Overview
- The UK Health Security Agency recorded 6,069 giardiasis cases in 2025, an 11.4% increase from 2024 and the largest total reported since 2016.
- London reported the most cases (1,568) followed by the North West (1,029), with infections peaking in the autumn months.
- Officials say they are investigating causes that may include increased post‑pandemic travel, climate effects on water sources, and improved testing that finds more infections.
- Health guidance stresses hygiene and travel precautions: drink bottled water abroad, eat cooked food rather than raw produce washed in tap water, avoid swallowing swimming water, and do not swim for two weeks after diarrhoea stops.
- Most infections cause diarrhoea, bloating and weight loss and are treated with a short course of antibiotics, but children, the elderly and people with weakened immune systems can face longer or more serious illness so they should seek GP or NHS 111 advice for worsening or prolonged symptoms.