Tetanus is an acute noncontagious infectious disease caused by the bacterium Clostridium tetani.
It is a Gram-positive bacillus that grows only in the absence of oxygen (i.e., it is anaerobic), and it occurs naturally in both vegetative and spore form. The germ in vegetative form produces a toxin, called tetanospasmin, which is neurotoxic and causes the clinical symptoms of the disease. It is one of an extremely potent toxin, so much so that the lethal amount for a human is about 7 millionths of a milligram.
