Detection of Ehrlichia chaffeensis DNA in Amblyomma americanum ticks in Connecticut and Rhode Island

Abstract

Ehrlichia chaffeensis, the causative agent of human monocytic ehrlichiosis, is transmitted by Amblyomma americanum ticks, which are most abundant in the southern United States. Because serologic evidence suggests that residents of Connecticut are exposed to E. chaffeensis, A. americanum ticks were collected in Connecticut and Rhode Island for PCR analysis to detect E. chaffeensis DNA. Eight of 106 (7.6%) A. americanum ticks from Connecticut and 6 of 52 (11.5%) from Rhode Island contained E. chaffeensis DNA. Thus, E. chaffeensis is present in ticks in southern New England and transmission of E. chaffeensis may occur there.

FIG. 1

PCR amplification of the 16S gene fragment of E. chaffeensis following DNA extraction from A. americanum ticks. Lane 1, DNA size marker; lanes 2 and 3, negative controls; lane 4, positive control; lanes 5 through 13, positive samples from A. americanum ticks; lanes 14 through 18, negative samples from I. scapularis ticks.