Paratuberculosis

Question 1

common name for paratuberculosis

Answer 1

Johne’s Disease

Question 2

what causes it

Answer 2

m avium subspecies paratuberculosis

Question 3

who more susceptible

Answer 3

calves

Question 4

transmission

Answer 4

oral ingestion of organisms shed from feces of infected animals or pooled contaminated colostrum

Question 5

pathogenesis

Answer 5

-chronic diarrhea, loss of body condition
-intracellular pathogen
-ingested mycobacteria taken up by M cells
-organisms cross intestinal epithelial layer
-engulfed by macrophages – can survive and replicate in them
-interferes with maturation of phagosome-lysosome function
-granuloma formation in lamina propria and submucosa of GI tract
-enteropathy –> loss of plasma proteins and malabsorption of nutrient and water

Question 6

what cells take up mycobacterium

Answer 6

M cells

Question 7

clinical signs

Answer 7

-diarrhea – persistent and profuse
-weight loss
-mucosa of terminal small intestine and large intestine thickened and folded into transverse corrugations
-mesenteric and ileocecal lymph nodes enlarged and edematous

Question 8

when do affected cattle show signs

Answer 8

after age 2

Question 9

diagnosis

Answer 9

-biopsies, histopathology, ZN staining, bacterial isolation
-postmortem tissue samples
-serology – complement fixation, ELISA, immunodiffusion, IFN-y assay
-intradermal test (Johnin)
-PCR

Question 10

control

Answer 10

isolate sick animals
facility hygiene
inactivated and live attenuated vaccines available

Question 11

skin tests

Answer 11

johnin – mycobacterium avium var paratuberculosis
brucella abortus
mallein – burkholderia mallei
histoplasmin – histoplasmosis
coccidioidin – coccidioidomycosis