159. Proliferative enteropathies of swine.

Question 1

Occurence, aetiology and epidemiology?

Answer 1

Diseases: Intestinal adenomatosis; Necrotic enteritis; Regional ileitis; Proliferative haemorrhagic enteropathy

Occurrence: worldwide, frequent

Aetiology: Lawsonia intracellularis (Gr -ve)

• Obligate Intracellular: enterocytes
• Replication in cell cultures (can’t culture in artificial culture, need tissue culture)
• Wide host range: swine, horse, sheep, dog, rodents etc.
• Resistance: 2 weeks in faeces – enough time to each a new host

Epidemiology

• Introduction: faeces of infected animals (long carriage), vehicle, boot, rodents
• Infection: feed, water, environment
• Asymptomatic carriage can occur

Question 2

Pathogenesis and clinical signs?

Answer 2

Pathogenesis

• Infection PO (from faeces)
• Proliferation in the enterocytes (intra cellular)
• MM becomes thicker: decreased absorption, flow of fluid in the gut lumen, diarrhoea
• Degeneration, reparation: precipitation of fibrin, necrosis, haemorrhages in the gut
• The disease is limited to the gut
• Spontaneous healing or becomes chronic

Clinical signs

• Swine
• Acute form: 4-12 months old pigs - haemorrhagic diarrhoea, anaemia
• Chronic form: 6-20 week old piglets - incubation 2-3 weeks, anorexia, sometimes diarrhoea, reduced

weight gain

• Foals: 4-7 months old - diarrhoea, colic, oedema

Question 3

Pathology and diagnosis?

Answer 3

Pathology

• Intestinal adenomatosis:

o Distal ileum, proximal large intestine

o Mucous membrane of the gut becomes thicker (tube-like), oedema

o Similar to paratuberculosis

• Necrotic enteritis: mucous membrane of the gut becomes thicker, necrosis
• Regional ileitis: Hypertrophy of the muscular layer of the gut (thick tube) Necrosis of the mucous membrane
• Proliferative haemorrhagic enteropathy: MM of the gut becomes thicker, blood, black faeces, anaemia

Diagnosis

• Epidemiology – clinical signs – post mortem lesions
• Histology
• Detection of the agent: silver impregnation, IF, IP, PCR, (bacterium culture – not easy, only tissue culture)

Question 4

Differential diagnosis and prevention?

Answer 4

Differential diagnosis:

• swine dysentery

Treatment: antibiotic treatment

• Swine: macrolides, tiamulin (drinking water)
• Horse: macrolides, tetracyclines, erythromycin- rifampicin

Prevention

• General epidemiological prevention methods
• Replacement from disease free herds
• Attenuated vaccine: 5-6 weeks old piglets PO

o Good local immunity

o Foals can also be vaccinated