Correction: Comparative Genomics of Emerging Human Ehrlichiosis Agents
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PROVIDER: S-EPMC1756906 | biostudies-literature | 2006 Dec
REPOSITORIES: biostudies-literature
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Project description:Anaplasma (formerly Ehrlichia) phagocytophilum, Ehrlichia chaffeensis, and Neorickettsia (formerly Ehrlichia) sennetsu are intracellular vector-borne pathogens that cause human ehrlichiosis, an emerging infectious disease. We present the complete genome sequences of these organisms along with comparisons to other organisms in the Rickettsiales order. Ehrlichia spp. and Anaplasma spp. display a unique large expansion of immunodominant outer membrane proteins facilitating antigenic variation. All Rickettsiales have a diminished ability to synthesize amino acids compared to their closest free-living relatives. Unlike members of the Rickettsiaceae family, these pathogenic Anaplasmataceae are capable of making all major vitamins, cofactors, and nucleotides, which could confer a beneficial role in the invertebrate vector or the vertebrate host. Further analysis identified proteins potentially involved in vacuole confinement of the Anaplasmataceae, a life cycle involving a hematophagous vector, vertebrate pathogenesis, human pathogenesis, and lack of transovarial transmission. These discoveries provide significant insights into the biology of these obligate intracellular pathogens.
| S-EPMC1366493 | biostudies-literature
Project description: Not available
2005-01-01 | E-TIGR-125 | biostudies-arrayexpress
Project description:This study is to determine and compare the transcriptomes in two eukaryotic hosts (mammalian host - DH82 canine cell line and tick vector - ISE6 Ixodes scapularis cell line) of eight Ehrlichia chaffeensis strains in three divergent genetic groups, including Arkansas, Heartland, Jax, Liberty, Osceola, St. Vincent, Wakulla, and West Paces, and one Ehrlichia sp. HF strain.
2014-04-01 | GSE56339 | GEO
Project description:BackgroundHuman ehrlichioses are emerging life-threatening diseases transmitted by ticks. Animal models have been developed to study disease development; however, there is no valid small animal model that uses a human ehrlichial pathogen. The objective of this study was to develop a mouse model for ehrlichiosis with the newly discovered human pathogen, Ehrlichia muris-like agent (EMLA).MethodsThree strains of mice were inoculated with different doses of EMLA by the intravenous, intraperitoneal, or intradermal route and evaluated for clinical and pathologic changes during the course of infection.ResultsEMLA infected C57Bl/6, BALB/c, and C3H/HeN mice and induced lethal or persistent infection in a route- and dose-dependent manner. The clinical chemistry and hematologic changes were similar to those of human infection by Ehrlichia chaffeensis or EMLA. Bacterial distribution in tissues differed after intradermal infection, compared with the distribution after intravenous or intraperitoneal injection. Lethal infection did not cause remarkable pathologic changes, but it caused fluid imbalance. EMLA infection of endothelium and mononuclear cells likely plays a role in the severe outcome.ConclusionsThe EMLA mouse model mimics human infection and can be used to study pathogenesis and immunity and for development of a vector transmission model of ehrlichiosis.
| S-EPMC4351372 | biostudies-literature
Project description:This study is to determine and compare the transcriptomes in two eukaryotic hosts (mammalian host - DH82 canine cell line and tick vector - ISE6 Ixodes scapularis cell line) of eight Ehrlichia chaffeensis strains in three divergent genetic groups, including Arkansas, Heartland, Jax, Liberty, Osceola, St. Vincent, Wakulla, and West Paces, and one Ehrlichia sp. HF strain. RNA samples for the Arkansas (reference), Heartland, Jax, Liberty, Osceola, St. Vincent, Wakulla, and West Paces strains in both tick and canine cell lines, including two uninfected controls, will be isolated in triplicate. As such 108 libraries will be constructed and sequenced corresponding to (8 strains + 1 control) x 2 conditions (tick cells + dog cells) x 3 biological triplicates x 2 molecules sequenced (eukaryotic RNA + prokaryotic RNA). The transcriptomes are obtained with Illumina HiSeq reads obtained from paired end libraries. The bacterial reads will be mapped against the reference genome and compared through a differential expression analysis. The eukaryotic reads from the same cell types (i.e. tick or canine) will be assembled with Trinity. The reads will then be mapped back to this assembly for the differential expression analysis.
