Infectious diarrhoea

Infectious diarrhoea remains a major cause of morbidity and mortality world wide. Viruses, bacteria and protozoa are responsible for the majority of infections, which are transmitted most commonly by the faecal–oral route through water, food and person-to-person transmission. Clinical presentation of infectious diarrhoea conforms to three patterns: acute watery diarrhoea; dysentery; and persistent diarrhoea, which can include steatorrhoea. Diagnosis still rests heavily on stool microscopy and culture, although faecal antigen tests and molecular assays are increasingly used. Oral rehydration therapy continues to be the most important supportive intervention, particularly in acute watery diarrhoea, when death from dehydration and acidosis can be prevented in the vast majority of sufferers. There have been some important advances in the development of new approaches to antibiotic therapy. The non-absorbable antibiotic, rifaximin, is highly effective in the treatment of traveller’s diarrhoea and is free from the majority of adverse effects associated with systemically absorbed antibiotics. The broad-spectrum antimicrobial, nitazoxanide, is often effective in the treatment of cryptosporidiosis but is also effective in giardiasis, amoebiasis and Clostridium difficile infection. Recent meta-analyses suggest that probiotics are probably not effective in the prevention or treatment of antibiotic-associated diarrhoea but they do shorten attacks of acute diarrhoea in children.