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Also known as: TGEV
Antigenicity
- Single serotype
Hosts
- Pigs
Pathogenesis
- Malabsorptive diarrhoea
- All ages susceptible but effects vary on age:
- Less than 2 weeks of age: typically fatal
- Over 5 weeks of age: recovery and immunity
- For more, see here
Epidemiology
- Largely replaced by a respiratory variant in Europe
- Highly contagious spread by orofecal transmission
- Two forms of infection can occur:
- Epizootic: Explosive infection
- Introduction to a non-immune herd spreads quickly
- Enzootic: Persistent infection
- Immune sows provide passive immunity but piglets will suffer mild symptoms post-weaning
- Epizootic: Explosive infection
Diagnosis
- Fluorescent microscopy on SI sections
Control
Explosive infection:
- Separate sows 2 weeks from farrowing
- Exposure of flock will serve to immunise
- No effective vaccines exist
- Caused by a coronavirus.
- Known as Epidemic diarrhoea or TGE.
- Produces an explosive diarrhoeic disease, which spreads through the farm rapidly.
- Epidemiologically, the disease is easy to recognise, since all ages of pigs scour.
- This is the means of diagnosis.
- Consequences of disease differ with the age of the animal.
- In very young animals, mortality may be up to 100%.
- In animals 1-3 weeks old, mortality is around 50%.
- Over 3 weeks of aged, mortality is 25%.
- Older pigs tend to recover from the disease.
Pathology
- Villi are shortened and more rounded, with a degree of fusion.
- Epithelial cells over the villi are flattened.
- The lamnia propria is congested and oedemetous.
- These changes are in contrast to coliform infections, which show much more normal villi.
- Many gram-negative bacteria can be seen adhering to the villi wall if a gram stain is used.