Bovine Tuberculosis

Question 1

Public health measures in bovine tuberculosis (PQ)

Answer 1

• Zoonotic disease! Notify medical if animals infected, notify vets if humans infected by eating meat
• Notification to state medical service
• Informing the keeper, owner
• Personal disinfection
• Protective clothes, gloves and footwear
• Control of products (raw milk used to be important source for human!)
• Can be in Swine and other Ruminants: deer – inner side of thigh with thin skin

Question 2

Definition of a tuberculosis free herd (bovine tuberculosis) (minimum q)

Answer 2

• No clinical signs
• All animals over 6 weeks: two official intradermal tuberculin tests
o First: 6 months after the removal of infected animals
o Second: 6 months later; or 60th day after collection form free herds
• Animals introduced: from officially free herds or tested (within 30 days)
• All that die – go for PM → Meat inspection, lesions: → complete investigation
• (Every two) yearly tuberculin testing all animals above 12 months
• General preventive measures (isolation of the holding, record of comp. laboratory
examinations, control of movements of visitors, animals, vehicles, control of dogs
and cats on the holding etc.)

Question 3

Suspicion of bovine tuberculosis in a herd

Answer 3

• Suspicion (positive test or pm inspection)
• Positive reactor: slaughtered, examination
• If not confirmed: all animals over 6 weeks tested (min. 60d after the removal of reactor)
• Withdrawal: isolation of M. bovis, or: on the basis of epidemiological, pathological findings – free
status of herd is withdrawn
• Restoration of free status: (slaughter all animals) or strict cleaning, disinfection

Question 4

How can we do a Tuberculin Test?

Answer 4

Tuberculin tests shall be carried out by injecting tuberculin(s) into the skin of the neck. The injection
sites shall be situated at the border of the anterior and middle thirds of the neck.
• When both avian and bovine tuberculins are injected in the same animal, the site for injection of
avian tuberculins shall be about 10 cm from the crest of the neck and the site for the injection of
bovine tuberculin about 12,5 cm lower on a line roughly parallel with the line of the shoulder or on
different sides of the neck; in young animals in which there is not room to separate the sites
sufficiently on one side of the neck, one injection shall be made on each side of the neck at identical
sites in the centre of the middle third of the neck.
• Injection sites shall be clipped and cleansed. A fold of skin within each clipped area shall be taken
between the forefinger and thumb and measured with callipers and recorded.
• The dose of tuberculin shall then be injected by a method that ensures that the tuberculin is
delivered intradermal
• A short sterile needle, bevel edge outwards, with graduated syringe charged with
tuberculin, inserted obliquely into the deeper layers of the skin may be used.
• A correct injection shall be confirmed by palpating a small pea-like swelling at each site of
injection. The skin-fold thickness of each injection site shall be re-measured 72 hours (±4
hours) after injection and recorded (swelling)
• The interpretation of reactions shall be based on clinical observations and the recorded
increase(s) in skin- fold thickness at the sites of injection 72 hours after injection of tuberculin(s).

Question 5

Test procedures

Answer 5

• 1) Intradermal test
o Single intradermal test: a single injection of bovine tuberculin,
o Intradermal comparative test: one injection of bovine tuberculin and one injection
of avian tuberculin given simultaneously.
• The dose of tuberculin injected shall be (purified protein):
o Not less than 2 000 IU of bovine tuberculin,
o Not less than 2 000 IU of avian tuberculin.
• 2) Subcutaneous test
o inject protein SC and may result in exacerbation of clinical signs in animal – see very serious
clinical signs if they are infected, which is why we don’t use it so much