Page 57 - 15Diarrhoeaandvomiting

Diarrhoea and vomiting caused by gastroenteritis in children under 5 years

The most frequent pathogens causing bacterial gastroenteritis reported in the published studies
and the HPA website were campylobacter, salmonella and E. coli, while cryptosporidium was
the most common protozoal infection detected. There were no published population-based
data comparing the detection of viral pathogens with bacterial pathogens, but results from the
population-based study suggest that cases of non-bacterial gastroenteritis are less likely to be
reported to the national surveillance authority than the cases of bacterial gastroenteritis.

Clinical question
Which enteric pathogens are most commonly identified in children returning to the UK with
traveller’s diarrhoea?

Gastroenteritis is the most commonly reported travel-associated illness in England and Wales.
No published data were identified to provide information on this question. Information was
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again collected from the HPA website, as given in Table 3.6, but the age-specific data were not
available.
Evidence summary

Salmonella was the most commonly reported cause of gastroenteritis associated with overseas
travel. The other commonly reported enteric pathogens were campylobacter, shigella and
cryptosporidium. While salmonella, campylobacter and cryptosporidium were reported to be
associated with travel in Europe, infections with shigella, giardia and entamoeba were associated
with travel to the Indian subcontinent and sub-Saharan and southern Africa.

GDG translation from evidence to recommendations
Rotavirus is the predominant single pathogen responsible for gastroenteritis in children. Other
viral pathogens, although individually less common, collectively accounted for many other
cases. Norovirus has been recognised increasingly as an important cause of gastroenteritis. A
range of other viruses, including adenovirus, astrovirus, and calicivirus may also be responsible.
Bacterial infections, particularly campylobacter and salmonella species, and protozoal infections
such as cryptosporidium may also cause gastroenteritis. In those with a history of recent overseas
travel, the likelihood of infection with salmonella, campylobacter, cryptosporidium and other
infections unusual in the UK is greater.
The GDG agreed that in, in keeping with current practice, children presenting with acute diarrhoea
do not usually require stool microbiological investigation. Most have viral gastroenteritis. Even
if the illness is due to a bacterial or protozoal enteric infection, most children do not require
antimicrobial treatment (see Chapter 7 on antibiotic therapy), and so identification of a specific
pathogen is not generally required.

However, the GDG agreed that in some circumstances microbiological investigation should be
considered, as listed below.
• If the clinician is in doubt about the diagnosis of gastroenteritis, isolation of a stool pathogen
can provide diagnostic reassurance. Using routine microbiological techniques including
stool microscopy, culture and standard viral detection methods, a causative pathogen can be
identified in most patients with gastroenteritis.
• It is also important to investigate those who present with bloody and/or mucoid diarrhoea,
because this can be due to a range of important and potentially serious disorders.
– Various non-infective inflammatory bowel disorders may present with bloody stools.
Infants (both breastfed and bottle-fed) may present with bloody diarrhoea due to non-
specific colitis; this may be an allergic phenomenon, although the aetiology is often
uncertain. Inflammatory bowel disease (ulcerative colitis or Crohn’s disease) may
sometimes begin in early childhood, and the presentation can be acute and associated
with bloody diarrhoea. Without evidence of an infective cause, it may be impossible
to distinguish between bacterial or amoebic dysentery and a first episode of bloody
diarrhoea due to ulcerative colitis or Crohn’s colitis.
– Various surgical disorders, such as intussusception, could also be associated with passage
of blood and/or mucus. Although most children with bloody diarrhoea due to an enteric

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