_:vb50949025 . _:vb50949025 . _:vb50949025 "url:http://www.cdc.gov/std/syphilis/STDFact-Syphilis.htm"^^ . _:vb50949025 "url:http://www.merck.com/mmpe/sec14/ch194/ch194i.html?qt=syphilis&alt=sh"^^ . _:vb50949025 "A primary syphilis that is characterized by occurence of painless sores on the anus, which is caused by the spirochete Treponema pallidum."^^ . _:vb50949025 . _:vb50949025 . _:vb50949025 .