Posted by: Patrick Allen Foster | April 13, 2014

The 1815 Volcanic Eruption That Led to a New Cholera Strain

1815 tambora explosion B

Mount Tambora is a stratovolcano on the island of Sumbawa, in the south-central part of the archipelago of mordern Indonesia. The 1815 eruption of Tambora was possibly the most powerful volcanic eruption in recorded history. Some 100,000 people died in the immediate neighborhood of the volcano, but the effects of the thick ash that the eruption hurled into the atmosphere had more widespread and long-lasting consequences. Indeed, the ripple effects were global in scale.

In anticipation of the 200th anniversary of the event, Gillen D’Arcy Wood (Prof. of English, Univ. of Illinois Urbana-Champaign) has an excellent post looking at the cascading effects of the eruption. An excerpt (emphasis added):

… With the help of modern scientific instruments and old-fashioned archival detective work, the Tambora 1815 eruption can be conclusively placed among the greatest environmental disasters ever to befall mankind. The floods, droughts, starvation, and disease in the three years following the eruption stem from the volcano’s effects on weather systems, so Tambora stands today as a harrowing case study of what the human costs and global reach might be from runaway climate change.

Tambora’s greatest claim to infamy lies not in the impact it had on what was then the Dutch East Indies (which were terrible enough), but its indirect effects on the disease ecology of the Bay of Bengal. The enormous cloud of sulfate gases Tambora ejected into the atmosphere slowed the development of the Indian monsoon, the world’s largest weather system, for the following two years.

Drought brought on by the eruption devastated crop yields across the Indian sub-continent, but more disastrously gave rise to a new and deadly strain of cholera. Cholera had always been endemic to Bengal, but the bizarre weather of 1816-17 triggered by Tambora’s eruption – first drought, then late, unseasonal flooding – altered the microbial ecology of the Bay of Bengal. The cholera bacterium, which has an unusually adaptive genetic structure highly sensitive to changes in its aquatic environment, mutated into a new strain. This met with no resistance among the local population, and it spread across Asia and eventually the globe. By century’s end, the death toll from Bengal cholera stood in the tens of millions.

Just as the biological disaster known as the Black Death defined the 14th century in Europe and the Near East, so cholera shaped the nineteenth century like no other calamity. Much of our medical science, and our modern public health institutions, originate in the Victorian-era battle against cholera.

Interesting read.

Image Credit: Map showing the thickness of volcanic ashfall (red areas) from the 1815 Mount Tambora eruption. Source: Wikimedia Commons.


  1. interesting!

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