Severe Fever with Thrombocytopenia Syndrome Virus in Ticks Collected from Humans,South Korea, 2013

We investigated the infection rate for severe fever with thrombocytopenia syndrome virus (SFTSV) among ticks collected from humans during May–October 2013 in South Korea. Haemaphysalis longicornis ticks have been considered the SFTSV vector. However, we detected the virus in H. longicornis, Amblyomma testudinarium, and Ixodes nipponensis ticks, indicating additional potential SFTSV vectors.     

Hedgehogs as Amplifying Hosts of Severe Fever with Thrombocytopenia Syndrome Virus,China

Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tickborne bandavirus mainly transmitted by Haemaphysalis longicornis ticks in East Asia, mostly in rural areas. As of April 2022, the amplifying host involved in the natural transmission of SFTSV remained unidentified. Our epidemiologic field survey conducted in endemic areas in China showed that hedgehogs were widely distributed, had heavy tick infestations, and had high SFTSV seroprevalence and RNA prevalence. After experimental infection of Erinaceus amurensis and Atelerix albiventris hedgehogs with SFTSV, we detected robust but transitory viremias that lasted for 9–11 days. We completed the SFTSV transmission cycle between hedgehogs and nymph and adult H. longicornis ticks under laboratory conditions with 100% efficiency. Furthermore, naive H. longicornis ticks could be infected by SFTSV-positive ticks co-feeding on naive hedgehogs; we confirmed transstadial transmission of SFTSV. Our study suggests that the hedgehogs are a notable wildlife amplifying host of SFTSV in China.     

Transovarial Transmission of Heartland Virus by Invasive Asian Longhorned Ticks under Laboratory Conditions

We demonstrated experimental acquisition and transmission of Heartland bandavirus by Haemaphysalis longicornis ticks. Virus was detected in tick salivary gland and midgut tissues. A total of 80% of mice exposed to 1 infected tick seroconverted, suggesting horizontal transmission. H. longicornis ticks can transmit the virus in the transovarial mode.     

Haemaphysalis flava ticks as a competent vector of severe fever with thrombocytopenia syndrome virus

Severe fever with thrombocytopenia syndrome virus (SFTSV), a tick-borne Bunyavirus, causes an emerging hemorrhagic fever in humans with a high fatality in Asia. The tick vectors and hosts of SFTSV are not well studied. We evaluated SFTSV transmission in laboratory reared Haemaphysalis flava ticks. RT-PCR demonstrated that after acquisition feeding in SFTSV-infected rabbits, 10 % (4/40) engorged larvae, 25% (5/20) engorged nymphs, and 50% (5/10) engorged females of H. flava became SFTSV RNA positive; after engorged larvae and nymphs molted into nymphs and adults, respectively, 12.5% (3/24) newly molted nymphs and 20% (2/10) newly molted adults were SFTSV RNA positive. Among 30 engorged females that oviposited, 10% (3/30) clutches of eggs and 3.3% (1/30) colonies of larvae were RNA positive for SFTSV. RT-PCR also showed that 6 days after being infested with SFTSV-infected ticks, 100% (3/3) rabbits infested with larvae, 100% (2/2) rabbits infested with nymphs, and 100% (2/2) rabbits infested with adult ticks became SFTSV RNA positive. In conclusion, H. flava can acquire SFTSV from infected rabbits by feeding; there is transstadial and transovarial transmission of the virus and all three stages of H. flava can transmit SFTSV to rabbits by feeding. Thus, H. flava tick is an effective vector of SFTSV and may play a role in the transmission of SFTSV in wild animals and humans.     

