The systemic manifestations of tetanus are caused by the powerful exotoxin, liberated during the actively growing phase, of Clostridium tetani, a spore-forming organism. Like diphtheria, the infection remains localized. Infection is almost always acquired from a contaminated wound.
Etiology - Clostridium tetani is an anaerobic, spore-bearing organism, widely distributed in soil in many parts of the world. The bacillus is frequently found in the intestinal tracts of herbivores and, at times, of man. Under suitable conditions the tetanus bacillus produces several poisons: a lysine for red blood cells, a substance injurious to leukocytes and a neurotropic toxin (tetanospasmin) which produces muscle
rigidity and spasms. Unlike diphtheria toxin, tetanus toxin produces no skin reaction suitable for the assessment of immunity.Epidemiology – Tetanus occurs most frequently in areas where soil contamination is heavy and standards of cleanliness and care of wounds are poor. It is rare in the newborn infant when aseptic obstetrics is practiced, but otherwise it constitutes a serious problem. In 1950, 486 cases were reported in the United
States with 336 (69 per cent) deaths. During World War II active immunization of the personnel of the armed services with toxoid almost completely prevented its occurrence (eight cases with three deaths).Pathogenesis – There is no typical wound that gives rise to tetanus. It may result from the most trivial scratch or insect bite, and the portal of entry is often not apparent. Injuries most likely, however, to lead to tetanus are deep puncture wounds, because they afford ideal anaerobic conditions, and crushing wounds and burns, because they provide necrosis of tissue. The site of infection has been reported in the tonsil, the alimentary tract and in ocular and aural lesions. A number of cases have resulted from the use of contaminated catgut and serologic products. Though tetanus occasionally results from smallpox vaccination, it is practically always due to improper case of the secondarily infected lesion rather than to contaminated virus - William Bradford. That’s it, thank you for reading.