Views / Citizen Scientist

How likely are you to catch something nasty from swimming?

A red flag at the beach should be taken to heart

Unsafe swimming water can spread skin infections, stomach bugs and earaches, among other nasty illnesses.

Graham Paine/Metroland

Unsafe swimming water can spread skin infections, stomach bugs and earaches, among other nasty illnesses.

I’ve always been a little skeptical of beaches being closed because of bacteria. You’re not going to drink out of the lake. So what’s the big deal? 
I should say up front: I’m biased. I spent childhood summers frolicking in rivers, ponds and lakes with no worries and no municipality monitoring the water. I swam, along with other neighbourhood kids, in a literal ditch by the side of the road one glorious spring after a torrential rain.  
It was incredible fun. But was it dangerous?
According to a  2013 literature review in the journal Canadian Family Physician, recreational swimming is the most common cause of acute gastrointestinal illness (a.k.a. stomach flu) in the summer — more common than food poisoning or catching a bug from another person. 
Kids are most at risk because they play in shallow water and stick their wet, sandy hands in their mouths. But adults can get sick too, sometimes, evidence suggest, from casual contact with water, such as fishing or boating.
The best-known, but far from only, culprit is E. coli. Public health agencies monitor this bacteria because it’s a good indicator the water is contaminated with human and animal poo that could harbour other infection-causing bacteria, parasites and viruses like norovirus and rotavirus.
The CFP review made swimming illness sound like a massive public health crisis; an overlooked epidemic. That seemed like a bit much to me, so I ran the review past Toronto pediatrician Dr. Daniel Flanders, who also happens to be the doctor at a summer camp where kids swim in the lake every day but stomach bugs are, thankfully, rare.
“So much depends on the circumstances,” Flanders said. “Urban beaches or swimming sites close to farms (i.e. at risk of manure run-off) would be way higher risk settings than the camp where I'm working, or a well-managed pool.”
So, scary as water borne illness is, it’s no reason to give up one of the best parts of summer.
And there are ways you can protect yourself. Nothing is 100 per cent safe, but here’s what I picked up from various public health agencies: Don’t swallow water, don’t swim if you have any sores or wounds, and don’t swim near drain pipes. If the water looks cloudy or there’s been heavy rain in the last 48 hours, skip it. Also, kids can get a vaccine to protect against rotavirus, one of the most common and serious stomach bugs.
Oh, and maybe stay out of the ditch.  

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