GPT and syphilis: 4.0% and 4.8% of the participants exhibited with abnormal blood levels of ALT and creatinine, respectively; 0.36% of the participants tested positive for syphilis; 0.44% and 3.6% of the female participants tested positive for Neisseria gonorrhoeae and Chlamydia trachomatis, respectively; and 0.84% and 1.8% of the female participants tested positive for cytomegalovirus (IgM) and Toxoplasma gondii (IgM), respectively.