东海县发热伴血小板减少综合征病毒鼠携带情况调查

目的了解东海县鼠类携带发热伴血小板减少综合征病毒(SFTSV)情况,为防治工作提供依据。方法采用鼠笼法在野外及居民区捕鼠,计算鼠密度及鼠种分类,并取其心、肝、脾、肺、肾、脑等脏器;采用荧光定量RT-PCR检测鼠体内SFTSV核酸。结果主要鼠种有黑线姬鼠、大仓鼠、小仓鼠、麝鼳、褐家鼠、小家鼠等6种。野鼠密度为13.47%,主要鼠种为黑线姬鼠;家鼠密度为6.98%,主要鼠种为小家鼠、褐家鼠。野鼠SFTSV带毒率为6.90%,家鼠为7.87%;野鼠心、肝、脾、肺、肾、脑均带有病毒,且两种或两种以上脏器带毒;家鼠多为单一脏器感染。病毒核酸的基因测序与Gen Bank公布的SFTSV的NP基因序列同源性在95%以上。结论东海县6种鼠类除小仓鼠外,其余5种均携带SFTS病毒,是该地SFTSV的宿主动物,但作为发热伴血小板减少综合征传染源的作用有待进一步研究。     

Phylogenetic analysis of severe fever with thrombocytopenia syndrome virus in Korean water deer (Hydropotes inermis argyropus) in the Republic of Korea

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging zoonotic tick-borne disease caused by SFTS virus, which circulates among ticks and their host animals, including wildlife. However, few studies have examined SFTS virus infection in wildlife present in the Republic of Korea (ROK). We evaluated SFTS virus infection in tissue samples from Korean water deer (Hydropotes inermis argyropus), one of the most common wild ungulates in ROK. In this study, we evaluated tissue samples of 129 water deer carcasses collected in 2017 and detected SFTS viral RNA by conventional PCR. SFTS viral RNA was found in 3 of the 129 carcasses, showing a prevalence of 2.3 %; 2 of which were collected in Gyeongsangnam-do and 1 of which was in the Gangwon-do region. Among the 6 internal organs studied, only the spleen samples were positive. Phylogenetic analysis revealed close relationships between deer- and human-derived strains. The medium segments of the three positive cases clustered with genotype B, which is the predominant genotype in ROK. In the small segment, two cases clustered with genotype B, samples 17WD044 and 17WD065. The third sample, 17WD068 from Gangwon-do province, showed genotype A, which circulates mainly in China. The disagreement in the genotypes of the two tested segments suggests a potential reassortment between genotype A and B, resulting in genetic recombination as observed in sample 17WD068, which may be co-circulating in China and Korea. Further studies in wildlife and humans are necessary to understand the genetic characteristics of SFTS viruses circulating in ROK.     

发热伴血小板减少综合征流行病学研究进展

发热伴血小板减少综合征(SFTS)是我国中东部农村地区新出现的由布尼亚病毒(SFTSV)感染引起的发热伴血小板减少综合征。蜱叮咬是其主要传播途径,可通过人-人接触传播。该病起病急,病情进展较快,主要临床表现为发热、血小板减少、白细胞减少以及胃肠、肝肾功能异常等,部分患者可因多脏器功能衰竭而死亡,平均报告病死率约10%。本文采用查阅文献资料的方法,对近年来该病的流行分布特点以及传播媒介、宿主动物、传播途径和人群易感性的最新研究进展做一综述。     

发热伴血小板减少综合征患者核衣壳蛋白特异性IgM水平与病情严重程度的相关性

目的探讨核衣壳蛋白(N蛋白)特异性Ig M抗体水平与发热伴血小板减少综合征(SFTS)疾病病情严重程度的相关性。方法回顾性分析某三甲医院30例SFTS患者的临床特点及实验室检查结果,比较N蛋白特异性Ig M(+)组与N蛋白特异性Ig M(-)组患者的临床特点及预后转归;根据患者疾病严重程度分为轻症组和重症组,比较轻症组患者与重症组患者Ig M抗体滴度与发热伴血小板减少综合征病毒(SFTSV) RNA载量的相关性;从而观察分析N蛋白特异性Ig M抗体滴度、SFTSV-RNA载量与患者病情严重程度的相关性。结果 N蛋白特异性Ig M(-)组中有神经症状、死亡及病重例数均明显较Ig M(+)组多(均P 0. 05); N蛋白特异性Ig M抗体水平与SFTSV-RNA载量、凝血酶原时间(PT)、乳酸脱氢酶(LDH)、天门冬氨酸氨基转移酶(AST)均呈负相关(r值分别为-0. 495、-0. 440、-0. 367、-0. 280,均P 0. 05);而与血小板(PLT)呈正相关(r=0. 335,P=0. 002)。SFTSVRNA载量与PT、LDH、AST均呈正相关(r值分别为0. 606、0. 604、0. 587,均P 0. 001);而与PLT呈负相关(r=-0. 384,P 0. 001)。发病第10～13天时轻症组患者N蛋白特异性Ig M抗体滴度高于重症组患者(P 0. 05)。结论N蛋白特异性Ig M抗体的出现及滴度的升高有助于SFTSV的清除,且对患者凝血功能及肝损伤、心肌损伤有修复作用; N蛋白特异性Ig M抗体可能是预测患者预后的重要因素。     

