An Assessment for the Presence of Powassan Virus in Ixodes scapularis Nymphs from Locations in Virginia, Maryland, New Jersey, Pennsylvania, New York, and Connecticut

Abstract : Powassan virus (POWV) is a naturally occurring tick-borne flavivirus in North America that can cause severe encephalitic illness and death in humans. Cases of the disease have increased significantly over the last 10 years. Many of these cases have been attributed to deer tick virus (DTV), a distinct genotype of POWV. Deer tick virus is transmitted by Ixodes scapularis (Say 1821), an aggressive tick that readily bites humans. This study collected I. scapularis from sites along the U.S. East Coast, including locations south of where DTV has been previously reported in ticks. The collected ticks were individually homogenized with a portion of each homogenate pooled into groups of 10 by collection site. A reverse transcriptase polymerase chain reaction (RT-PCR) was conducted to amplify portions of the DTV ns-5 gene for the purpose of detecting the presence of the DTV virus. Nine of the studys 11 sites, including the two most southern sites in Virginia, contained ticks infected with DTV. New state records for the presence of DTV in I. scapularis are reported for New Jersey, Pennsylvania, Maryland, and Virginia. The results of this study indicate that DTV is circulating in ticks far south of what has previously been documented.