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Volume 32, Number 9—September 2026
Research Letter
Powassan Virus in Ixodes scapularis Tick Populations, Illinois, USA, 2025
Figure 2

Figure 2. Maximum-likelihood phylogenetic tree of Powassan 3′ untranslated region created for study of Powassan virus in Ixodes scapularis tick populations, Illinois, USA, 2025. Branch lengths estimated using Hasegawa-Kishino-Yano substitution model with a gamma-distributed rate variation across 4 site categories. Bootstrap values >80% (1,000 replicates) are shown. Orange squares indicate samples from this study, clustering within lineage II together with samples previously detected in Wisconsin, USA. CAN, Canada; RUS, Russia.
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