Which geographic distribution describes Seoul virus?

• A. North America only
• B. Worldwide
• C. Europe only
• D. Asia only

Answer: (B)

Seoul virus has a worldwide distribution because its reservoir is the brown rat (Rattus norvegicus), a species that thrives in human environments across the globe. Wherever these rats are found, the virus can be present, and human exposure can occur. Infections and seroprevalence have been documented on multiple continents, including Asia, Europe, and North America, reflecting the rat’s global range. If a virus relies on a cosmopolitan host, it isn’t confined to a single region, which is why the correct understanding here is that Seoul virus is worldwide.