Genetic Variants of<i>Ehrlichia phagocytophila</i>1<i>,</i>Rhode Island and Connecticut

Massung, Robert F.; Mauel, Michael J.; Owens, Jessica H.; Allan, Nancy; Courtney, Joshua W.; Stafford, Kirby C.; Mather, Thomas N.

doi:10.3201/eid0805.010251

Cited by 127 publications

(108 citation statements)

References 28 publications

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“…Phylogenetic analysis of this region of the gene failed to resolve any well-supported divergence among the 'strains' examined, including those of UK sheep isolates and isolates associated with disease in humans, even though variations in this region of the gene have been reported to have ecological significance (Massung et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

“…Some studies have already suggested that variations in either 16S rRNA gene or p44 sequences from USA isolates may be associated with ecological or clinical characteristics of A. phagocytophilum (Carter et al, 2001;Massung et al, 2002). In the present study, we have investigated the hypothesis that differences in either 16S rRNA gene or p44 sequences may occur amongst UK isolates from ruminants (that have yet to be associated with human disease), and isolates from other parts of the world, particularly the USA, where human disease does occur.…”

Section: Introductionmentioning

confidence: 99%

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Groupings of highly similar major surface protein (p44)-encoding paralogues: a potential index of genetic diversity amongst isolates of Anaplasma phagocytophilum

et al. 2004

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Anaplasma phagocytophilum is a tick-borne bacterium that is zoonotic in the USA and southern Europe, but although the bacterium is endemic in the UK, no cases of clinical human disease have yet been detected in that country. Potential genomic differences amongst UK and USA isolates were investigated by comparing partial 16S rRNA gene and p44 paralogue sequences amplified by PCR from 10 UK ruminant or tick isolates, with published sequences from USA isolates. No significant clustering among the isolates was resolved by phylogenetic analysis of alignments containing 16S rRNA gene sequences. The structure of predicted proteins encoded by p44 paralogues, amplified from 81 clones obtained from the UK isolates, was similar to that described previously for paralogues from USA isolates. Paralogue sequences did not obviously cluster by country, host species or isolate, but most paralogues were 30-70 % similar, making meaningful alignments difficult. Some p44 paralogues from different isolates formed clusters of sequences that were more than 90 % similar to one another ('similarity groups'). The paralogues in each cluster were particularly similar in gene regions most likely to code for ligands. In the sample studied, 95 % of the similarity groups comprised paralogues from either USA or UK isolates only and occurred with greater frequency amongst paralogues from USA rather than UK isolates. These findings raise the hypothesis that sequences of paralogues in similarity groups may provide an index of adaptation of different 'strains' of A. phagocytophilum to specific reservoir hosts in different geographical locations, and any associations with infectivity for different species including humans.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Groupings of highly similar major surface protein (p44)-encoding paralogues: a potential index of genetic diversity amongst isolates of Anaplasma phagocytophilum

et al. 2004

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“…Roe deer (Capreolus capreolus) in Spain, Austria and the Czech Republic, wild boars (Sus scrofa) in the Czech Republic and foxes (Vulpes vulpes) in Austria have also been shown by molecular tools to be exposed to this bacteria [99,111]. Usually, genetic variants are often identified when A. phagocytophilum is detected in vectors, people or animals [86].…”

Section: Natural History Of Anaplasma Phagocytophilummentioning

confidence: 99%

Tick- and flea-borne rickettsial emerging zoonoses

2005

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- Between 1984 and2004, nine more species or subspecies of spotted fever rickettsiae were identified as emerging agents of tick-borne rickettsioses throughout the world. Six of these species had first been isolated from ticks and later found to be pathogenic to humans. The most recent example is Rickettsia parkeri, recognized as a human pathogen more than 60 years after its initial isolation from ticks. A new spotted fever rickettsia, R. felis was also found to be associated with fleas and to be a human pathogen. Similarly, bacteria within the family Anaplasmataceae have been considered to be of veterinary importance only, yet three species have been implicated in human diseases in recent years, including Ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis, Anaplasma phagocytophilum, the agent of human anaplasmosis (formerly known as "human granulocytic ehrlichiosis agent", E. equi and E. phagocytophila), and finally Ehrlichia ewingii, which causes granulocytic ehrlichiosis in humans. We present here an overview of the various tick-and flea-borne rickettsial zoonoses described in the last 20 years, focusing on the ecological, epidemiological and clinical aspects.

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“…Previously, Massung et al suggested that distribution of the genetic variants of A. phagocytophilum (formerly Ehrlichia phagocytophila) are likely to be associated with ecological factors that support their maintenance in the natural environment and that competition between a human agent and its variants may influence incidence of clinical cases (11). Our previous study showed that only two base pairs of 16S rDNA were different among the three genetic variants of Ehrlichia sp.…”

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confidence: 99%

Molecular Identification of Ehrlichia Species and ‘Candidatus Neoehrlichia mikurensis’ from Ticks and Wild Rodents in Shizuoka and Nagano Prefectures, Japan

Naitou

Kawaguchi

Nishimura

et al. 2006

Microbiology and Immunology

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A total of 293 ticks and 111 wild rodents that were collected in Shizuoka and Nagano Prefectures, Japan, were examined for infection of Ehrlichia species and ‘Candidatus Neoehrlichia mikurensis.’ The 16S rDNA or the omp‐1 gene of these bacterial DNAs were detected from the spleens of tick‐inoculated mice (5 positive/total 29 mice) or from the spleens of wild rodents (25 positive/total 111 rodents) by PCR amplification. Sequencing of the 16S rDNA revealed Ehrlichia spp. from the 5 tick‐inoculated mice and 8 wild rodents, and ‘Candidatus N. mikurensis’ from 17 wild rodents. The data suggest the presence of additional genetic variants, and potential vectors and/or reservoirs for these bacteria in central Japan.

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Genetic Variants ofEhrlichia phagocytophila1,Rhode Island and Connecticut

Cited by 127 publications

References 28 publications

Groupings of highly similar major surface protein (p44)-encoding paralogues: a potential index of genetic diversity amongst isolates of Anaplasma phagocytophilum

Groupings of highly similar major surface protein (p44)-encoding paralogues: a potential index of genetic diversity amongst isolates of Anaplasma phagocytophilum

Tick- and flea-borne rickettsial emerging zoonoses

Molecular Identification of Ehrlichia Species and ‘Candidatus Neoehrlichia mikurensis’ from Ticks and Wild Rodents in Shizuoka and Nagano Prefectures, Japan

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