842 MICROBIOLOGY OF DISEASES OF MAN AND DOMESTIC ANIMALS 



TETANUS* 

 Bacillus tetani 



This disease is found throughout the world but more frequently in 

 warmer than in colder climates. Certain localities are particularly 

 affected. Man and domestic animals are susceptible. 



The incubation period varies: a few hours in the case of small ani- 

 mals receiving injections of toxin; several days or weeks in cases of 

 natural infection in man, or even several months as in some cases of 

 wounded soldiers who had received injections of protective serum. 

 Tetanus has followed operations in which old healed wounds have been 

 opened up. 



Under natural conditions the disease follows a wound of a punc- 

 tured type with contamination by earth, especially in injuries of hands 

 and feet. 



It is characterized by tonic spasms of the voluntary musculature 

 usually beginning in some one group of muscles and finally becoming 

 general. The parts first affected are, in cases artificially produced, 

 those at the site of inoculation, but in natural infections in man it is 

 more common for the disease to manifest itself by stiffening of the 

 muscles of the neck and face, producing what is ordinarily termed " lock- 

 jaw." In less severe infections in man local pain and stiffness are the 

 first indications. The spasms occur in paroxysms which are spon- 

 taneous or excited by effort. They are more or less prolonged and ex- 

 hausting and are accompanied by greater or less pain. Death results 

 from general loss of strength or involvement of the respiratory muscles. 

 The shorter the incubation period the higher the mortality. Few 

 recover when the incubation period is less than ten days, about half the 

 cases recover when the period is more than fifteen days. In the British 

 army in the first two years of the war, the mortality ran over 50 per 

 cent, and after that about 25 per cent. 



The nerves may show injury as indicated by swelling and redness 

 and microscopically nerve cells have been observed in a state of granu- 

 lar degeneration; there is a more or less distinct general congestion of 

 the organs. 



While lockjaw has been known clinically for centuries, it was not 



Prepared by Edward Fidlar. 



