Seoul Virus (SEOV): The Global Hantavirus
Seoul virus is the only hantavirus found on every inhabited continent — carried by the cosmopolitan Norway rat (Rattus norvegicus). While causing much milder disease than Sin Nombre or Andes virus (under 1% mortality), Seoul virus creates unique exposure risks through pet rats, urban rat populations, and the global movement of its reservoir host.
🌍 Why Seoul Virus Is Everywhere
Most hantaviruses are geographically restricted because their rodent reservoirs are geographically restricted. Seoul virus breaks this pattern: its host, the Norway rat (Rattus norvegicus), has spread to every inhabited continent as a commensal species — following human trade routes, ships, and agriculture for thousands of years.
This makes Seoul virus the one hantavirus that can affect people anywhere in the world — including densely urban environments that no other hantavirus strain reaches. Documented Seoul virus infections have occurred in the US, UK, France, the Netherlands, Brazil, Japan, China, Korea, Australia, and many other countries.
Between 2017 and 2020, Seoul virus outbreaks linked to domestic rat breeding operations affected 14 US states and 2 UK clusters. Infected breeding animals were sold through pet networks and distributed nationwide. The 2017 US outbreak involved 31 confirmed cases across 11 states — all linked to a single multi-state rat breeding network.
🏥 Disease Profile: HFRS
Seoul virus causes Hemorrhagic Fever with Renal Syndrome (HFRS) — kidney disease, not lung disease. The clinical course:
- Febrile phase (days 1–3): Sudden high fever, headache, back pain, abdominal pain, nausea
- Hypotensive phase (days 3–6): Blood pressure may drop; hemorrhagic signs (petechiae, bleeding from injection sites) in more severe cases
- Oliguric phase (days 5–11): Reduced urine output; acute kidney injury; risk of fluid overload
- Polyuric phase (days 11–21): Urine output returns; risk of dehydration and electrolyte imbalance
- Recovery phase: Kidney function gradually normalizes over weeks to months
Most Seoul virus HFRS is mild — many patients only notice the febrile phase. Severe acute kidney failure requiring dialysis occurs in a minority. Long-term kidney damage from Seoul virus HFRS is rare but documented in some cases with severe oliguric phase.
Seoul Virus FAQ
Can I get Seoul virus from pet rats?
Yes — this is the primary Seoul virus risk in Western countries. Multiple US and UK outbreaks between 2012 and 2020 were traced to domestically bred rats sold through pet stores and breeding networks. Infected rats appear completely healthy. If you own rats or breed them, have your animals tested if you experience unexplained fever and kidney pain. Use gloves when cleaning cages and handling animals. Alert your veterinarian if animals in your network have tested positive.
Is Seoul virus dangerous?
Seoul virus causes HFRS (kidney disease), not HPS (lung disease). Most cases resolve without intensive care, and the case fatality rate is under 1%. However, severe cases can cause acute kidney failure requiring dialysis during the oliguric phase. Pregnant women are at higher risk of serious complications. The disease is much less severe than Sin Nombre or Andes HPS — but it is still a real illness requiring medical attention.
Can I catch Seoul virus from wild rats in my city?
Yes, theoretically. Wild Norway rats in many cities carry Seoul virus, and exposure to their droppings or urine in a home or workplace carries infection risk. However, documented urban Seoul virus cases from wild rat exposure are rare in Western countries — most cases involve direct rat contact (pet store workers, sewer workers) rather than passive environmental exposure. Standard rodent-proofing and cleanup precautions protect against Seoul virus exactly as they do against other hantaviruses.
How is Seoul virus different from other hantaviruses?
Seoul virus is unique in two ways: (1) Its reservoir, the Norway rat, has achieved global distribution through human commerce — making Seoul virus the only hantavirus found on every inhabited continent including urban environments. (2) It causes HFRS (kidney disease) with very low mortality, unlike the high-mortality HPS caused by Sin Nombre and Andes virus. Seoul virus is also distinctive in that exposure can occur in any country of the world, not just specific endemic regions.