title: Molecular diagnostics of Rickettsia africae infection in travelers returning from South Africa to The Netherlands.
abstract: BACKGROUND
  African tick-bite fever (ATBF) is frequently diagnosed in The Netherlands in travelers returning from South Africa. It is caused by Rickettsia africae and diagnosis is based on travel history and clinical presentation and usually confirmed by detecting serum antibodies against rickettsiae of the spotted fever group. However, these typically occur late in the course of the disease, and a mild clinical course or early antibiotic treatment can diminish antibody production.
  
  
  RESULTS
  Four travelers presented with (sub)febrile temperatures and eschar(s), several days after returning from South Africa. R. africae DNA was amplified and sequenced from skin biopsies of the eschars of all patients. Initial immunofluorescence assays yielded no immunoglobulin M (IgM)/IgG antibodies directed against spotted fever group rickettsiae; however, serology in the convalescent phase-several weeks after the patients had fully recovered-was positive.
  
  
  CONCLUSIONS
  ATBF should be considered in travelers returning from South Africa to The Netherlands with febrile illness and (multiple) skin lesions. The diagnosis can be confirmed by (paired) serology; however, polymerase chain reaction and sequencing on skin biopsies could be a (faster and more accurate) confirmatory test. Advantages of molecular methods over serology are species identification and high sensitivity early in the course of the disease.
authors.affiliation: Department of Infectious Diseases, Tropical Medicine, and AIDS, Division of Internal Medicine, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Rosanne W
authors.initials: RW
authors.lastname: Wieten
authors.forename: Joppe W R
authors.initials: JW
authors.lastname: Hovius
authors.forename: Emilie J
authors.initials: EJ
authors.lastname: Groen
authors.forename: Allard C
authors.initials: AC
authors.lastname: van der Wal
authors.forename: Peter J
authors.initials: PJ
authors.lastname: de Vries
authors.forename: Matthijs F C
authors.initials: MF
authors.lastname: Beersma
authors.forename: Ellen
authors.initials: E
authors.lastname: Tijsse-Klasen
authors.forename: Hein
authors.initials: H
authors.lastname: Sprong
authors.forename: Martin P
authors.initials: MP
authors.lastname: Grobusch
mesh_terms: D000368:Aged; D000907:Antibodies, Bacterial; D017931:DNA Primers; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D016133:Polymerase Chain Reaction; D012281:Rickettsia / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D012282:Rickettsia Infections / Q000097:blood / Q000175:diagnosis*; D012867:Skin / Q000473:pathology; D013019:South Africa; D017282:Tick-Borne Diseases / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology*; D014195:Travel
chemical_list: D000907:Antibodies, Bacterial; D017931:DNA Primers