J.R. McNeill: Malarial Mosquitoes Helped Defeat British in Battle that Ended Revolutionary War
[McNeill is a Georgetown University professor of environmental history and author of many books, including "Mosquito Empires: Ecology and War in the Greater Caribbean, 1620-1914."]
Major combat operations in the American Revolution ended 229 years ago on Oct. 19, at Yorktown. For that we can thank the fortitude of American forces under George Washington, the siegecraft of French troops of Gen. Jean-Baptiste Donatien de Vimeur, the count of Rochambeau - and the relentless bloodthirstiness of female Anopheles quadrimaculatus mosquitoes.
Those tiny amazons conducted covert biological warfare against the British army. Female mosquitoes seek mammalian blood to provide the proteins they need to make eggs. No blood meal, no reproduction. It makes them bold and determined to bite.
Some anopheles mosquitoes carry the malaria parasite, which they can inject into human bloodstreams when taking their meals. In eastern North America, A. quadrimaculatus was the sole important malaria vector. It carried malaria from person to person, and susceptible humans carried it from mosquito to mosquito. In the 18th century, no one suspected that mosquitoes carried diseases.
Malaria, still one of the most deadly infectious diseases in the world, was a widespread scourge in North America until little more than a century ago. The only people resistant to it were either those of African descent - many of whom had inherited genetic traits that blocked malaria from doing its worst - or folks who had already been infected many times, acquiring resistance the hard way. In general, the more bouts you survive, the more resistant you are....
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Jon Kukla - 10/20/2010
When McNeill writes that
"The British army, commanded by Gen. Charles Cornwallis, consisted of lads from Britain and Germany. Very few had grown up with malaria. Most were highly susceptible. Cornwallis's army, although a superior fighting force, suffered from a malaria-resistance gap."
He may be understating the presence of endemic malaria - a world-wide disease - in many parts of Britain and Europe as far north as Sweden - its not just a tropical disease.
Indeed, we have at least one well- documented instance of the transmission of malaria FROM England INTO colonial Virginia : See “Kentish Agues and American Distempers: The Transmission of Malaria from England to Virginia in the Seventeenth Century,” Southern Studies 25 (Summer 1986): 135-147.