Correlation between genotypes of Orientia tsutsugamushi and clinical characteristics of patients with scrub typhus in Guangzhou,China

Objective:To explore the correlation between genotypes of Orientia(O.)tsutsugamushi and clinical characteristics of scrub typhus patients.Methods:Clinical data of patients with scrub typhus admitted to different types of medical institutions in Guangzhou from September 2012 to December 2016 were collected using medical records.Demographic data,clinical manifestations,as well as hematological and biochemical indicators of patients infected with different genotypes were analyzed and compared.Results:A total of 192 patients were included in this study,including 121 patients with Karp genotype of O.tsutsugamushi infection(63.0%),36 patients with Gilliam genotype(19.0%),23 patients with Kato genotype(12.0%),and 12 patients with TA763 genotype(6.0%)infection.The median value of albumin in patients with Karp genotype infection was significantly lower than that of Gilliam-infected patients(P=0.032).Patients with Karp genotype infection had a significantly longer hospital stay(9 days)than those with Gilliam genotype(7 days)(P=0.009)and Kato genotype infection(6 days)(P=0.005).Karp-infected patients also represented for the largest number of patients with complicated organ involvement(88/133,66.2%).Furthermore,Karp-infected patients had higher risk of developing multiple organ dysfunction syndrome(18.2%)and requiring intensive care unit treatment(15.9%).Besides,patients with Gilliam genotype(8 days)and TA763 genotype infection(7.5 days)had shorter fever duration than those with Karp genotype(9 days)and Kato genotype(9 days)infection,respectively.Conclusions:Genotypes of Orientia tsutsugamushi were associated with varying clinical manifestations,organ involvement,and treatment outcomes,suggesting that genotypes ranged in virulence.

Real-world utility of serological tests in patients with suspected scrub typhus in the Republic of Korea:A single-center,retrospective,observational study

Objective:Serological tests are widely used for scrub typhus diagnosis;however,their limitations are evident.This study aims to assess their practical value in clinical settings.Methods:We analyzed the data of adult patients with suspected scrub typhus who visited a tertiary care hospital in the Republic of Korea from September to December from 2019 to 2021.The included patients had an acute fever and at least one of the following ten secondary findings:myalgia,skin rash,eschar,headache,thrombocytopenia,increased liver enzyme levels,lymphadenopathy,hepatomegaly,splenomegaly,and pleural effusion.The diagnoses were grouped as scrub typhus or other diseases by two infectious disease physicians.Results:Among 136 patients who met the eligibility criteria,109 had scrub typhus and 27 had different diseases.Single and paired total antibodies using immunofluorescence assay(IFA),and total antibodies using immunochromatography-based rapid diagnostic testing(ICT)were measured in 98%,22%,and 75%of all patients,respectively.Confirmation using paired samples for scrub typhus was established at a median of 11[interquartile range(IQR)10-16]days following the first visit.Among the 82 admitted patients,the median admission time was 9(IQR 7-13)days.According to IFA,58(55%)patients with scrub typhus had total immunoglobulin titers≥1:320,while 23(85%)patients with other disease had titers<1:320.Positive ICT results were observed in 64(74%)patients with scrub typhus and 10(67%)patients with other diseases showed negative ICT results.Conclusions:Serological testing for scrub typhus is currently insufficient for decision-making in clinical practice.

Longitudinally extensive transverse myelitis associated with scrub typhus:A case report

Rationale:Longitudinally extensive transverse myelitis(LETM)is a rare inflammatory demyelinating disease predominantly associated with autoimmune and inflammatory disorders.Scrub typhus can cause a variety of neurological complications,which may result in poor recovery and long-term disability.This report reveals a rare linkage between LETM and scrub typhus.Patient concerns:A 24-year-old female presented with a history of fever for 10 days associated with progressive quadriparesis.Physical examination revealed bilateral lower limb weakness(grade 0/5)and bilateral upper limb weakness(grade 2/5)with reduced sensation below the T3 dermatome.Diagnosis:Scrub typhus presenting with longitudinally extensive transverse myelitis.Interventions:Steroid pulse therapy with antibiotics supported by early intensive rehabilitation.Outcomes:Complete recovery was achieved.Lessons:This case report highlights the importance of considering scrub typhus as a potential cause of LETM in endemic regions,particularly in patients presenting with febrile illness and neurological symptoms.

