Epidemiology - Clostridium tetani

Epidemiology

◗ Geographical distribution

Tetanus is a disease found worldwide. The condition is pre-dominantly a disease of underdeveloped countries. The disease is common in areas where soil is cultivated, in rural areas, in warm and damp climates, and during summer months. Tetanus affects all age groups, with the highest prevalence among newborns and young people. Overall, the annual incidence of tetanus is 0.5–1 million cases, mostly in underdeveloped countries. Neonatal tetanus accounts for 50% of the tetanus-related deaths in developing countries.

◗ Habitat

C. tetani organisms are found in soil, in animal feces,and, occasionally, in human feces as well as on inanimate objects. The spores may survive for years in some environ-ments and are resistant to disinfectants and even to boiling for 20 minutes.

◗ Reservoir, source, and transmission of infection

C. tetani spores are the infective form of the bacteria. Soil,animal feces, and, occasionally, human feces as well as inani-mate objects contaminated with spores are the primary source of infection.

Risk factors for neonatal tetanus include unvaccinated mothers, home delivery, and unhygienic cutting of the umbili-cal cord. Animal dung, clarified butter, etc., applied to the umbilical stump are the other risk factors for neonates.

The following types of wounds are more susceptible to tetanus: (a) grossly contaminated wounds; (b) wounds exposed to saliva or feces; (c) stellate, ischemic, or infected wounds; (d) deep ( 1 cm) wounds; as well as (e) avulsions, punctures, or crush injuries.