发热伴血小板减少综合征研究进展

发热伴血小板减少综合征（sFTs）是近年来在我国部分地区相继出现的感染性疾病,以发热、血小板减少和多脏器功能损害为主要临床表现,死亡率达10％。目前已经证实其由发热伴血小板减少综合征布尼亚病毒（SFTSV）感染所致。该文就SFTS的临床特征、动物模型的发病机制研究和SFTSV的流行病学、检测方法及复制特点做一概述。     

从革螨和恙螨中检测到发热伴血小板减少综合征病毒核酸

目的调查革螨、恙螨携带发热伴血小板减少综合征布尼亚病毒(SFTSV)情况。方法收集黑线姬鼠和山羊体表革螨和恙螨,按属种分类,用荧光定量PCR和常规RTPCR法检测革螨和恙螨体内是否携带SFTSV基因组核酸。结果黑线姬鼠体表收集的5组小盾纤恙螨SFTSV基因组核酸均为阳性,黑线姬鼠体表收集的3组毒棘厉螨和山羊体表收集的1组毒棘厉螨SFTSV基因组核酸均为阳性。基因测序结果显示,与SFTSVJS4株NP基因比对,其同源性在99%～100%。结论小盾纤恙螨和毒棘厉螨均可携带SFTSV,具有传播SFTS的可能。     

发热伴血小板减少综合征血清学监测

目的调查发热伴血小板减少综合征(SFTS)病毒在人群及动物中的隐性感染情况,为制定防治对策提供依据。方法在东海县SFTS发病地区与非发病区采集不同年龄健康人群及牛、鸡、猪、犬、羊等动物血,用双抗原夹心ELISA法检测血清中STFSV总抗体。结果人群血清中未检测到SFTSV抗体,在发病区与非发病区的牛、鸡血清中检测到SFTSV抗体。结论与人密切接触的牛、鸡能够感染SFTSV并可能携带病毒,要加强对牛、鸡的SFTSV疫情监测。     

浙江省舟山市2011－2013年发热伴血小板减少综合征流行特征分析

目的 分析浙江省舟山市2011－2013年发热伴血小板减少综合征(SFTS)病例的流行特征,为防控提供建议和对策.方法 收集整理舟山市2011－2013年SFTS病例个案调查表及人口学资料,利用描述性流行病学方法分析病例临床和流行病学特征.结果 2011－2013年舟山市共报告SFTS 45例,病死率为11.11%(5/45),其中岱山县41例(91.11%).病例以山区丘陵>50岁人群为主(93.33%),5－7月为发病高峰(84.44%),多数为农民(42.22%)和家务待业(31.11%),男女性发病率差异无统计学意义(P>0.05).大部分病例有发热(97.78%)、食欲减退(91.11%)、乏力(62.22%)、畏寒(44.44%)等非特异性临床表现,且均伴有血小板、白细胞水平进行性下降.病例居住地环境卫生普遍较差,且病前2周进行农田种植等户外活动的比例为68.89%(31/45),部分病例发病前有明确蜱叮咬史,并发现3起流行病学相关事件.结论 舟山市SFTS是由新布尼亚病毒感染引起,具有清晰流行病学特征的自然疫源性疾病,蜱为主要的传播媒介,且可能存在人传人现象.改善居住环境卫生条件及做好户外防护措施对降低发病具有一定意义.     

