Holidaymakers are being urged to take precautions against a parasitic stomach bug, giardiasis, following an 11.4% rise in cases. Figures from the UK Health Security Agency (UKHSA) show that cases in England increased to 6,069 from 5,450 the previous year, marking the highest total since 2016.
London recorded the highest number of infections with 1,568 cases, while the North West reported 1,029. Officials suggested in 2025 that the rise, which peaked in autumn, may be linked to post-pandemic travel, climate change, or improved testing.
Giardia, a parasite causing giardiasis, can be contracted in the UK and overseas through contaminated food and water, direct contact with infected individuals or animals, and sexual transmission. The UKHSA notes infections are observed in people returning from Southern Asia, South-Eastern Asia, Africa, and South America.
Symptoms include diarrhoea, bloating, burping, wind, and weight loss. While usually treated with antibiotics within a week, the NHS warns of potential longer infections. Nicola Love, senior food safety surveillance lead at UKHSA, stated that untreated cases can lead to serious complications, particularly in young children, the elderly, and those with weakened immune systems.
To avoid giardia, experts recommend drinking only bottled water when travelling and consuming cooked food instead of raw items washed in tap water. The UKHSA also advises against swimming in rivers, lakes, and the sea when abroad.