1. Tetanus

2. Caused by Clostridium Tetani Gram positive Spore-forming Anaerobic rod
Tetanus
Caused by Clostridium Tetani
Gram positive
Spore-forming
Anaerobic rod

3. Reservoir Spores of C. tetani are found in soils throughout the world
Spores are very resistant to harsh conditions
heat
radiation
chemicals
drying
Spores can survive for a long time in environment---100yrs possibly!

4. Tetanus (cont’d)
Entry of C. tetani into the body usually involves implantation of spores into a wound
After gaining entry, C. tetani spores can persist in the body for months, waiting for the proper low oxygen growth conditions to develop

5. Tetanus (cont’d)
When the oxygen levels of the surrounding tissue is sufficiently low, the implanted C. tetani spore then germinates into a new, active vegetative cell that grows and multiplies and most importantly produces tetanus toxin

6. Tetanospasmin is an extremely lethal neurotoxin
Tetanus (cont’d)
The virulence factor (toxin) responsible for the symptoms of tetanus is called tetanospasmin
Tetanospasmin is an extremely lethal neurotoxin
Induces spastic paralysis
by inhibiting release of inhibitory neurotransmitters
Physiologic consequence is uncontrolled muscle contractions

7. Tetanus (cont’d)
As growing cells of C. tetani produce tetanospasmin at the wound site, the toxin starts to migrate along nerves into the Central Nervous System where it blocks the release of inhibitory neurotransmitters
As a consequence of too much “activator transmitters”, muscles are OVERstimulated to repeatedly contract—called spastic paralysis

8. Tetanus (cont’d)
A person suffering from tetanus undergoes convulsive muscle contractions of the jaw--called LOCKJAW
The contractions by the muscles of the back and extremities may become so violent and strong that bone fractures may occur
Unfortunately, the affected individual is conscious throughout the illness, but cannot stop these contractions

9. Tetanus (cont’d)
Death may occur from tetanus, often from cardiac (heart) and respiratory (lung) effects or secondary complications from the infection

10. Diagnosis of Tetanus
Tetanus is suspected upon exposure to a bite or puncture wound
Because C. tetani exhibits such exquisite sensitivity to oxygen, it is very difficult to recover and/or grow from clinical specimens
As a result, diagnosis is made on the basis of clinical findings and history

11. Tetanus is not common in U.S.A. because of mandatory vaccination
Tetanus (cont’d)
Tetanus is not common in U.S.A. because of mandatory vaccination
However, a few cases/year in non- vaccinated or improper booster individuals
Tetanus is still very common in Third World countries—causing several hundred thousand deaths per year
Many of these deaths involve neonatal tetanus due to the umbilical cord being unsterilely cut

12. Treatment of Tetanus
Very difficult to treat once symptoms have developed
Antitoxin is administered
Muscle relaxants
Supportive therapy (ventilator)
Cleansing of the wound

13. Treatment of Tetanus (cont’d)
If recovery does occur, there are usually no long-term side effects.
Recovered individuals do not necessarily develop “natural Immunity” against the infection--- because the very small amount of tetanus toxin produced during the infection does not elicit a strong, protective immune response which would produce enough antibodies against future re-infection

14. Prevention of Tetanus A highly effective vaccine is available
Tetanus immunity is achieved using a formalized tetanus toxoid
Toxoid is administered as part of the childhood DPT vaccine
4 primary immunizations starting at 2 months of age
Boosters every 10 yrs
they hurt!!