蓬莱市发热伴血小板减少综合征监测分析

目的研究蓬莱市发热伴血小板减少综合征(简写SFTS)流行病学特征和感染状况,为制定防控策略提供科学依据。方法对2010-2013年蓬莱市发热伴血小板减少综合征病例采用描述性流行病学方法,分析其流行病学特点,用间接法ELISA对病例地区1 525名蓬莱市民的血清进行SFTSV-Ig G抗体检测,采集病例地区动物宿主血清标本通过双抗原夹心法ELISA进行SFTSV的总抗体检测,通过Realtime RT-PCR进行SFTSV的核酸检测。结果 2010-2013年蓬莱市发热伴血小板减少综合征病年均发病率为4.55/10万,死亡率0.89/10万,病死率为19.51%,病例覆盖全市9.57%村社区,病例以农民为主,6-9月为高发季节,年龄以40~79岁为主。蓬莱市健康人群SFTSV-Ig G阳性率为9.05%,动物宿主牛、羊、跑山鸡、狗、猪和圈养鸡、抗体阳性率分别为63.86%、44.76%、42.31%、31.46%、6.96%和6.00%。结论蓬莱市是发热伴血小板减少综合征病流行地区,存在着新型布尼亚病毒隐性感染情况,牛羊狗可能是病毒主要的动物宿主。     

招远市健康人群发热伴血小板减少综合征血清流行病学及感染危险因素调查

目的 了解山东省招远市健康人群发热伴血小板减少综合征（SFTS）感染现况及感染的危险因素,为科学防控提供依据。方法 通过多阶段分层随机抽样方法,选择健康人群检测新型布尼亚病毒（SFTSV） IgG。采用1∶3配对的病例对照研究,开展危险因素调查;应用条件Logistic回归分析感染危险因素。结果 招远市800名健康居民中,SFTSV IgG阳性率为2.00%,5个区域间SFTSV IgG阳性率无统计学差异（χ2 = 2.213, P = 0.713）;招远市男性SFTSV IgG阳性率3.58%,女性为0.86%,不同性别的阳性率差异有统计学意义（χ2 = 7.360,P = 0.007）;60岁以上SFTSV IgG阳性率最高（4.61%）,不同年龄组之间阳性率差异有统计学意义（χ2 = 10.876,P = 0.012）。接触带有蜱虫的宠物是感染SFTSV的危险因素。结论 招远市健康人群SFTSV IgG阳性率较高,男性感染SFTSV多于女性,高年龄组人群感染率最高,人群感染SFTSV的危险因素是接触带有蜱虫的宠物。     

山东省烟台市人与动物新型布尼亚病毒感染调查及同源性分析

目的 了解山东省烟台市人和动物发热伴血小板减少综合征布尼亚病毒 （SFTSV）感染及流行情况。方法 2011年4－11月分别在烟台市的蓬莱和莱州2个SFTS病例高发地区连续采集与人密切接触的5种家养动物 （羊、 牛、 猪、 犬、 鸡） 血清标本3 576份,应用双抗原夹心ELISA方法和Real time RT-PCR方法检测血清中SFTSV总抗体和病毒核酸; 观察不同月份感染情况; 采集两地人群血清2 590份,应用间接ELISA方法检测SFTSV IgG抗体; 用Vero细胞从核酸阳性的人和动物血清中分离病毒,通过RT-PCR方法对 SFTSV S片段进行序列扩增、 同源性分析。结果 3 576份动物血清标本中SFTSV血清总抗体阳性1 439份,阳性率为40.24%,病毒核酸阳性163份,阳性率为4.56%。其中羊、 牛、 鸡、 犬、 猪抗体阳性率分别为62.78%、 52.97%、 45.56%、28.73%和1.45%,核酸阳性率分别为5.72%、 4.63%、 3.02%、 5.25%和3.73%。动物体内的抗原抗体随季节消长而变化。2 590份人群血清SFTSV IgG抗体阳性率为5.41%。对10株来自人的毒株和3株来自动物的毒株进行S片段基因序列扩增分析,显示其同源性在95.23%～100.00%,与国内其他省市分离毒株比较,其同源性在94.72%～99.13%,高度同源。结论 烟台地区存在SFTSV流行,人与家养动物普遍易感,其基因序列高度同源,提示家养动物可能作为SFTSV的增殖宿主和扩散宿主,应引起高度重视。     

