Question

why cant most stis be transmitted through casual contact with people or contaminated objects?

Explanation:

Most STIs are caused by pathogens (viruses, bacteria, parasites) that require specific conditions to survive and infect. These pathogens are fragile outside the human body—they die quickly when exposed to air, temperature changes, or dry surfaces. Casual contact (like shaking hands, hugging) or contaminated objects (doorknobs, utensils) don’t provide the moist, warm environment these pathogens need to stay viable long enough to transmit to a new host. Additionally, most STIs require direct exchange of bodily fluids (semen, vaginal fluids, blood) or intimate skin-to-skin contact to spread, which casual interactions don’t involve.

Answer:

Most STIs are caused by pathogens that are fragile outside the human body and require direct exchange of bodily fluids or intimate skin-to-skin contact to spread—conditions not met by casual contact or contaminated objects.