Sti

Sexually transmitted infection (STI) is an infection transmitted primarily through sexual contact, including vaginal, anal, and oral sex. Some infections spread through skin-to-skin contact or shared needles. STIs may affect genital, rectal, or oral sites, but can involve other parts of the body. Many STIs are asymptomatic in early stages, and untreated infections can cause complications such as pelvic inflammatory disease, infertility, pregnancy problems, cancer, or increased risk of acquiring or transmitting other infections. Prevention relies on safer sex, vaccination, testing, and timely treatment of partners.

Common bacterial STIs include chlamydia, gonorrhea, and syphilis; viral infections include HIV, herpes simplex virus, human papillomavirus, and hepatitis B. HPV and HBV vaccines prevent associated cancers and liver disease. Some infections, such as HIV and herpes, are not curable but can be managed to control symptoms and reduce transmission.

Diagnosis may use urine tests, swabs, blood tests, nucleic acid amplification tests (NAAT), or cultures. Screening practices vary by country and risk, but routine testing is recommended for sexually active individuals, pregnant people, and those with new or multiple partners or exposure.

Treatment depends on the infection. Bacterial STIs are typically curable with antibiotics. HIV is treated with antiretroviral therapy and can achieve viral suppression; other chronic infections are managed to reduce symptoms and transmission. Vaccination remains a primary prevention strategy for HPV and hepatitis B.

Prevention includes correct condom use, vaccination, regular screening, limiting partners, and prompt notification of partners after exposure. Reducing stigma and ensuring access to confidential testing are important public health goals.