The toxin is produced during cell growth, sporulation and lysis. It migrates along neural paths from a local wound to sites of action in the central nervous system . The clinical pattern of generalized tetanus consists of severe painful spasms and rigidity of the voluntary muscles . It is an early symptom which is followed by progressive rigidity and violent spasms of the trunk and limb muscles. Spasms of the pharyngeal muscles cause difficulty in swallowing.
Death usually results from interference with the mechanics of respiration.
Neonatal tetanus accounts for about half of the tetanus deaths in developing countries. It usually results from a failure of aseptic technique during the birthing, but certain cultural practices may contribute to infection. There have been 11 strains of C. tetani distinguished primarily on the basis of flagellar antigens. Tetanospasmin is encoded on a plasmid which is present in all toxigenic strains. Tetanus toxin is one of the three most poisonous substances known, the other two being the toxins of botulism and diphtheria.