Polyplax spinulosa is a sucking louse (Anoplura) from the genus Polyplax. It occurs worldwide and commonly infects its type host, the brown rat (Rattus norvegicus), and related species like the black rat (Rattus rattus), Rattus pyctoris, Rattus nitidus, Rattus argentiventer, Rattus tanezumi, Rattus exulans, and Bandicota indica.[1] It is also occasionally found in other rodents, such as the marsh rice rat (Oryzomys palustris) in North America.[2]