The exclusive positive selection of TLR9 and TLR10 (or TLR1) pathways in Europeans may be related to more recent responses that could have been related to the introduction of agriculture and zoonotic diseases (e.g. Brucella, Coxiella) or the major epidemics of the medieval periods (e.g. Yersinia pestis causing pandemics including pneumonic, septicaemic and bubonic plague). The gene discussed is TLR9; the disease is bubonic plague.