Incident syphilis was classified into early syphilis (including primary, secondary, and early latent syphilis), late syphilis (including late latent syphilis and syphilis with unknown duration), and others, including neurosyphilis and ocular syphilis [11,12].
![[This page as RDF]](http://data.gesis.org/somesci/static/rdf-icon.gif){kind=icon}