Flying Squirrel–associated Typhus, United States

T fever from Rickettsia prowazekii infection is a severe and occasionally fatal disease in humans. Frequently referred to as epidemic typhus or louse-borne typhus, this disease can cause large epidemics when conditions are favorable for person-to-person spread of body lice (Pediculus humanus humanus). For the last few decades, reported outbreaks have been confined mainly to the cold mountainous regions of Africa and South America and have disproportionately affected impoverished and displaced communities (1). Infections with R. prowazekii are rarely described in the United States. From 1976 to 2001, a total of 39 human R. prowazekii infections were documented in persons with no reported contact with body lice or persons with lice (2–5). Nearly all of these cases were in the eastern United States, and in approximately one third of cases, contact with flying squirrels (Glaucomys spp.) or with flying squirrel nests occurred before disease onset. Flying squirrels are the only known vertebrate reservoir of R. prowazekii, other than humans, and contact with these animals has been linked to most sporadic typhus cases in the United States. Interest in this disease was high in the 10 years after the first isolation of R. prowazekii from flying squirrels (6,7), but few cases have been reported since 1985. We describe two cases of flying squirrel–associated typhus that occurred in West Virginia and Georgia in 2002 and provide a contemporary summary of this disease in the United States. Case Reports