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说说洛基山斑疹热(Rocky Mountain Spotted Fever)
作者:home99
发表时间:2010-04-02
更新时间:2010-04-02
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天气好不容易暖和起来了,于是下班回来之后带两个宝在外面玩了几次,这两天却有些顾虑重重,为什么呢?还是要从两天前的傍晚说起啊。那天照例在外面两个宝玩得很开心,回来吃了晚饭休息了一会才上楼给两个宝洗澡,小宝刚进澡盆就发现她左胳膊上有个tick,老公让我赶紧找出凡士林,涂在她手臂tick所在部位;我找来一把镊子交给老公,是那种比较紧的小镊子,但折腾了半天也没弄出来。

小宝似乎也不舒服,我想至少有蚊子叮咬的那种感觉吧。我在一旁看得着急,也怕小宝着凉了。于是决定一试,才发现这个tick真有劲,紧紧地吸在皮下,身子只出来一部分,比上次在老公胳膊上发现的那个大了许多(http://www.mitbbs.com/pc/pccon_3509_t0_84393.html),大概有绿豆大小吧。后来将它紧紧夹住,直直地给拔出来,其间不能松劲,可能这个比较大,一次只夹出了身体大部,都怪我们太大意,回来没有及时检查和换衣,所以很可能钻进去已经有一阵子,这也是我担心的地方。

夹出来已经不是完整的tick,我们将所有的碎片都放到一个瓶内,按道理要写上日期及时送给PED检查。并用酒精棉球擦了一下被咬的部位。胳膊里的小“虫子”被夹出来之后,小宝似乎顿觉轻松,还说了声“Thanks!”

老公让我这段时间多留意小宝,如果发烧有红色斑点要及时去看PED,并让我去查Rocky Mountain Spotted Fever,一查才发现如果被感染的tick咬到,不及时治疗还是相当危险的,而且这在美国并不少见。我家后院除了天冷经常有deer出没,我问老公这些tick都在什么地方,是否我家的猫身上也有。因为小宝在外面只是跑着玩,草还没怎么长起来,但有不少落叶,除了摔了一跤,并没有接触什么。老公说是Deer带来的,其它动物身上可能都会有。

根据我看到的资料,下面的一两周内都要注意小宝的变化,第二天我们看了一下,有一个红包,象让蚊子咬过的那样。希望我的乖乖运气好,只是被一个健康的tick咬了一口啊。所以提醒JMs,宝宝从外面回来,特别草丛或动物出没的地方回来,要及时换衣,检查有无tick之类。

我也查到了相应的中文,将我收集到的中英文资料贴出来与JMs分享啊!

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Rocky Mountain Spotted Fever(RMSF,洛基山斑疹热,洛矶山斑疹热/斑点热)

【病名】立氏立克次体斑疹热
【别称】立克氏立克次氏体斑疹热;落基山斑点热;落矶山斑疹热;蜱传热;蜱传斑疹伤寒
【英文】Rocky mountain spotted fever;typhus fever,tick-borne;Fiebre manchada;Fiebre petequial;Febre maculosa;Sao Paulo typhus
【概述】立氏立克次体斑疹热是由立氏立克次体经蜱传播引起的一种急性地方性传染病;本病也称落基山斑点热;蜱传斑疹伤寒(typhus fever;tick- borne;美国疾病控制中心命名);Fiebre manchada(墨西哥命名);Fiebre petequial(哥伦比亚命名);Febre maculosa或Sao Paulo typhus(巴西命名)。临床特征有发热、头痛和皮疹;重型患者可危及生命。

洛基山斑疹热(Rocky mountain spotted fever,RMSF)由立氏立克次体引起,由蜱传播。表现为持续高热,肌肉及关节疼痛和出血性皮疹。流行于美国及南美洲。在美国东部儿童感染率比西部为高,而在成人则相反。在美国大陆,每年有90%立克次氏体病是RMSF。报告的RMSF病例中95%发生在4~9月间,夏威夷无RMSF。

一、概述:

●蜱传病症
●人畜共患性病症
●急性感染
●节肢动物/螨/蜱传感染
●传染性血管炎/毛细管炎
●实验室/生物接触传染病原/危险的
●经皮肤传播病原
●细胞内病原微生物
●特定病原感染
●立克次体感染

立氏立克次体斑疹热是由立氏立克次体经蜱传播引起的一种急性地方性传染病,本病也称落基山斑点热,蜱传斑疹伤寒(typhus fever,tick- borne,美国疾病控制中心命名),Fiebre manchada(墨西哥命名),Fiebre petequial(哥伦比亚命名),Febre maculosa 或Sao Paulo typhus(巴西命名)。

发病高峰季节为夏季。儿童和青年常见。潜伏期2~14 天,平均为7 天。立氏立克次体感染量越大,潜伏期越短,病情也越严重。潜伏期后,部分患者可有1~3 天的前驱期,表现为食欲减退、疲倦、四肢无力和畏寒等症状。

落矶山斑点热是在美国最严重及广泛报告的立克次体疾病,亦在美洲等地有病例。落矶山斑点热在其他国家亦被称为“壁虱斑疹伤寒”、“托比亚热”(哥伦比亚)及“圣保罗热”或“斑疹热”(巴西)。这种病是由一种由虱所传播的细菌立氏立克次体所引发。初发的征状包括突然的发热、头痛及肌痛,接着会发起皮疹。这种病症在初期很难诊断,但若没有即时及适当的治疗,是可以致命的。

落矶山斑点热首先于1896年在美国爱德荷州的蛇河谷发现,并因其皮疹的特征而被称为“黑麻疹”。这种可怖及致命的病症影响着这个地区数以百计的人。在1900年代早期,病症的漫延北至华盛顿及蒙大拿州,及南至加利福尼亚州、亚利桑那州及新墨西哥州。

哈佛·泰勒·立克次就是第一个发现引发落矶山斑点热生物的人。他记述了这个病症的流行病征,包括壁虱在传播时的角色。他们的研究发现落矶山斑点热是由立氏立克次体所引致。这种生物在自然界中的生存是一个涉及壁虱及哺乳动物的复杂循环,而人类是在意外的情况下成为它们的宿主,并非它们自然传播内的一份子。然而造化弄人,他在完成有关落矶山斑点热的研究后不久,于1910年在墨西哥因斑疹伤寒(另一种立克次体疾病)而去世。

落矶山斑点热这个名字带点误导,因为这个病于1930年代开始时,已不限于落矶山地区,并传播至美国的其他地区。现时这个病已经漫延至美洲的其他地区,包括加拿大南部、中美洲、墨西哥,及部份南美洲。在1981年及1996年之间,除了夏威夷州、佛蒙特州、缅因州及阿拉斯加州外,以达至整个美国。

落矶山斑点热今天仍然是严重及危害生命的疾病。纵然现今的治疗技术的提升,仍然有3~5%的患病者死亡。但是,有效的抗体疗法却大幅减少死亡的人数:在1940年代末,未发现四环素及氯霉素前,死于此病的人数可达至患病者的30%。

二、病菌传播

落矶山斑点热与所有立克次体疾病一样,同被分类为动物病。动物病是指一种在动物的疾病传染至人类。大部份动物病都必须有一个带菌者(例如蚊、虱或螨)将疾病由动物宿主传至人类宿主身上。而落矶山斑点热中,虱就是自然的宿主,同时也是立氏立克次体带菌者。虱在主要是在咬脊椎动物时将细菌传播。另外,接触虱的组织、体液或粪便,亦有可能受到感染。