Omadacycline in the treatment of scrub typhus:Three case reports

BACKGROUND Scrub typhus is a naturally occurring acute infectious disease that is primarily transmitted through the bites of chiggers or larval mites infected by Orientia tsutsugamushi(O.tsutsugamushi).Omadacycline,a novel tetracycline,exhibits potent antibacterial efficacy against both typical bacteria and atypical pathogens.However,omadacycline application in the treatment of scrub typhus remains limited.CASE SUMMARY In the present work,we report several cases of scrub typhus,with the main clinical symptoms being fever,the formation of eschars or ulcers,local or systemic lymphadenopathy,headache,myalgia and rash.Blood samples were collected before omadacycline was administered,and O.tsutsugamushi infection was confirmed through targeted next-generation sequencing(tNGS).After two days of treatment,the patients’symptoms,including fever,were alleviated,with no adverse drug reactions.CONCLUSION tNGS is an effective method for diagnosing scrub typhus.Omadacycline can be considered an alternative option for antiinfective therapy in patients with O.tsutsugamushi infections.

Myositis and rhabdomyolysis in scrub typhus infection: A case report

Rationale:Fever with myositis and rhabdomyolysis is a medical emergency requiring prompt diagnosis and management.Scrub typhus associated myositis with rhabdomyolysis is rare.Patient concerns:A 36-year-old female presented with intermittent fever up to 38.6℃,jaundice and progressive weakness of all four limbs.Diagnosis:Scrub typhus associated myositis and rhabdomyolysis.Intervention:Doxycycline 100 mg twice daily and injection of ceftriaxone 1 gm twice daily along with continuous intravenous fluids.Outcome:Fever resolved with normalization of liver function and recovery of muscle power.Lessons:Presence of myositis and rhabdomyolysis is uncommon in scrub typhus;high clinical suspicion should be kept in patients with atypical manifestations of scrub typhus.

Epidemiology and clinico-laboratory manifestations of scrub typhus in Hadoti region of Rajasthan,India:A cross-sectional study

Objective:To study epidemiology,clinical manifestations,and laboratory parameters of scrub typhus in Hadoti region of Rajasthan,India.Methods:A cross-sectional study was conducted on 50 patients with scrub typhus between August 2022 and November 2022.Scrub typhus was diagnosed by ELISA IgM scrub typhus antibody.The data about demography,vital parameters,and lab investigations were collected and analyzed.Results:Ninety-two percent of the patients were from a rural background(92%),86% were farmers and the majority were females.Most patients were 40-60 years old.The major complaints were fever(100%),myalgia(100%),headache(82%),and body swelling(80%).Major complications were pneumonia(68%),multiple organ dysfunction syndrome(62%),hepatitis(44%),and acute kidney injury(42%).Triglyceride levels were>200 mg/dL in 80% of patients,albumin<3.5 g/dL in 98% and eschar mark was present in 24%of patients.Conclusions:Scrub typhus is a serious acute febrile illness that can lead to multi-organ dysfunction and is associated with significant mortality.Increasing awareness regarding disease in endemic regions,early screening of patients,and treatment as early as possible could help prevent the patient from severe life-threatening complications.

