title: Anaplasma phagocytophilum in horses and ticks in Tunisia.
abstract: BACKGROUND
  Anaplasma phagocytophilum , the causative agent of granulocytic anaplasmosis, affects several species of wild and domesticated mammals, including horses. We used direct and indirect methods to compare and evaluate exposure to A. phagocytophilum in horses in northern Tunisia.
  
  
  METHODS
  Serum from 60 horses was tested by IFA for antibodies to A. phagocytophilum , and whole blood was tested for A. phagocytophilum 16S rRNA gene using a nested-PCR. To examine the risk of A. phagocytophilum transmission, 154 ticks that had been collected from horses were examined for the presence of A. phagocytophilum by nested-PCR targeting 16S rRNA gene.
  
  
  RESULTS
  This is the first time that A. phagocytophilum has been detected in horses in Tunisia, with an overall seroprevalence of 40/60 (67%). Six of the seroreactive samples (10%) had an IFA titer of 1:80, 14 (23%) of 1:160, 8 (13%) of 1:320 and 12 (20%) a titer 1 ≥ 640. The seroprevalence revealed no significant regional and sex differences. In contrast, a significant difference was observed between breeds. Eight (13%) of the horses were positive for A. phagocytophilum in the PCR, with no significant breed and age differences. Hyalomma marginatum was a predominant tick species (130/154), and 3 were infected by A. phagocytophilum (a prevalence of 2.3%). The concordance rate of A. phagocytophilum detection between IFA and PCR had a k value of -0.07.
  
  
  CONCLUSIONS
  The results presented in this study suggest that horses infested by ticks in Tunisia are exposed to A. phagocytophilum.
authors.affiliation: Laboratoire d'Épidémiologie et Microbiologie Vétérinaire, Service d'Entomologie Médicale, Institut Pasteur de Tunis, Tunis 1002, Tunisia.
authors.forename: Youmna
authors.initials: Y
authors.lastname: M'ghirbi
authors.forename: Hèla
authors.initials: H
authors.lastname: Yaïch
authors.forename: Abderazek
authors.initials: A
authors.lastname: Ghorbel
authors.forename: Ali
authors.initials: A
authors.lastname: Bouattour
mesh_terms: D041081:Anaplasma phagocytophilum / Q000302:isolation & purification*; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D016873:Ehrlichiosis / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006734:Horse Diseases / Q000453:epidemiology* / Q000382:microbiology; D006736:Horses / Q000382:microbiology*; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D016036:Seroepidemiologic Studies; D013987:Ticks / Q000382:microbiology*; D014416:Tunisia / Q000453:epidemiology
chemical_list: D000907:Antibodies, Bacterial; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S