We’re lucky to have probably the world’s finest water in Scotland, so most hillwalkers think nothing of swigging straight from the burn – in fact, it’s one of my greatest outdoor pleasures (especially when combined with a local single malt…). Even in Scotland precautions need to be taken though, extracting water downstream of a dead sheep is never wise, and ensuring that you’re well above farmland and any surface run-off is a good move. Risks from contaminated water include waterborne pathogens – protozoa (causing, for example, cryptosporidiosis), bacteria (eg. dysentery) and viruses (eg. hepatitis). There’s also the matter of particulate…