House Rat Louse

Polyplax spinulosa · Order: Psocodea · Family: Polyplacidae

Also called: Spiny rat louse, Sucking louse, spined rat louse

No source yet on danger. We have no source yet on whether it bites, stings or damages anything.
House Rat Louse
Photo: iNaturalist user, CC0

Polyplax spinulosa is a sucking louse in the genus Polyplax. It lives worldwide and commonly infests brown rats and many related rat species.

Source: Wikipedia

How to recognize it

Polyplax spinulosa belongs to the sucking louse group (Anoplura) and is in the genus Polyplax.

Source: Wikipedia

Where it lives

It is found worldwide on its main host, the brown rat (Rattus norvegicus), and also on other rat species such as the black rat and Bandicota indica.

Source: Wikipedia

Where it comes from

The species occurs worldwide.

Source: Wikipedia

Where it is found in the US

Recorded in 26 of 51 states and DC. Most records: Georgia, Texas, Iowa, Virginia, California, Mississippi, Florida, Ohio.

Darker = more records. Counts are museum and citizen-science records, not population size.

Source: GBIF

Status: native in North America; native in Canada. Source: iNaturalist

Months it is reported in the US

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Source: GBIF

Sources

  • Wikipedia: https://en.wikipedia.org/wiki/Polyplax_spinulosa

Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia

Text written 2026-10-27 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-27.

How this page works

This is one bug's fact sheet. The colored box at the top says whether it is dangerous. Sections below cover how to recognize it, whether it is a pest, and how to deal with it. The US map shows which states have records; tap a state to see other bugs there.

Every fact on Bug FAQ comes from a named source (university extension sites, government agencies, GBIF, iNaturalist, Wikipedia). The source is linked next to each section. If we have no source for something, we leave it out.