and forms the largest group within the arachnida. although mitochondrial genomes are widely utilised for phylogenetic and population genetic studies, only 20 mitochondrial genomes of acari have been determined, of which only one belongs to the diverse order of the sarcoptiformes. in this study, we describe the mitochondrial genome of ...200919284646
effect of o. porcinus tick salivary gland extract on the african swine fever virus infection in domestic pig.african swine fever is a haemorrhagic disease in pig production that can have disastrous financial consequences for farming. no vaccines are currently available and animal slaughtering or area zoning to restrict risk-related movements are the only effective measures to prevent the spread of the disease. ornithodoros soft ticks are known to transmit the african swine fever virus (asfv) to pigs in farms, following the natural epidemiologic cycle of the virus. tick saliva has been shown to modulate ...201626828597
experimental infection of ornithodoros erraticus sensu stricto with two portuguese african swine fever virus strains. study of factors involved in the dynamics of infection in ticks.african swine fever (asf) is a frequently devastating hemorrhagic disease of domestic pigs and wild boar and ornithodoros erraticus sensu stricto argasid ticks are the only biological vectors of african swine fever virus (asfv) known to occur in europe. recently this disease emerged in eastern europe and russian federation, showing a huge potential for a rapid spread between countries. there is some risk of re-emergence of asf in the countries where these ticks exist, that can contribute for the ...201526366570
ubiquitous bacteria borrelia crocidurae in western african ticks ornithodoros sonrai.in west africa, tick-borne relapsing fever is a neglected arthropod-borne infection caused by borrelia crocidurae transmitted by the argasid tick ornithodoros sonrai. from an epidemiological point of view, it is of interest to know whether some genotypes of the vector are specialized in carrying certain genotypes of the pathogen.201526382232
scafos: a tool for selection, concatenation and fusion of sequences for phylogenomics.phylogenetic analyses based on datasets rich in both genes and species (phylogenomics) are becoming a standard approach to resolve evolutionary questions. however, several difficulties are associated with the assembly of large datasets, such as multiple copies of a gene per species (paralogous or xenologous genes), lack of some genes for a given species, or partial sequences. the use of undetected paralogous or xenologous genes in phylogenetic inference can lead to inaccurate results, and the us ...200717288575
genetic characterization of african swine fever virus isolates from soft ticks at the wildlife/domestic interface in mozambique and identification of a novel genotype.african swine fever virus (asfv) is one of the most threatening infectious diseases of pigs. there are not sufficient data to indicate the importance of the sylvatic cycle in the spread and maintenance of the disease locally and potentially, globally. to assess the capacity to maintain asf in the environment, we investigated the presence of soft tickreservoirs of asfv in gorongosa national park (gnp) and its surrounding villages. a total of 1,658 soft ticks were recovered from warthog burrows an ...201728921895
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