只有硬蜱科的虱会自然地感染立氏立克次体。硬蜱科的生命周期有着四个阶段,分别是卵、幼虫、若虫及成虫,每一个阶段必须喂哺一次以发展到另一个阶段。

雌性的虱会透过一个过程将立氏立克次体传至所产的卵。当在幼虫或若虫时咬到立氏立克次体宿主的血液亦会受到感染。当虱发展至另一阶段时,立氏立克次体亦会透过喂哺传染。另外,雄性的虱在交配时亦会透过体液或精子传染雌性。这些不同种类的传染方式,显示不断维持受感染的虱。一旦感染后,虱整生会是带菌者。

虱在喂哺时的唾液会把立氏立克次体传予脊椎动物,但需要几个小时。因而面临虱传播立氏立克次体的风险是很低。一般来说,约为1%~3%的虱会带有病菌,包括是有人类感染的地区。

在美国,有两种立氏立克次体的带菌者,它们是矩头蜱属的美洲大革蜱及落矶山革蜱。美洲大革蜱广泛分布于洛矶山脉东面及太平洋海岸的一些地区。它们会依附在犬只或中等身型的哺乳动物,亦是现时发现一般传播立氏立克次体至人类的品种。落矶山革蜱分布于洛矶山脉的州郡及加拿大西南部。它们约须2~3年的时间成虫,成虫一主要是依附在大型的哺乳动物,而幼虫或若虫则是依附在较细小的啮齿目。

其他种类的虱亦有发现感染立氏立克次体或是在实验中成为带菌者。但是,这些品种却在病菌的生态上占有很渺小的地位。

三、立氏立克次体斑疹热专业介绍

1、疾病描述

立氏立克次体斑疹热是由立氏立克次体经蜱传播引起的一种急性地方性传染病,本病也称落基山斑点热,蜱传斑疹伤寒(typhus fever,tick- borne,美国疾病控制中心命名),Fiebre manchada(墨西哥命名),Fiebre petequial(哥伦比亚命名),Febre maculosa 或Sao Paulo typhus(巴西命名)。临床特征有发热、头痛和皮疹,重型患者可危及生命。

2、疾病原因

立氏立克次体的形态以球杆状为主,大小为(0.3μm~0.6μm)×(1.2μm~2.0μm),革兰染色阴性。对热和消毒剂敏感。耐低温,在受感染细胞内置-70℃以下可长期存活。动物接种能使家兔、小白鼠、豚鼠和猴子发病。可用鸡胚和Vero 细胞来分离立氏立克次体。

3、病理生理变化

立氏立克次体有两种表面蛋白,分子量分别为1.2×10^5 和1.55×10^5,与致病力有关。立氏立克次体主要侵犯动静脉内皮细胞造成血管炎症和通透性增加。严重时凝血系统和激肽系统被激活,引起血栓性阻塞、血管肌层坏死以及中枢神经系统的微栓塞,使心脏、肺脏、肾脏和中枢神经系统等主要器官功能损害。病理变化程度比恙虫病和斑疹伤寒严重。

4、鉴别诊断

本病的主要鉴别诊断为麻疹,可借助麻疹口腔黏膜科氏斑的特征进行鉴别。有中枢神经系统症状的患者应与流行性脑脊髓膜炎败血症型相鉴别,可借助流行性脑脊髓膜炎败血症型的瘀点和瘀斑出现早,脑脊液呈化脓性改变进行鉴别。

5、并发症

立氏立克次体斑疹热的并发症有休克、心脏和肾衰竭等。一些患者病情恢复后可有耳聋、视力下降、肢体瘫痪和反复发作的大疱性红斑等后遗症。

6、流行病学

Howard T.Ricketts 按照本病的发现地理位置美国落基山来命名。

①传染源:为被立氏立克次体感染的兔、松鼠、鹿和熊等动物,以及既能作为贮存宿主又能作为传播媒介的硬蜱。

②传播途径:主要为硬蜱类,如美洲犬蜱、安得逊革蜱、变异革蜱及血红扇头蜱等。立氏立克次体在某些蜱类和动物中维持循环,当人进入本病流行区,经蜱叮咬而发生感染。另外,当碾碎蜱或接触蜱粪便时,立氏立克次体可通过破损的皮肤和眼结膜进入人体,也可通过误输被污染的血液或在实验室内吸入被污染的气溶胶而受感染。

③易感人群:人群普遍易感。立氏立克次体斑疹热可产生保护性免疫,未见再次感染的报告。

④流行特征:本病主要流行于美洲,包括美国、加拿大、墨西哥、哥伦比亚、巴拿马和哥斯达黎加等。发病高峰季节为夏季。儿童和青年常见。

【流行病学】

经感染的蜱叮咬而传播。蜱吸食感染动物(包括狗、啮齿类和其他小动物)的血后成为携带者。接触被压碎的蜱组织或排泄物亦可受染。RMSF无人与人之间传播。

在美国,落矶山斑点热首先于1918年发生,在过往的50年,每年约有250~1200宗个案。有超过90%的病人是在四月至八月之间感染,这个期间正是矩头蜱属成虫及若虫的增长季节。个案的60%为因被虱咬或曾经过虱的聚居地而感染。

超过一半的美国个案是在南大西洋地区发生,包括有德拉瓦州、马利兰州、华盛顿哥伦比亚特区、维吉尼亚州、西维吉尼亚州、北卡罗莱那州、南卡罗莱那州、佐治亚州及佛罗里达州。感染个案亦在美国其他地区发生,如太平洋区的华盛顿州、奥勒冈州及加利福尼亚州及中南区西部的阿肯色州、路易西安纳州、奥克拉荷马州及得克萨斯州。

当中最多个案的分别是北卡罗莱那州及奥克拉荷马州,两个州份由1993年至1996年的总个案数目为全美的35%。虽然最初发现此症的是洛矶山脉的州份,但同期的总数却少于3%。

而个案发生率占多数的是男性、白种人及孩童。15岁以下孩童的感染个案占孩童感染个案的三分之二,当中最高的年龄界别为5~9岁。而经常与犬只接触,或是居住在近林木或草原地区的人会有较高的感染风险。

感染立氏立克次体的个案亦有在阿根廷、巴西、哥伦比亚、哥斯达黎加、墨西哥及巴拿马发生。与立氏立克次体有近亲关系的细菌亦在世界其他地区引发其他的病症。

【症状体征】

潜伏期2~14天,平均为7 天。立氏立克次体感染量越大,潜伏期越短,病情也越严重。潜伏期后,部分患者可有1~3天的前驱期,表现为食欲减退、疲倦、四肢无力和畏寒等症状。

典型患者突然起病,体温急剧上升到39~40℃,严重患者可出现41℃以上的超高热。伴有寒战、剧烈头痛、全身肌肉和关节疼痛、畏光和眼球后痛。肝、脾可出现肿大。未经病原治疗,发热不退,热程可达2~3 周,以后多数患者发热缓慢消退。立氏立克次体斑疹热与其他斑点热不同的是在蜱叮咬处不出现溃疡或焦痂(初疮),如果叮咬处发生细菌感染可有化脓性炎症改变或脓疱。

80%天90%患者在发热后3~4天出现皮疹,开始位于手腕和踝部,以后扩展到手臂、双足、胸腹部和颌面部。皮疹形态为粉红色斑疹,直径2~5mm。出疹2~3 天后,皮疹出现融和,转变为红色或紫色。恢复期皮疹逐渐消退,在手掌、足底、踝周和腋窝的皱褶处皮疹变为瘀点,形成立氏立克次体斑疹热皮疹的特征性分布。皮疹消退后可有短暂的色素沉着和糠皮样脱皮。

