Comparison of Hantaan and Seoul viral infections among patients with hemorrhagic fever with renal syndrome (HFRS) in Heilongjiang, China

BACKGROUND: Hemorrhagic fever with renal syndrome (HFRS) is a serious public health problem in China, and is primarily caused by either the Hantaan virus (HTNV) or Seoul virus (SEOV) strains. However, the causative hantavirus has only been definitively identified in a few HFRS cases, and detailed comparisons of patient data for the 2 strains are limited. METHODS: We conducted a 1-y prospective study in Heilongjiang Province, China. A total of 152 patients from 3 hospitals met the HFRS diagnostic criteria used in China. The diagnosis was further confirmed by specific immunoglobulin M to HTNV or SEOV. In addition, serum samples were tested for the presence of HTNV or SEOV using a reverse transcription-polymerase chain reaction (RT-PCR). Clinical manifestations and laboratory findings in patients with the 2 hantaviruses were subsequently compared. RESULTS: Eighty (61.1%) HTNV and 51 (38.9%) SEOV infections were identified. Fever and proteinuria, key to the diagnosis of HFRS, were observed in all patients. The clinical manifestations of hemorrhage and renal injury from SEOV infection were milder than those of HTNV infection. Interestingly, compared to patients with HTNV infection, patients with SEOV presented with a significantly longer febrile period, more normal white blood cell counts or even transient leukocytopenia, a higher incidence of liver injury related to disease severity, and a lower occurrence of the 5 typical phases of HFRS. The mortality was 6.3% in HTNV infections and 0% in SEOV infections. CONCLUSIONS: Clinical manifestations of SEOV infection appear to be milder and less typical than HTNV. This information may help us to improve the diagnosis of SEOV-infected patients.