Causative agent
- Most common serovars :
Salmonelal typhimurium (0-4 group),
S. dublin (0-9, 12 group) and others
Differential diagnosis
- Colibacillosis
- Necrotic enteritis
- Coccidiosis
- BVD-MD
- Bovine coronavirus infection
- Bovine rotavirus infection
1. History taking
- High morbidity and moderate mortality
- Introduction of apparent healthy carrier animals.
- Most common in animals up to 3 months of age
- Enzootic in particular feed-lot farm
- Predisposing factor is stress caused by
transportation and others
- Abortion among pregnant cow
2. Clinical examination
- Anorexia
- Depression, dullness defecation high fever,
peculiar smell and bloody mucus
- Severe dehydration, achromasia in visible mucus
membrane
- Incoordination and nystagmus
- Arthritis or nervous symptoms in chronic cases
3. Necropsy
- Inflammation in the large and smalll intestine
- Multiple mucosal erosion and petechial
hemorrhage of the abdominal wal
- Extensive submucosal and subserous petechial
hemorrhage
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- Contents of small intestine are yellow or yellow-
whitish with bad smell
- Thicken wall of caecum and colon
- Swollen and hyperemia of mesenteric lymph nodes
- Fibrinous peritonitis
4. Histopathlogical observation
- Hemorrhage, edema, necrosis and marked
leukocyte infiltration (mostly macrophages) in
mucosa of intestine
- Small necrotic foci in liver
- Fibrinocellular exudate in villi surface
- Fibrin thrombi in proprial capillaries
- Necrotic payer's patches
5. Bacterial isolation
Specimen : spleen, liver, mesenteric lymph nodes
and feces
- Propagational and selective media with common
media as described in avian salmonellosis
- Identified by biochemical characters (see 51.
Salmonellosis in pig)
6. Serotyping
- Confimation of O-group (antigen) by slide
agglutination test
Control
- Pervention of introduction of infected or carrier
animals
- Isolation of newly introduced animals from herd
- Identification and removal of carrier in herd
- Disposal of contaminated materials
- Prevention and treatment with broad spectrum
antibiotics
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