A review of the epidemic and clinical study on scrub typhus in China(2010-2020)

Scrub typhus is an acute febrile vector-borne zoonotic disease caused by the obligate intracellular growth bacterium Orientia tsutsugamushi(Ot).Mites are the primary vectors and rodents play a pivotal role in the transmission of scrub typhus.Due to the climate warming,increased human activity and other factors,cases of scrub typhus have been increased sharply during the past decade in China,especially in the northern China.To understand the incidence trend,epidemic pattern,clinical sign,diagnosis and therapy of this diseases as well as genotype evolution of Orientia tsutsugamushi,we summarized and analyzed the current knowledge of scrub typhus in China from 2010 to 2020.The data indicated that the dominate genotypes of scrub typhus in China were Karp,Kato and Gilliam.Although the disease was distributed national wide,Yunnan,Guangzhou and Fujian showed the highest incidence rate.The main vector of scrub typhus in southwest,middle east and southeast of China appeared a geographic preference respectively.Seasonal timing,age and occupation were the key factors that relate to the peak incidence of scrub typhus.Notably,farmer was the occupation with the highest risk of Ot infection.Further study on the epidemic characteristics,risk factors,diagnosis and treatments of scrub typhus will be of benefit to a comprehensive guideline for prevention and control of this ancient disease.

恙虫病临床诊疗专家共识

恙虫病是由恙虫病东方体感染引起的一种自然疫源性疾病,流行于东亚和东南亚地区,主要表现为发热、焦痂或溃疡、淋巴结肿大及皮疹。恙虫病早期症状不典型,容易误诊和漏诊。中国微生物学会人兽共患病病原学专业委员会和中国医药生物技术协会生物诊断技术分会相关专家,根据领域相关研究进展和诊疗经验,并参考国内外相关文献与指南,结合我国临床实践与咨询论证,形成本共识。

基于Scrubbing的空间SRAM型FPGA抗单粒子翻转系统设计

基于SRAM工艺的FPGA在空间环境下容易受到单粒子翻转(Single Event Upsets,SEU)的影响而导致信息丢失或功能中断.在详细讨论三模冗余(Triple Modular Redundancy,TMR)和刷新(Scrubbing)的重要原理及实现细节的基础上,实现了一种高可靠性、TMR+Scrubbing+Reload的容错系统设计,用反熔丝型FPGA对SRAM型FPGA的配置数据进行毫秒级周期刷新,同时对两个FPGA均做TMR处理.该容错设计已实际应用于航天器电子系统,可为高可靠性电子系统设计提供参考.

福建某高岭土伴生石英提纯试验研究

以福建某高岭土伴生石英为研究对象,采用X射线衍射仪(XRD)和X射线荧光光谱仪(XRF)检测矿样的物相组成和化学成分,然后依次进行擦洗、磁选、浮选、分级-分选条件试验,结果表明:试样中SiO_(2)质量分数较低,为85.16%;石英主要以两种形式存在,一种是单体,另一种存在于岩屑中,与长石、云母等共生;浮选试验结果显示捕收剂用量和浮选浓度对降低Al_(2)O_(3)含量影响较大;分级-分选试验揭示了在相同工艺条件下,+0.6 mm粒级石英精矿中杂质含量远低于-0.6+0.1 mm粒级的石英精矿;最终获得的精矿中杂质Al_(2)O_(3)质量分数为2918.68μg/g,Fe_(2)O_(3)质量分数为63.53μg/g,达到了光伏发电玻璃面板所用石英砂的质量要求。

浸没射流条件下气溶胶水洗机理研究

反应堆严重事故发生后,气溶胶池式水洗现象常发生于抑压水池排放过程中,掌握此条件下的气溶胶水洗特性对于严重事故后的放射性评估具有重要意义。本文针对浸没射流条件下的气溶胶水洗效率开展了实验研究,探究了气溶胶直径、液池温度、淹没深度、喷放压力等参数对气溶胶水洗效率的影响。气体穿过破口或喷管以射流的形式向液相内喷放时,由于高速气流剪切作用而产生的夹带液滴会通过惯性效应将气溶胶大量滞留在液相中,喷放压力的增加会增强此效应,而淹没深度的增加也会提高滞留时间及气溶胶接触气液界面的概率。液池温度降低后由于温度梯度及蒸汽冷凝速率的增加,会使水洗效率得到进一步地提高,但热泳、扩散泳等热驱动效应与惯性、液位效应间的作用占比存在一定的制约,通过对现有相关实验进行总结,并基于主导的水洗机制拟合了预测浸没射流条件下水洗效率的经验关系式,可为相关实验及模型提供数据及理论支撑。

