128. Salmonellosis of cattle.

Question 1

Occurence of salmonellosis of Cattle?

Answer 1

Occurrence

• Calves endemic, adult sporadic
• Predisposing factor:
• selling young calves,
• transport, overcrowding (viral infections not as important in cattle more so in poultry)
• Connected with animal breeding technology
• Common in countries where young calves are regularly sold at few weeks old & collected in large
• fattening units → salmonellosis (Britain, Ireland, Canada, US)
• Not common in countries where animal fattening is rare (Continental Europe)

Question 2

Aetiology?

Answer 2

Aetiology

• S. Typhimurium, S. Dublin, S. Newport
• S. Enteritidis, S. Agona, S. Derby,
• S. Abortusbovis (can cause all abortion, sporadic – but rare)

Question 3

Epidemiology?

Answer 3

Epidemiology

• Source of infection:

• newly introduced animals;
• rodents, birds; feed

• Infection:

• per os:
• faeces;
• feed, water, pasture

Predisposing factors:

• transport,
• getting cold,
• hygienic problems,
• mixing

Question 4

Pathogenesis?

Answer 4

Pathogenesis

• Most frequent in 2-6 week old calves, in adults sporadic
• Acute

o Per os infection → gut, proventriculi → gastroenteritis (diarrhoea)

o Sometimes bacteraemia → Parenchymal organs (focal inflammation, necrosis)

• Chronic (Ab response):

• arthritis,
• tendovaginitis,
• bursitis;
• mastitis, drop in milk production;
• abortion
• Subclinical infection, shedding

Question 5

Clinical signs?

Answer 5

Clinical signs

• Acute:

• fever,
• anorexia,
• depression;
• diarrhoea (thin, watery, gas bubbles, fibrin clots & blood appear at the end);
• cough, dyspnoea

• Chronic:

lameness (arthritis),

mastitis,

abortion (middle of pregnancy)

Question 6

Pathological lesions?

Answer 6

Pathologic lesions

• Acute:

• enteritis (small intestine,
• haemorrhages,
• fibrin,
• yellowish watery faeces, necrosis);
• enlarged LNs,
• paratyphomas

• Chronic:

• arthritis,
• aborted foetus

Question 7

Diagnosis?

Answer 7

Diagnosis

• Epidemiology – clinical signs – post mortem lesions
• Detection of the agent: bacterium isolation, carriage of bacteria (intermittent shedding – repeat isolation)
• Detection of Abs: ELISA (serum, milk) – serological diagnosis only useful in chronic phase!

Question 8

Differential diagnosis?

Answer 8

Differential diagnosis:

1. E.coli,
2. coronavirus,
3. rotavirus,
4. coccidiosis,
5. cryptosporidiosis (differentiate with smear),
6. BVD (mucosal erosion present in BVD),
7. paratuberculosis

Question 9

Treatment?

Answer 9

Treatment

• Antibiotics, trimethoprim-sulfonamide, quinolons - parenteral, (p.o.)
• Reduction of diarrhoea, rehydration
• Shedding animals: culling

Question 10

Prevention?

Answer 10

Prevention

• General epidemiological prevention methods - isolation, no mixing, hygiene!
• Salmonella free food, water
• Milk has to be heat treated
• No irrigation with sewage water
• Prevent predisposing factors
• Vaccination: inactivated, live

o Application: pregnant cows, newborn calves

o Do not prevent carriage