In 1854, a London anesthesiologist and amateur sleuth made a history-changing discovery about the link between contaminated water and human disease.

Several years before Louis Pasteur’s groundbreaking experiments that established what came to be called germ theory, Dr. John Snow thought he’d figured out why there were so many cholera cases in a central London neighborhood now known as Soho. The prevailing belief at the time was that cholera was caused by miasma — bad air.

Snow had another idea. He persuaded civic officials to remove the handle from the Broad Street pump, a water source for the neighboring businesses and residents. And fairly quickly, the cholera cases stopped.

Over a century and a half later, it appears some in modern society want the Broad Street pump handle back.

Just as some people extoll the so-called benefits of unpasteurized milk, a segment of the bottled water market is now embracing the idea of “raw” water. The argument: It tastes better. It’s more natural. It doesn’t contain additives like fluoride, which is often added to municipal water supplies to combat tooth decay.

But while the notion of crystal clear water bubbling up from a pristine spring sounds enticing, in reality there can be risks.

“When water is untreated, there is more uncertainty regarding what’s in it — and it may contain harmful germs,” explained Vincent Hill, chief of the Centers for Disease Control and Prevention’s waterborne disease prevention branch.

Think of them as nature’s additives. While these bugs — things like Cryptosporidium, Giardia, Shigella, and E. coli — can look lovely when captured by an electron micrograph, what they can do to your gastric tract definitely isn’t.

Take a glimpse.

 

In the water
A microorganism covered by spiky projections giving it an appearance of a sea urchin. Janice Haney Carr/CDC
In the water
A number of rod-shaped objects may have been vegetative in nature, possibly algae. There were patches of biofilm present as well. Janice Haney Carr/CDC
In the water
A mass of gelatinous biofilm studded with microorganisms, including amoebae and bacteria. Janice Haney Carr/CDC
In the water
Another close-up view of an untreated water specimen extracted from a wild stream, mainly used to control flooding during inclement weather, revealed the presence of unidentified organisms, which included bacteria, protozoa, and algae. Janice Haney Carr/CDC
In the water
This microscopic “pin cushion” was tethered to its surroundings by a biofilm within which many bacteria and amoeboid protozoa could be seen as well. Janice Haney Carr/CDC
In the water
A microorganism covered by numerous projections. Janice Haney Carr/CDC
In the water
An unidentified round microorganism has an almost perfectly rounded smooth, flawless surface. Janice Haney Carr/CDC
In the water
An unidentified amorphous mucoidal biofilm, which appeared to have amoeboid organisms lodged inside.

Janice Haney Carr/CDC
In the water
What appears to be diatomic, bacterial, and protozoan species, which were just a few of the inhabitants of this fresh water stream. Janice Haney Carr/CDC
In the water
A single copepod-like microorganism appears to have an outer shell of armour-like plates or scales. Janice Haney Carr/CDC
In the water
These rod-shaped objects may have been vegetative in nature, possibly algae. Janice Haney Carr/CDC

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