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Paratuberculosis in livestock
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Paratuberculosis in livestock
Paratuberculosis in livestock
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1
Question
What animals does paratuberculosis primarily affect worldwide?
Page 1
Answer
Cattle, sheep, goats, llamas, camels, and farmed deer, mainly ruminants on large-scale farms
2
Question
What is the causative agent of paratuberculosis?
Page 1
Answer
M. avium subsp. paratuberculosis (M. paratuberculosis), a fastidious mycobacterium requiring mycobactin
3
Question
How does M. paratuberculosis appear under Ziehl-Neelsen staining?
Page 1
Answer
Ziehl-Neelsen positive in nests
4
Question
What is the environmental survival time of M. paratuberculosis?
Page 1
Answer
High resistance, survives several months in soil and 6-9 months in the environment
5
Question
When does fecal shedding of M. paratuberculosis begin after infection?
Page 1
Answer
3-5 months after infection, before clinical signs, with large numbers of bacteria shed
6
Question
How long does milk shedding of M. paratuberculosis last?
Page 1
Answer
Lifelong shedding
7
Question
What are the main routes of infection for paratuberculosis?
Page 1
Answer
Via feces, food, and water
8
Question
Which age group of animals is more susceptible to developing clinical paratuberculosis?
Page 1
Answer
Young animals infected at 0-6 months show clinical signs later; infections after 6 months are asymptomatic with shedding
9
Question
What is the typical incubation period for clinical signs in calves with early paratuberculosis infection?
Page 1
Answer
Symptoms appear at 2-5 years of age
10
Question
What are examples of aggravating factors for paratuberculosis clinical signs?
Page 1
Answer
Pregnancy, nutritional deficiency, BVD, parasite infection, and immunosuppression
11
Question
In which species are clinical signs of paratuberculosis less frequent?
Page 1
Answer
Sheep and goats
12
Question
What are the two phases of paratuberculosis pathogenesis?
Page 1
Answer
Tuberculoid and lepromatous
13
Question
Where does initial replication of M. paratuberculosis occur?
Page 1
Answer
Intracellularly in T-lymphocytes and macrophages in the small intestine and lymph nodes
14
Question
What are the main clinical findings in paratuberculosis?
Page 1
Answer
Long incubation (9 months minimum), weight loss, decreased milk yield, severe watery diarrhea that is smelly and squirting (jet-like), with oedema in cattle
15
Question
Describe the gross pathology of paratuberculosis in cattle intestines.
Page 1
Answer
Wall of the small intestine diffusely thickened, sometimes proximal large intestine (like oesophagus), transverse folds that cannot be smoothed away (gyrus brain-like), enlargement of lymph nodes
16
Question
What histological features are seen in paratuberculosis lesions?
Page 1
Answer
Epithelioid cells and giant cells; milder lesions in sheep and goats
17
Question
What immunodiagnostic tests are used for tuberculoid form of paratuberculosis?
Page 1
Answer
LST and gamma-interferon test
18
Question
What serology tests are used for the lepromatous form of paratuberculosis?
Page 1
Answer
CFT, AGD, iIF, ELISA
19
Question
What is the key challenge with vaccination against paratuberculosis?
Page 1
Answer
Cross-reaction with M. bovis TB, limiting use in TB-free countries; attenuated/inactivated vaccines given once in first month prevent clinical signs and reduce carriage
20
Question
How can paratuberculosis be prevented in young calves?
Page 1
Answer
Good hygiene to reduce fecal contamination of feed and water, clean water without puddles or pools, cull diseased animals, source replacements from paratuberculosis-free herds
21
Question
What strategy is recommended for eradicating paratuberculosis from a herd?
Page 1
Answer
Test and slaughter (difficult due to long uncertain generation shift); or full herd replacement with disease-free animals, separating calves after colostrum using milk replacers
22
Question
In Crohn's disease, can the paratuberculosis agent be regularly detected?
Page 2
Answer
Yes, the agent can be regularly detected and cultured, and antibodies against it can be detected
23
Question
What remains unverified regarding the paratuberculosis agent and Crohn's disease?
Page 2
Answer
The direct causative role of the agent cannot be verified