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What caused the Black Death?
1School of Biological Sciences, University of Liverpool, UK.
Postgraduate Medical Journal
|May 10, 2005
Summary
The Black Death and European plagues were likely viral hemorrhagic fevers, not bubonic plague. This ancient disease may have influenced the CCR5-Delta32 mutation frequency in Europeans.
Area of Science:
- Epidemiology
- Genetics
- History of Medicine
Background:
- Historically, European plagues from 1347-1670, including the Black Death, were attributed to *Yersinia pestis* (bubonic plague).
- This long-held belief is challenged by new interpretations of historical disease patterns and genetic evidence.
Observation:
- The disease presented with a prolonged incubation period of 32 days, facilitating widespread transmission via medieval transport.
- Evidence suggests the pathogen originated in Ethiopia as a viral hemorrhagic fever before impacting Eurasian civilizations.
Findings:
- The CCR5-Delta32 genetic mutation, offering HIV-1 protection, is proposed to have originated before 1000 BC.
- Epidemics of hemorrhagic plague are hypothesized to have gradually increased the CCR5-Delta32 allele frequency, reaching 5 x 10(-5) by the Black Death.
Implications:
- Reclassifying these historical epidemics as viral hemorrhagic fevers necessitates a re-evaluation of their origins and spread.
- The selective pressure of hemorrhagic plague epidemics likely shaped the current distribution of the CCR5-Delta32 mutation in European populations.
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