-
Secretion of infected animals i.e. sputum, urine, semen, uterine
discharges, and milk
-
Discharges from open peripheral lymph nodes
-
Re-ingestion of sputum and excreted in feaces
-
Wild animals e.g. deer are the reservoir
Mode
of Transmission:
-
Through inhalation and ingestion.
-
During grazing, animal may ingest sputum of infected animal.
-
Under natural conditions animal having T.B drinks water from the
pond of stagnant water and goes away. That water remains
contaminated for 80 days. Then other animals drink from that
water and get infection. In running water there is no such
problem.
-
Drinking infected milk; it is more common in calves.
-
Contaminated feed
-
Contaminated semen, saliva and sputum
Clinical Signs:
-
Progressive emaciation
-
Weakness
-
Anorexia
-
Fluctuating temperature
-
Initially cough is low (once or twice a day) but with time
loudness increases. Cough is more in morning and cold weather.
-
Nasal discharge
-
Difficult breathing
-
Digestive tract involves rarely but if involved there is
diarrhea and indigestion
-
Swelling of L.N.
-
Lower jaw becomes immoveable
-
In case of reproductive tract involvement abortion may occur
-
Sever decrease in milk production
-
Sometimes greenish pus in milk
Diagnosis:
Single Intradermal Tuberculin Test:
Tuberculin is purified protein derivative of Mycobacterium bovis. It
is more potent and specific. 0.1 ml of tuberculin is injected to
each animal of herd in cervical fold of skin in centre of neck or
anal and caudal region. If animal is positive for T.B then there
will be diffused swelling at injection site after 48 hours.
Short Thermal Test:
Inject 4 ml of tuberculin subcutaneously in neck of animal having temperature
102.5 oF. Check temperature after 2, 4, 6, and 8 hours.
If increase in temperature after 2 hours of injection then animal is
positive. After 2 hours temperature may reach upto 104.5 oF
and it remains upto 6 hours.
Comparative Tuberculin Test:
Inject avian tuberculin at upper side of neck and inject bovine
tuberculin 12 cm apart at lower side of first injection at neck.
Where is more swelling after 4 - 48 hours that is positive.
Avian tuberculin is used because it is antigenically similar to
Jhone’s Disease. The Johne’s organism i.e. Mycobacterium
paratuberculosis is present intracellularly and does not give good
response to antibiotics.
Treatment:
No specific treatment available because very much expensive and time
consuming. So people prefer to slaughter. There are chances of
reoccurrence of this disease as the organism is intracellular. Huge
quantity of antibiotics are required and for long term.
|
