dc.contributor.author |
Nakao, Ryo
|
|
dc.contributor.author |
Magona, Joseph W.
|
|
dc.contributor.author |
Zhou, Lijia
|
|
dc.contributor.author |
Jongejan, Frans
|
|
dc.contributor.author |
Sugimoto, Chihiro
|
|
dc.coverage.spatial |
Uganda |
en |
dc.date.accessioned |
2011-09-08T06:55:35Z |
|
dc.date.available |
2011-09-08T06:55:35Z |
|
dc.date.issued |
2011-07-15 |
|
dc.description |
Additional file 1: Neighbour-joining phylogenetic tree based on
concatenated sequences obtained from all eight loci. The tree was
constructed based on a 3,419-bp concatenated sequence of eight
housekeeping genes. One thousand bootstrap replicates were performed
for each analysis. Bootstrap values are shown at the nodes. |
en |
dc.description |
Additional file 2: Split graph constructed from the sequences of
each locus. |
en |
dc.description.abstract |
BACKGROUND: The rickettsial bacterium Ehrlichia ruminantium is the causative agent of heartwater in ruminants. A better understanding of the population genetics of its different strains is, however, needed for the development of novel diagnostic tools, therapeutics and prevention strategies. Specifically, the development of effective vaccination policies relies on the proper genotyping and characterisation of field isolates. Although multi-locus sequence typing (MLST) has been recently developed, only strains from geographically restricted collections have been analysed so far. The expansion of the MLST database to include global strains with different geographic origins is therefore essential. In this study, we used a panel of reference strains from geographically diverse origins and field samples of E. ruminantium detected from its vector, Amblyomma variegatum, in heartwater-endemic areas in Uganda. RESULTS: A total of 31 novel alleles (six, four, six, three, two, five, three, and two for gltA, groEL, lepA, lipA, lipB, secY, sodB, and sucA loci, respectively) and 19 novel sequence types (STs) were identified. Both neighbour-joining and minimum spanning tree analyses indicated a high degree of genetic heterogeneity among these strains. No association was observed between genotypes and geographic origins, except for four STs from West African countries. When we performed six different tests for recombination (GeneConv, Bootscan, MaxChi, Chimaera, SiScan, and 3Seq) on concatenated sequences, four possible recombination events were identified in six different STs. All the recombination breakpoints were located near gene borders, indicating the occurrence of intergenic recombination. All four STs that localized to a distinct group in clustering analysis showed evidence of identical recombination events, suggesting that recombination may play a significant role in the diversification of E. ruminantium. CONCLUSIONS: The compilation of MLST data set across the African continent will be particularly valuable for the understanding of the existing genetic diversity of field isolates in African countries. Comprehensive information on the degree of cross-protection between strains and further understanding of possible relationships between genotypes and phenotypes such as vaccine efficacy are expected to lead to the development of region-specific vaccination strategies. |
en |
dc.description.sponsorship |
The first author was supported by a research grant fellowship from the Japanese Society for the Promotion of Science (JSPS) for young scientists. This work was supported by Grant-in-Aid
for JSPS fellows and for Scientific Research from the Ministry of Education,
Culture, Sports, Science and Technology of Japan (MEXT), the program of
the Funding Research Center for Emerging and Re-emerging Infectious
Disease, MEXT, and the Asia-Africa S & T Strategic Cooperation Promotion
Program from the Special Coordination Funds for Promoting Science &
Technology, MEXT. |
en |
dc.description.uri |
http://www.parasitesandvectors.com/ |
en |
dc.identifier.citation |
Nakao et al.: Multi-locus sequence typing of Ehrlichia ruminantium strains from geographically diverse origins and collected in Amblyomma variegatum from Uganda. Parasites & Vectors 2011 4:137. |
en |
dc.identifier.issn |
1756-3305 |
|
dc.identifier.other |
10.1186/1756-3305-4-137 |
|
dc.identifier.uri |
http://hdl.handle.net/2263/17238 |
|
dc.language.iso |
en |
en |
dc.publisher |
BioMed Central |
en |
dc.relation.requires |
Adobe Acrobat Reader |
en |
dc.rights |
© 2011 Nakao et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited. |
en |
dc.subject |
Ehrlichia ruminantium |
en |
dc.subject |
Amblyomma variegatum |
en |
dc.subject.lcsh |
Ehrlichiosis |
en |
dc.subject.lcsh |
Amblyomma |
en |
dc.title |
Multi-locus sequence typing of Ehrlichia ruminantium strains from geographically diverse origins and collected in Amblyomma variegatum from Uganda |
en |
dc.type |
Article |
en |