<p>The characteristics of HFRS cases by clusters.</p>

Previous studies have identified three distinct clusters of HFRS epidemic in Jiangxi Province, characterized by geographical separation and heterogeneous incidence levels. We hypothesized that clinical severity and healthcare-seeking behaviors may vary across these clusters, and thus conducted a retrospective study to examine this hypothesis.</p> <p>Methods</p><p>We retrospectively analyzed 4,614 HFRS cases (13-year period) from 63 counties.

Cases were classified into four areas based on prior spatial study, representing distinct hilly and plain regions with different proximity to major water bodies and mountains. Data on HFRS cases were collected by county-level CDC staff using a nationally standardized case investigation questionnaire. Clinical severity and healthcare-seeking behaviors (hospital level, onset-to-visit interval) were compared.</p> <p>Results</p><p>HFRS cases in Cluster I exhibited the highest clinical severity (22.41% severe, 6.65% critical), while cases in Cluster II were strikingly mild (2.62% severe, 1.31% critical).