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. 2012 Mar;87(3):233-9.
doi: 10.1016/j.mayocp.2011.09.008.

Clinical findings and diagnosis in human granulocytic anaplasmosis: a case series from Massachusetts

Ana A Weil  1 , Elinor L Baron, Catherine M Brown, Mark S Drapkin
Affiliations

Clinical findings and diagnosis in human granulocytic anaplasmosis: a case series from Massachusetts

Ana A Weil et al. Mayo Clin Proc. 2012 Mar.

Erratum in

  • Mayo Clin Proc. 2012 Jun;87(6):606

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.

Patients and 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.

Conclusion: 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.

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Figures

FIGURE 1
FIGURE 1
Morulae (arrows) in neutrophils of a 65-year-old man with a 2-day history of fever and diarrhea (Wright stain, original magnification ×100).
FIGURE 2
FIGURE 2
Concentration of human granulocytic anaplasmosis infections by zip code area surrounding Newton-Wellesley Hospital during the 2009 transmission season.
FIGURE 3
FIGURE 3
Epidemiologically confirmed cases of human granulocytic anaplasmosis in Massachusetts, 2005-2010 (as of August 20, 2011).
See this image and copyright information in PMC

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