Changes

In healthy animals, there is a balance between multiplication of ''Clostridium perfringens'' and its passage in the faeces. This ensures that infection is maintained at a low level.  However, ''C. perfringens'' is saccharolytic and is therefore able to multiply rapidly when large quantities of fermentable carbohydrate are introduced to the anaerobic conditions of the abomasum and small intestine, leading to build-up of exotoxin. Gut statis, for example due to insufficient dietray fibre or a high gastrointestinal parasite burden, can also contribute to the accumulation of toxins.  

In healthy animals, there is a balance between multiplication of ''Clostridium perfringens'' and its passage in the faeces. This ensures that infection is maintained at a low level.  However, ''C. perfringens'' is saccharolytic and is therefore able to multiply rapidly when large quantities of fermentable carbohydrate are introduced to the anaerobic conditions of the abomasum and small intestine, leading to build-up of exotoxin. Gut statis, for example due to insufficient dietray fibre or a high gastrointestinal parasite burden, can also contribute to the accumulation of toxins.  

Enterotoxaemia due to ''Clostridium  perfringens''  type B causes severe enteritis and dysentery with a high mortality in young lambs (lamb dysentery), but also in calves, pigs, and foals. The β toxin it produces is highly necrotising and is responsible for severe intestinal damage. ε toxin also plays a part in pathogenesis. The incidence of lamb dysentery declined over the past 20 years or so, due to the widespread use of clostridial vaccins³, but the condition is now becoming a problem again as complacency reduces flocks vaccinating for the disease. Outbreaks of lamb dysentery typically occur during cold,  wet lambing periods when lambing ewes are confined to small areas of shelter which rapidly become unhygienic. Most cases are seen in stronger, single lambs³, because these animals consume the largest quantities of milk which functions as a growth medium for ''C. perfringens''.

Enterotoxaemia due to ''Clostridium  perfringens''  type B causes severe enteritis and dysentery with a high mortality in young lambs (lamb dysentery), but also affects calves, pigs, and foals. The β toxin it produces is highly necrotising and is responsible for severe intestinal damage. ε toxin also plays a part in pathogenesis. The incidence of lamb dysentery declined over the past 20 years or so, due to the widespread use of clostridial vaccines³, but the condition is now becoming a problem again as complacency reduces the use of vaccination. Outbreaks of lamb dysentery typically occur during cold,  wet lambing periods when lambing ewes are confined to small areas of shelter which rapidly become unhygienic. Most cases are seen in stronger, single lambs³ because these animals consume the largest quantities of milk, which functions as a growth medium for ''C. perfringens''.

==Signalment==

==Signalment==