How woolly clothes helped a deadly disease spread

Have you ever thought about how your clothes could affect your health? It turns out, what people wore thousands of years ago actually helped a dangerous disease take hold among humans. Let’s journey back in time and see how woolly fashion became a cozy invitation for body lice and a deadly infection!

The surprising link between wool and disease

Long ago, humans started domesticating sheep in the Middle East and soon discovered the comfort of wool clothing. Wool kept people warm, but it also gave body lice (tiny insects that live on humans) the perfect place to lay their eggs. As people across Europe and Asia began wearing more wool, these lice found it easier to travel from person to person. Scientists recently uncovered that this change in clothing habits may have opened the door for a nasty bacterium called Borrelia recurrentis, which causes louse-borne relapsing fever (LBRF), to spread widely (read the original study).

What is louse-borne relapsing fever?

Louse-borne relapsing fever is a serious disease that causes high fevers that come and go in cycles, making people very sick. It’s spread by body lice, which pick up the Borrelia recurrentis bacterium from one person and pass it to another when they feed on blood. Today, this disease is mostly found in places where people live in crowded and tough conditions, like parts of Ethiopia, Somalia, and Sudan. Sadly, if not treated with antibiotics, up to 40% of people with LBRF can die from it, making it a very dangerous illness.

How scientists solved the ancient disease mystery

Researchers wanted to know when and how this germ first started infecting humans. They carefully studied ancient human DNA from skeletons found in Britain, looking for traces of old infections. In their search, they found four people who had B. recurrentis infections between 2,300 and 600 years ago. By sequencing these ancient germs and comparing them to both a medieval case from Norway and modern bacteria, the team discovered that B. recurrentis split from a less deadly tick-borne cousin, Borrelia duttonii, about 4,000 to 6,000 years ago—right when wool clothing was spreading (full scientific details here).

Why your wardrobe mattered in ancient times

This story shows that big changes in what people wear can have surprising effects on health. In this case, the spread of wool clothing made it easier for body lice to thrive, which then allowed the louse-borne fever to emerge. It’s a great reminder that even inventions meant to help us, like warm clothes, can sometimes have hidden side effects!

If you’ve ever wondered why people sometimes avoid certain foods or crave others, you might enjoy this SlothMD article about why we crave sugar. Our choices—whether in food or fashion—can shape our health in unexpected ways.

What it means for patients today

Luckily, we have antibiotics now that can cure most cases of louse-borne relapsing fever. But the disease still appears in places where people do not have easy access to medical care or where living conditions are very crowded. Health experts hope that by understanding how diseases like LBRF emerged, we can be more prepared in the future and prevent new infections from spreading.

In fact, new health AI tools, like those being developed for platforms such as SlothMD, help researchers and doctors track how diseases spread and where outbreaks might happen.

Fashion, germs, and the future of health

It’s fascinating to realize how something as simple as wearing wool could shape the history of disease! This research also shows why it’s important to study the past: by understanding how germs jumped from animals or insects to humans, we can better protect ourselves today. If you’re curious about how your own health habits (like eating or even avoiding certain foods) are shaped by biology and environment, check out this SlothMD article on why we hate certain foods for more fun science.

The next time you put on a sweater, remember: history and health are woven together in ways you might never have guessed!