The blood of syphilis patients generally contains syphilis spirochetes, so direct contact with the blood of syphilis patients can lead to the transmission of syphilis. There are also clinical examples of syphilis infection through blood transfusions, because the blood of syphilis patients who have been refrigerated for more than three days still has the syphilis spirochete alive, which can lead to infection if imported. However, not all patients with syphilis are infectious for life. Clinically, patients are often not infectious even if they have not been treated and have been infected for more than four years. The vast majority of syphilis patients can be clinically cured through regular antibiotic treatment, so to see if the blood has syphilis spirochetes will be contagious, but also depends on the course of the patient’s illness and treatment, not all syphilis patients are infectious.