Orthohantavirus infections in humans and rodents in the Yichun region, China, from 2016 to 2021

Author summaryHFRS caused by orthohantavirus is a serious public health problem in the Yichun region in Jiangxi Province, China. However, little information is known about the infection of orthohantavirus in humans and rodents, and the genetic characteristics of the epidemic orthohantavirus in the region. To reveal the above problems, we analyzed the epidemiology of HFRS and performed a molecular investigation of orthohantavirus in the Yichun region. During 2016-2021, a total of 1,573 HFRS cases were recorded with an average fatality rate of 0.70%. HFRS consistently occurred and peaked in winter and early summer in the Yichun region, it was a mixed epidemic area of HFRS dominated by HTNV. We identified new genetic variants of SEOV, HTNV, and DBSV from rodent lung samples in the Yichun region, which shows the high genetic diversity of the orthohantaviruses. Special attention should be paid to the high genetic diversity of orthohantavirus when developing vaccines and antiviral drugs. We also found the new genetic variant of HTNV from rodents caused human infection and was the main prevalent virus of human infection in the Yichun region. These results will provide very important information for HFRS control in the Yichun region and other areas in the world. BackgroundRodents are the predominant natural hosts of orthohantavirus and the source of human infection, hemorrhagic fever with renal syndrome (HFRS) caused by orthohantavirus is a severe public health problem in the Yichun region, Jiangxi Province, China. However, little information is known about the infection of orthohantavirus in humans and rodents, and the genetic characteristics of the epidemic orthohantavirus in the region. MethodsThe clinical data of HFRS cases in 2016-2021 was analyzed. Virus infection in rodents was analyzed by orthohantavirus antigen detection using immunofluorescent assay, and the species of orthohantaviruses in rodents and patients were identified by real-time RT-PCR and gene sequencing. The S and M segments of orthohantaviruses from rodents and patients were recovered and analyzed. ResultsA total of 1,573 HFRS cases were reported in the Yichun region from 2016 to 2021, including 11 death cases. HFRS cases peaked twice each year: in winter from November to January and early summer from May to June. Farmers constituted the predominant population suffering from HFRS. The orthohantavirus antigen was identified in five species of rodents: Apodemus agrarius (A. agrarius), Rattus norvegicus (R. norvegicus), Sorex araneus, Rattus losea (R. losea), and Niviventer confucianus (N. confucianus). The real-time RT-PCR test and genetic analysis results showed that Hantaan orthohantavirus (HTNV), Seoul orthohantavirus (SEOV), and Dabieshan orthohantavirus (DBSV) were circulated in the rodents. HTNV, SEOV, and DBSV from the rodents were distantly related to other known orthohantaviruses and belonged to novel genetic lineages. SEOV and HTNV were found in HFRS patients, but 97.8% (90/92) of the infections were caused by HTNV. Winter and early summer peaks were both caused by HTNV. The HTNV sequences recovered from HFRS cases were closely related to those from A. agrarius. ConclusionsIn the Yichun region, the orthohantaviruses transmitted in rodents include HTNV, SEOV, and DBSV, which have obvious genetic characteristics and high genetic diversity. At the same time, this region is an HFRS mixed epidemic area dominated by HTNV, with two peaks every year, which deserves our high attention.

Automated summary

HFRS caused by orthohantavirus is a serious public health problem in the Yichun region in Jiangxi Province, China. Little information is known about the infection of orthohantavirus in humans and rodents, as well as the genetic characteristics of the epidemic orthohantavirus in the region. This study analyzed the epidemiology of HFRS and performed a molecular investigation, revealing the high genetic diversity of orthohantaviruses and the dominance of HTNV in causing human infections in the Yichun region.