Travellers' diarrhoea: bacterial causes, prevention and care

The illness arises when food or water contaminated with faecal matter is swallowed. TravelHealthPro lists bacteria, viruses and parasites among the pathogens involved. Among bacteria, the World Health Organization names Campylobacter, enterotoxigenic E. coli (ETEC) and Shigella as common causes of fever, headache, nausea, vomiting, abdominal pain and diarrhoea. ETEC is linked with raw fruit and vegetables, Shigella with fresh produce and ready-to-eat salads, and Campylobacter with undercooked poultry, raw milk and meat.

Which organism is responsible usually remains unknown, because most people recover without a stool test.

TravelHealthPro advice centres on water safety and careful food selection. None of these measures removes risk completely, but together they reduce it.

• Drink factory-sealed bottled drinks, or water boiled or chemically treated; avoid ice and untreated tap water.

• Choose food that is thoroughly cooked and served hot, and avoid food that has been left standing.

• Peel fruit yourself and choose pasteurised dairy.

• Avoid salads, uncooked produce, buffets, unpasteurised products and raw seafood.

• Be wary of street food unless it is visibly prepared fresh.

• Wash hands with soap and water before eating and after the toilet.

Older adults, young children, pregnant women and people with weakened immunity should be especially careful and seek advice earlier. TravelHealthPro adds that those taking acid-reducing medicines have a higher chance of infection, because stomach acid is part of the body's defence against swallowed bacteria. Anyone with an inflammatory bowel condition or a chronic illness may wish to discuss a plan with their GP or a travel clinic before departure.

Fluids are the priority. The NHS advises drinking small sips of water or squash often, eating when you feel able, avoiding fatty or spicy food, and continuing to feed babies as usual. Oral rehydration sachets from a pharmacy help to replace salts. Fruit juice, fizzy drinks and anti-diarrhoea medicines are not advised for children under 12.

The NHS says diarrhoea usually stops within five to seven days and vomiting within one or two days. Good hand hygiene and staying away from others, including not preparing food, helps prevent spreading the infection to travelling companions.

Most episodes are self-limiting and do not need antibiotics. Antibiotics are reserved for more severe illness and are best prescribed after assessment, as travellers who use them casually can acquire resistant bowel bacteria and carry them home. The World Health Organization warns that misuse and overuse of antibiotics are principal drivers of resistance. Discuss medicines to carry with a travel health professional rather than self-medicating from abroad.

TravelHealthPro advises seeking prompt medical attention for fever of 38 degrees or above, blood in the stool, confusion, severe abdominal pain or jaundice, and consulting a doctor if diarrhoea lasts beyond three days. The NHS lists dehydration, bloody stools, diarrhoea beyond seven days or vomiting beyond two days as reasons to call NHS 111, and vomiting blood, a severe headache with a stiff neck, severe abdominal pain or difficulty breathing as reasons to call 999 or attend A&E.

If symptoms continue or recur after travel, a GP can arrange stool tests to look for bacteria and parasites. Mention where you went and when, since some infections such as typhoid, cholera and parasitic diseases need specific treatment. Persistent bowel upset after an infection is not unusual and can last for some weeks, but fever or weight loss should be reviewed.