In the case of third-stage syphilis, it is generally not asymptomatic, as it is already a late stage of the disease that invades multiple systems, such as the musculoskeletal system, nervous system, and even the cardiovascular system. When these systems are invaded, they become damaged, leading to various complications. Therefore, third-stage syphilis typically presents with various signs of organ dysfunction, and it is unlikely to be without any symptoms once it has progressed to this stage.