Although there is some overlap (e.g. Salmonella spp. and Campylobacter spp. can both cause non-inflammatory diarrhoea), the pathogens causing inflammatory diarrhoea form a distinct group (Table 50.4). Their site of action is usually the distal ileum and colon and they produce disease by destroying parts of the enteric mucous membranes, leading to an inflammatory response. This in turn leads to the excretion of neutrophils and erythrocytes in faeces, which can be detected by simple wet film microscopy or myeloperoxidase by ELISA.