The milk here has been poisoning people for more than 100 years, and the root cause is still unknown

When you arrive in a new place, your safety will be closely related to your understanding of the local ecology.

Next time you drink milk, you might think of this story. It first appeared in the United States more than 200 years ago. At that time, people had no systematic research methods for some sudden diseases and were deeply afraid of them.

Image source: Pixabay

Milk poisoning

In the early 19th century, when some settlers expanded to the Midwestern frontier of the United States with their cattle, a strange disease began to appear among them. Based on the symptoms of the disease, they called it "sluggishness", "staggering" and "trembling disease". As they discovered the possible cause of the disease - the patients had drunk milk, they changed the name to "milk sickness" . However, it took a long time to figure out why drinking milk would cause this disease.

The progression of milk poisoning was horrific. Within days, a healthy person would be bedridden with vomiting and gastrointestinal symptoms, often followed by coma, and then death. Daniel Drake, a doctor in Cincinnati (Ohio), thought the symptoms were tricky and confusing— the patient started with "general weakness and malaise" that seemed to get worse in a very slow way.

Image source: Pixabay

The mortality rate of this disease is very high, and it usually strikes after the summer season with little rain. In some counties in some Midwestern states of the United States, "milk poisoning" even became the main cause of death. In some settlements, half of the people may die from milk poisoning. Doctors at the time would use bloodletting therapy, which obviously did not help. The settlers at the time believed that the emergence of this disease was due to some kind of curse in the area. In order to avoid this disease, they abandoned parts of the Wabash River Valley in Indiana and Illinois. Kentucky, which borders these two states, once offered a reward of $2,000 (equivalent to nearly $70,000 today) to encourage people to find the cause of the disease.

People were as afraid of milk poisoning as they were of infectious diseases such as cholera and yellow fever. It was not until 30 years later that Anna Hobbs, a careful midwife in Hardin County, Illinois, first discovered the cause of milk poisoning.

Young midwife

Anna Hobbs grew up under the shadow of this disease. After completing her medical training, she returned to Hardin County where she was born and became the only doctor there. Her family was also very unfortunate. Her mother and sister-in-law died of milk poisoning. Therefore, she wanted to uncover the cause of this disease. She realized that the reason why milk was poisonous might be related to the plants that cows eat.

Then, she began to observe carefully based on this clue and record the various plants eaten by cattle. It is said that during this period, she met the local indigenous people, an elderly Shawnee woman. This woman had a clear understanding of local herbs and plants. After hearing about milk poisoning, she took Hobbes to a plant with clusters of white flowers, saying that people's deaths might be related to this plant.

The plant, white snakeroot , is a perennial shrub that can grow to more than a meter tall and has flat-topped clusters of small white flowers at the ends of its branches. The plant is common in the area, especially in the areas near the Ohio River and its tributaries where the settlers first settled . The settlers often grazed in areas where white snakeroot grew, and they were not familiar with the plant and its properties because it was not native to the East Coast.

White snake root, scientifically known as Ageratina altissima, is a poisonous plant that causes milk poisoning.

When Hobbes fed the plant to cows, she found that they developed symptoms similar to milk poisoning a few days later. Based on this, she believed that the toxins in the plant entered the cow's entire body, such as in the secreted milk . As the milk was consumed by humans, the toxins entered the human body and began to poison humans. The spread of this disease is also related to the scarcity of pastures or drought due to the lack of rain in the summer. In fact, cows will not eat this plant unless there is no other food.

As Hobbes told the public about this, they began to actively eradicate the plant and eventually got rid of the disease. However, since scientific papers could not be published at the time, this discovery was not widely disseminated. In some other areas, settlers still became sick and even died.

As the 20th century began, milk poisoning became less common, in large part because of the new industrialization of agriculture, which led to safer, standardized methods of feeding cows and processing milk . Today, the disease has almost disappeared.

Mysterious toxin

Fifty years after Hobbes' death, the truth about milk poisoning began to be widely revealed. In 1927, JF Couch, a researcher at the US Department of Agriculture, first isolated a straw-colored oil, Tremetol , from white snakeroot and another similar plant, Isocoma pluriflora. Tremetol is a mixture of complex sterols and methyl ketone benzofuran derivatives. Scientists have now identified 11 compounds from it.

Trimethoprime affects the muscles, causing them to degenerate, but the biggest harm is undoubtedly the heart muscles . This can lead to heart irregularities, abnormalities in the cardiac conduction system, and ultimately death. Over time, trimethoprime accumulates in the body, and signs of poisoning begin to appear in 1-3 weeks when 0.5%-1.5% of the animal's body weight has been consumed (the toxin destroys the muscles, causing weight loss).

Four benzofuranone compounds in white snakeroot and goldenrod, picture from the paper

Previously, many studies have shown that the toxic substances in white snake root are benzofuran ketones. However, in recent years, some scientists have discovered that there may be a new toxic substance through experiments in sheep . They extracted benzofuran ketones from white snake root and soaked other plants that cattle and sheep often eat in this type of compound. Then they used these grasses to feed sheep. Unexpectedly, the sheep did not show obvious signs of poisoning after eating.

They also fed the white snake root residue after extracting benzofuranones to sheep, and the sheep showed no signs of poisoning. This also made them begin to suspect that there was another chemical that caused the sheep poisoning, but it was lost in the process of extracting benzofuranones. In 2015, some researchers also extracted tromethamine and other benzofuranones and fed tromethamine and benzofuranone to goats at similar concentrations as in the original white snake root, but the goats were not poisoned. This discovery also confirmed the existence of other unknown toxic substances.

With the development of compound analysis technology, I believe this mystery may be solved soon.

References

[1]https://www.smithsonianmag.com/innovation/how-1800s-midwife-solved-poisionous-mystery-180982343/

[2]https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/tremetone

[3]https://carnegiemnh.org/poisons-carnegie-white-snakeroot/

[4]https://www.ars.usda.gov/ARSUserFiles/oc/np/PoisonousPlants/Fall2017/snakeroot.pdf

Planning and production

Source: Global Science

Written by | clefable Editor | Yang Yaping