Which one of the following sexually transmitted infections is transmitted by methods other than sexual intercourse?

What measures should be taken to avoid the transmission of $STD$s?
$I$. Avoid sex with unknown partners
$II$. Avoid sex with multiple partners
$III$. Use protection during sex
$IV$. Avoid sharing needles

Which one of the following common sexually transmitted diseases is completely curable when detected early and treated properly?

Which of the following principles are used to prevent $STD$ infection?
$(i)$ Avoid sex with unknown partners
$(ii)$ Use condoms during coitus
$(iii)$ Blood transfusion
$(iv)$ All of these

'Syphilis' is a sexually transmitted disease caused by

$..........$ are a major threat to a healthy society.