Spirochetes are a bit of a headache clinically to be honest.
Luckily for us, the secondary stage & neurosyphilis (the 3rd stage) are not commonly seen anymore thanks to awareness and ATB usage. We still have to learn it, in the case we encounter it, but nowadays is rare.
Even more rare are the complications you mentioned about them like Aortic Aneurysm.
Nice information!
RE: Medical Microbiology, Spirochaetes and Syphilis / Microbiologia medica, Spirochete e Sifilide