Historical Disease Trivia: The Milk Sickness

snakeroot75I’m reading Team of Rivals right now, a book about Lincoln’s presidency. In the section on Lincoln’s childhood, it mentioned his mother died of the “milk sickness,” which was apparently pretty common at that time.

What? The milk sickness? Was this some mysterious, old infectious disease I’d never heard of? I was hooked!

It turns out that no, it is not an infectious disease–although at the time, there was a lot of confusion about that. It occurs when someone is unlucky enough to drink dairy products or eat meat from cattle that have been eating white snakeroot, a plant that contains the poison tremetol. It causes trembling, vomiting, and severe nausea.

Apparently, when settlers from the Northeast started expanding to the south and west in the early 19th century, they weren’t familiar with a lot of the vegetation. They would let their cattle roam around the woods by their homes, not knowing that the white snakeroot they were eating was dangerous. Wikipedia says that this sickness claimed thousands of lives during this period, although I’m not sure how accurate that number is. There were reports that in some settlements, as many as half the people had died of this illness. In the epidemic that claimed Nancy Hanks Lincoln’s life, her great-aunt,  great-uncle, and two neighbors also died.

The story of how the cause of milk sickness was discovered is pretty interesting in its own right. As early as 1811, people had hypothesized that milk sickness was caused by tainted milk, and that the origin of the poison was probably something that cows had eaten.

Apparently the mystery of milk sickness was solved in southern Illinois in the early 1830s, when a female doctor named Anna Pierce Hobbs learned from an elderly Shawnee acquaintance that white snakeroot was responsible. Hobbs had become a doctor to minister to the needs of the pioneers she had grown up among, and at the time, she was the only health practitioner in southeastern Illinois. Personal tragedy sparked her interest in the disease. Milk sickness killed her mother and sister-in-law and almost took her father. After she learned that the cause was tainted milk, she pleaded with her neighbors to abstain from eating and drinking dairy products, and she initiated a successful snakeroot eradication campaign in the region.

However, despite her efforts, when she died in 1869, the medical establishment was still arguing about whether white snakeroot was the cause.  There was a prominent contingent of researchers who were convinced that the illness was caused by some sort of microbe. Reports from the frontlines by people like Hobbs and Shawnee medicine women were discounted. Finally, in 1928, chemists were able to isolate the compounds responsible for milk sickness from tainted milk and snakeroot, and the case was closed.

This is probably a good lesson for researchers today about not being able to let go of pet hypotheses and being willing to seriously consider research coming from unusual sources.