TETANUS

History - The goat had this symptoms, after parturition.

SYMPTOMS

    1.The muscles are contracted.

    2.The third eyelid droops.

    3.Lock jaw, saliva drools.

    4.The animal falls and it cannot rise again.

    5.Neck show opisthotonous or orthotonus.

    6.The fore legs are extended stiffly forward and the hind legs backward.

PATHOLOGICAL CONDITION

     The pathological condition of the symptoms mentioned above for the goat was TETANUS. 

     Tetanus(synonym - Lockjaw) is a highly fatal infectious disease caused by the exotoxin of clostridium tetani, a gram positive, sporulating  anaerobe. The spore are terminal giving the organism a drum stick appearance.

SUSCEPTIBILITY

     Horse and mules are more susceptible. Sheep, goat, dogs and swine may also be infected. Mice, rabbits, guinea pigs and rats are susceptible. Cattle are least susceptible. Birds are resistance.

ROUTES OF INFECTION

     Wound infection, surgical wound, deep punctured wound(horse gathered nail), particularly, are more conducive for the growth of the organism affording anaerobic environment. Wounds that occur during shearing, docking, and parturition in females and through the umbilical vein in young. The organism is voided with the dung and so it is found normally in the soil and stables.

PATHOGENESIS

     The spores that enter a wound require certain favourable conditions to vegetate and liberate the toxin. When necrosis or hemorrhage or other aerobic and pyogenic bacteria are present, producing anaerobiasis, the spores vegetate. The organisms liberate the toxin locally. This toxin consists of three components.

    1. a hemolysin - tetanolysin, which is not of much importance.

    2. a neurotoxin - tetanospasmin, Which is responsible for the nervous symptoms.

    3. A fibrinolysin, which is not very potent.

The toxin is absorbed by the axons of the peripheral nerves. It passes with the intercellular fluid along the interneural spaces  centripetally to the neurones of the spinal cord and the brain. This passage centripetally is brought about by the pressure exerted during muscular contraction. The toxin may reach the CNS by way of blood also. The exact action of the toxin on the nervous system is not known. The tetanus toxin gets fixed to a substance called PROTAGON in the nervous tissue. The protagon is a complex made up of cerebroside plus oligosaccharides like N-acetyl galactosamine and galactose. It acts on the inhibitory synapses interfering with the action of the inhibitory transmitter thus producing spastic action. The toxin causes hyperirritability responsible for the tetanic spasms.

INCUBATION PERIOD

      One to three weeks. 

LESIONS

      No characteristic lesions are found.

DIAGNOSIS

      There are no tests to confirm a diagnosis. The organism is local and does not become septicemic. Symptoms alone are helpful.