Holidaymakers are being urged to take precautions against a parasitic stomach bug, as cases of the infection rise by more than 10 per cent.
Figures from the UK Health Security Agency (UKHSA) revealed that cases of giardiasis rose to 6,069 in England – up from 5,450 the previous year and the highest total since 2016.
London reported the highest number of cases (1,568), followed by the North West (1,029).
Officials said in 2025 that cases peaked in autumn and said that the 11.4 per cent rise may be driven by post-pandemic travel, climate change or improved testing.
The stomach bug can be contracted both in the UK and overseas. It spreads through contaminated food and water, direct contact with infected people or animals and it can be sexually transmitted.
What is giardia?
Giardia is a type of parasite that can cause a tummy bug known as giardiasis.
It’s found in lakes, streams and public water supplies, such as swimming pools, spas and wells.
According to the UKHSA, infections are being seen in people returning from Southern Asia, South-Eastern Asia, Africa and South America. However, it can also be found in the UK.
What are the symptoms and how is it treated?
Symptoms include diarrhoea, bloating, burping, wind and weight loss. In rare, untreated cases, children can experience malnutrition and stunted growth.
It is usually treated with a course of antibiotics and is cured within a week, but the NHS warns it can cause longer infections.
Nicola Love, senior food safety surveillance lead at UKHSA, said: “Symptoms can last from weeks to several months and if left untreated, it can cause serious complications especially in young children, the elderly and those with weakened immune systems.”
How can you avoid giardia?
Experts say the parasite can be avoided by only drinking bottled water when travelling, and eating cooked rather than raw food, such as salads and fruit that have been washed in tap water.
The UKHSA also advises against swimming in rivers, lakes and even the sea when abroad to avoid giardia.
Ms Love said: “There are some simple precautions everyone can take to reduce their risk, whether you are planning an autumn getaway somewhere warm or staying in the UK.
“Good hygiene can help prevent giardiasis and other common gastro illnesses.
“Wash your hands with soap and water after using the toilet, after changing nappies, and before preparing food.
“Encourage children to wash their hands regularly too. If you have a giardia infection, continue to hydrate yourself and see your GP – do not go swimming until two weeks after your diarrhoea has stopped.
“Parents should contact their GP or NHS 111 if they or their children are ill with dehydration, or if diarrhoea worsens or lasts longer than three days.”
