urban vs rural Old World hantaviruses
Seoul virus vs Dobrava virus
| Feature | Seoul virus (SEOV) | Dobrava-Belgrade virus (DOBV) |
|---|---|---|
| Syndrome | HFRS (mild–moderate) | HFRS (severe) |
| Reservoir | Brown rat (Rattus norvegicus), black rat (Rattus rattus) | Yellow-necked mouse (Apodemus flavicollis); striped field mouse for related lineages |
| Geography | Worldwide — wherever Rattus is present (notably East Asia, Europe, Americas) | Balkans, Central and Eastern Europe, parts of Russia |
| CFR | ≈ 1–2% | ≈ 10–15% |
| Setting | Urban, port, pet-rat owners, laboratory workers | Rural forest and forest-edge |
| Notable outbreaks | 2017–2018 US/Canada pet-rat cluster | Ongoing endemic transmission in Slovenia, Croatia, Bosnia |
Seoul virus (SEOV) and Dobrava-Belgrade virus (DOBV) sit at opposite ends of the Old World hantavirus severity spectrum — and at opposite ends of the urban-rural axis.
SEOV is the worldwide urban hantavirus. Its reservoir is the brown rat (Rattus norvegicus) and its black-rat congener, which means SEOV travels with global commerce. It has been documented in port cities on every inhabited continent and is the single hantavirus most likely to circulate in temperate North America without anyone noticing. SEOV-HFRS is typically a mild-to-moderate illness with CFR of 1–2%, and is increasingly recognised in pet-rat owners and laboratory workers — the 2017–2018 US/Canada outbreak in pet-rat networks confirmed active human transmission via this route.
DOBV is the severe Balkan hantavirus. Its reservoir is the yellow-necked mouse (Apodemus flavicollis), a forest species, and its endemic range covers Slovenia, Croatia, Bosnia, Serbia, Montenegro, Albania, Greece, and parts of Bulgaria. DOBV-HFRS is clinically indistinguishable from severe Hantaan disease, with bleeding, shock, oliguric AKI requiring dialysis, and case-fatality of 10–15%.
Why the difference? Reservoir ecology. Rattus rodents live in close, sustained contact with humans, but the SEOV lineage has co-adapted to relatively limited pathology. Apodemus mice live in rural-forest settings; spillover to humans is less frequent but the viral lineage is more pathogenic. The clinical bottom line: in the Balkans, an HFRS suspicion requires aggressive supportive care and nephrology consult; in temperate cities, SEOV is more often a diagnostic afterthought — even though it is far more widely distributed.