You can transmit sti thru oral, rectal, and vaginal intercause, also if someone has an sti and gives you oral depending what infection they have in sure you can catch thru saliva, like herpes etc hope this helps
I understand how you catch an S.T.D what I'm asking is if you only gave someone a blowjob (i.e no other sexual contact) would your symptoms only be restricted to your mouth and your throat? Or could the infection spread from there to your genitals.