Syphilis
Syphilis, caused by the bacterium Trepenoma pallidum, is transmitted through sexual contact or exchange of blood, or through the placenta to a fetus. The disease progresses through several stages. During the primary stage, the chief sign is a painless open sore, called a chancre, at the point of contact. The chancre heals within 1 to 5 weeks. From 6 to 24 weeks later, signs and symptoms such as a skin rash, fever, and aches in the joints and muscles usher in the secondary stage, which is systemic- the infection spreads to all major body systems. When signs of organ degeneration appear, the disease is said to be in tertiary stage. If the nervous system is involved, the tertiary stage is called neurosyphilis. As motor areas become damaged extensively, victims may unable to control urine and bowel movements. In addition damage to the cerebral cortex produces loss of memory and changes in personality that range from irritability to hallucinations.