tuberculinization

Question 1

what are immunological methods

Answer 1

serological and allergological (tuberculin test)

Question 2

what is hypersensitivity

Answer 2

the state of heightened or excessive immune response to repeated exposure to a specific antigen

Question 3

how does sensitisation happen

Answer 3

on the first contact of a immunocompetent macro-organism and he substance with antigenic properties, the macroorganism is sensitised
ie it becomes hypersensitive so that it creates sensitised T lymphocytes or antibodies

Question 4

what happens on second contact with substance

Answer 4

if in contact with same substance again, an antigen-antibody complex is created or antigen sensitised T lymphocytes and an excessive immune response, which leads to tissue damage or signs of inflammation

Question 5

early phase hypersensitivity

Answer 5

seen quickly after repeat contact with the antigen/allergen
carriers = antibodies of all immunoglobulin classes

Question 6

late phase hypersensitivity

Answer 6

seen in hours or days after contact between the previously sensitised macroorganism and the antigen/allergen
carriers = sensitised T lymphocytes

Question 7

what is tuberculosis

Answer 7

chronic, contagious infectious disease
cause = mycobacterium complex - M.bovis, M.caprae, M.tuberculosis, M.africanum
most common zoonosis worldwide

Question 8

immune response

Answer 8

when infected with mycobacteria cattle become hypersensitive to the protein antigen of the causative agent
cellular hypersensitivity leads to sensitised T lymphocytes leads to lymphokines which activate monocytes and mononuclear cells

Question 9

consequences of immune response

Answer 9

the cascade immune response leads to inflammation and manifestation of hypersensitive reaction
best expressed 48-72h after introduction of the antigen to previously sensitised cattle

Question 10

individual skin test testing for TB

Answer 10

fill out form
L neck - 10cm in front of shoulder and 20cm below ridge of neck
clip 5cm2
measure thickness of skin
apply 0.1ml of purified protein derivative of M.bovis intradermally
check it has been applied appropriately - rice size lump under finger
check reaction after 72h

Question 11

what is assessment of reaction to tuberculin test based on

Answer 11

clinical exam of swelling at site of application
exam of regional lymph nodes - submandibular and prescapular
measure thickness of skin fold using cutimeter

Question 12

negative reaction to individual skin test

Answer 12

only limited swelling at site, no sign of infection (edema, temp, redness, pain)
lymph nodes without signs
increase in skin fold not greater than 2mm

Question 13

doubtful reaction individual skin test

Answer 13

no changes at site or on lymph nodes but increase in skin thickness is more than 2mm but less than 4mm

Question 14

positive reaction individual skin test

Answer 14

inflammation seen at site of application or lymph nodes
or increase in skin fold greater than 4mm

Question 15

descrive comparative intradermal test

Answer 15

at least 42 days after reading of individual test
clip 2 areas on neck
measure skin with cutimeter
0.1ml avian 10cm below ridge of neck
0.1ml bovine 15cm lower in line parallel with shoulder
read test after 72h

Question 16

negative reaction comparative test

Answer 16

if reaction to bovine is the same or less than the reaction to avian and no clinical signs of inflam

Question 17

doubtful reaction comparative test

Answer 17

reaction to bovine is 1-4mm larger than reaction to avian without clinical signs

Question 18

positive reaction comparative test

Answer 18

reaction to bovine is more than 4mm larger than reaction to avian with or without clinical signs

Question 19

tuberculinisation of goats

Answer 19

all goats older than 12 months kept on farms where there is dairy cattle must be tested by individual TB test
doing and reading the results the same as in cattle

Question 20

tuberculinisation of pigs

Answer 20

intradermal application of bovine and/or avain on dorsal side of head, where ear joins head
0.1ml in each site
read results 48h after

Question 21

positive pig reactions

Answer 21

if inflammation at site of application of either
erythema, sometimes necrosis
skin swelling with central necrosis = dominant signs hypersensitivity

Question 22

pig reactions if TB to no TB

Answer 22

on pig farm with NO TB, positive reaction is a swelling larger than 20mm, and swelling 10-20mm is doubtful
on farm with confirmed TB, positive is when swelling large than 10mm and doubtful if less than 10mm

Question 23

negative pig test

Answer 23

NO TB = negative if no reaction or less than 10mm swelling
TB farm = negative if no reaction

Question 24

tuberculinisation in horses

Answer 24

performed the same as in cattle
usually caused by M.avium complex but can be M.bovis and M.tuberculosis
up to 70% of clinically healthy horses can have a positive test - v low specificity test

Question 25

how to confirm tb in horses

Answer 25

isolation mycobacteria from affected organs and tissues in lab

Question 26

tuberculinisation in dogs and cats

Answer 26

intradermal TB test on inner side of ear using live attenuated vaccine against TB which contains Mycobacterium bovis BCG (Bacillus Calmette-Guerin)
assess reaction 48-72h after

Question 27

another way of TB testing dogs and cats

Answer 27

sub dermal application of bovine tuberculin PPD
measure temp immediately before application. if dog normothermic, apply 0.75ml sub dermally
monitor body temp q2h for 12h
if temp rises by 1.1 degree then test is positive

Question 28

disease transmission owners and dogs

Answer 28

more common from owner to animal