微纳气泡对气溶胶池洗去除特性影响研究

反应堆发生严重事故时,微纳米级放射性气溶胶颗粒随高压气体排入抑压水池,在池洗机理作用下滞留在水池中,从而达到防止放射性外泄的目的。已有研究表明,气溶胶池洗效率曲线呈U型分布,当气溶胶粒径在0.1~1μm范围内时,其池洗效率最低。为了提高该粒径范围内的气溶胶池洗效率,本研究借鉴微纳气泡在环境治理方面能够高效去除环境杂质的优势,开展了微纳气泡水中气溶胶池洗效率实验。通过设置对照实验,研究了微纳气泡水的基本特性与去离子水的不同,并将含气溶胶气体分别注入去离子水和微纳气泡水中,对比分析了两种池洗液体中的气溶胶池洗效率,从而探究了微纳气泡对气溶胶池洗去除特性的影响规律。实验结果表明,微纳气泡能够降低池洗液体与固体表面的接触角,提高池洗液体的负zeta电位,使气溶胶更容易穿透气液界面进入到液相中;同时,常规气泡在微纳气泡水中的尺寸更小,单位时间内脱离喷嘴的常规气泡数量增加,使微纳气泡水中常规气泡具有更大的比表面积,且能够在液相中滞留更长时间。这些变化使得微纳气泡水中0.25~1μm粒径范围内气溶胶颗粒的池洗效率显著提高。本研究可以为气溶胶池洗系统设计优化提供实验基础和理论依据。

大连市NGS确诊恙虫病致脓毒症1例

本文报告了大连市2023年首例恙虫病病例,该患者以“发热”为首发症状,伴有特征性焦痂、肝损害、肺炎等临床表现,逐渐进展为脓毒症,最终经NGS确诊,调整抗生素为多西环素,经过积极治疗后病情好转出院。以下详细分析了患者的症状、诊治经过及相关预防措施,通过对这一病例的深入研究,旨在提高公众对恙虫病的认知,并为大连地区恙虫病的预防与控制提供科学依据。

锰矿区大叶胡枝子灌丛土壤的丛枝菌根真菌多样性

大叶胡枝子(Lespedeza davidii)为一种豆科灌木,具有较强耐受重金属胁迫及固氮能力,也是矿区一种重要修复植物。丛枝菌根真菌(Arbuscular mycorrhizal fungi, AMF)是一类植物共生真菌,它在矿区与植物共生可促进植物生长、提高植物的抗逆性;但其种类、分布及其影响机制尚不够清楚。以大叶胡枝子灌丛土壤AMF群落为研究对象,采集矿区与非矿区大叶胡枝子冠下及其相邻空旷地土壤进行内部转录间隔区(ITS)测序,分析土壤理化性质,揭示不同样地土壤AMF群落的多样性及其影响因素。研究结果表明:(1)土壤样本共得到2961个可操作分类单元(OTU),其中属于AMF的OTU为66个;Silva数据库比对发现AMF有7目10科16属24种。AMF总体物种丰度为矿区相邻空旷地土壤>矿区冠下土壤>非矿区冠下土壤>非矿区相邻空旷地土壤,Shannon指数和Simpson指数与该趋势保持一致。(2)矿区土壤AMF群落以内养囊霉属(Entrophospora)等为优势属,非矿区冠下以斗管囊霉属(Funneliformis)等为优势属。稀有内养囊霉(Entrophospora infrequens)是4个样地共有的优势种,该种为广谱生态型种;Archaeospora sp.和Paraglomerales sp.为矿区冠下的优势种,它们对锰胁迫有较强的耐受性;Funneliformis sp.为非矿区冠下的优势种。(3)冗余分析(RDA)表明,AMF的种类和数量受到锰含量、土壤pH值以及全磷含量的显著影响。本研究结果说明AMF种类及多样性受到土壤理化性质的影响;矿区一些耐性AMF的存在提高了AMF多样性,它们有利于逆境条件下植物的生长。

