Prevalence and distribution of Powassan/deer tick virus in Pennsylvania

Powassan/deer tick virus (POWV/DTV), a tick-borne flavivirus, is emerging in the United States. However, little work has assessed spatial distribution and infection prevalence and density of infected vector ticks in Pennsylvania (PA). Therefore, we conducted active surveillance for Ixodes scapularis in every PA county and screened for pathogen presence by real-time RT-PCR. A total of 1,672 pools were assayed for 5,588 adult I. scapularis collected. We detected POWV/ DTV in three counties. Minimum infection rates (MIRs) ranged between 1.01 and 1.47%. Mean statewide MIR was 0.06% +/- 0.28%, well below infection estimates from more northern studies, suggesting a relatively more recent emergence of POWV/ DTV in PA. These data should help efforts to raise awareness among regional public health practitioners of POWV/DTV prevalence and distribution.

Automated summary

This study conducted active surveillance for Ixodes scapularis in every Pennsylvania county and found POWV/DTV presence in three counties. The statewide mean infection rate was relatively low, indicating a more recent emergence of the virus in the region.