Occurrence of Clostridium tetani in soil and horses

The annual incidence of tetanus in the RSA is up to 300 cases with more than 50% of these coming from Natal/KwaZulu. The condition of playing fields and the excretion of Clostridium tetani by horses was therefore investigated. The overall contamination rate of soils in the Durban area is lower than that of published data from other parts of the world, for instance 28% for Durban in comparison with 31-42% for Japan and Quebec. A rugby field in the Transvaal showed 40% contamination and a pasture used for horses for more than 20 years 65%. No case of human or equine tetanus has ever been reported from either the playing field or the pasture. A permanent carrier state in horses could not be established; the organisms were only excreted for 3-4 days. At any one time only 2 out of 27 horses in a stable were excreting C. tetani. Only 7 of 118 faeces samples were positive over a period of 4 months (5-9%).