i didnt feel like going through all the pages, so sorry if someone already mentioned this, but its actually STI.
QUOTE
Infection simply means that a germ – virus, bacteria, or parasite – that can cause disease or sickness is present inside a person’s body. An infected person does not necessarily have any symptoms or signs that the virus or bacteria is actually hurting their body (they do not necessarily feel sick).
A disease means that the infection is actually causing the infected person to feel sick, or to notice something is wrong.
For this reason, the term STI – which refers to infection with any germ that can cause an STD, even if the infected person has no symptoms – is a much broader term than STD."
-wikipedia.org