Presence of Raccoon Roundworm (Baylisascaris procyonis) in Habitat Associated with Allegheny Woodrats (Neotoma magister) in Western Virginia, USA, 2022-24.

Baylisascaris procyonis is a roundworm that does not affect its definitive host, raccoons (Procyon lotor), but may have a devastating effect when ingested by paratenic hosts such as Allegheny woodrats (Neotoma magister). Despite being considered a major factor in woodrat population extirpation and decline in states northward, there have been no large-scale surveys for raccoon roundworm in Virginia, US. From 2022 to 2024, we visited 60 karst or nonkarst rocky habitats known (current or historical) or suspected to be Allegheny woodrat locations in western Virginia. We opportunistically collected raccoon feces as individual piles or subsampled from visible latrines. We used fecal flotation to determine the presence and prevalence of raccoon roundworm eggs in samples collected from 44 sites across 15 counties and 1 independent city. We found evidence of this roundworm at eight (18.2%) sites in six counties. Because woodrats are especially vulnerable to fatal larval infections with B. procyonis, the presence of the parasite at multiple sites suggests conservation measures should be implemented to protect these populations.