Amblyomma americanum nymphal population distributions for 1999, 2000,and 2001 (2001 data pending analysis) were compared using geostatistical spatial analysis. The nymphs showed a clumped but spatially shifting distribution across years. Spatial analysis showed that 88% of the A. americanum nymphs (1999 n=1,295; 2000 n=157) occupied just 22.4% of the 170 hectare study area in 1999 and 23.4% of the study area in 2000. The A. americanum nymph and adult infection rate for Ehrlichia chaffeensis [agent of human monocytic ehrlichiosis (HME)] was a minimum (some samples pooled) of 1.4% in 1999 (n=435 tests) and 3.4% (n=263 tests) in 2000. The distribution of E. chaffeensis infected ticks did not always correspond to areas of high tick density. The spatial presentation of these data raises several interesting points regarding the ability to target intervention strategies to appropriate areas, sampling over time, disease threat, and the need to determine appropriate action thresholds.
Species 1: Parasitiformes Ixodidae Amblyomma americanum (lone star tick)
Species 2: Rickettsiales Rickettsiaceae Ehrlichia chaffeensis
Keywords: Geostatistical Spatial Analysis, Landscape Ecology
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA