title: Persistent and relapsing babesiosis in immunocompromised patients.
abstract: BACKGROUND
  Human babesiosis is a tickborne malaria-like illness that generally resolves without complication after administration of atovaquone and azithromycin or clindamycin and quinine. Although patients experiencing babesiosis that is unresponsive to standard antimicrobial therapy have been described, the pathogenesis, clinical course, and optimal treatment regimen of such cases remain uncertain.
  
  
  METHODS
  We compared the immunologic status, clinical course, and treatment of 14 case patients who experienced morbidity or death after persistence of Babesia microti infection, despite repeated courses of antibabesial treatment, with those of 46 control subjects whose infection resolved after a single course of standard therapy. This retrospective case-control study was performed in southern New England, New York, and Wisconsin.
  
  
  RESULTS
  All case patients were immunosuppressed at the time of acute babesiosis, compared with <10% of the control subjects. Most case patients experienced B cell lymphoma and were asplenic or had received rituximab before babesial illness. The case patients were more likely than control subjects to experience complications, and 3 died. Resolution of persistent infection occurred in 11 patients after 2-10 courses of therapy, including administration of a final antimicrobial regimen for at least 2 weeks after babesia were no longer seen on blood smear.
  
  
  CONCLUSIONS
  Immunocompromised people who are infected by B. microti are at risk of persistent relapsing illness. Such patients generally require antibabesial treatment for >or=6 weeks to achieve cure, including 2 weeks after parasites are no longer detected on blood smear.
authors.affiliation: Division of Infectious Diseases, Connecticut Children's Medical Center, and Department of Pediatrics, University of Connecticut School of Medicine, Farmington, Connecticut 06106, USA. PKrause@ccmckids.org
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Krause
authors.forename: Benjamin E
authors.initials: BE
authors.lastname: Gewurz
authors.forename: David
authors.initials: D
authors.lastname: Hill
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Marty
authors.forename: Edouard
authors.initials: E
authors.lastname: Vannier
authors.forename: Ivo M
authors.initials: IM
authors.lastname: Foppa
authors.forename: Richard R
authors.initials: RR
authors.lastname: Furman
authors.forename: Ellen
authors.initials: E
authors.lastname: Neuhaus
authors.forename: Gail
authors.initials: G
authors.lastname: Skowron
authors.forename: Shaili
authors.initials: S
authors.lastname: Gupta
authors.forename: Carlo
authors.initials: C
authors.lastname: McCalla
authors.forename: Edward L
authors.initials: EL
authors.lastname: Pesanti
authors.forename: Mary
authors.initials: M
authors.lastname: Young
authors.forename: Donald
authors.initials: D
authors.lastname: Heiman
authors.forename: Gunther
authors.initials: G
authors.lastname: Hsue
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Gelfand
authors.forename: Gary P
authors.initials: GP
authors.lastname: Wormser
authors.forename: John
authors.initials: J
authors.lastname: Dickason
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Bia
authors.forename: Barry
authors.initials: B
authors.lastname: Hartman
authors.forename: Sam R
authors.initials: SR
authors.lastname: Telford
authors.forename: Diane
authors.initials: D
authors.lastname: Christianson
authors.forename: Kenneth
authors.initials: K
authors.lastname: Dardick
authors.forename: Morton
authors.initials: M
authors.lastname: Coleman
authors.forename: Jennifer E
authors.initials: JE
authors.lastname: Girotto
authors.forename: Andrew
authors.initials: A
authors.lastname: Spielman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000981:Antiprotozoal Agents / Q000627:therapeutic use; D001404:Babesiosis / Q000188:drug therapy / Q000276:immunology* / Q000469:parasitology; D016022:Case-Control Studies; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012189:Retrospective Studies; D015047:Zoonoses / Q000469:parasitology
chemical_list: D000981:Antiprotozoal Agents