Risk is low, but pathogen's typical range may be expanding.
The medical equivalent of lightning striking twice in the same place occurred in Minnesota this week. Two years after a 7-year-old Stillwater girl's tragic death from a rare waterborne infection, state health officials have linked another child's death to the same pathogen -- and, likely, the same small lake.
Jack A. Erenberg, a 9-year-old who loved the outdoors, died Tuesday -- apparently from a brain infection that occurs when a certain kind of amoeba is inhaled in a noseful of lake or river water. The microscopic organism then travels to the brain through nasal passages and is almost always fatal.
The boy's death sent shudders through parents across the state and put a grim spotlight on the small lake where both children swam before they died -- 36-acre Lily Lake in Stillwater. City and county officials reacted quickly and appropriately, closing it to swimming while state health officials determine whether there's something uniquely risky about the popular swimming spot.
While "What's wrong with Lily Lake?" should be the first question answered, it shouldn't be the last. This is a public health issue far broader than one small suburban lake.
Even though these infections remain extremely rare, the two Minnesota deaths strongly suggest that the common amoeba has dramatically expanded the geographic range in which it's capable of making people sick. Figuring out why, and what the implications are for other northern lakes and rivers, should take on even greater urgency in the wake of Erenberg's death.
That's a critical issue to keep in mind as looming automatic federal budget cuts threaten medical and scientific research funding in the months ahead. Advances are needed to determine how the complex intermingling of everything from water temperature to acidity to organic material may increase the risk of infection. Merely testing the water isn't enough, because this type of amoeba is so common.
It's not a stretch to say that the first Minnesota death stunned the world's infectious-disease experts. Before little Annie Bahneman of Stillwater fell victim in 2010, infections linked to Naegleria fowleri, as the amoeba is known, were reported only in the southern United States. Bahneman's death occurred 550 miles north of the previously reported northernmost case, in Missouri.
While Naegleria has long been found in freshwater all over the world -- including water bodies in cold climates -- the Minnesota deaths indicate that something has changed. Scientists have taken notice.
Answers remain elusive, but several journal articles carefully note in dry journalese that warming weather patterns could impact the frequency of this infection. Translation: Global warming may have led to conditions in which Naegleria proliferates in lakes where it previously did not. Lily Lake might be an early warning of unknown yet serious health risks rising temperatures may bring.
Policymakers should take heed. So should parents. As frightening as these infections are, they're not a reason to avoid the beach. Naegleria deaths remain extremely rare -- about two to three occur each year in the United States.
Kids, because they're more active, may be more likely to inhale infected water. Caregivers should be aware of the conditions in which Naegleria seems to flourish: brackish, sluggish water that's filled with algae and other organic matter and warmed by long stretches of very warm weather.
When in doubt, it's best to err on the side of caution, and avoid water like this or full immersion in it. The risk is very low, but the Minnesota deaths indicate that it shouldn't be ignored.
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