Syphilis is an infectious disease spread through sexual contact. If you are infected with syphilis and receive appropriate treatment, all syphilis bacteria in your body will disappear. However, if not adequately treated, latent syphilis may remain. Additional treatment may be needed to prevent latent syphilis from progressing to neurosyphilis. Syphilis is an infectious disease spread through sexual contact. If you are infected with syphilis and receive appropriate treatment, all syphilis bacteria in your body will disappear. However, if not adequately treated, latent syphilis may remain. Additional treatment may be needed to prevent latent syphilis from progressing to neurosyphilis. When Treponema pallidium spreads through the genitals, painless sores form around the genitals. This is primary syphilis. Primary syphilis gets better without treatment. However, if Treponema pallidum spreads throughout the body through the blood, secondary syphilis, such as a rash, occurs. Secondary syphilis also improves without treatment. Secondary syphilis can progress to tertiary syphilis, or latent syphilis can remain asymptomatic for years or decades and then manifest as arteritis and cranial nerve syphilis, which are forms of tertiary syphilis.