title: Clinical findings and diagnosis in human granulocytic anaplasmosis: a case series from Massachusetts.
abstract: OBJECTIVE
  To describe clinical findings and the use of a tick-associated pathogen panel in a series of patients with human granulocytic anaplasmosis (HGA) at a suburban Boston hospital.
  
  
  METHODS
  Medical records were reviewed for inpatients and outpatients at Newton-Wellesley Hospital with a positive polymerase chain reaction (PCR) result for Anaplasma phagocytophilum during the study period March 1 through November 30, 2009. A PCR panel was used to test for tick-borne pathogens. Postal ZIP code data from the patients' areas of residence were used to estimate the area of disease transmission.
  
  
  RESULTS
  Thirty-three cases were confirmed during the 2009 transmission season, and 14 of these patients (42%) required hospitalization. Thrombocytopenia and/or leukopenia were observed at the time of presentation in 25 of 30 patients (86%) in whom both white blood cell and platelet counts were determined, and 28 of 33 patients (85%) reported fever. Rash occurred in only 2 of the 33 patients (6%), and 25 (76%) reported one or more respiratory or gastrointestinal symptom. Cases were geographically distributed diffusely throughout the hospital catchment area, with one possible focus of infection identified in Weston, MA. Due to a lack of clinical data reporting to the Massachusetts Department of Public Health, only 20 of 32 HGA cases (63%) fulfilled the case confirmation criteria.
  
  
  CONCLUSIONS
  Diagnosis of HGA requires a high suspicion for infection even in endemic areas. Use of a tick-associated pathogen panel that includes PCR assays for several organisms could improve detection of underrecognized tick-borne diseases in endemic areas. Lack of epidemiological follow-up to confirm corroborating clinical findings prevents accurate case reporting and assessment of the true HGA burden.
authors.affiliation: Department of Medicine, Massachusetts General Hospital, 15 Parkman St., Boston, MA 02114, USA. aweil@partners.org
authors.forename: Ana A
authors.initials: AA
authors.lastname: Weil
authors.forename: Elinor L
authors.initials: EL
authors.lastname: Baron
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Brown
authors.forename: Mark S
authors.initials: MS
authors.lastname: Drapkin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D041081:Anaplasma phagocytophilum; D000712:Anaplasmosis / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology / Q000635:transmission; D000818:Animals; D005076:Exanthema / Q000209:etiology / Q000382:microbiology; D005260:Female; D006801:Humans; D007970:Leukopenia / Q000209:etiology / Q000382:microbiology; D008297:Male; D008404:Massachusetts / Q000453:epidemiology; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D013921:Thrombocytopenia / Q000209:etiology / Q000382:microbiology; D013987:Ticks / Q000382:microbiology; D055815:Young Adult