Ricketts, Howard T

Ricketts, Howard T(aylor)

(born Feb. 9, 1871, Findlay, Ohio, U.S.—died May 3, 1910, Mexico City, Mex.) U.S. pathologist. He received his medical degree from Northwestern University. He discovered the bacterium (named rickettsia) that causes Rocky Mountain spotted fever and epidemic typhus. He demonstrated in 1906 that the former could be transmitted by the bite of a certain tick and identified a bacterium in the blood of infected animals, in the ticks, and in their eggs. He found that epidemic typhus in Mexico was transmitted by a louse and found a related bacterium in the victim's blood and in the lice. He transmitted the disease to monkeys, which developed immunity. He died of typhus later that year.