Table 3.
Infection Prevalence (%) of Ehrlichia chaffeensis and Ehrlichia ewingii, Reported by Previous Studies in the United States
| Pathogen/host | Adult male | Adult female | Nymph pool | Study | State/region where collection was made |
|---|---|---|---|---|---|
| E. chaffeensis | |||||
| A. americanum | 3.8 (10/262) | Irving et al. (2000) | Ohio | ||
| A. americanum | 0.0 (0/151), 0.9 (1/111), 9.3 (12/129) | Whitlock et al. (2000) | Georgia Coast and Barrier Islands | ||
| A. americanum | 9.8 (57/579) | 1.7 | Steiert and Gilfoy (2002) | Missouri | |
| A. americanum | 44/190 (4.6)a | 54/1128 (4.4)b | — | Mixson et al. (2006) | 29 sites in 9 states in the eastern and southeastern United States |
| Dermacentor variabilis | 8/120 (6.7) | 0.6 | Steiert and Gilfoy (2002) | Missouri | |
| E. ewingii | |||||
| A. americanum | 2/217 (0.9) | 1/245 (0.4) | 5/106 (4.7) | Wolf and McPherson (2000) | North Carolina |
| A. americanum | 31/579 (5.4) | 3/115 (0.6) | Steiert and Gilfoy (2002) | Missouri | |
| D. variabilis | 4/120 (3.3) | — | Steiert and Gilfoy (2002) | Missouri | |
ab
Overall prevalence from 29 sites. Prevalence in individual collection sites varied between 0 to 30 in varied number of male A. americanum ticks.
Numbers within parenthesis indicate the number of specimens that tested positive for a pathogen among total number of ticks collected in that study.