Coronavirus 2019 outbreak pathogenesis: Why China and Italy?

COVID-19 has spread to most countries in the world. However, there are differences in the rate of infection in different countries. Specifically, high incidence was reported in specific areas in China (Wuhan) and Italy (Lombardy). These differences may be related to different Human Leucocyte Antigen (HLA) patterns in various geographic areas. We suggest HLA spreading between Italy and China is related to the travels of Marco Polo through the Silk Road as a potential historic explanation to COVID-19 spreading.