Tell me how spirochete syphilis gets into your brain.?

Thru blood. Syphilis has one or more phases where it travels in the blood to get to any location that your blood goes, including your brain. It generally starts its journey by entering the skin of your genitals where it drills into your genital skin & may leave an initial painless dug out sore. As it reproduces & spreads locally it will eventually take that vast highway of your blood vessels to go anywhere.