For the first time in 20 years, nine cases of locally acquired malaria have occurred this summer in the United States: seven in Florida, one in Texas, and one in Maryland. The feverish illness is caused by infection through the bites of mosquitoes carrying protozoan parasites.
The parasites were introduced to the Americas via colonization and the transatlantic slave trade and adapted to local mosquito species. "By 1850 malaria had become established in practically every settlement from New England westward to the Columbia River valley and from the southernmost part of Florida to the inland valleys of California," wrote the Tulane University parasitologist Ernest C. Faust in 1951. The U.S. Census Bureau reported that in 1850, malaria was responsible for 45.7 out of every 1,000 deaths nationally and 7.8 percent of deaths in the South.
