1. Tetanus ( Lock jaw )
by:
Abobakr M Gamal
Ahmed M Bekhiet

2. Back history of C.tetani :
Neurotoxic clostridia, non invasive, highly toxigenic, gram+ve, large sized, strict anaerobic, spore forming bacilli, the spores are spherical, terminal and bulging (Drum stick appearance), slightly proteolytic, motile.

3. Tetanus ( Lock jaw )
Def : An infectious disease of man and animals caused by C. tetani ch ch by stiffness of muscles and closure of jaw. R.O.I: deep wound. Symptoms: convulsion, parlysis,…

4. Host :
N.B: 1: Poultry : non affected ::: have antitoxin in the brain. 2: Cattle : less susceptible ::: because the grass contain spores so due to sublethal dose , resistance occur. 3: Horse : more susceptible ::: because the HCL in the stomach juice destroy the spores contained in grass so the animal not exposed to sublethal dose.

5. : Virulence determinants of C.tetani
C. tetani produces 2 exotoxins (Tetanospasmin and Tetanolysin). Tetanospasmin is potent neurotoxin that produced spasms and voluntary muscular contraction (Tetanus). Tetanolysin is a hemolysin that causing .hemolysis of the RBCs N.B: Tetanus toxin or tetanospasmin is one of the three most poisonous substances known, the other two being the toxins of botulism and diphtheria.

6. Pathogenesis:
C.tetani is normal inhibitant in intestine of horse & other herbivorus animals.

7. Pathogenesis :
Deep wound infection (anaerobic conditions) Germination of spores Multiplication Neurotoxins (tetanospasmin) inhibit the release of neurotransmitter glycin Stiffness of muscles (masseter and facial) death due to asphyxiation
(spasm of diaphragmatic muscles) 

8. Grossly: Spasms of head muscles (lockjaw)
In horses, the ears are erect, the tail stiff and extended.
The third eyelid prolapsed.
Walking, turning, and backing are difficult.
Spasms of the neck and back muscles a “sawhorse” stance.
Sweating is common , increased heart rate, rapid breathing, and congestion of mucous membranes.

9. Tetanus (lock jaw)    

10. Tetanus (lock jaw)    

11. Tetanus (lock jaw)    

12. Micro :
Not characteristic.

13. Thank you