Introduction

Classification

Taxonomy

• Kingdom: bacteria.
• Phylum: firmicutes.
• Class: clostridia.
• Order: clostridiales.
• Family: clostridiaceae.
• Genus: clostridium.
• Species: C. tetani.

Etymology

• Gk: Clostridium: klōstēr - a spindle. L:tétanos- muscle spasm/stretch.

Active Forms

Resting Forms

Clinical Effects

Epidemiology

Habitat

• Found in soil (particularly cultivated soil) and intestinal tracts.
• Can be transiently found in feces.

Lifecycle

• Spores germinate in an anerobic environment, such as devitalized tissue.
• Proliferation of the bacterium results in neurotoxin production.

Transmission

Pathological effects

• The spores of C. tetani are not able to grow in healthy tissue or in wounds which have normal oxidation-reduction potential of the circulating blood.
• Acquired resistance depends on circulating antitoxin.
• Surviving animals are susceptible to reinfection.
• Cattle are relatively susceptible to tetanus Tetanus.
• The endospores enter wounds or trauma sites (eg through the umbilicus, or after castration, or into the uterus after dystocia). If tissue necrosis is apparent the spores can grow. The toxin is released when the bacterial cells undergo autolysis.
• Anerobic conditions are provided by the presence of facultative anerobes and the spores germinate in devitalized tissues.
• The cells multiply and produce two exotoxins: tetanolysin (a hemolysin), which is apparently insignificant, and the neurotoxic tetanospasmin.
• The toxin interferes with the release of inhibitory neurotransmitters from the presynaptic nerve endings. Toxin can also be carried via the lymphatic system  to the bloodstream and thus to the CNS (descending tetanus).

Other Host Effects

• Transient in the intestinal tract. Commensals unless they gain access to wounds or traumatized tissue.

Control

Control via animal

• Undertake surgical procedures and calving in a clean environment.
• Clean and debride wounds.
• Euthanisation of cattle with late stage disease.
• Animals should be managed in a quiet environment with supportive fluid therapy.

Control via chemotherapies

• Large doses of penicillin G  Penicillin.
• Antitoxin is probably of little value unless given in the very early stages.
• In some cases sedatives and relaxants can aid recovery.

Vaccination

• Tetanus toxid vaccines are available.

Diagnosis

Further Reading

Publications

Refereed Papers

• Recent references from PubMed and VetMedResource.
• Driemeier D, Schild A L, Fernandes J C T, Colodel E M, Corrêa A M R & Cruz C E F & Barros C S L (2007) Outbreaks of Tetanus in Beef Cattle and Sheep in Brazil Associated with Disophenol Injection. J Vet Med Series A 54, 333–335 PubMed.
• Benavides E, Ortiz D & Benavides J (2000) Association of botulism and tetanus as causative agents of an outbreak of bovine paraplegic mortality in the eastern plains of Colombia. Ann N Y Acad Sci 916, 646–649 PubMed.
• Thompson R W (1997) Idiopathic tetanus in fattening cattle. Vet Rec 140, 435–436 PubMed.
• Whitehead J G M & D H Ellicott (1996) Idiopathic tetanus. Vet Rec 138, 651.
• Preece D L & Bostelmann R W (1996) Idiopathic tetanus. Vet Rec 139, 48 PubMed.
• Chapleo D E (1991) Outbreak of tetanus. Vet Rec 129, 40.
• Gray D, M J Allen & G G Matthews (1991) Outbreak of tetanus. Vet Rec 129, 79 PubMed.
• Whitaker D A (1991) Outbreak of tetanus. Vet Rec 129, 59–60.

Other sources of information

• Biberstein E L (1990) The Clostridia. In:Review of Veterinary Microbiology. Eds: E L Biberstein & Y C Zee. Blackwell Scientific, USA. pp. 306-309.