title: Differential strain-specific diagnosis of the heartwater agent: Ehrlichia ruminantium.
abstract: Ehrlichia ruminantium is the causative agent of heartwater, a major tick-borne disease of livestock in Africa introduced in the Caribbean and threatening to emerge and spread in the American mainland. Complete genome sequencing was done for two isolates of E. ruminantium of differing phenotype, isolates Gardel (Erga) from Guadeloupe Island and Welgevonden (Erwe) originating from South Africa and maintained in Guadeloupe. The type strain of E. ruminantium (Erwo), previously isolated and sequenced in South Africa; is identical to Erwe with respect to target genes. They make the Erwe/Erwo complex. Comparative analysis of the genomes shows the presence of 49 unique CDS and 28 truncated CDS differentiating Erga from Erwe/Erwo. Three regions of accumulated differences (RAD) acting as mutational hot spots were identified in E. ruminantium. Ten CDS, six unique CDS and four truncated CDS corresponding to major genomic changes (deletions or extensive mutations) were considered as targets for differential diagnosis on four isolates of E. ruminantium: Erga, Erwe/Erwo, Senegal and Umpala. Pairs of PCR primers were developed for each target gene. PCR analysis of the target genes generated strain-specific patterns on Erga and Erwe/Erwo as predicted by comparative genomics, but also for isolates Senegal and Umpala. The target genes identified by bacterial comparative genomics are shown to be highly efficient for strain-specific PCR diagnosis of E. ruminantium and further vaccine management tools.
authors.affiliation: CIRAD TA A-15/G, Campus International de Baillarguet, 34398, Montpellier Cedex 05, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Vachiery
authors.forename: Gael
authors.initials: G
authors.lastname: Maganga
authors.forename: Thierry
authors.initials: T
authors.lastname: Lefrançois
authors.forename: Yane
authors.initials: Y
authors.lastname: Kandassamy
authors.forename: Frédéric
authors.initials: F
authors.lastname: Stachurski
authors.forename: Hassane
authors.initials: H
authors.lastname: Adakal
authors.forename: Conchita
authors.initials: C
authors.lastname: Ferraz
authors.forename: Anne
authors.initials: A
authors.lastname: Morgat
authors.forename: Albert
authors.initials: A
authors.lastname: Bensaid
authors.forename: Eric
authors.initials: E
authors.lastname: Coissac
authors.forename: Frédéric
authors.initials: F
authors.lastname: Boyer
authors.forename: Jacques
authors.initials: J
authors.lastname: Demaille
authors.forename: Alain
authors.initials: A
authors.lastname: Viari
authors.forename: Dominique
authors.initials: D
authors.lastname: Martinez
authors.forename: Roger
authors.initials: R
authors.lastname: Frutos
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis / Q000382:microbiology; D002478:Cells, Cultured; D004269:DNA, Bacterial / Q000032:analysis / Q000302:isolation & purification; D016995:Ehrlichia ruminantium / Q000235:genetics / Q000302:isolation & purification*; D005260:Female; D016680:Genome, Bacterial; D005843:Geography; D006041:Goats; D006357:Heartwater Disease / Q000175:diagnosis* / Q000382:microbiology*; D051379:Mice; D012756:Sheep; D013045:Species Specificity
chemical_list: D004269:DNA, Bacterial