_:vb50952719 "A syphilis that is the first stage of syphilis, marked by the development of a chancre, which is characterized by mononuclear leukocytic infiltration, macrophages, and lymphocytes."^^ . _:vb50952719 . _:vb50952719 . _:vb50952719 . _:vb50952719 . _:vb50952719 . _:vb50952719 "url:http://www2.merriam-webster.com/cgi-bin/mwmednlm?book=Medical&va=primary+syphilis"^^ .