2014-04-01 | E-GEOD-56339 | biostudies-arrayexpress
Project description:In retrospective analyses, we report 3 febrile patients in Japan who had seroconversion to antibodies against Ehrlichia chaffeensis antigens detected by using an immunofluorescence and Western blot. Our results provide evidence of autochthonous human ehrlichiosis cases and indicate ehrlichiosis should be considered a potential cause of febrile illness in Japan.
| S-EPMC9622265 | biostudies-literature
Project description:Ranaviruses, a genus of the Iridoviridae, are large double-stranded DNA viruses that infect cold-blooded vertebrates worldwide. Ranaviruses have caused severe epizootics in commercial frog and fish populations, and are currently classified as notifiable pathogens in international trade. Previous work shows that a ranavirus that infects tiger salamanders throughout Western North America (Ambystoma tigrinum virus, or ATV) is in high prevalence among salamanders in the fishing bait trade. Bait ATV strains have elevated virulence and are transported long distances by humans, providing widespread opportunities for pathogen pollution. We sequenced the genomes of 15 strains of ATV collected from tiger salamanders across western North America and performed phylogenetic and population genomic analyses and tests for recombination. We find that ATV forms a monophyletic clade within the rest of the Ranaviruses and that it likely emerged within the last several thousand years, before human activities influenced its spread. We also identify several genes under strong positive selection, some of which appear to be involved in viral virulence and/or host immune evasion. In addition, we provide support for the pathogen pollution hypothesis with evidence of recombination among ATV strains, and potential bait-endemic strain recombination.
| S-EPMC4704714 | biostudies-literature
Project description:Comparison of Transcriptome Profiles of Human Ehrlichiosis Agents
| PRJNA243269 | ENA
Project description:Streptococcus halichoeri is an emerging pathogen with a variety of host species and zoonotic potential. It has been isolated from grey seals and other marine mammals as well as from human infections. Beginning in 2010, two concurrent epidemics were identified in Finland, in fur animals and domestic dogs, respectively. The fur animals suffered from a new disease fur animal epidemic necrotic pyoderma (FENP) and the dogs presented with ear infections with poor treatment response. S. halichoeri was isolated in both studies, albeit among other pathogens, indicating a possible role in the disease etiologies. The aim was to find a possible common origin of the fur animal and dog isolates and study the virulence factors to assess pathogenic potential. Isolates from seal, human, dogs, and fur animals were obtained for comparison. The whole genomes were sequenced from 20 different strains using the Illumina MiSeq platform and annotated using an automatic annotation pipeline RAST. The core and pangenomes were formed by comparing the genomes against each other in an all-against-all comparison. A phylogenetic tree was constructed using the genes of the core genome. Virulence factors were assessed using the Virulence Factor Database (VFDB) concentrating on the previously confirmed streptococcal factors. A core genome was formed which encompassed approximately half of the genes in Streptococcus halichoeri. The resulting core was nearly saturated and would not change significantly by adding more genomes. The remaining genes formed the pangenome which was highly variable and would still evolve after additional genomes. The results highlight the great adaptability of this bacterium possibly explaining the ease at which it switches hosts and environments. Virulence factors were also analyzed and were found primarily in the core genome. They represented many classes and functions, but the largest single category was adhesins which again supports the marine origin of this species.
| S-EPMC7049441 | biostudies-literature
Project description:BackgroundThe Gram-negative bacterium Photorhabdus asymbiotica (Pa) has been recovered from human infections in both North America and Australia. Recently, Pa has been shown to have a nematode vector that can also infect insects, like its sister species the insect pathogen P. luminescens (Pl). To understand the relationship between pathogenicity to insects and humans in Photorhabdus we have sequenced the complete genome of Pa strain ATCC43949 from North America. This strain (formerly referred to as Xenorhabdus luminescens strain 2) was isolated in 1977 from the blood of an 80 year old female patient with endocarditis, in Maryland, USA. Here we compare the complete genome of Pa ATCC43949 with that of the previously sequenced insect pathogen P. luminescens strain TT01 which was isolated from its entomopathogenic nematode vector collected from soil in Trinidad and Tobago.ResultsWe found that the human pathogen Pa had a smaller genome (5,064,808 bp) than that of the insect pathogen Pl (5,688,987 bp) but that each pathogen carries approximately one megabase of DNA that is unique to each strain. The reduced size of the Pa genome is associated with a smaller diversity in insecticidal genes such as those encoding the Toxin complexes (Tc's), Makes caterpillars floppy (Mcf) toxins and the Photorhabdus Virulence Cassettes (PVCs). The Pa genome, however, also shows the addition of a plasmid related to pMT1 from Yersinia pestis and several novel pathogenicity islands including a novel Type Three Secretion System (TTSS) encoding island. Together these data suggest that Pa may show virulence against man via the acquisition of the pMT1-like plasmid and specific effectors, such as SopB, that promote its persistence inside human macrophages. Interestingly the loss of insecticidal genes in Pa is not reflected by a loss of pathogenicity towards insects.ConclusionOur results suggest that North American isolates of Pa have acquired virulence against man via the acquisition of a plasmid and specific virulence factors with similarity to those shown to play roles in pathogenicity against humans in other bacteria.
| S-EPMC2717986 | biostudies-literature