Baby with tetanus (tetanus neonatorum). This is a disease of the central nervous system caused by infection of a wound with spores of the bacterium Clostridium tetani. A newborn may become infected in the umbilical area during pregnancy, often as a result of ritualistic practices. The spores multiply and produce a toxin which acts on nerves controlling muscle activity. This causes stiffness of the jaw (lockjaw), facial and trunk muscles. Painful muscle spasms may develop, and if these affect the chest wall or larynx, asphyxia may result, which requires an urgent tracheostomy followed by connection to a ventilator.