没有得到有效治疗的患者,立氏立克次体可使血管内皮的损害加重,出现血栓形成和局部缺血性坏疽,在鼻尖、耳垂、阴囊部和指趾处的皮肤容易发生。如果大动脉血栓形成,可发生肢体坏死和偏瘫。重型患者常因心肌炎和肺水肿而死亡。

【临床表现】

●急性咳嗽
●咳嗽(15%)
●干咳无痰
●腹壁痛
●鼻衄/鼻出血
●畏光
●眶后痛
●肝脾肿大(30%)
●全身痛
●脸红

被感染蜱叮咬后7天出现症状,也可3~14天不等。
发热(可持续2~3周)、严重头痛、疲劳、眼红肿、深部肌肉疼痛、寒战。在2~6天内,腕和踝处出现典型皮疹,并迅速传播全身。

纵然由非常熟悉落矶山斑点热的医生作出诊断,但病症在早期仍然是很难去诊断的。一般的病患者会在病发第一周就诊,接着会有一段1~14天的潜伏期。早期的临床病征并不特别,甚至与其他病症相似,这些病征包括:发热、反胃、呕吐、头痛、肌痛及厌食。其后会有的病征包括斑丘疹、瘀点、腹痛、关节痛及腹泻。
落矶山斑点热的典型病征包括有发热、皮疹及曾被虱咬。但是早期的病人多不会有以上所有的病征。

皮疹会在发热后的2~5日出现,在开始时非常不明显。年幼的病人一般会较年长的病人早出现皮疹。开始时是在手腕、前臂及脚跟的细小、扁平、呈粉红色及不痒的斑点。这些斑点会转为淡色及最后在皮肤上凸起。呈红色的瘀点一般在其他病征出现前六日都是不能看见的,而约35%~60%的病人都会长这些瘀点。50%~80%的病人会在手掌及脚底长斑点,但是这些斑点在病症的后期未必会出现。而10%~15%的病却不会长出斑点。

患有落矶山斑点热的病人会有一些不正常的情况,包括血小板减少症、低钠血或攀升的肝脏酶水平。

落矶山斑点热是一种严重的病症,而病人都需要入院。因为立氏立克次体感染身体的血管壁细胞,严重的会影响呼吸系统、中央神经系统、消化系统或肾脏。大年纪及男性均是患有严重或致命落矶山斑点热的因素。

因落矶山斑点热而有的长期健康问题包括下肢局部麻痹、坏疽导致切除手指、脚趾、手臂或脚、听力衰退、失去控制膀胱能力、运动及语言障碍。这些问题在曾患有严重及危及生命病症,长期住院的病人会较易出现。

【诊断检查】

诊断措施
●病理检查/血管
●白细胞计数及分类
●心电图
●凝血酶原时间测量
●D-二聚体测定
●变形菌OX-19滴度
●病理检查/脑
●病理检查/细胞
●X线检查:常规胸片
●单核细胞计数

鉴别诊断
●病毒脑膜炎

诊断:2 周内到过蜱媒存在的小城镇或农村,与携带硬蜱的动物有接触史,或有被硬蜱叮咬史均是流行病学有用的参考资料。患者急性发热、剧烈头痛、畏光、眼球后痛以及手腕和踝部有粉红色皮疹,应高度怀疑本病。外-斐反应和免疫学阳性结果有利于临床诊断。皮肤、皮疹活检特异性免疫荧光抗体阳性和动物病原体分离阳性有确诊意义。

实验室检查:

1、血常规检查:外周白细胞计数早期减少,以后大多在正常范围。如果出现重型化或继发细菌感染可出现升高。病情后期可出现继发性贫血。

2、凝血机制检查:严重患者可出现纤维蛋白原减少,凝血酶原时间和部分凝血酶时间延长,甚至发生弥散性血管内凝血。

3、脑脊液检查:出现神经系统病变的患者,脑脊液检查可见压力升高,单核细胞计数和蛋白水平轻度增加。

4、免疫学检查:外-斐反应OX19 和OX2 可出现凝聚反应,间隔2 周复查OX19和OX2 的凝聚效价可有4 倍的升高;而OXk 不出现阳性。此外,间接免疫荧光抗体试验和补体结合试验也可出现阳性反应,在2~3 周后效价有4 倍的增高。皮肤和皮疹活检进行免疫荧光抗体试验,可发现立克司立克次体,试验过程仅需要4~6h,可在病程的3~4天就有阳性结果,有早期快速诊断意义。

5、病原学检查:立氏立克次体仅能在生长于真核细胞内,在游离的细胞培养上不能分离该立克次体。可用家兔或小鼠进行病原体分离,阳性结果有确诊意义。

其他辅助检查:腹部超声检查肝脾肿大。

【并发症】

●继发心肌炎
●败血症性休克
●手指坏疽
●血小板减少(症)
●贫血
●间质性肾炎
●脑膜脑炎(意识错乱, 昏睡, 谵妄)
●结膜炎(30%)
●脓毒性休克
●ADH不适当分泌综合征

【加重或协同因素】

●G6PD缺乏
●6-磷酸葡萄糖脱氢酶缺乏

【治疗】

●感染隔离
●土霉素
●四环素 10 mg/kg po q6h 7~10天
●抗生素
●地美环素
●抗生素类抗微生物药
●氯霉素

就医,抗生素治疗,早期治疗可提高治愈率。如近期被蜱叮咬,一旦发病应尽快就医。若在临床及流行病学的发现中怀疑病人患有落矶山斑点热,在初期便须使用合适的抗生素疗法。治疗不应因等候化验结果而延误。早期使用抗生素可使死亡率从20%显著降低到7%,并可预防大多并发症。

无有效疫苗可用,无切实有效方法消灭整个地区的蜱,但可通过控制小动物群体使地方性流行区蜱的数目下降。为预防蜱接触皮肤可将裤子塞进长靴或长袜,穿长袖衬衫,在皮肤表面涂擦25%~40%二乙基甲氨(diethyltoluamide),衣服上使用苄氯菊酯能有效驱蜱,但在儿童有毒性反应的报道。应保持良好卫生习惯,特别在儿童,要经常检查有无蜱粘附身体。已吸过血的蜱应小心除去,不要用手指压碎,防止感染。可用小钳咬住蜱的头部慢慢拉出,粘附处用酒精消毒。

在地方性流行区被蜱咬伤后,但无临床症状者,不要立即给予抗生素。但病人或其父母应密切注意早期症状的出现,如有发热,头痛和疲乏出现,不管有无皮疹,抗生素治疗应迅速开始。所有立克次体病都需要特异性化疗和支持疗法。在此介绍适于所有感染的处理措施。特殊措施在埃里希体病,立克次体痘,Q热和战壕热处介绍。

当疹子一出现时即开始治疗,症状会迅速缓解。由于RMSF病人不经治疗很可能在血清学诊断确立前变得非常严重甚至死亡,因此一旦拟诊即应开始治疗。 36~48小时内可见到明显的临床改善,2~3天热度退去。在恙虫病,反应更迅速。

若病人在发病的首4~5日接受治疗,在使用适合的抗生素(一般是四环素)24~72小时后发热会退下来。事实上,若对四环素没有反应,有主张认为病人所患的并非落矶山斑点热。严重病患者,尤其是多种器官受到破坏,则需要较长期的治疗,直到退热。对未发病者的预防性治疗有可能会延误病发,所以并不建议。