宇航用总线型上注刷新ASIC的设计

当前宇航任务中,SRAM型FPGA易受到单粒子效应的影响,造成非预期的功能失效。为消减单粒子效应的影响、减小FPGA在轨维护重复开发和测试的工作量,设计了一款支持多种总线、适配多型FPGA和存储器的上注刷新ASIC芯片,用于完成FPGA的程序加载、动态刷新、程序上注等操作。首先介绍了ASIC系统层级、模块层级设计、工作流程规划,并简述了ASIC抗单粒子原理。通过对通信协议的兼容设计,ASIC同时支持CAN总线、RS485总线;通过对FPGA配置位流结构分析,ASIC支持9种FPGA的加载和刷新,并实现国产兼容;通过对存储器数据格式转换,ASIC能够在BPI Flash、SPI Flash、PROM等多种存储器中存储配置位流;对刷新的触发、SEFI检测、刷新的执行进行了论述。对影响ASIC上注速度的因素进行了分析和仿真验证;使用原型验证板、ASIC验证板配合可插拔的FPGA、存储器上浮小板完成流片前后的各项功能验证,验证结果符合预期。评估刷新的效果并与其他在轨维护方案进行对比,总线型FPGA上注刷新ASIC具有一定优势,可以高效、可靠地满足宇航FPGA的多种在轨维护需求。

应用熵权法构建适用于基层医疗机构的不典型恙虫病诊断模型

目的提高玉林市基层医疗机构对无焦痂不典型恙虫病的早期诊治能力,有效控制恙虫病的疫情,构建适用于华南和西南亚热带区域的不典型恙虫病诊断模型。方法选取2016年6月至2022年12月在玉林市红十字会医院呼吸科首诊的发热患者作为研究对象,共纳入546例患者,男性335例,女性211例,年龄14~100岁。基于恙虫病在流行病学、临床表现和理化检查3个方面的特点,应用熵权法将其划分为恙虫病、不典型恙虫病、非恙虫病3个组别。经受试者操作特征曲线(ROC)评价、小样本验证与优化,确定不典型恙虫病诊断模型。以间接免疫荧光抗体试验(IFAT)为诊断恙虫病的金标准,评价不典型恙虫病诊断模型和外斐反应OXK对77例恙虫病疑似病例的诊断效能。采用χ^(2)检验。结果依据恙虫病各诊断要素的占比情况,确定恙虫病/不典型恙虫病诊断模型雏形,ROC分析最佳分界值为2.95分,相应曲线下面积(AUC)为0.9628,灵敏度和特异度分别为90.0%、100.0%,小样本(25例)对诊断模型雏形二次评价的灵敏度和特异度分别为90.0%(9例)、86.7%(13例)。不典型恙虫病诊断模型和IFAT在恙虫病诊断方面的效能差异无统计学意义(P>0.05),前者对恙虫病疑似病例诊断的灵敏度、特异度、约登指数、符合率、Kappa值分别为96.7%、70.6%、0.67、90.9%、0.72;而外斐反应OXK与IFAT相比,诊断效能方面差异有统计学意义(P<0.05),对应的诊断灵敏度、特异度、约登指数、符合率、Kappa值分别为5.0%、100.0%、0.05、26.0%、0.02。结论不典型恙虫病诊断模型有助于临床医生客观地分析非特异性的临床资料,为早期诊断和治疗恙虫病提供重要的参考依据,有望在华南和西南亚热带区域诊断技术和设备有限的基层医疗机构推广应用。

