To investigate two clusters of severe fever with thrombocytopenia syndrome virus (SFTSV) in Xinyang City, Henan Province, in 2022, and analyze their causes, transmission route, risk factors, and the characteristics of virus genetic variation. Case search and case investigation were carried out according to the case definition. Blood samples from cases, family members and neighbors and samples of biological vectors were collected for RT-PCR to detect SFTSV. The whole genome sequencing and bioinformatics analysis were performed on the collected positive samples. A total of two clustered outbreaks occurred, involving two initial cases and ten secondary cases, all of which were family recurrent cases. Among them, nine secondary cases had close contact with the blood of the initial case, and it was determined that close contact with blood was the main risk factor for the two clustered outbreaks. After genome sequencing analysis, we found that the SFTSV genotype in two cases was type A, which was closely related to previous endemic strains in Xinyang. The nucleotide sequence of the SFTSV in the case was highly homologous, with a total of nine amino acid mutation sites in the coding region. It was not ruled out that its mutation sites might have an impact on the outbreak of the epidemic.
Humans ; Severe Fever with Thrombocytopenia Syndrome/epidemiology* ; Bunyaviridae Infections/epidemiology* ; Thrombocytopenia/complications* ; Phlebovirus/genetics* ; Disease Outbreaks ; China/epidemiology*

To investigate two clusters of severe fever with thrombocytopenia syndrome virus (SFTSV) in Xinyang City, Henan Province, in 2022, and analyze their causes, transmission route, risk factors, and the characteristics of virus genetic variation. Case search and case investigation were carried out according to the case definition. Blood samples from cases, family members and neighbors and samples of biological vectors were collected for RT-PCR to detect SFTSV. The whole genome sequencing and bioinformatics analysis were performed on the collected positive samples. A total of two clustered outbreaks occurred, involving two initial cases and ten secondary cases, all of which were family recurrent cases. Among them, nine secondary cases had close contact with the blood of the initial case, and it was determined that close contact with blood was the main risk factor for the two clustered outbreaks. After genome sequencing analysis, we found that the SFTSV genotype in two cases was type A, which was closely related to previous endemic strains in Xinyang. The nucleotide sequence of the SFTSV in the case was highly homologous, with a total of nine amino acid mutation sites in the coding region. It was not ruled out that its mutation sites might have an impact on the outbreak of the epidemic.
Humans ; Severe Fever with Thrombocytopenia Syndrome/epidemiology* ; Bunyaviridae Infections/epidemiology* ; Thrombocytopenia/complications* ; Phlebovirus/genetics* ; Disease Outbreaks ; China/epidemiology*

Objective: To understand the epidemiological characteristics of tick-borne infectious diseases (TBID) and the risk factors of severe illness and death in Hubei Province from 2016 to 2021. Methods: Based on the incidence data of fever with thrombocytopenia syndrome (SFTS), tsutsugamushi disease, typhus and other TBID reported during 2016-2021, the epidemiological analysis was conducted. Field investigation results of TBID in areas with high incidence in 2021, logistic regression analysis of population characteristics, epidemiological history and other factors were used to explore the risk factors of severe and fatal cases. In the field vector investigation, free ticks and surface ticks of the host animals in the cases' home and surrounding grassland were monitored and detected. Results: A total of 3 826 TBID cases were reported in Hubei from 2016 to 2021, of which 71.30% (2 728/3 826) were SFTS, 13.04% (499/3 826) were tsutsugamushi disease and 15.66% (599/3 826) were typhus. A total of 44 cases died in 6 years; the fatality rate was 1.15% (44/3 826). In the peak seasons of incidence from May to July, the cases in people engaged in agriculture related work accounted for 84.61% (3 237/3 826). The incidence rate in women was higher than that in men, and the cases aged ≥50 years accounted for 81.02% of the total (3 100/3 826), and the incidence rate increased with age (P<0.001). The TBID cases were distributed in 86 counties and districts in 16 prefectures (municipality). The incidence rates of different areas had significant differences (P<0.05), and there was a certain spatial-temporal clustering and expasion. Bovis microplus and Haemaphysalis longicornis were captured in the field, and the positive rates in host animals and grassland ticks were 10.94% (7/64) and 40.00% (2/5), respectively. Univariate logistic regression analysis results showed that age ≥50 years and leukocyte <2.0×10⁹/L were risk factors for severe illness and death. Conclusions: The TBID reported in Hubei were mainly SFTS, tsutsugamushi disease and typhus. In order to reduce the incidence of TBID, it is necessary to strengthen the prevention and control in women aged ≥50 years and reduce field exposure and tick bites during the epidemic period.
Animals ; Female ; Typhus, Epidemic Louse-Borne ; Scrub Typhus/epidemiology* ; Severe Fever with Thrombocytopenia Syndrome ; Ticks ; Communicable Diseases ; Phlebovirus ; China/epidemiology* ; Tick-Borne Diseases/epidemiology*

Humans ; Severe Fever with Thrombocytopenia Syndrome ; Phlebovirus

Animals ; Biological Assay ; Nucleic Acid Amplification Techniques ; Phlebovirus/isolation & purification* ; Psychodidae/virology* ; Recombinases/metabolism* ; Reverse Transcription

The incidence of severe fever with thrombocytopenia syndrome (SFTS) has increased in Korea since a first report in 2013. We investigated whether SFTS existed before 2013 using real-time reverse transcription polymerase chain reaction and stored blood samples from febrile patients with thrombocytopenia. Four cases of SFTS were identified, with the earliest occurring in 2008.
Fever* ; Humans ; Incidence ; Korea* ; Lymphohistiocytosis, Hemophagocytic* ; Phlebovirus ; Polymerase Chain Reaction ; Retrospective Studies* ; Reverse Transcription ; Thrombocytopenia*

