Not all STIs are symptomatic, and symptoms may not appear immediately after infection.
Doctors used to think this STD threatened only women. The culprit: Human papillomavirus (HPV), the same sexually transmitted infection associated with cervical cancer in women.
A huge spike in the number of head and neck cancers linked to HPV over nearly two decades is raising alarms about the risk of the sexually contracted infections in a whole new population: men. The study also predicts that by 2020, oropharyngeal cancer will be the most common HPV-associated cancer in the U.
In either case, the condition may not exhibit signs or symptoms.
Increased understanding of infections like HPV, which infects a significant portion of sexually active individuals but cause disease in only a few, has led to increased use of the term STI.
Parasitic STIs include trichomoniasis among others. While usually spread by sex, some STIs can also be spread by non-sexual contact with contaminated blood and tissues, breastfeeding, or during childbirth.