Seroprevalence of antibodies that react with Anaplasma phagocytophila, the agent of human granulocytic ehrlichiosis, in different populations in Westchester County, New York.
We determined the frequencies of antibodies to Anaplasma phagocytophila, the agent of human granulocytic ehrlichiosis (HGE), in different groups of adults and children from Westchester County, New York. The groups included 159 adult blood donors and 215 children who were seronegative for Borrelia burgdorferi antibodies, 118 adult patients and 57 children who were seropositive for B. burgdorferi antibodies, and 42 adult patients with culture-confirmed erythema migrans. Eighteen (11.3%) of the blood donors and 11 (5.1%) of the B. burgdorferi-seronegative children were found to have A. phagocytophila antibodies by indirect immunofluorescent-antibody assay (IFA). Nine of 42 (21.4%) patients with culture-confirmed erythema migrans tested at the baseline visit, 42 of 118 (35.6%) adults, and 3 of 57 (5.3%) children whose sera were reactive for B. burgdorferi antibodies also tested positive for A. phagocytophila antibodies. The geometric mean titer ranged from 219 to 315 for all groups, and the differences in titers among the groups were not statistically significant. Only one-third of the healthy blood donors reactive by IFA were confirmed to be positive by immunoblotting. We conclude that a significant proportion of adults and children without clinical evidence of HGE will test positive for A. phagocytophila antibodies when the conventional cutoff titer of 80 is used in the IFA. This information must be considered in interpretation of test results.
Aguero-Rosenfeld
Maria E
ME
Division of Infectious Diseases, Department of Medicine, New York Medical College and Westchester Medical Center, Valhalla, New York 10595, USA. m_aguero-rosenfeld@nymc.edu
Donnarumma
Lorraine
L
Zentmaier
Lois
L
Jacob
Jobby
J
Frey
Michael
M
Noto
Richard
R
Carbonaro
Carol A
CA
Wormser
Gary P
GP
D000293:Adolescent; D000328:Adult; D000709:Anaplasma / Q000276:immunology; D000712:Anaplasmosis / Q000453:epidemiology* / Q000276:immunology*; D000907:Antibodies, Bacterial / Q000097:blood*; D001782:Blood Donors; D025065:Borrelia burgdorferi / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D004536:Ehrlichia / Q000276:immunology; D016873:Ehrlichiosis / Q000453:epidemiology* / Q000276:immunology*; D015787:Erythema Chronicum Migrans / Q000276:immunology; D005260:Female; D006801:Humans; D008193:Lyme Disease / Q000276:immunology; D008297:Male; D009518:New York / Q000453:epidemiology; D016036:Seroepidemiologic Studies; D014922:Wisconsin / Q000453:epidemiology
D000907:Antibodies, Bacterial