四环素和氯霉素特别有效,它们是抑制立克次体而非杀死立克次体。适宜的治疗方案包括首次口服四环素25mg/kg或氯霉素50mg/kg,随后将同样剂量分每天3~4次口服。不能服药者可行静脉注射。

四环霉素是一种适合落矶山斑点热的药物,成人的剂量是每12小时100mg,而轻于45kg的孩童则每日每公斤4mg,分两剂服用。在退热后治疗需要连续3日,直至有确定的临床改善证据,整个疗程一般最少是5~10日。严重或复杂的病症需要较长的疗程。四环霉素亦是用于治疗犬艾利希体症的药物,这是另一种由虱所传染的病症,与落矶山斑点热有相似的病征。

氯霉素是另一种药物可以治疗落矶山斑点热。但是,这种药物有着不同的副作用,且需要小心监察血液水平(因它会引发再生不良性贫血)。

在晚期才开始治疗的病人,临床改善很慢,热度会持续较长时间。斑疹伤寒群和斑点热群立克次体病严重患者常有循环衰竭,少尿,无尿,氮血症,贫血,低钠血症,低氯血症,水肿和昏迷。在中轻度病人,这些变化缺如,因而处理较简单。对严重病例晚期就诊者,可连续3天给予大剂量皮质类固醇和特异性抗生素。

严重的RMSF和流行性斑疹伤寒病人在疾病晚期血管通透性显著增加,因此静脉输液应特别小心,避免肺和脑水肿。对弥散性血管内凝血病人不主张使用肝素。

【治疗方案】

影响细菌蛋白质合成的抗菌药物对立氏立克次体有特效。四环素,成人,250~500mg/次,3 次/d 或4 次/d,口服;或者1g/d,静脉滴注。多西环素,成人,100mg/次,1 次/12h,口服。氯霉素,成人,250~500mg/次,3 次/d 或4次/d,口服;或者1~2g/d,静脉滴注。一般患者病原治疗2~3 天体温下降,抗菌药物疗程为6 天。尚未见有对四环素和氯霉素耐药的报告,复发罕见。喹诺酮类抗菌药物也有特效。由于立克次体缺乏细胞壁,青霉素和头孢霉素类抗菌药物无效。重型患者应给予积极的支持疗法,提供足够营养和热量,维持水、电解质和酸碱平衡,保护重要脏器功能。中毒症状明显或头痛剧烈时可适量使用糖皮质激素。

【预防】

最有效减少落矶山斑点热感染的方法是限制曝露于虱当中。若曝露于虱群的环境中,须立即小心检查及移除身体上的虱,以防止疾病。由虱传染病菌至宿主需要几个小时。现时,并未有任何落矶山斑点热的疫苗。

最好的方法是避免接触蜱。当无法避开蜱活动区时,要经常检查身体或衣服有无蜱附着。到有蜱活动的野外时,可喷驱避剂在衣服上。在小径和住房周围喷洒杀蜱剂,控制蜱的繁殖。清除院内杂草,降低住房周围蜱数量。

1、控制传染源:灭鼠和灭蜱。
2、切断传播途径:在牧场、灌木、草地和住宅有蜱隐蔽的地方可使用2%马拉硫磷溶液喷洒灭蜱。
3、保护易感人群:在野外工作应穿防护服,也可在外露的部位使用乙酰苯胺丁酯等驱避剂。鸡胚卵黄囊疫苗有部分保护作用,能延长潜伏期,缩短热程,减轻病情,但是,不能防止发病。临时需要进入疫区,可口服多西环素预防。

【[预后】

不会再感染。RMSF康复后,可产生完全的免疫,因此患病后不会再感染。

立氏立克次体斑疹热是一种人体宿主全身性细胞受累的严重感染性疾病,如果没有进行有效病原治疗,病死率可达20%~30%。使用及时有效的抗菌药物可把病死率降低到3%。暴发型患者病理改变呈不可逆进行性发展,可在3~5 天内死亡。重型患者的发生与下列因素有关,包括高龄患病,有效抗菌药物使用不及时和患者葡糖-6-磷酸脱氢酶缺乏等。症状出现4~5 天之后应用有效的抗菌药物死亡率相差数倍。故此,立氏立克次体斑疹热患者应该住院治疗,密切观察肺部体征、血压、尿量、心功能和颅内压的改变。

★★★如何去除附着的蜱?

用镊子尽可能靠近皮肤夹起蜱,保持稳定的压力,向上向外拔除。亦可戴橡皮手套或用纸巾帮助操作。避免裸手接触蜱。注意不要压挤或刺蜱体,除蜱后用肥皂和水清洗叮咬部位和手。发现蜱应迅速及时去除之,不要用汽油、烟头或其他家庭药品除去蜱,那样可能会增加感染的危险。

四、立氏立克次体斑疹热科普

别名:立克氏立克次氏体斑疹热;落基山斑点热;落基山斑点热;落矶山斑疹热;蜱传热;蜱传斑疹伤寒;

临床表现:潜伏期2~14天,平均为7天立氏立克次体感染量越大,潜伏期越短病情也越严重潜伏期后,部分患者可有1~3天的前驱期,表现为食欲减退疲倦、四肢无力和畏寒等症状。

典型患者突然起病体温急剧上升到39~40℃严重患者可出现41℃以上的超高热。伴有寒战、剧烈头痛、全身肌肉和关节疼痛畏光和眼球后痛肝、脾可出现肿大。未经病原治疗发热不退热程可达2~3周,以后多数患者发热缓慢消退。

立氏立克次体斑疹热与其他斑点热不同的是在蜱叮咬处不出现溃疡或焦痂(初疮),如果叮咬处发生细菌感染可有化脓性炎症改变或脓疱。

80%天90%患者在发热后3~4天出现皮疹,开始位于手腕和踝部以后扩展到手臂、双足、胸腹部和颌面部皮疹形态为粉红色斑疹直径2~5mm。出疹2~3天后,皮疹出现融和转变为红色或紫色。恢复期皮疹逐渐消退,在手掌足底踝周和腋窝的皱褶处皮疹变为瘀点形成立氏立克次体斑疹热皮疹的特征性分布皮疹消退后可有短暂的色素沉着和糠皮样脱皮。

没有得到有效治疗m的患者立氏立克次体可使血管内皮的损害加重,出现血栓形成和局部缺血性坏疽在鼻尖耳垂、阴囊部和指趾处的皮肤容易发生。如果大动脉血栓形成,可发生肢体坏死和偏瘫重型患者常因心肌炎和肺水肿而死亡。

并发症:立氏立克次体斑疹热的并发症有休克、心脏和肾衰竭等,一些患者病情恢复后可有耳聋、视力下降肢体瘫痪和反复发作的大疱性红斑等后遗症。

诊断:2周内到过蜱媒存在的小城镇或农村与携带硬蜱的动物有接触史或有被硬蜱叮咬史均是流行病学有用的参考资料。患者急性发热剧烈头痛畏光、眼球后痛以及手腕和踝部有粉红色皮疹应高度怀疑本病。外-斐反应和免疫学阳性结果有利于临床诊断。皮肤皮疹活检特异性免疫荧光抗体阳性和动物病原体分离阳性有确诊意义。

鉴别诊断:本病的主要鉴别诊断为麻疹,可借助麻疹口腔黏膜科氏斑的特征进行鉴别有中枢神经系统症状的患者应与流行性脑脊髓膜炎败血症型相鉴别可借助流行性脑脊髓膜炎败血症型的瘀点和瘀斑出现早脑脊液呈化脓性改变进行鉴别。

