No. 45: May-Jun 1986
Every year a few people in the Arizona New Mexico region contract bubonic plague. Where did this persistent pocket of infection come from? One school of thought has the germ arriving with the rats on ships docking in California during the Gold Rush of 1849. But how could the plague have crossed the mountains and across several radically different ecosystems? One would anticipate finding records of the plague as it made its way into the Southwest. It is true that a less virulent disease, the sylvatic plague, transmitted by similar mechanisms, does exist in the Pacific Coast area; but the bubonic plague does seem highly localized in Arizona and New Mexico.
Perhaps another explanation can be discovered in the history of the bubonic plague and the settlement of the Southwest. The plague seems to have commenced in Athens about 430 BC. More or less isolated epidemics followed, but from 1334 to 1351 the disease decimated most of the known world: Europe, Asia, and North Africa. Of course, the American Southwest was not part of the "known world" of 1334-1351. But, coincidentally (?),this was just about the time that the Hohokam and Anasazi cultures began to decline rapidly in the Southwest. Link this observation to the purported Roman and Hebrew artifacts in the region (SF#43), and one sees the possibility that Old World travellers brought the bubonic plague to the New World well before Columbus landed!
(Underwood, L. Lyle; "Bubonic Plague in the Southwest," Epigraphic Society, Occasional Publications, 14:207, 1985.)