Table 2.

Estimated Associations of Host-Level and Ecological Covariates and 95% Confidence Interval Limits of Infection Prevalence by Ehrlichia chaffeensis and Ehrlichia ewingii Among Amblyomma americanum Ticks Collected in Woodland and Pasture Sites in a Periurban Landscape Around Pittsburg, Kansas

Pathogen/factora	Coefficient	Standard error	exp	p Value	95% CIb
E. chaffeensis
Stage and sex	0.118	0.0	—	0.008**	—
Adult female	0.580	0.011	1.786	0.012*	1.747, 1.824
Adult male	0.273	0.152	1.313	0.094	0.975, 1.769
Nymph	Reference category
Edge density	0.684	0.122	1.981	0.010*	1.560, 2.517
% of pasture perimeter with shrub vegetation	0.341	0.214	1.406	0.104	0.924, 2.139
E. ewingii
Total edge contrast index	0.451	0.024	1.560	0.010*	1.497, 1.645
Patch cohesion	0.072	0.031	1.074	0.216	1.011, 1.141
% of pasture perimeter that was less than 20 meters from woodland areas	0.315	0.014	1.370	0.031*	1.011, 1.141

^aMultivariate logistic models for individual pathogens included several covariates screened in the univariate procedure with a liberal p value (≤0.2) in addition to the covariates retained in the reduced final models (presented in the Table 2). The full model for E. chaffeensis included the covariates, patch cohesion and connectance, the full model for E. ewingii included type of major landscape lying outside pasture, and the full model for Rickettsia rickettsii included month of collection and surface area of forest cover within 1-km buffer.

^b95% confidence limits for the exponential of model covariates.

^*p < 0.05.

^**p < 0.01.