Enlarge / A child cools off under a water sprinkler. (credit: Getty | JASON SOUTH)

In 1989, a city in Utah upgraded its drinking water system, putting in a whole new system and repurposing the old one to supply cheap untreated water for irrigating lawns and putting out fires. That meant that the treated water suitable for drinking flowed from new spigots, while untreated water gushed from the old ones. Decades went by with no apparent confusion; residents seemed clear on the two different water sources. But, according to an investigation report published recently by state and county health officials, that local knowledge got diluted as new residents moved into the area. And last summer, the confusion over the conduits led to an outbreak of life-threatening illnesses among children.

In July and August of 2023, state and local health officials identified 13 children infected with Shiga toxin-producing Escherichia coli (STEC) O157:H7. The children ranged in age from 1 to 15, with a median age of 4. Children are generally at high risk of severe infections with this pathogen, along with older people and those with compromised immune systems. Of the 13 infected children, seven were hospitalized and two developed hemolytic uremic syndrome, a life-threatening complication that can lead to kidney failure.

Preliminary genetic analyses of STEC O157:H7 from two of the children suggested that the children's infections were linked to a common source. So, health officials quickly developed a questionnaire to narrow down the potential source. It soon became clear that the irrigation water—aka untreated, pressurized, municipal irrigation water (UPMIW)—was a commonality among the children. Twelve of 13 infected children reported exposure to it in some form: Two said they drank it; five played with UPMIW hoses; three used the water for inflatable water toys; two used it for a water table; and one ran through sprinklers. None reported eating fruits or vegetables from home (noncommercial) gardens irrigated with the UPMIW.

Enlarge / A glass of fresh raw milk in the hand of a farmer. (credit: Getty | Pierre Crom)

To drink raw milk at any time is to flirt with dangerous germs. But, amid an unprecedented outbreak of H5N1 bird flu in US dairy cows, the risks have ratcheted up considerably. Health experts have stepped up warnings against drinking raw milk during the outbreak, the scope of which is still unknown.

Yet, raw milk enthusiasts are undaunted by the heightened risk. The California-based Raw Milk Institute called the warnings "clearly fearmongering." The institute's founder, Mark McAfee, told the Los Angeles Times this weekend that his customers are, in fact, specifically requesting raw milk from H5N1-infected cows. According to McAfee, his customers believe, without evidence, that directly drinking high levels of the avian influenza virus will give them immunity to the deadly pathogen.

Expert Michael Payne told the LA Times that the idea amounts to "playing Russian roulette with your health." Payne, a researcher and dairy outreach coordinator at the Western Institute for Food Safety and Security at UC Davis, added, "Deliberately trying to infect yourself with a known pathogen flies in the face of all medical knowledge and common sense."

Enlarge / Holstein dairy cows in a freestall barn. (credit: Getty | )

The US Department of Agriculture this week posted an unpublished version of its genetic analysis into the spillover and spread of bird flu into US dairy cattle, offering the most complete look yet at the data state and federal investigators have amassed in the unexpected and worrisome outbreak—and what it might mean.

The preprint analysis provides several significant insights into the outbreak—from when it may have actually started, just how much transmission we're missing, stunning unknowns about the only human infection linked to the outbreak, and how much the virus continues to evolve in cows. The information is critical as flu experts fear the outbreak is heightening the ever-present risk that this wily flu virus will evolve to spread among humans and spark a pandemic.

But, the information hasn't been easy to come by. Since March 25—when the USDA confirmed for the first time that a herd of US dairy cows had contracted the highly pathogenic avian influenza H5N1 virus—the agency has garnered international criticism for not sharing data quickly or completely. On April 21, the agency dumped over 200 genetic sequences into public databases amid pressure from outside experts. However, many of those sequences lack descriptive metadata, which normally contains basic and key bits of information, like when and where the viral sample was taken. Outside experts don't have that crucial information, making independent analyses frustratingly limited. Thus, the new USDA analysis—which presumably includes that data—offers the best yet glimpse of the complete information on the outbreak.

Enlarge / A dog gets examined by veterinary technicians in Texas. (credit: Getty | Michael Paulsen)

Two separately owned dogs in New Jersey tested positive last year for a dreaded, extensively drug resistant bacterial strain spread in the US by contaminated artificial eye drops manufactured in India. Those drops caused a deadly multi-state outbreak in humans over many months last year, with at least 81 people ultimately infected across 18 states. Fourteen people lost their vision, an additional four had eyeballs surgically removed, and four people died.

The preliminary data on the dogs—presented recently at a conference of disease detectives hosted by the Centers for Disease Control and Prevention—highlights that now that the deadly outbreak strain has been introduced around the US, it has the potential to lurk in unexpected places, spread its drug resistance to fellow bacteria, and cause new infections in people and animals who may have never used the drops.

The two dogs in New Jersey were not known to have received the drops linked to the outbreak: EzriCare Artificial Tears and two additional products made by the same manufacturer, which were recalled in February 2023. Such over-the-counter products are sometimes used in animals as well as people. But the dogs' separate owners said they didn't recall using the drops either. They also didn't report any exposures in health care settings or recent international travel that could explain the infections. One of the dogs did, at one point, receive eye drops, but they were not an outbreak-associated brand. The only connection between the two dogs was that they were both treated at the same veterinary hospital, which didn't stock the outbreak-associated eyedrops.