Other sexually-transmitted infections may be affected as well, but they could not draw definite conclusions from the research they were working with. In particular, these include STIs associated with ulcerative lesions that may be present on body surfaces where the condom does not cover, such as human papillomavirus (HPV), genital herpes simplex (HSV), chancroid, and syphilis. If contact is made with uncovered lesions, transmission of these STIs may still occur despite appropriate condom use. Additionally, the absence of visible lesions or symptoms cannot be used to decide whether caution is needed.