Download Tetanus ( Lock jaw )

Tetanus ( Lock jaw )
by:
Abobakr M Gamal
Ahmed M Bekhiet
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.
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,…
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.
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.
Pathogenesis:
C.tetani is normal inhibitant in intestine of horse &
other herbivorus animals.
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)
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.
Micro :

Not characteristic.