Laboratory investigations found slightly elevated C-reactive protein (CRP 1.11 mg/dl, nr < 0.5), normal STI check for syphilis, chlamydia, gonococci and trichomonas, but positive Monkeypox DNA from swap (Ct-value = 18.62; in-house modified LightMix Modular Monkeypox Virus-PCR/TibMolBiol, Roche Diagnostics, Mannheim/Germany; Ct-value ≥ 40 = negative). The gene discussed is CRP; the disease is syphilis.