NonSTI

NonSTI, short for non-sexually transmitted infection, is a non-formal term used to describe infections that are not primarily spread through sexual contact. It is often used in clinical and public health discussions to distinguish infections acquired by routes other than sexual activity from sexually transmitted infections (STIs) such as HIV, chlamydia, gonorrhea, and syphilis. The term is not a formal diagnosis or a strict category; many pathogens can be transmitted by multiple routes, and an infection may be acquired sexually in some situations and non-sexually in others.

Transmission and examples. Non-STIs arise from a variety of routes, including airborne or droplet spread (influenza, common cold, COVID-19), fecal-oral transmission (norovirus, certain enteric bacteria), foodborne or waterborne infection (Salmonella, Giardia), vector-borne diseases (malaria, dengue), and direct contact or contaminated surfaces leading to skin or soft tissue infections. In addition, many infections can be transmitted via blood or bodily fluids through non-sexual exposures, such as needle sharing or healthcare-associated contact. Prevention and control strategies therefore emphasize vaccination where available, hygiene, safe food and water practices, vector control, infection control in healthcare settings, and reducing exposure to known transmission routes.

Clinical and public health relevance. The term helps clinicians consider a broad differential diagnosis for symptoms that resemble STIs but arise from non-sexual sources. It also informs patient counseling and public health messaging about transmission risks and preventive measures. Note that some pathogens can be transmitted via multiple routes, including sexual contact, so classification as a “non-STI” may depend on the context of exposure.