Histogram of residual values showing the frequency of each value interval versus residual values.

Residuals represent the difference between true and predicted values using our final logistic regression models. It can be seen that residuals are concentrated around zero and have a normal distribution and also are not skewed and contain no outliers. (A) L. pneumophila, (B) C. burnetii, (C) Brucella spp, and (D) Bartonella spp.