Bovines Spongyform Encephalopathy / BSE / Madcow
Introduction:-
Non-febrile, slow + progressive, neurological disorder + mainly
with prolong incubation period + prolong illness.
Consider as a disease of adult animals due to the long Incubation Period which is
2.5-8 years.
Zoonotic diseases + in human causes creutfelt Jacob syndrome +
causes chronic wasting disease in wild animals/deer.
Also called rusk, scrapie in sheep
Called transmissible encephalopathy because of highly transmissible.
Subacute, from a clinical point of view.
Etiology:-
Prions, protease-resistant neurological + R-chains.
prion protein effected.
These proteins bind with other proteins + also cause a change in
them.
Highly heat-stable + can survive at 132 degrees C.
Resistant to ordinary disinfectants like NaOH, Na2CO3.
They cause denaturation of proteins but
Epidemiology:-
Prions reported in 1986, 1st outbreak epidemic in with
one lac 86 thousand cases were reported + found animal that is offered with the feed of animal source (bone + meat).
In daily severe outbreak because feed change (animal originated
feed) herbivore à
carnivore.
Prevalent in other countries like European countries Italy,
Germany, Canada, Polland, USA à
also, the case was found but major in the UK.
4-5 years à
clinical case age + no test for it. That’s why persist & but prevalence dec
with time.
Cases also reported in Japan à in 15 years age à
infection at calf age (6 months age) + then show signs of 4-5 years (in 2014-15
à
cases reported in Polland & Germany).
Source of Infection:-
MBM à
meat bone meal. Horizontal & verticle transmission. Debatable when in
acute sign. Transmission from the dam to baby à case-control study à milk suckling transmission not reported may be through fetal fluid
à
minor à
major source infestation.
(Indian sub-continent or from 300 deaths of animals à consumed & cause BSE)
(2000-2001 à the feed from Indian sub-continent)
Pathogenesis:-
Ingestion à
intestine à
Payer’s patchesà
splanchnic + vagus nerve.
Transmission to brain & cause vacuolar defense. In the brain, due to
vagus nerve involvement à
bradychardiaà because vagus nerve parasympathetic (heartburn due to acidity)
Clinical findings:-
Slow insidious infection
The clinical course of the disease is 1-8 months
Alteration in behavior (different from routine i.e. in dairy
animals during milking, not pass through lane, kicking), movement + temperature
Animal reluctant to move in milking sheds, kick during milking,
hyperesthesia to touch and sound
There are four tests for this
1.
Bang
test
2.
Flash
test
3.
Stick
test
Bang test
·
Metallic
rings striked and animal behave aggressively and walk away
Stick test
·
Feet strikes and animal move aggressively
Flash test
·
Light
flash used
Disorientation, ataxia, twitching of ears, muscle tremors, throwing
head sideways
Isolation from Herd,
Animal show more grooming tendency
Licking (severe itching due to scrape )
Hind limb ataxia
Swing gait, mostly abduction of limb, hind limb kicking, stumbling,
falling on the ground, most of the time unchecked, mostly animals slaughtered
Treatment:-
No treatment
Avoid animal origin feed
Properly processed feed
