OBJECTIVETo study the subcellular localization of severe fever with thrombocytopenia syndrome virus (SFTSV) in macrophages and understand the replication and assembly mechanism of SFTSV in host cells.

METHODSUsing two types of human macrophage cell lines THP-1 and U937, the study analyzed the intracellular colocalization of SFTSV with Golgi apparatus and endoplasmic reticulum by immunefluorescence staining and confocal microscopy.

RESULTSSFTSV infected macrophage cell lines THP-1 and U937. Immunofluorescence staining showed that the SFTSV nuclear protein colocalized with Golgi apparatus and closely surrounded by endoplasmic reticulum in the perinuclear region.

CONCLUSIONThe results suggested that Golgi complex and endoplasmic reticulum are probably the sites for formation and maturation of SFTSV viral particles.

Bunyaviridae ; isolation & purification ; Cell Line, Tumor ; Endoplasmic Reticulum ; virology ; Fever ; virology ; Golgi Apparatus ; virology ; Humans ; Macrophages ; virology ; Thrombocytopenia ; virology

Larvae, nymphs, and adult stages of 3 species of ixodid ticks were collected by tick drag methods in Seoul during June-October 2013, and their infection status with severe fever with thrombocytopenia syndrome (SFTS) virus was examined using RT-PCR. During the period, 732 Haemaphysalis longicornis, 62 Haemaphysalis flava, and 2 Ixodes nipponensis specimens were collected. Among the specimens of H. longicornis, the number of female adults, male adults, nymphs, and larvae were 53, 11, 240, and 446, respectively. Ticks were grouped into 63 pools according to the collection site, species, and developmental stage, and assayed for SFTS virus. None of the pools of ticks were found to be positive for SFTS virus gene.
Animals ; Female ; Fever/virology ; Humans ; Ixodidae/*classification/*virology ; Larva/pathogenicity ; Male ; Phlebotomus Fever/virology ; Phlebovirus/*isolation & purification ; Republic of Korea ; Thrombocytopenia/virology ; Tick Infestations/*virology

Bunyaviridae Infections ; pathology ; Fever ; virology ; Humans ; Leukopenia ; virology ; Orthobunyavirus ; classification ; pathogenicity ; Thrombocytopenia ; virology

Ebolavirus ; pathogenicity ; Endemic Diseases ; Hemorrhagic Fever, Ebola ; epidemiology ; virology ; Humans

BACKGROUNDHemorrhagic fever with renal syndrome (HFRS) is endemic in Junan county, Shandong Province, China. We conducted geographic information system (GIS)-based spatial analysis with the objective of estimating the spatial distribution of rodent populations and their hantavirus infection patterns, to describe the spatial relationships of hantavirus strains in small ecological areas and to identify key areas in endemic areas of HFRS for future public health planning and resource allocation.

METHODSRodent sampling was conducted in seven villages in Junan county from February 2006 to January 2007 using field epidemiological surveillance. Dynamics of hantavirus infection and population densities in rodents were investigated. Spatial statistical techniques including Ripley' L index and nearest neighbour hierarchical (NNH) clustering analysis were conducted to reveal the spatial structure of rodent populations in seven villages. Phylogenetic analysis and two-dimensional minimal spanning tree (2-D MST) models were employed to describe the spatial relationship of hantavirus strains.

RESULTSData showed that Mus musculus was the most common species in our study area, followed by Rattus norvegicus. Ripley's L index and NNH analysis showed that the spatial distribution of all captured rodents, Mus musculus and Rattus norvegicus in seven villages were clustered and there were hotspot areas of rodent distribution. The branches of 2-D MSTs had similar topologies to those of corresponding phylogenetic trees, and hantavirus strains exhibited obvious connective traces in seven villages.

CONCLUSIONSThese results contribute to the understanding of the spatial distribution of rodent populations and hantavirus infection patterns in small areas, and identify priority areas within the epidemic areas for the development of a better prevention strategy against hemorrhagic fever with renal syndrome in a small ecological area.

Animals ; Geographic Information Systems ; Hantavirus ; Hemorrhagic Fever with Renal Syndrome ; epidemiology ; virology ; Humans ; Rats ; Rodentia ; virology

OBJECTIVETo develop an assay for titration of severe fever with thrombocytopenia syndrome virus (SFTSV) based on double antibody sandwich ELISA.

METHODSA double antibody sandwich ELISA was developed for detection of SFTSV based on SFTSV nucleocapsid (N) protein specific poly- and monoclonal antibodies, procedures were optimized and evaluated. This ELISA based titration assay was compared with fluorescence assasy and plaque assay based titration method.

RESULTSThe results suggested that the titers obtained by ELISA based method are consistent with those obtained by IFA based method (R = 0.999) and the plaque assay titration method (R = 0.949).

