雅思阅读 091: The Oldest Plague — Siberian Hunter-Gatherers, 5,500 Years Ago

Adapted from "Could this ancient burial site be the oldest lethal plague outbreak?" by Jackie Flynn Mogensen, Scientific American, 17 June 2026.

Reading Passage

Plague has terrified humans for thousands of years. In the 1300s the Black Death killed as much as half the population of Europe. Around 540 CE, the Justinian plague weakened the Roman Empire. But when and where plague first arose has long been a mystery.

Now a study published in Nature claims to have identified the earliest known lethal plague outbreak — in hunter-gatherer communities near Lake Baikal in Siberia, some 5,500 years ago.

The research team analysed human remains from cemeteries dating to the mid-Holocene, about 7,000 to 5,000 years ago. Genetic tests revealed that many individuals were infected with Yersinia pestis, the bacterium that causes plague. Multiple members of the same family were infected, suggesting the disease spread from person to person. Children aged eight to eleven were particularly likely to die.

"This is the first direct evidence of mass lethality and outbreaks of plague in prehistoric hunter-gatherer societies," says lead author Ruairidh Macleod of the University of Oxford.

The finding overturns an assumption: plague was thought to require dense, settled farming populations to spread. The Siberian communities were small, mobile groups of hunter-gatherers. Yet plague still caused severe, clustered deaths.

Y. pestis had been found in ancient farming communities before, but no one knew how deadly the oldest strains were. The new study shows they were already lethal.

The researchers also examined how the bacterium spread. The infamous Black Death strain carried a mutation that allowed it to live in fleas, which then jumped to humans via rats. But samples older than 3,800 years lack that mutation. The Siberian plague was therefore probably not spread by fleas. The team hypothesises the bacterium may have jumped to humans from marmots — a type of ground squirrel whose remains were also found at the burial sites.

Today, Y. pestis is far less deadly thanks to antibiotics and genetic changes in the bacterium itself. Yet it still survives in wild animal reservoirs and can spill over into people.

"Understanding how plague moved between animals, landscapes and people in the past helps us assess zoonotic risk today," says Roman Wölfel of the Bundeswehr Institute of Microbiology. "Plague is often treated as a disease of the past, but its evolutionary history remains relevant to public health."

Questions 1–5

Choose the correct letter, A, B, C or D.

1. The oldest known lethal plague outbreak occurred about

   • A. 500 years ago.
   • B. 1,500 years ago.
   • C. 5,500 years ago.
   • D. 10,000 years ago.

2. Where were the graves found?

   • A. Near Lake Baikal in Siberia
   • B. In the Roman Forum
   • C. In medieval London
   • D. In the Egyptian desert

3. Who was most likely to die from the Siberian plague?

   • A. Elderly men
   • B. Children aged 8 to 11
   • C. Newborn babies
   • D. Women in their thirties

4. Why wasn't the Siberian plague spread by fleas?

   • A. Fleas had not yet evolved.
   • B. The strain lacked the flea-colonising mutation.
   • C. There were no rats in Siberia.
   • D. The climate was too cold.

5. The bacterium may have jumped to humans from

   • A. cattle.
   • B. marmots.
   • C. mosquitoes.
   • D. birds.

Questions 6–10

Do the following statements agree with the information?

Write:

• TRUE
• FALSE
• NOT GIVEN

6. The Black Death killed about half of Europe's population in the 1300s.
7. The Siberian communities were large farming villages.
8. The plague spread between family members.
9. Modern Y. pestis is more deadly than ancient strains.
10. Antibiotics have helped reduce plague deaths.

Questions 11–13

Complete the summary. Choose ONE WORD ONLY.

The research overturns the assumption that plague needed dense 11 populations. The Siberian communities were small 12 groups. Today the bacterium survives in wild animal 13 and can still infect people.

Answers

1. C — "some 5,500 years ago."
2. A — "near Lake Baikal in what is now Siberia."
3. B — "Children between the ages of eight and eleven were particularly likely to die."
4. B — "samples older than about 3,800 years don't have that mutation."
5. B — "jumped to humans from marmots."
6. TRUE — "killing as many as half of all the people in Europe."
7. FALSE — They were small hunter-gatherer groups.
8. TRUE — "many members of the same family were infected."
9. FALSE — Modern plague is far less deadly.
10. TRUE — "thanks to antibiotics."
11. urban / farming
12. hunter-gatherer
13. reservoirs

Key Vocabulary