Viruses such as HIV, genital herpes, human papillomavirus, hepatitis, and cytomegalovirus cause STDs/STIs that cannot be cured. People with an STI caused by a virus will be infected for life and will always be at risk of infecting their sexual partners. However, treatments for these viruses can significantly reduce the risk of passing on the infection and can reduce or eliminate symptoms. STIs caused by bacteria, yeast, or parasites can be cured using appropriate medication.