Question 3
In syphilis the painless blisters heal by themselves, and the fever and sore throat that follow also subside. Why is this dangerous?
The right answer is the one marked above.
The bacterium is still in the blood, still spreading through the body and still transmissible. It can live there inactively for several years while reaching other organs.
Treatment does still work — in fact identifying the disease at an early stage and treating it properly is what cures it, which is what “medicinal treatment will no longer work” gets wrong. The danger is precisely that the person seems well and so does not seek treatment.