恙虫病合并急性呼吸窘迫综合征研究进展

恙虫病为恙螨幼虫叮咬后感染的地方疫源疾病,是东方立克次氏体感染所致的一种胞内菌,最初表现无明显特异性,与流感症状类似,如发热、头痛、咳嗽、肌肉酸痛、听力短暂丧失等,部分患者查体可见特异性焦痂、淋巴结肿大。该病可累及全身多个器官,重症患者常有急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)、急性肾衰竭、心肌炎、脑膜炎、DIC等并发症。目前人们对该病的认知参差不齐,大部分医师尤其是基层首诊医生对恙虫病的认知不足,造成恙虫病误诊、漏诊率仍较高。恙虫病不同地区的毒株类型、疾病检测时间、群体遗传学均存在差异,导致常见的检测方法例如外斐试验阳性率较低。目前对恙虫病合并急性呼吸窘迫综合征的研究较少,本文对恙虫病合并急性呼吸窘迫综合征的诊断以及临床治疗的最新研究进展进行综述,旨在为恙虫病合并ARDS的临床诊疗提供参考。

云南某风化磷矿浮选试验研究

针对云南某风化矿开发利用的问题,经过系统性工艺研究,开发出了一套适用于风化矿的擦洗-浮选联合工艺流程。通过该工艺处理后,将风化矿从P_(2)O_(5)、MgO、SiO_(2)的质量分数从23.52%、1.0%、26.0%,提升到精矿的28.07%、0.85%、19.89%,满足了下游化工企业的生产要求,为其开发利用提供了技术依据。

广东某风化花岗岩中有价矿物综合回收试验研究

为实现广东某风化花岗岩中石英、长石、云母、高岭土等有价矿物的回收利用,开展了选矿综合回收试验研究。针对石英砂+12目颗粒采用“擦洗-分级-磨矿-分级-磁选-浮选云母-浮选长石-酸擦洗”工艺流程,经过高梯度除铁,HK-1和HK-2反浮长石,十二胺反浮云母,石油磺酸钠反浮钛铁矿,最终可获得满足JC/T 2314-2015《光伏玻璃用硅质原料》要求的石英砂精矿,对所得精矿增加酸浸工艺可获得高端电子玻璃砂;-12+150目颗粒采用“擦洗-分级-磨矿-分级-磁选-浮选云母-浮选长石”工艺流程,可获得满足GB 11614-2022《平板玻璃》要求的石英精矿;对流程中产生的中矿和尾矿进行提纯试验,分离出了品质较好的云母、长石和高岭土,实现了有价矿物的综合回收。

位于少见部位的无焦痂恙虫病1例

目的报道1例由恙虫病东方体(Orientia tsutsugamushi,Ot)感染引起的不典型皮疹病例,以增进临床医师对该致病微生物及相关疾病的认识,为临床诊断和治疗提供参考。方法回顾性分析2023年6月收治于山西医科大学第一医院的1例恙虫病(scrub typhus,ST)病例,并对相关文献进行复习。结果患者,男,77岁,主诉左前臂皮疹持续1周,并伴有4天的发热,初次入院时被诊断为软组织感染,接受经验性抗感染治疗,包括静脉滴注头孢曲松钠和头孢哌酮钠舒巴坦钠,然而治疗后患者体温未见下降,皮疹亦未见改善。通过病原宏基因组学二代测序检测结果显示Ot阳性,随后口服盐酸多西环素肠溶胶囊治疗,5小时后患者体温恢复正常,3天后病情明显好转并获准出院,1个月后复诊未见并发症。结论ST病例相对较为罕见,且临床表现多样、复杂,尤其是在无典型皮疹表现的患者中诊断相对困难。尽管ST的总体死亡率较低,但若未能及时诊断并给予针对性治疗,可能导致严重并发症甚至危及生命。因此,临床医生应加强对该致病微生物及其感染的认识,尽早识别感染并积极治疗,以免发生严重并发症。