Direct Transmission of Severe Fever with Thrombocytopenia Syndrome Virus from Domestic Cat to Veterinary Personnel

Two veterinary personnel in Japan were infected with severe fever with thrombocytopenia syndrome virus (SFTSV) while handling a sick cat. Whole-genome sequences of SFTSV isolated from the personnel and the cat were 100% identical. These results identified a nosocomial outbreak of SFTSV infection in an animal hospital without a tick as a vector.     

Seroprevalence of severe fever with thrombocytopenia syndrome virus in medium-sized wild mammals in Miyazaki,Japan

Severe fever with thrombocytopenia syndrome (SFTS) is a fatal emerging tick-borne zoonotic disease caused by the SFTS virus (SFTSV). SFTSV infection in humans and companion animals is a matter of concern in endemic areas. Various wild animals are involved in the transmission cycle of SFTSV with vector ticks. Because the home range of medium-sized wild mammals commonly overlaps with humans’ living spheres, this study aimed to reveal the endemicity of SFTSV in such mammals. This study investigated the prevalence of antibodies against SFTSV and viral RNA in medium-sized wild mammals in Miyazaki Prefecture, Japan where human cases have been most frequently reported in Japan and performed a phylogenetic analysis to compare the detected SFTSV with those previously reported. Forty-three of 63 (68%) Japanese badgers (Meles anakuma) and 12 of 53 (23%) Japanese raccoon dogs (Nyctereutes procyonoides viverrinus) had antibodies against SFTSV. Japanese marten (n = 1), weasels (n = 4), and Japanese red fox (n = 1) were negative. Two of 63 (3%) badgers tested positive for SFTSV RNA, whereas the other species were negative. Phylogenetic analysis of the partial nucleotide sequence of SFTSV revealed that viral RNA detected from badgers exhibited 99.8% to 100% similarity to SFTSV, as previously reported in humans, cat, and ticks in the study area. This study demonstrated high seropositivity of antibodies in medium-sized wild mammals and suggested that SFTSV could be shared among these mammals, humans, and companion animals in endemic areas.     

2011-2013年济南市发热伴血小板减少综合征流行病学及病原学特征分析

目的分析济南市2011-2013年发热伴血小板减少综合征（severe fever with thrombocytopenia syndrome,SFTS）的流行病学特征和病原学特性,为更好地预防和控制SFTS提供科学依据。方法采用实时荧光定量RT-PCR方法检测济南市2011-2013年SFTS疑似病例急性期血清样本和蜱虫样本中的SFTS布尼亚病毒核酸,采用RT-PCR方法进行扩增并测序,使用DNASTAR和MEGA软件对测序结果进行序列比对和进化分析;用描述性流行病学方法对监测数据进行统计分析。结果 2011-2013年济南市共确诊95例SFTS病例,检测出3只蜱虫样本中的SFTS布尼亚病毒核酸阳性;发病地区主要集中在章丘市。对SFTS布尼亚病毒的S片段基因进行测序,结果显示2012年SFTS布尼亚病毒基因与安徽、江苏、河南分离株遗传距离相对较近。2013年SFTS布尼亚病毒基因与山东本地分离株遗传距离相对较近。结论济南市发热伴血小板减少综合征病例以新布尼亚病毒为其主要病原;夏秋季多发;中老年农民为主,具有明显职业性;发病范围逐年扩大,局部地区疫情活跃。应加强传染源的管理控制,深入开展对高危人群宣传教育和行为干预。     

Severe Fever with Thrombocytopenia Syndrome Virus Infection,Thailand, 2019–2020

Infection with severe fever with thrombocytopenia syndrome (SFTS) virus, which can cause hemorrhagic febrile illness, is often transmitted by ticks. We identified 3 patients with SFTS in or near Bangkok, Thailand. Our results underscore a need for heightened awareness by clinicians of possible SFTS virus, even in urban centers.