★什么叫落矶山斑疹热?
落矶山斑疹热是立克次体引起的急性病症,立克次体由蜱传播给人。在春季和夏季较为常见。它不会人从人传染给另一人。 狗和啮齿动物身上可能有蜱,因此落矶山斑疹热可发生在市区或乡镇。

★落矶山斑疹热有哪些表现?
通常蜱咬后2~5天内,出现高烧伴冷颤、红色皮疹首先在手和脚出现,然后传播到腕和踝,最后传播到腿和、躯干。 肌肉无力伴肌肉疼痛、头疼、 恶心和呕吐、 气短和咳嗽、精神错乱。

★如何诊断落矶山斑疹热?
实验室检查。

★如何治疗落矶山斑疹热?
急性阶段应住院治疗。可使用抗生素,例如四环素或氯霉素。应该避免阿司匹林,防止可能的出血并发症。 患者应该卧床休息,直到热退。饮食无特殊要求,应该鼓励多饮水。抗生素不要同牛奶和抗酸剂同时服用。

★病人注意事项?
● 完成抗生素全部疗程。 通常需要的一星期才能退热。
● 发烧时,要多饮水并。
● 发烧时卧床休息。
● 取暖电毯可缓解肌肉疼痛。
● 使用非阿司匹林药物减少发热或疼痛。
● 避免蜱叮咬。
● 不要使用阿司匹林或含阿司匹林药物。避免导致出血并复杂化。
● 服抗生素2 小时内不要喝牛奶或服抗酸剂。

★应何时就诊?
● 出现胸痛、气短加剧。
● 有脱水表现,皮肤干燥、尿减少。
● 皮疹出现感染。
● 非阿司匹林药物不能退热。
● 出现严重头疼或癫痫。
● 有严重腹痛。
● 出现出血现象。

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Rocky Mountain Spotted Fever

Rocky Mountain spotted fever (RMSF) is a tickborne disease first recognized in 1896 in the Snake River Valley of Idaho. It was originally called “black measles” because of the look of its rash in the late stages of the illness, when the skin turns black. It was a dreaded, often fatal disease, affecting hundreds of people in Idaho. By the early 1900s, the disease could be found in western states as far north as Washington and Montana and as far south as California, Arizona, and New Mexico.

1、Overview

Rocky Mountain spotted fever (RMSF) is a tickborne disease first recognized in 1896 in the Snake River Valley of Idaho. It was originally called “black measles” because of the look of its rash in the late stages of the illness, when the skin turns black. It was a dreaded, often fatal disease, affecting hundreds of people in Idaho. By the early 1900s, the disease could be found in western states as far north as Washington and Montana and as far south as California, Arizona, and New Mexico.

In response to this health problem, the U.S. Public Health Service sent University of Chicago pathologist Dr. Howard T. Ricketts to the Bitterroot Valley of Montana, one of the disease hotspots. In 1906 Dr. Ricketts demonstrated that the disease was transmitted by the bite of the Rocky Mountain wood tick. The work of Dr. Ricketts laid the foundation for what later became the Rocky Mountain Laboratories (RML) in Hamilton, Montana. Today, hundreds of scientists continue to study tick-borne as well as other diseases at RML, which is now part of the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health in Bethesda, Maryland.

Though U.S. health care providers typically report about 250 to 1,200 cases of RMSF each year to the Centers for Disease Control and Prevention (CDC), a record 1,514 cases were reported in 2004.

RMSF is found throughout the United States from April through September. More than half of all cases occur in the mid-Atlantic to southern region of the United States (Delaware, Maryland, Washington, D.C., Virginia, West Virginia, North Carolina, South Carolina, Georgia, Oklahoma, and Florida). North Carolina and Oklahoma report the greatest number of people with RMSF. Although the disease was first discovered in the Rocky Mountains, that area has relatively few cases today. The disease also has been found in Canada and in Central and South America.

2、Cause

Rocky Mountain Spotted Fever is caused by the bacterium known as Rickettsia ricketsii.

3、Transmission

You can get Rocky Mountain Spotted Fever (RMSF) disease from the bite of an infected tick. In the United States, the American dog tick and the Rocky Mountain wood tick are the main vectors (carriers) of RMSF bacteria. The wood tick is found mainly in the Rocky Mountain States, including Montana, Idaho, Colorado, Wyoming, Utah, and Nevada.

The dog tick is found from the Great Plains to the East Coast, in Alaska and Hawaii, and in parts of California. The dog tick is not found in the interior northwest.

http://www3.niaid.nih.gov/NR/rdonlyres/163D6DCF-635E-43D5-BE2F-EBA80D302F1E/0/american_dog_tick.jpg
http://www3.niaid.nih.gov/NR/rdonlyres/8A9D2AE1-D311-42C3-A089-B839019EB4F6/0/rocky_mtn_wood_tick.jpg

4、Symptoms

The first symptoms of Rocky Mountain Spotted Fever (RMSF) may include

● Moderate to high fever, which can persist for 2 to 3 weeks if the infection is untreated
● Nausea
● Vomiting
● Severe headache
● Deep muscle pain
● Significant tiredness
● Chills
● Lack of appetite

You usually will see the rash 2 to 5 days after the fever begins. The red-spotted rash often starts as small, flat, pink, non-itchy spots on your wrists, forearms, and ankles. These spots turn pale when you apply pressure. They eventually become raised on your skin. In the late stages of the illness, skin tissue begins to die and turn black – thus the original local name “black measles.” A few people with RMSF never develop a rash.

Some people develop additional symptoms later in the disease, including rash on the palms of their hands or soles of their feet, abdominal pain, joint pain, and diarrhea.

5、Diagnosis

Your health care provider can diagnose Rocky Mountain Spotted Fever by evaluating your symptoms and doing laboratory tests.

6、Treatment

Your health care provider will treat your Rocky Mountain Spotted Fever with an antibiotic, possibly doxycycline. You should continue to take the medicine for at least 3 days after the fever goes away and after your symptoms end.

7、Prevention

To help prevent Rocky Mountain Spotted Fever (RMSF), you should avoid walking in areas of tall grass and brush where there may be ticks. If you do go into these areas, be sure to

● Wear light-colored clothing.
● Tuck your pants legs into your socks so ticks can’t get up inside your pants legs.
● Wear a long-sleeved shirt and tuck it inside your pants.
● Spray insecticide containing permethrin on boots and clothing. The effects will last several days.
● Apply insect repellent containing DEET to your skin. Because DEET lasts only a few hours, you may need to reapply it.
● Look for ticks on your body, including in your hair, when you return from hiking or walking.
● Check children and pets for ticks.

Generally, a tick needs to be attached to your body for at least 24 hours before it can infect you. You should remove it with fine-tipped tweezers. Centers for Disease Control and Prevention has more information on how to prevent tick bites and to remove ticks.

8、Complications

Rocky Mountain Spotted Fever (RMSF) can be a very severe illness that requires hospitalization. The bacteria infect cells that line blood vessels throughout the body. This infection can cause problems in the respiratory system, central nervous system, gastrointestinal system, or kidneys.

Some people infected with RMSF develop long-term health problems including

● Partial paralysis of the legs
● Gangrene requiring amputation of fingers, toes, arms, or legs
● Hearing loss
● Loss of bowel or bladder control
● Difficulty moving
● Language disorders

These problems are most frequent in those recovering from severe, life-threatening disease, often following lengthy hospitalizations.

