Prevalence of the Rickettsial Agent of Human Granulocytic Ehrlichiosis in Ticks from a Hyperendemic Focus of Lyme Disease

Abstract

Human granulocytic ehrlichiosis, a newly discovered tick-borne infection originally described in the upper Midwest,¹ has recently been reported in 29 patients from Westchester County, New York.² We used the polymerase chain reaction (PCR) to examine 173 host-seeking ticks (Ixodes scapularis) collected from vegetation in Westchester County for the presence of the agent of human granulocytic ehrlichiosis, as well as the agent of Lyme disease, Borrelia burgdorferi. After extracting DNA from dissected tissues, we used the 23S ribosomal DNA (rDNA) primers of Schwartz et al.³ for B. burgdorferi and the 16S rDNA primers of Pancholi et al.⁴ for the agent of human granulocytic ehrlichiosis and confirmed the presence of the latter by sequencing PCR products from 10 randomly selected samples. We also examined 100 adult specimens of I. scapularis collected similarly from the same site in 1984 and preserved in 70 percent ethanol.