Rift Valley fever (RVF) is an acute, febrile zoonotic disease that is caused by the RVF virus (RVFV). RVF is mainly prevalent on the Arabian Peninsula, the African continent, and several islands in the Indian Ocean near southeast Africa. RVFV has been classified by the World Organisation for Animal Health (OIE) as a category A pathogen. To avoid biological safety concerns associated with use of the pathogen in RVFV neutralization assays, the present study investigated and established an RVFV pseudovirus-based neutralization assay. This study used the human immunodeficiency virus (HIV) lentiviral packaging system and RVFV structural proteins to successfully construct RVFV pseudoviruses. Electron microscopy observation and western blotting indicated that the size, structure, and shape of the packaged pseudoviruses were notably similar to those of HIV lentiviral vectors. Infection inhibition assay results showed that an antibody against RVFV inhibited the infective ability of the RVFV pseudoviruses, and an antibody neutralization assay for RVFV detection was then established. This study has successfully established a neutralization assay based on RVFV pseudoviruses and demonstrated that this method can be used to effectively evaluate antibody neutralization.
Africa ; Animals ; Blotting, Western ; HIV ; Indian Ocean ; Islands ; Methods ; Microscopy, Electron ; Product Packaging ; Rift Valley fever virus ; Rift Valley Fever ; Zoonoses

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease that is caused by the genus phlebovirus in the family Bunyaviridae. The syndrome is characterized by fever, gastrointestinal symptoms, neutropenia, and thrombocytopenia. The number of reported cases and deaths in endemic areas, such as China and Japan, has increased each year. Since the first SFTS patient was identified in 2013, the number of cases have also been increasing every year in South Korea and the disease is posing a great public health concern. The number of patients is increasing and there is a high mortality rate, but there is no established treatment that has proven to be effective. The purpose of this review was to elucidate the various treatment modalities, such as plasma exchange, antiviral agents, e.g. ribavirin, high-dose steroids, and interferon.
Antiviral Agents ; Bunyaviridae ; China ; Communicable Diseases ; Fever* ; Humans ; Interferons ; Japan ; Korea* ; Mortality ; Neutropenia ; Phlebovirus ; Plasma Exchange ; Public Health ; Ribavirin ; Steroids ; Thrombocytopenia*

The incidence of mite- and tick-borne infectious disease is increasing with climate change and the development of diagnostic tools. Tick-borne infectious diseases include Lyme disease, anaplasmosis, ehrlichiosis, severe fever with thrombocytopenia syndrome (SFTS), and Japanese spotted fever. Rickettsial pox and scrub typhus are mite-borne infectious diseases. Scrub typhus and SFTS are the most common mite- and tick-borne infectious diseases in Korea, respectively. They are often difficult to diagnose at an early stage of disease. To make a definite diagnosis of mite- and tick-borne infectious disease, polymerase chain reaction (PCR) tests or serologic testing for antibodies during the acute and convalescent periods are necessary. If patients with nonspecific symptoms, such as fever, headache, nausea, and vomiting, have a history of outdoor activity or a tick bite, it is reasonable to consider the possibility of mite- or tick-borne infectious diseases clinically. There are no vaccinations against mite- and tick-borne infectious diseases. Therefore, preventing mite or tick bites is the best way to prevent the diseases.
Anaplasmosis ; Animals ; Antibodies ; Asian Continental Ancestry Group ; Climate Change ; Communicable Diseases* ; Diagnosis ; Ehrlichiosis ; Fever* ; Headache ; Humans ; Incidence ; Korea* ; Lyme Disease ; Mites ; Nausea ; Phlebovirus ; Polymerase Chain Reaction ; Scrub Typhus* ; Serologic Tests ; Thrombocytopenia* ; Tick Bites ; Tick-Borne Diseases ; Vaccination ; Vomiting

BACKGROUND/AIMS: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by severe fever with thrombocytopenia syndrome virus (SFTSV), a novel bunyavirus. As yet, there is no effective antiviral therapy for SFTS. Ribavirin is a broad-spectrum antiviral agent, which has been tried for treatment of SFTS. In this study, antiviral activity of ribavirin against SFTSV has been investigated. METHODS: Vero cell-grown SFTSV strain Gangwon/Korea/2012 was treated with ribavirin at various concentrations. Antiviral activity of ribavirin was evaluated by inhibition of the SFTSV cytopathic effect in Vero cells and quantification of viral RNA load in culture supernatant using one-step real-time reverse transcription polymerase chain reaction. Cytotoxicity of ribavirin was determined by a tetrazolium-based colorimetric method. RESULTS: Ribavirin reduced SFTSV titers in a dose-dependent manner, with a half-maximal inhibitory concentration ranged from 3.69 to 8.72 μg/mL. Cytopathic effects were reduced as ribavirin concentration increased. No significant cytotoxicity was detected at ribavirin concentrations of ≤ 31.3 μg/mL. CONCLUSIONS: Ribavirin exhibited inhibitory activity against SFTSV replication in vitro, which suggests that ribavirin can be used as a potential antiviral agent for SFTS.
Antiviral Agents ; Bunyaviridae Infections ; Communicable Diseases, Emerging ; Fever* ; In Vitro Techniques* ; Methods ; Orthobunyavirus ; Phlebovirus ; Polymerase Chain Reaction ; Reverse Transcription ; Ribavirin* ; RNA, Viral ; Thrombocytopenia* ; Vero Cells