Authorities issue warnings to people walking the West Highland Way not to drink untreated water from rivers or streams after two hikers fall seriously ill in separate incidents. The reports say the cases occur on consecutive days and involve hikers who drink from a Highland river or stream rather than using treated or filtered water. In both incidents, the hikers’ symptoms are severe enough that they require rescue and medical attention and become unable to continue walking. One outlet describes the illness as “serious” and notes that the affected hikers become unwell after consuming contaminated water. Another reports the symptoms as violent, with hikers becoming so ill they are unable to walk. The guidance given to walkers is consistent across the coverage: do not drink water directly from the natural water sources along the route unless it has been properly treated. Authorities’ messaging focuses on preventing further cases by encouraging safe water practices while trekking.