WHO Publishes Documents on Drinking Water Germs

Posted in Food Policy,Our Blog on May 1, 2025

The World Health Organization (WHO) recently published a series of background documents for drinking water germs. Germs like Campylobacter, E. coli, hepatitis A virus, Shigella Toxoplasma gondii, Salmonella, Vibrio, Yersenia and others. These documents were published to assist potential revisions in drinking water guidelines as well as guidelines on sanitation and health.

So, why is this information important. And what did they find?

But first, what is the WHO and what do they have to do with drinking water?

Who are WHO?

The World Health Organization was founded in 1948 and is part of the United Nations agency. The organization connects nations, partners, and people to “promote health, keep the world safe, and serve the vulnerable.

Part of that mission is promoting access to clean water.

Why Is Categorizing Drinking Water Germs Important?

Based on the number of documents included in this series of reports, a lot of work went into this topic. So, why is categorizing these potential concerns for drinking water germs important?

The WHO focused on this topic for a few reasons.

First, understanding risks for these potential drinking water germs can help health authorities make more informed decisions. Particularly in areas where these germs are endemic.

Additionally, this information is especially important for travel advisories. Efforts to inform those traveling to endemic areas where these drinking water germs are a serious concern help people make better decisions.

Also, understanding which drinking water germs are of concern can potentially help mitigation efforts. As in, water treatment plans and drinking water advisories.

Biggest Concerns for Drinking Water Germs

Certain pathogens are considered serious concerns for drinking water germs based on study data. The documents referred to this as “strong evidence.”

So, what are these bad bugs?

• Diarrhoeagenic coli – causes watery diarrhea.
• Norovirus – causes abrupt onset of nausea, projectile vomiting, and diarrhea.
• Typhoidal and non-typhoidal Salmonella – causes diarrhea, fever, stomach pains, nausea, vomiting, and headaches.
• Campylobacter – causes diarrhea (sometimes bloody), fever, stomach cramps, and sometimes nausea and/or vomiting.
• Vibrio cholerae – causes milky white watery diarrhea, vomiting, leg cramps, and restlessness or irritability.
• Shigella – causes diarrhea that may be bloody and/or prolonged, fever, stomach pain, and feeling the need to pass stool (poop) even when bowels are empty.
• Toxoplasma gondii – most cases are asymptomatic, but 10-20% of those infected experience lymphadenopathy and/or flu-like illness.
• Cryptosporidium – causes diarrhea, fever, and fatigue.
• Giardia duodenalis – causes diarrhea, gas, smelly and greasy poop that can float, stomach cramps or pain, upset stomach or nausea, and dehydration. May cause fever, itchy skin, hives, swollen eyes and/or swollen joints.
• Entamoeba histolytica – most cases are asymptomatic, but 10-20% of those infected experience diarrhea, stomach pain, and stomach cramping.
• Rotaviruses – causes severe watery diarrhea, vomiting, fever, stomach pain, and possibly dehydration.
• Hepatitis A and E – causes dark urine or clay-colored stools, diarrhea, tiredness, fever, joint pain, loss of appetite, nausea, stomach pain, vomiting, and yellow skin or eyes (jaundice).

Moderate Concern for Drinking Water Germs

While not the biggest concerns, other pathogens have shown “moderate evidence” for waterborne transmission. Or so says the WHO background documents.

So, what are these potential drinking water germs and what are their symptoms?

• Yersinia enterocolitica – young children experience fever and diarrhea (sometimes bloody), and abdominal pain. Older children and adults often experience pain on the right side of the abdomen and sore throat.
• Cyclospora cayetanensis – causes watery diarrhea with frequent, and sometimes explosive bowel movements.
• Helicobacter pylori – causes gnawing or burning epigastric pain. Symptoms may include loss of appetite, nausea, or vomiting. This bacterial infection increases the risk of gastric cancer and mucosal associated lymphoid-type lymphoma by 2-6-fold.
• Burkholderia pseudomallei – causes fever, headache, respiratory distress, abdominal or chest discomfort, myalgias, disorientation, and/or seizure.
• Sapoviruses – causes nausea, projectile vomiting, and diarrhea.

Low Concern for Drinking Water Germs

Some pathogens show very little evidence of drinking water transmission. The WHO ranked these pathogens as “low health concern.”

• Staphylococcus aureus
• Cronobacter sakazakii
• Astroviruses

Using E. coli As an Indicator Organism

Many public health authorities use certain E. coli species as an “indicator organism,” to measure the effectiveness of water purification processes. If those E. coli bacteria (that are often present in feces) are detected, it is a signal that certain potentially harmful germs may also be present in the water.

For example, Salmonella, Campylobacter, Shigella, and E. coli species work well with E. coli coliform bacteria as an indicator of potential contamination.

But this isn’t true for all of the aforementioned drinking water germs on the lists.

Viruses, like norovirus, sapovirus, rotavirus, and hepatitis viruses are much smaller than E. coli bacteria. And therefore can make it though the filtration process that E. coli bacteria cannot. So while the presence of E. coli could indicate these viral contaminations, the absence of E. coli bacteria doesn’t tell much.

This is also true for Cryptosporidium, Toxoplasma gondii and Cyclospora. But for a different reason. The oocytes formed with this parasite are quite hardy and survive sanitation conditions that E. coli coliforms will not. So the absence does not mean anything. However, the presence of coliforms may indicate a Toxoplasma gondii contamination.

Has Information on These WHO Drinking Water Germs Documents Made You Think Differently About Water Safety?

We take clean, safe drinking water for granted. For the most part, anyway. In general, we can count on our water to be free of harmful microbes and chemicals.

We have systems in place to process our water supply. As well as regulatory agencies tasked with monitoring that this all happens. Information, like that found in these WHO background documents are used for those purposes.

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If you’d like to know more about food safety topics in the news, like “WHO Publishes Documents on Drinking Water Germs,” check out the Make Food Safe Blog. We regularly update trending topics, foodborne infections in the news, recalls, and more! Stay tuned for quality information to help keep your family safe, while The Lange Law Firm, PLLC strives to Make Food Safe!

By: Heather Van Tassell (contributing writer, non-lawyer)