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About RMSF

Rocky Mountain spotted fever (RMSF) is a bacterial infection that's transmitted to people by tick bites. It occurs most often in the spring and summer, during months when ticks are active — between April and early September.

Although RMSF is most common in the southeastern part of the United States (Virginia, Georgia, and the Carolinas), it occurs in other states as well. It's relatively rare (about 250–2,000 cases per year in the United States), but can be a serious disease if not treated properly.

The bacteria Rickettsia rickettsii that causes RMSF is transmitted by the dog tick (Dermacentor variabilis) in the eastern United States and by the wood tick (Dermacentor andersoni) in the Rocky Mountain states. On the West Coast, the lone star tick (Amblyomma americanum) also can transmit the bacteria.

RMSF gets its name from the trademark rash it causes — small red spots and blotches that begin on the wrists, ankles, palms, and soles. In addition to the rash, the infection can cause fever, chills, muscle aches, vomiting, and nausea. Typically, RMSF is treated with antibiotics and patients recover without any complications. But with late or no treatment, RMSF can cause serious health problems. If your child has fever, achiness, stiff neck, or rash and has or may have been bitten by a tick, it's important to talk with your doctor.

1、Signs and Symptoms

The symptoms of RMSF typically develop within 1 week of a tick bite but can take up to 2 weeks to appear. In many cases, the person doesn't even remember being bitten by a tick.

Symptoms of RMSF usually begin suddenly. There is a high fever — often 103° Fahrenheit (39° Celsius) to 105° Fahrenheit (40° Celsius) — with chills, muscle aches, and a severe headache. Eyes can become red, muscles may feel tender, and there may be abdominal pain, nausea, vomiting, poor appetite, and fatigue.

The trademark rash of this infection can begin anytime up to 10 days after the fever and headache start, but it most often appears on the third to fifth day. The rash looks like small red spots or blotches that begin on the wrists, ankles, palms, and soles. It spreads up the arms and legs toward the trunk. As the RMSF infection progresses, the original red spots might start to look more like bruises or bloody dots or patches under the skin.

2、Treating Rocky Mountain Spotted Fever

Doctors usually diagnose Rocky Mountain spotted fever based on enough symptoms to indicate infection. Test results for RMSF can take a while to be sent to the doctor, so treatment often starts before the results are available.

RMSF is typically treated with oral or IV antibiotics, depending on the severity of the infection. Complications may require prolonged treatment.

Untreated, RMSF can lead to serious health problems, so it's important to call your doctor promptly if you notice any symptoms of RMSF, such as:

● high fever
● headache
● chills
● muscle aches
● red eyes
● rash

Without antibiotic treatment, RMSF can lead to health problems that involve the heart, lungs, and brain. In the most severe case, it can be fatal.

If your child is recovering from RMSF at home, follow the doctor's instructions for giving antibiotics. Allow your child to rest in bed until the fever and other symptoms are gone.

3、Prevention

RMSF can be prevented by avoiding tick-infested areas, like woods and tall grasses, brush, shrubs, and low tree branches, and by taking precautions when spending time outdoors.

When they're playing outdoors, have kids wear light-colored clothing that makes ticks more visible if they get onto them and, if it's practical, long-sleeved shirts and long pants. Use an insect repellant that fends off ticks, being careful to follow the label instructions. Be sure to use a repellent that contains 10% to 30% concentration of DEET (look for N,N-diethyl-meta-toluamide).

Not all ticks carry the RMSF bacteria, but it's a good idea to remove any immediately. The longer a tick stays attached to the skin, the greater the chance of infection. It usually takes several hours for a tick to transmit the bacteria that cause RMSF once it has become attached to the skin.

To remove a dog tick, use tweezers to grasp it by the head (not just the body) as close to the skin as possible. Pull steadily until the tick dislodges. Without touching the tick, preserve it in a jar or plastic bag until you can show it to your doctor. Disinfect the bite area with alcohol, wash your hands, and call your doctor.

Since pets can also bring ticks into your home, check their skin and fur for ticks whenever they have been playing in tick-infested areas. Follow your veterinarian's advice about collars and other products that can be used to keep your pet tick-free.

If you have any concerns, talk with your doctor.

4、Evaluate Your Child's Lyme Disease Risk

In warm weather, the threat of Lyme disease might make you think that your kids would be safer in the comfort of a climate-controlled living room rather than the great outdoors. Though a child's risk of getting Lyme disease after being bitten by a tick is only about 1–3%, it's important to consider the factors that affect someone's Lyme disease risk.

★Location

It's true that Lyme disease is the leading tick-borne disease in the United States, with more than 23,000 cases reported to the Centers for Disease Control and Prevention (CDC) in 2005. Most cases of Lyme disease occur in the Northeast, upper Midwest, and Pacific coast areas of the United States. Lyme disease incidence has been reported in other states, but those that have been hardest hit are:

● Connecticut
● Delaware
● Maine
● Massachusetts
● Maryland
● Minnesota
● New Hampshire
● New Jersey
● New York
● Pennsylvania
● Wisconsin

Cases have also been reported in Asia, Europe, and parts of Canada. Most cases of Lyme disease occur between April and October, particularly in June and July.

★Outdoor Activities and Pets

Besides living in one of these areas, other factors that might increase a child's tick risk include:

● spending a lot of time outdoors in tall grass, brush, shrubs, or wooded areas
● having pets that may carry ticks indoors
● participating in activities such as landscaping, hiking, camping, fishing, or hunting in tick-infested areas

★Safety Tips

So your teen got a job as a landscaper this summer and you're planning a family camping trip — does that mean Lyme disease is in your family's future? No, but it does mean that you should take some precautions to protect your family — such as using insect repellent and wearing light-colored clothing when outdoors to make spotting ticks easier — and know how to remove a tick, just in case.

If you find a tick:

● Call your doctor, who may want you to save the tick after removal for identification as the type that may carry Lyme disease or another type of illness. You can put the tick in a jar of alcohol to kill it.
● Use tweezers to grasp the tick firmly at its head or mouth, next to the skin.
● Pull firmly and steadily on the tick until it lets go of the skin. If part of the tick stays in the skin, don't worry, it will eventually come out — although you should call your doctor if you notice any irritation in the area or symptoms of Lyme disease.
● Swab the bite site with alcohol.

One note of caution: Don't use petroleum jelly or a lit match to kill a tick — they're not effective.

It's important to remove the tick as soon as possible. The longer the tick is attached, the greater the chance that Lyme disease has been transmitted. Usually, bacteria from a tick bite will enter the bloodstream only if the tick stays attached to the skin for 36–48 hours or longer. If the tick is removed within 1 to 2 days, it is less likely have transmitted Lyme disease.

5、Tick Removal: A Step-by-Step Guide

Boy, your child's freckles really stand out in the sun - but wait, that one looks like it's moving! It isn't a freckle at all. It's a tick. What should you do?

First, don't panic. It's true that Lyme disease is the most common tick-borne disease in the United States, but your child's risk of developing Lyme disease after being bitten by a tick is very low.

To be safe, though, you'll want to remove the tick as soon as possible because risk of infection increases between 24 to 72 hours after the tick attaches to the skin.

One note of caution: don't use petroleum jelly or a hot match to kill and remove a tick.

Reviewed by: Steven Dowshen, MD
Date reviewed: September 2007

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Rocky Mountain spotted fever

1、Definition

Rocky Mountain spotted fever is a potentially serious bacterial infection transmitted to humans by tick bites. The illness is named after the Rocky Mountain region, where the disease was first identified. Rocky Mountain spotted fever occurs when an infected tick attaches to your skin and feeds on your blood. The infection then has the potential to spread to your bloodstream and other areas of your body.

