Increased recognition of Powassan encephalitis in the United States, 1999-2005.

Powassan virus (POWV) disease is a rare human disease caused by a tick-borne encephalitis group flavivirus maintained in a transmission cycle between Ixodes cookei and other ixodid ticks and small and medium-sized mammals. During 1958-1998, only 27 POWV disease cases (mostly Powassan encephalitis) were reported from eastern Canada and the northeastern United States (average, 0.7 cases per year).

Risk factors for infection during a dengue-1 outbreak in Maui, Hawaii, 2001.

Autochthonous dengue virus transmission, last identified in the state of Hawaii in 1945, was detected again in 2001. A seroepidemiological survey in a high-incidence community (Nahiku) and a nearby low-incidence community (Hana Subdivision) was implemented. The two communities studied differed in median household size (two vs.

Early season crow mortality as a sentinel for West Nile virus disease in humans, northeastern United States.

The 1999 New York epidemic of human West Nile virus (WN) encephalitis and meningitis was preceded by a crow die-off also caused by WN infection. As one component of the subsequently developed national surveillance system, crow mortality data were collected to detect WN activity before humans might become infected. However, predicting areas at risk for human WN disease likely requires assessment of multiple factors, including the intensity and timing of crow epizootics.