traveller's diarrhoea

introduction

80% bacterial eg. enterotoxigenic Escherichia coli (ETEC), Salmonella, Campylobacter, etc.
up to 20% are parasitic eg. giardiasis, Cryptosporidium, Cyclospora, amoebiasis (usually starts after 6wks or so), Fasciola (liver flukes)
remainder are viral eg. norovirus (especially on cruise ship outbreaks), rotavirus, adenovirus, calicivirus
- hepatitis A and hepatitis E viruses (HEV) may cause diarrhoeal illness

oral rehydration solutions
mild symptoms (< 3 loose stools/day):
- no Rx or loperamide 4mg stat then 2mg after each loose stool to max. 16mg/day (do not use in children under 2 years)
moderate symptoms (3 or more stools /day):
- loperamide as above
- single dose antibiotics is generally effective (longer course if fever or bloody stools):
  - norfloxacin 800mg, or, azithromycin 1g
incapacitating symptoms, fever or bloody diarrhoea:
- avoid loperamide if dysenteric symptoms (fever, bloody diarrhoea)
- double dose antibiotic Rx as above initially then usual dose
persistent symptoms despite above:
- stool culture
- consider parasitic or drug resistant cause

patients with persistent fevers who have not been to typhoid-prone areas should be considered for invasive Salmonella enteridis infection
these patients should have stool culture, 2 sets of blood cultures
ciprofloxacin is the preferred antibiotic NOT norfloxacin which is really only useful for non-invasive enteritis

amoebiasis may result in mild diarrhoea 6-12 weeks after infection but may then develop a hepatic abscess with raised LFTs and inflammatory markers
hepatitis A
hepatitis E viruses (HEV)