Bovine Tuberculosis
Introduction:-
·
It is a zoonotic disease caused by mycobacterium
(myco. tuberculosis)
·
John’s disease is caused by myco. paratuberclosis
·
It is a disease of mammals and most susceptible
hosts are cattle, goats, pigs, horse, and deer
·
Sheep’s are naturally resistant to this disease
Source of Infection:-
·
Secreted in all the secretions, exhaled air, sputum,
feces, semen, milk, vaginal and urine discharge, nasal discharges, and ocular
discharges
·
TB affects all the body organs but bovine TB most
commonly to the digestive tract and in the human’s respiratory system
·
Mainly through ingestion, inhalation, intra-uterine,
during coitus, intramammary during passing contaminated siphon, in young dairy
during suckling and milk ingestion
Pathogenesis:-
2 stages
1. Primary complex formation
2. Post-primary dissemination
1. Primary complex
form
Formation of granulomatous lesions on the
site of injury, regional lymph nodes, and mostly through inhalation.
When through ingestion not necessarily
lesions formation, it mainly affects tonsils and mucosa
Primary foci form 8 days after entry then
start of calcification of lesion starts 2 wks. Later surrounded by granular
tissues, monocytes, plasma cells and result in the formation of pathognomonic signs
of tuberculosis
2. Post-primary
dissemination form
Bacteria inter to the other organs and
produce some lesion
In 90 % of cases of cattle lesions formation
on the caudal lobe of the lung and in calves it occurs in pharyngeal lymph nodes
Clinical
Finding:-
·
Emaciation
·
Capricious appetite
·
Fluctuating body temperature
·
Roughness of body coat
·
And overall animal become sluggish and docile
Pulmonary
Tuberculosis
·
In this case chronic cough of more than 2 wks. and
more intensive at night time
·
Bronchopneumonia and moist cough
·
Coughing is induced by pressing the trachea or after
exercise (exercise intolerance)
·
Coughing at night only in a cold environment
·
When pulmonary tissues destroyed then advance stages
then dyspnea characterized by increased respiratory rate, consolidation of
lungs, fibrosis of lungs, there will be dull sounds
·
In further advanced stages crackle because of
pleurisy
·
There is the involvement of bronchial and mediastinum
and due to enlargement of mediastinal lymph nodes recurrent tympany
·
In the case of the alimentary tract
·
There should be diarrhea but diarrhea is very rare
in TB cases
·
Enlargement of retropharyngeal and tonsillar lymph
nodes hence dyspnea and rise in breathing
·
Chronic painful swelling of submaxillary lymph nodes
Uterine
Tuberculosis
Not common in cattle, otherwise bursitis,
salpingitis peritonitis
Metritis leading to infertility may or
may not, when conception occurs then concurrent abortion in late stages of
pregnancy.
Newborn calf borne but immediately died
after birth.
In males very less in metritis purulent
discharges.
Mastitis
Residue in other tissues marked in
duration and hypertrophy of udder. Mostly rare quarters are involved. Enlargement
of supra memory lymph nodes.
In TB follicles appear in milk in the last
portion. If in test tube follicles descend down and leave behind umber color
fluid.
Diagnosis:-
1 SCID:
Ø Tuberculin PPD inj 0.1 ml in a skin fold.
Ø Observe reaction 12 to 48 hours later.
Ø Swelling measured by Vernier caliper if
more than 4 mm then the test is positive.
2 Short thermal
test:
Ø Temperature measured 4 ml of tuberculin
inj ID into the neck of an animal.
Ø Rectal temperature of the animal is 102 F but
after 24hour body temperature rises up to 108 F.
Ø 20 mg / kg body weight PO ionized for 4
to 9 months.
Ø Streptomycin 5g / animal prolong therapy.
Ø 30% human cases from bovine.
3 Double ID
Test:
Avian and mammalian tuberculin injected
to check either bovine or avian origin. Screening is most important.
Those bacteria when giving false-positive
result with tuberculin