Rocky Mountain spotted fever doesn't spread directly from person to person. If treated promptly, a case of Rocky Mountain spotted fever is usually fairly mild. In a small number of people, the disease can be serious, even fatal, especially in older adults. Because Rocky Mountain spotted fever can progress rapidly, prompt treatment is important.

2、Symptoms

Initial signs and symptoms of Rocky Mountain spotted fever often are nonspecific and can mimic those of other illnesses:

● High fever — body temperature reaching 102 F (38.9 C) or greater
● Chills
● Severe headache
● Sensitivity to light (photophobia)
● Nausea and vomiting
● Abdominal pain
● Loss of appetite
● Fatigue

Later on, these signs and symptoms of Rocky Mountain spotted fever can develop:

● Red-spotted or blotchy rash on your wrists or ankles
● Widespread aches and pains
● Diarrhea
● Restlessness
● Delirium

Although many people experience symptoms within the first week after being bitten by an infected tick, the illness could incubate for up to 14 days after the tick bite.

Characteristic red rash
In most cases of Rocky Mountain spotted fever, a red, blotchy rash develops on the wrists and ankles, spreading to the palms of your hands and soles of your feet. This usually occurs between days three and five of infection. The rash often spreads up your arms and legs to your torso.

A few people who are infected don't ever develop a rash. If your skin is darkly pigmented, a rash might not be readily apparent. However, the absence of a rash doesn't indicate a milder form of illness and may make the condition more difficult to diagnose.

When to see a doctor
See your doctor if you develop a rash or become sick after a tick bite. Rocky Mountain spotted fever and other infectious diseases carried by ticks can progress rapidly and may be life-threatening. If possible, take the tick along with you to your doctor's office for laboratory testing.

3、Causes

Rocky Mountain spotted fever is caused by infection with the organism Rickettsia rickettsii. The bacterium infects you when you come in contact with an infected tick in one of these circumstances:

● Tick bites. Rocky Mountain spotted fever most often is spread to humans by tick bites. Ticks can attach themselves to your skin and feed on your blood. They can lodge anywhere on your body, but often are found in your hair, around your ankles and in your genital area. Once embedded in your skin, ticks can cause a small, hard, itchy lump surrounded by a red ring or halo. The longer an infected tick stays attached to your skin, the greater your chance of acquiring infection.

● Broken skin. Rocky Mountain spotted fever can also occur after contact with the bacteria through broken skin, such as a cut or scrape on your hands or fingers. Bacteria that cause this disease circulate in the fluids of a tick's body. If you squeeze or crush a tick as you remove it from yourself, another person or a pet, an infection can occur if the fluid comes in contact with an area of broken skin. It's also possible to develop an infection if you touch your eye after coming into contact with an infected tick.

The culprit ticks
The bacterium that causes Rocky Mountain spotted fever typically is carried by a family of ticks known as Ixodidaeor hard ticks. These ticks live in the low bushes and tall grasses of wooded areas and are more abundant in late spring and early summer.

In the western United States, Rocky Mountain spotted fever is transmitted by the wood tick (Dermacentor andersoni). In the eastern United States, where the disease is most common, it's transmitted by the American dog tick (Dermacentor variabilis). In the southern United States, Central America and South America, Rocky Mountain spotted fever is transmitted by other ticks, such as the cayenne tick (Amblyomma cajennense) and the brown dog tick (Rhipicephalus sanguineus).

Rocky Mountain spotted fever primarily occurs when ticks are most active and during warm weather when people tend to spend more time outdoors.

4、Risk factors

Your risk of contracting Rocky Mountain spotted fever depends on:

● What part of the United States you're in
● How much time you spend in grassy or wooded areas
● How well you protect yourself from tick bites

It's important to take precautions against exposure to ticks and to be sure to check yourself and your dog for ticks after being outside.

5、Complications

If detected in its early stages, Rocky Mountain spotted fever can be most successfully treated with medication. Left untreated, the infection can spread from the site of the bite via your bloodstream, potentially causing infection in other areas of your body. Rocky Mountain spotted fever may cause serious complications involving your joints, heart, lungs, kidneys, and central and peripheral nervous system, such as:

● Heart, lung or kidney failure
● An infection of the membranes and fluid surrounding your brain and spinal cord (meningitis)
● Brain damage
● Problems with blood clotting
● Gangrene and possible amputation of fingers, toes, arms or legs
● Shock

In a small percentage of cases, Rocky Mountain spotted fever causes death, usually because treatment is delayed or is never sought.

6、Preparing for your appointment

You'll likely start by first seeing your family doctor or primary care provider. In some cases, you might be referred immediately to a doctor who specializes in infectious diseases.

Here's some information to help you prepare for your appointment, and what to expect from your doctor.

★What you can do

● Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance to prepare for common diagnostic tests.
● Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
● Make a list of your key medical information, including any other conditions for which you're being treated, and the names of any medications, vitamins or supplements you're taking.
● Consider questions to ask your doctor and write them down. Bring along notepaper and a pen to jot down information as your doctor addresses your questions.

For Rocky Mountain spotted fever, some basic questions to ask your doctor include:

● What might be causing my symptoms?
● What kind of tests do I need? Do these tests require any special preparation?
● What treatments are available?
● Will I need to be hospitalized?
● How long will it be before I'm feeling better?
● Do you have any brochures or other printed material that I can take home with me?

★What Web sites do you recommend visiting?

In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time if you don't understand something.

★What to expect from your doctor
Your doctor or health care provider is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on.

★Questions your doctor might ask include:

● How long have you experienced your symptoms?
● Does anything seem to make your symptoms better or worse?
● Is anyone else in your family ill?
● Have you recently been bitten by a tick?
● Do you spend a lot of time outdoors in grassy or wooded areas?
● Have you traveled anywhere recently?

7、Tests and diagnosis

Your doctor will diagnose Rocky Mountain spotted fever by:

● Evaluating your signs and symptoms
● Conducting a physical examination
● Testing a blood sample, rash specimen or the tick itself for the presence of the organism that causes the infection

8、Treatments and drugs

Treatment for Rocky Mountain spotted fever involves:

● Carefully removing the tick from your skin
● Taking antibiotic medication, such as doxycycline, for seven to 10 days, and at least three days after your fever and other symptoms subside, to eliminate the infection

The sooner treatment begins, the better. The disease can progress rapidly and may cause serious illness. People who develop Rocky Mountain spotted fever are much more likely to survive if treated within five days of developing symptoms. That's why your doctor will probably have you begin antibiotic therapy before receiving conclusive test results, if he or she suspects Rocky Mountain spotted fever is the cause of your symptoms.

Doxycycline is the most effective treatment for Rocky Mountain spotted fever, but it's not a good choice if you're pregnant. In that case, your doctor may prescribe chloramphenicol as an alternative.

★★★How to safely remove a tick

If you find a tick crawling on your skin, carefully remove it. Don't crush it between your fingers. Instead, burn it, bury it or flush it. Be sure to wash your hands afterward.

If a tick has already bitten you and is holding on to your skin, follow these steps:

● Remove the tick by gently grasping it near its head or mouth, preferably with a tweezers.
● Don't squeeze or crush the tick, but pull carefully and steadily.
● Save the tick by sealing it in a plastic bag and storing it in the freezer. This allows the tick to be tested for specific bacteria by your doctor if you become sick from the bite. If no signs or symptoms of infection occur within two weeks after the bite, dispose of the tick by burning it, burying it or flushing it.
● Disinfect the tweezers with alcohol or antibacterial soap and water.
● Wash that area of your skin thoroughly and apply antiseptic to the bite area after the tick has been removed.
● Wash your hands thoroughly.

