Sexually transmitted infections

Sexually transmitted infections are caused by bacteria, viruses and parasites that pass between people during vaginal, anal or oral sex, and some can also pass from mother to child. They are common worldwide, and more than 30 pathogens are known, of which eight account for most cases. Chlamydia, gonorrhoea, syphilis and trichomoniasis are curable, whereas hepatitis B, herpes simplex virus, HIV and human papillomavirus are viral infections. Many cause no symptoms; when present they include unusual genital discharge, pain passing urine, itching, rash, sores, blisters or warts. Complications include pelvic inflammatory disease, infertility, cancers, pregnancy problems and a higher risk of acquiring HIV. Diagnosis uses urine tests, blood tests and swabs from the genitals or anus. Antibiotics treat the curable infections, antivirals control herpes and HIV without curing them, and partners are treated too; condoms and vaccines against hepatitis B and HPV help prevent spread.

Seek urgent care for a high fever with a stiff neck, rash, confusion, difficulty breathing, or fever after travel to a malaria area. See a doctor when a fever lasts more than three days, when symptoms return after treatment, or when you may have been exposed to an infection that needs testing. Call the local emergency number for any symptom that is sudden and severe. This page is a reference for healthcare professionals and does not replace an assessment.