"Beginning in the summer of 1830, and recurring each summer for several years thereafter, the lower and Willamette River valleys were visited by yet another "new" disease, called "fever and ague" (by the Americans) or "intermittent fever" (by the British). Although there has been some controversy over the identity of this disease, current consensus favors malaria ... Cumulatively, the "fever and ague" epidemics had a devastating impact on the and n peoples of the area. From a total population something under the 15,545 estimated by and the in the early decades of the 1800s, numbers for these two groups dropped to around 1,932 by 1841, a decline of 88% ..."