Prevalence of Ehrlichia ewingii in Amblyomma americanum in North Carolina

• Published in: Journal of clinical microbiology Vol. 38; no. 7; p. 2795
• Main Authors: Wolf, Leslie, McPherson, Todd, Harrison, Bruce, Engber, Barry, Anderson, Alice, Whitt, Parker
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01.07.2000
• Subjects: Amblyomma americanum; analysis; Animals; Arachnid Vectors; Arachnid Vectors - microbiology; disease vectors; DNA, Bacterial; DNA, Bacterial - analysis; Ehrlichia; Ehrlichia - isolation & purification; Ehrlichia ewingii; Female; isolation & purification; Ixodidae; Letters to the Editor; Male; microbiology; North Carolina; Nymph; Nymph - microbiology; Polymerase Chain Reaction; Ticks; Ticks - microbiology; USA, North Carolina; North Carolina
• ISSN: 0095-1137; 1098-660X
• DOI: 10.1128/JCM.38.7.2795-2795.2000

Ticks as vectors of Ehrlichia parasites have been the subject of study in North Carolina since 1993. Recently, Ehrlichia ewingii, which causes canine granulocytic ehrlichiosis, was documented as causing human illness in Missouri. Previously, the Lone Star tick, Amblyomma americanum, was confirmed as the vector of this parasite in dogs. Accordingly, in 1999, we focused our efforts on determining the presence and infection rate of E. ewingii in A. americanum. Infection rates for E. ewingii were low in adult A. americanum ticks, 0.4% (1 of 245) in females and 0.9% (2 of 217) in males, and a pool-positive rate of 4.7% (5 of 106) was obtained when 1,308 nymphs in 106 pools were tested for E. ewingii. However, a minimum field infection rate for the nymphs was 0.4% (5 of 1,308 ticks).