1: MMWR Morb Mortal Wkly Rep. 2001 Sep 7;50(35):761-4. Related
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Outbreak of Powassan encephalitis--Maine and Vermont, 1999-2001.

Centers for Disease Control and Prevention (CDC).

Powassan (POW) virus, a North American tickborne flavivirus related to
the Eastern Hemisphere's tickborne encephalitis viruses, was first
isolated from a patient with encephalitis in 1958. During 1958-1998, 27
human POW encephalitis cases were reported from Canada and the
northeastern United States. During September 1999-July 2001, four Maine
and Vermont residents with encephalitis were found to be infected with
POW virus. These persons were tested for other arbovirus infections
found in the northeast after testing for West Nile virus (WNV)
infection was negative. This report describes these four cases,
summarizes the results of ecologic investigations, and discusses a
potential association between ticks that infest medium-sized mammals
and the risk for human exposure to POW virus. The findings underscore
the need for personal protective measures to prevent tick bites and
continued encephalitis surveillance.

Publication Types:
Case Reports

PMID: 11787585 [PubMed - indexed for MEDLINE]