DEVELOPMENT AND USE OF SPECIFIC POLYMERASE REACTION FOR THE DETECTIONOF AN ORGANISM RESEMBLING EHRLICHIA SP IN WHITE-TAILED DEER

The role of white-tailed deer (Odocoileus virginianus) in the epidemio logy of Ehrlichia chaffeensis and the agent of human granulocytic ehrl ichiosis (HGE) is not. fully understood, and diagnostic procedures may be complicated by the recent detection of 16S rDNA sequence from an E hrlichia sp.-like organism in wild deer. A specific forward primer (DG A) and an Ehrlichia spp, reverse primer (GAIUR) were constructed to am plify this new, distinct Ehrlichia sp.-like 16S rDNA. The DGA primer, a forward primer specific for E. chaffeensis (DCH), forward primer spe cific for the E. phagocytophila genogroup (GE9f) were each used with G A1UR in nested polymerase chain reactions to amplify 16S rDNA sequence s from control samples containing the deer Ehrlichia sp.-like organism , E. chaffeensis, or the HGE agent. Primer pairs DGA/GA1UR and DCH/GA1 UR specifically amplified 16S rDNA sequences from the corresponding ta rget organism, whereas GE9f/GA1UR amplified 16S rDNA sequence from bot h tile HGE agent and the deer Ehrlichia sp.-like organism. With a nest ed PCR using DGA/GA1UR and DCH/GA1UR on DNA extracted from white blood cells from 62 deer from 10 populations in four U.S. states, we observ ed a high prevalence (65%) of 16S rDNA sequences of the deer Ehrlichia sp.-like organism, and a low prevalence (5%) of the E. chaffeensis se quence. In this field survey, E. chaffeensis-reactive antibodies detec ted by indirect fluorescence assays were associated (P < 0.001) with P CR evidence of the deer Ehrlichia sp.-like organism, but not E. chaffe ensis. Infestations of Amblyomma americanum also were associated (P < 0.001) with PCR evidence of the deer Ehrlichia sp.-like organism. The potential for serologic cross-reactions and non-specific PCR products arising from the deer Ehrlichia sp.-like organism should be considered when evaluating the role of deer and their ticks in the epidemiology of ehrlichial pathogens of humans.