and is divided into early latent and late latent stages. Early latent syphilis is defined by the World Health Organization as less than 2 years after original infection. Early latent syphilis is infectious as up to 25% of people can develop a recurrent secondary infection (during which spirochetes are actively replicating and are infectious). Two years after the original infection the person will enter late latent syphilis and is not as infectious as the early phase. The latent phase of syphilis can last many years after which, without treatment, approximately 15-40% of people can develop tertiary syphilis. Tertiary Tertiary syphilis may occur approximately 3 to 15 years after the initial infection, and may be divided into three different forms: gummatous syphilis (15%), late neurosyphilis (6.5%), and cardiovascular syphilis (10%). Without treatment, a third of infected people develop tertiary disease. People with tertiary syphilis are not infectious. Gummatous syphilis or late benign syphilis usually occurs 1 to 46 years after the initial infection, with an average of 15 years. This stage is characterized by the formation of chronic gummas, which are soft, tumor-like balls of inflammation which may vary considerably in size. They typically affect the skin, bone, and liver, but can occur anywhere. Cardiovascular syphilis usually occurs 10–30 years after the initial infection. The most common complication is syphilitic aortitis, which may result in aortic aneurysm formation. Neurosyphilis refers to an infection involving the central nervous system. Involvement of the central nervous system in syphilis (either asymptomatic or symptomatic) can occur at any stage of the infection. It may occur early, being either asymptomatic or in the form of syphilitic meningitis; or late as meningovascular syphilis, manifesting as general paresis or tabes dorsalis. Meningovascular syphilis involves inflammation of the small and medium arteries of the central nervous system. It can present between 1–10 years after the initial infection. Meningovascular syphilis is characterized by stroke, cranial nerve palsies and spinal cord inflammation. Late symptomatic neurosyphilis can develop decades after the original infection and includes 2 types; general paresis and tabes dorsalis. General paresis presents with dementia, personality changes, delusions, seizures, psychosis and depression. Tabes dorsalis is characterized by gait instability, sharp pains in the trunk and limbs, impaired positional sensation of the limbs as well as having a positive Romberg's sign. Both tabes dorsalis and general paresis may present with Argyll Robertson pupil which are pupils that constrict when the person