Number of positive pigeon fever cases diagnosed between 2005–2013 (a), and during 2012/13 (b) at the Veterinary Health Center and Kansas State Veterinary Diagnostic Laboratory, Kansas State University.

<p>Number of positive pigeon fever cases diagnosed between 2005–2013 (a), and during 2012/13 (b) at the Veterinary Health Center and Kansas State Veterinary Diagnostic Laboratory, Kansas State University.</p

Case control distribution in the study region.

<p>Dark circles indicate case locations and open circles are control locations.</p

Potential explanatory variables considered in the study.

<p>A total of 35 variables were considered for univariate evaluations. There were 14 variables derived from the USDA SSURGO database, 11 from NLCD, and 10 variables from NASA’s MODIS and POWER sources. All variables except daytime land surface temperature and night-time land surface temperature were in continuous form. ≤ 25°<i>C</i> and ≤ 16°<i>C</i> were used as reference categories in the models for daytime land surface temperature and night-time land surface temperature, respectively. A total of 5 variables retained significance in the univariate screening, with a liberal <i>p</i>−<i>value</i> ≤ 0.2. They were, soil moisture (<i>p</i> = 0.001), mixed forests (<i>p</i> = 0.153), grassland/herbaceous cover(<i>p</i> = 0.122), total edge contrast index (<i>p</i> = 0.008), and day time land surface temperature (≥ 35°<i>C</i>) (<i>p</i> = 0.011).</p><p>Potential explanatory variables considered in the study.</p

Case-control characteristics enrolled in the study.

<p>Case-control characteristics enrolled in the study.</p

Odds ratios and 95% Bayes <i>CrI</i> from Bayesian geostatistical analysis.

<p>The smoothing parameter, <i>κ</i> in Bayesian spatial models controls the amount of spatial continuity with distance in the <i>S</i>_<i>i</i> term. The decay parameter, <i>ϕ</i> refers to the decay of spatial correlation in terms of distance measured in decimal degrees (1 decimal degree at the equator is approximately 120 kilometers). A Bayesian geostatistical model with all covariates selected in the univariate procedure had a DIC value of 684, and the removal of mixed forest and grassland herbaceous cover one at a time resulted in model DIC values of 679 and 681, respectively and were discarded. The removal of Daytime LST, TECI and soil moisture one at a time in that order resulted in DIC values of 694, 691 and 703, respectively and were retained in the final model. Age and sex covariates were inserted in the Bayesian geostatistical model with covariates, one at a time, and ≥10% changes to posterior median estimates was not noted following insertions. The ‘unknown’ groups for age and sex were used as reference categories.</p><p>Odds ratios and 95% Bayes <i>CrI</i> from Bayesian geostatistical analysis.</p