Causative agent
- Mycobacterium avium subsp. paratuberculosis
Differential diagnosis
- Amyloidosis
- BVD
- MD
- Fascioliasis
1. History Taking
- Introduction of cattle from the endemic area
- Introdution of imported cattle
2. Clinical examination
- Chronic intermittent diarrhea
- Decreased lactation
- Edema in the submandibular region
- Unthriftiness
3. Serological test
- Complement fixation test
- ELISA
4. Necropsy
- Pathognomonic corrugation of mucous
membrane of the small and large intestine,
especially ileum
- Swollen mesenteric lymph nodes
5. Histopathological observation
- Proliferation of epithelioid cell and
appearance of Langerhan's giant cells in
the lamina propria of intestinal wall and
mesenteric lymph nodes
- Demonstration of acid-fast bacteria within
the epithelioid cells and giant cells
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6. Bacteriology
6.1 Microscopic examination : detection of a
clump of acid fast bacteria in fecal smear
6.2 Bacterial isolation
- Specimen : feces, intestinal lesion, ileo-caecal
valve, mesenteric lymph nodes,
decontamination by
Hexadecylpyridinium chloride (HPC)
- Medium : Herrold egg yolk medium with
and without mycobactin
middlebrook 7H9, 7H10 and
7H11 enhanced with mycobactin
- Culture : for 8 to 13 weeks at 37°C,
smooth, grayish-white colonies,
complete dependency on
mycobactin
Control and Prevention
- Screening by serological tests
- Separate any unthrify animal from the herd
until condition is diagnosed
- Separate calf within 12 hours from infected
cow
- Serological diagnosis: 6 months intervals in
infected herd
- Fecal culture at 6 months intervals for all
animal over 20 months of age in infected
herd
- Remove & slaughter all positive culture
animals and their offspring
- Cleaning and disinfection of contaminated
animal house, equipments and barn with
orthophenyl phenol or 2-3% cresol solution
- Provide a clean environment for calving
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