ABSTRACT
BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is a newly identified viral zoonosis caused by a phlebovirus. Most reported SFTS cases are farmers living in rural areas. The seroprevalence of SFTS virus in farmers has not been investigated. The current knowledge of SFTS virus seroprevalence in animals, especially in wild animals, is still poor. OBJECTIVES: To investigate SFTS virus seroprevalence among farmers and a variety of animal species. STUDY DESIGN: SFTS virus antibodies in sera were determined using a double-antigen sandwich ELISA. Serum samples were collected from 2547 farmers and 2741 animals in 6 SFTS-endemic counties from March 2012 to February 2013 in Jiangsu province. The farmer participants aged from 15 to 90 years. All of them were interviewed using a structured questionnaire. The animals sampled included 6 domesticated animal species and 2 wild animal species. RESULTS: SFTSV antibodies were found in a total of 33 farmers (1.30%) and was more prevalent in males than in females (respectively 1.87% and 0.71%, P<0.01). The mean age of seropositive farmers was 56.5 years and seroprevalence increased gradually with age. Seroprevalence in animal species were: goats (66.8%), cattle (28.2%), dogs (7.4%), pigs (4.7%), chickens (1.2%), geese (1.7%), rodents (4.4%) and hedgehogs (2.7%). Multiple variable logistic regression analysis showed that grazing, grass mowing, raising cattle, age, farm work time and tick bites were risk factors for SFTS virus infection among farmers. CONCLUSIONS: SFTSV readily infects humans with farming-related exposures as well as numerous domestic and wild animals. Serological results further suggest that the virus circulates widely in Jiangsu province.
Subject(s)
Antibodies, Viral/immunology , Bunyaviridae Infections/epidemiology , Bunyaviridae Infections/immunology , Phlebovirus/immunology , Zoonoses/epidemiology , Zoonoses/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Agriculture , Animals , Antibodies, Viral/blood , China/epidemiology , Female , Humans , Male , Middle Aged , Occupational Exposure , Risk Factors , Seroepidemiologic Studies , Young AdultABSTRACT
The aim of this study was to develop and evaluate a two-tube multiplex real-time RT-PCR assay for the detection and identification of four viral hemorrhagic fever (VHF) pathogens, severe fever with thrombocytopenia syndrome virus (SFTSV), Hantaan virus (HTNV), Seoul virus (SEOV), and dengue virus (DENV), from human clinical samples. The two-tube multiplex real-time RT-PCR assay we developed has a sensitivity of 10 copies/µL for each of the targets, and the performance was linear within the range of at least 10(7) transcript copies. Moreover, we evaluated the specificity of the assay using other virus RNA as template, and found no cross-reactivity. This new assay is able to detect SFTSV, HTNV, SEOV and DENV in two reactions and brings a cost of 40 % compared to separate reactions. Evaluation of this assay with clinical serum samples from laboratory-confirmed patients and healthy donors showed 100 % clinical diagnostic sensitivity and over 99 % specificity. The assay was applied for scanning 346 clinical samples collected from patients admitted to the hospital with suspected VHF and compared with virus isolation and immunofluorescence assay (IFA). The assay indentified 59 SFTSV-, 12 HTNV-, 11 SEOV- and 9 DENV-positive samples and showed higher sensitivity. This assay thus provides a reliable and cost-effective screening tool for early clinical diagnosis of SFTSV, HTNV, SEOV and DENV in the acute phase.