CONCLUSIONThe novel ELISA based titration method with high sensitivity and specificity is easy to manage and perform, and can overcome the subjectivity associated with result determination of the fluorescence assay and plaque assay based methods. The novel ELISA based titration method can also be applied to high throughput detection.

Bunyaviridae ; isolation & purification ; Enzyme-Linked Immunosorbent Assay ; methods ; Fever ; virology ; Fluorescent Antibody Technique ; Humans ; Thrombocytopenia ; virology

Animals ; Bunyaviridae Infections ; epidemiology ; virology ; China ; epidemiology ; Fever ; epidemiology ; virology ; Humans ; Orthobunyavirus ; genetics ; isolation & purification ; physiology ; Thrombocytopenia ; epidemiology ; virology

Animals ; Genome, Viral ; Humans ; Viral Proteins ; genetics ; metabolism ; Yellow Fever ; virology ; Yellow fever virus ; genetics ; metabolism

OBJECTIVETo determine the infective status and natural distribution of Xinjiang hemorrhagic fever (XHF; Crimean-Congo hemorrhagic fever, CCHF) in ticks, rodents and livestock in the Tarim Basin.

METHODSThe pathogenic materials of ticks or rodents' viscera and blood samples of sheep were inoculated into sucking mouse of 24 to 48-hour old. Materials with typical clinic symptoms were identified with RPHA and IFA. RT-PCR was taken to detect special S gene segment of Crimean-Congo hemorrhagic fever virus (CCHFV) in the objective material.

RESULTSAll the samples of ticks, rodents' viscera and blood samples of sheep from 21 counties (cities) in the Tarim Basin were divided into 422 groups and inoculated into sucking mouse at laboratory. 49 materials with typical clinic symptoms were obtained. The morbidity rate with typical clinic XHF was high in Bachu, Yuli, Yutian and Ruoqiang. There were 43 samples identified with RPHA with 6 positive samples and positive rate of 1.4%. The materials with positive RPHA were found in Yuli, Luntai and Yutian. 42 samples were identified with IFA and 13 positive samples with the positive rate of 3.1%. The positive materials of IFA were found in Bachu, Yuli, Minfeng, Luntai and Yutian. 32 samples were detected with RT-PCR and there were 31 samples with special S gene segment of CCHFV (329- 548 nt). The positive materials was widely distributed in Aksu, Awat, Bachu, Luopu, Yuli, Minfeng, Qiemo, Ruoqiang, Luntai and Yutian. The highest infective rate was in Hyalomma asiaticum kozlovi, and followed by sheep. S gene segment was detected in viscera of M. meridianus.

CONCLUSIONXHF relied on the river in the southern part of Xinjiang and distributed in the areas with Populus euphratica shrub in desert and oasis in the Tarim Basin. The main vector and host were Hyalomma asiaticum kozlovi. Livestock such as sheep, camel, L. yarkandensis, M. meridianus and Euchoreutes naso could serve as the deposited host of XHF.

Animals ; Animals, Domestic ; virology ; China ; epidemiology ; Hemorrhagic Fever Virus, Crimean-Congo ; genetics ; isolation & purification ; Hemorrhagic Fever, Crimean ; epidemiology ; transmission ; Humans ; Morbidity ; Polymerase Chain Reaction ; Rodentia ; virology ; Ticks ; virology

The severe fever with thrombocytopenia syndrome virus (SFTSV) is a new member in the genus Phlebovirus of the family Bunyaviridae identified in China. The SFTSV is also the causative pathogen of an emerging infectious disease: severe fever with thrombocytopenia syndrome. Using immunofluorescent staining and confocal microscopy, the intracellular distribution of nucleocapsid protein (NP) in SFTSV-infected THP-1 cells was investigated with serial doses of SFTSV at different times after infection. Transmission electron microscopy was used to observe the ultrafine intracellular structure of SFTSV-infected THP-1 cells at different times after infection. SFTSV NP could form intracellular inclusion bodies in infected THP-1 cells. The association between NP-formed inclusion bodies and virus production was analyzed: the size of the inclusion body formed 3 days after infection was correlated with the viral load in supernatants collected 7 days after infection. These findings suggest that the inclusion bodies formed in SFTSV-infected THP-1 cells could be where the SFTSV uses host-cell proteins and intracellular organelles to produce new viral particles.
Cell Line ; China ; Humans ; Inclusion Bodies, Viral ; ultrastructure ; virology ; Macrophages ; ultrastructure ; virology ; Phlebotomus Fever ; virology ; Phlebovirus ; genetics ; physiology ; ultrastructure ; Thrombocytopenia ; virology