A parasitic stomach bug that can give you diarrhoea for months is sweeping the UK

Cases are they highest they’ve been since 2016 (Picture: Getty Images)

Health officials have issued fresh giardiasis warnings this week, amid surging rates of the parasitic stomach bug that can cause diarrhoea, cramps and bloating for months on end.

The UK Health Security Agency (UKHSA) recorded 6,069 laboratory-confirmed infections in England in 2025 — up 11.4% on the previous year, marking the highest number of annual cases since 2016.

The agency is investigating what’s behind the spike, which peaked between September and November, but said more effective testing, increased travel since the pandemic, and

1. Homepage
2. International
3. A parasitic stomach bug that can give you diarrhoea for months is sweeping the UK