Such infections will typically require medical treatment and possibly antibiotics, whereas the common, but troublesome travellers' diarrhoea is self-limiting and passes within a week. Contaminated food and drink. A typical example of this is if a chef or waiter is a little slapdash in going to the toilet, uses little toilet paper and does not bother washing his hands. He then warmly shakes the guest's hand before the latter picks up a chicken leg and puts his teeth into it without washing his hands. This is a typical way of contracting Shigella dysentery.
Prevention consists of washing the hands frequently, particularly before eating.
From faeces to food or drink and then to mouth. For example, the butcher, chef and farmer, etc have the same lack of hygiene as described above, but in this case transfer the infection directly to food or drink. And the farmer no doubt may also use cheap human manure rather than expensive commercial fertiliser for his salad crops. Remember that ice cubes may also be infected. In the latter case, the cause is a toxin from Bacillus cereus , and toxins of this kind cannot be removed by reheating or renewed boiling.