9、Prevention

You can decrease your chances of contracting Rocky Mountain spotted fever by taking some simple precautions:

● Wear long pants and sleeves. When walking in wooded or grassy areas, wear shoes, long pants tucked into socks and long-sleeved shirts. Try to stick to trails and avoid walking through low bushes and long grass.
● Use insect repellents. Products containing DEET (Off! Deep Woods, Repel) often repel ticks. Be sure to follow the instructions on the label. Clothing that has permethrin (Repel, Permanone) impregnated into the fabric is toxic to ticks and also may be helpful in decreasing tick contact when outdoors.
● Do your best to tick-proof your yard. Clear brush and leaves where ticks live. Keep woodpiles in sunny areas.
● Check yourself and your pets for ticks. Do this after being in wooded or grassy areas. Some ticks are no bigger than the head of a pin, so you may not discover them unless you are very careful.
● Don't assume you're immune. Even if you've had Rocky Mountain spotted fever before, it can occur in the same person more than once. Follow precautions and check yourself for ticks.
● Remove a tick with tweezers. Gently grasp the tick near its head or mouth. Don't squeeze or crush the tick, but pull carefully and steadily. Once you have the entire tick removed, apply antiseptic to the bite area.

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Rocky Mountain Spotted Fever FAQs

Rocky Mountain spotted fever (RMSF) is an infectious disease that's transmitted by the bite of a tick infected with the Rickettsia rickettsii bacterial organism. Initial symptoms of RMSF include fever, nausea, vomiting, muscle pain and severe headache. Later symptoms include rash, abdominal pain, joint pain, and diarrhea. Treatment usually involves a tetracycline antibiotic.

1、What is Rocky Mountain spotted fever?
2、How do people get Rocky Mountain spotted fever?
3、What are the symptoms of Rocky Mountain spotted fever?
4、In the United States, where do most cases of Rocky Mountain spotted fever occur?
5、How is Rocky Mountain spotted fever diagnosed?
6、How is Rocky Mountain spotted fever treated?
7、Can a person get Rocky Mountain spotted fever more than once?
8、How can Rocky Mountain spotted fever be prevented?
9、What is the best way to remove a tick? ★★★
10、Do folklore remedies work?
11、How can ticks be controlled?


1、What is Rocky Mountain spotted fever?

Rocky Mountain spotted fever (RMSF) is the most severe tick-borne rickettsial illness in the United States. This disease is caused by infection with the bacterial organism Rickettsia rickettsii.

2、How do people get Rocky Mountain spotted fever?

The organism that causes Rocky Mountain spotted fever is transmitted by the bite of an infected tick. The American dog tick (Dermacentor variabilis) and Rocky Mountain wood tick (Dermacentor andersoni) are the primary athropods (vectors) which transmit Rocky Mountain spotted fever bacteria in the United States. The brown dog tick Rhipicephalus sanguineus has also been implicated as a vector as well as the tick Amblyomma cajennense in countries south of the United States.

3、What are the symptoms of Rocky Mountain spotted fever?

Patients infected with R. rickettsii usually visit a physician in their first week of illness, following an incubation period of about 5-10 days after a tick bite. The early clinical presentation of Rocky Mountain spotted fever is often nonspecific and may resemble many other infectious and non-infectious diseases. Initial symptoms may include fever, nausea, vomiting, muscle pain, lack of appetite and severe headache. Later signs and symptoms include rash, abdominal pain, joint pain, and diarrhea. Three important components of the clinical presentation are fever, rash, and a previous tick bite, although one or more of these components may not be present when the patient is first seen for medical care. Rocky Mountain spotted fever can be a severe illness, and the majority of patients are hospitalized.

4、In the United States, where do most cases of Rocky Mountain spotted fever occur?

Rocky Mountain spotted fever is a seasonal disease and occurs throughout the United States during the months of April through September. Over half of the cases occur in the south-Atlantic region of the United States (Delaware, Maryland, Washington D.C., Virginia, West Virginia, North Carolina, South Carolina, Georgia, and Florida). The highest incidence rates have been found in North Carolina and Oklahoma. Although this disease was first discovered and recognized in the Rocky Mountain area, relatively few cases are reported from that area today.

5、How is Rocky Mountain spotted fever diagnosed?

A diagnosis of Rocky Mountain spotted fever is based on a combination of clinical signs and symptoms and specialized confirmatory laboratory tests. Other common laboratory findings suggestive of Rocky Mountain spotted fever include thrombocytopenia, hyponatremia, and elevated liver enzyme levels.

6、How is Rocky Mountain spotted fever treated?

Rocky Mountain spotted fever is best treated by using a tetracycline (Achromycin) antibiotic, usually doxycycline (Vibramycin). This medication should be given in doses of 100 mg every 12 hours for adults or 4 mg/kg body weight per day in two divided doses for children under 45 kg (100 lbs). Patients are treated for at least 3 days after the fever subsides and until there is unequivocal evidence of clinical improvement. Standard duration of treatment is 5 to 10 days. Because laboratory confirmation is generally not available during acute illness, treatment is initiated based on clinical and epidemiological information.

7、Can a person get Rocky Mountain spotted fever more than once?

Infection with R. rickettsii is thought to provide long lasting immunity against re-infection. However, prior illness with Rocky Mountain spotted fever should not deter persons from practicing good tick-preventive measures or visiting a physician if signs and symptoms consistent with Rocky Mountain spotted fever occur, especially following a tick bite, as other diseases may also be transmitted by ticks.

8、How can Rocky Mountain spotted fever be prevented?

Limiting exposure to ticks reduces the likelihood of infection with Rocky Mountain spotted fever. In persons exposed to tick-infested habitats, prompt careful inspection and removal of crawling or attached ticks is an important method of preventing disease. It may take extended attachment time before organisms are transmitted from the tick to the host.

It is unreasonable to assume that a person can completely eliminate activities that may result in tick exposure. Therefore, prevention measures should emphasize personal protection when exposed to natural areas where ticks are present:

● Wear light-colored clothing which allows you to see ticks that are crawling on your clothing.

● Tuck your pants legs into your socks so that ticks cannot crawl up the inside of your pants legs.

● Apply repellents to discourage tick attachment. Repellents containing permethrin can be sprayed on boots and clothing, and will last for several days. Repellents containing DEET (n, n-diethyl-m-toluamide) can be applied to the skin, but will last only a few hours before reapplication is necessary. Use DEET with caution on children. Application of large amounts of DEET on children has been associated with adverse reactions.

● Conduct a body check upon return from potentially tick-infested areas by searching your entire body for ticks. Use a hand-held or full-length mirror to view all parts of your body. Remove any tick you find on your body.

● Parents should check their children for ticks, especially in the hair, when returning from potentially tick-infested areas. Ticks may also be carried into the household on clothing and pets and only attach later, so both should be examined carefully to exclude ticks.

9、What is the best way to remove a tick?

● Use fine-tipped tweezers or notched tick extractor, and protect your fingers with a tissue, paper towel, or latex gloves. Persons should avoid removing ticks with bare hands.

● Grasp the tick as close to the skin surface as possible and pull upward with steady, even pressure. Do not twist or jerk the tick; this may cause the mouthparts to break off and remain in the skin. (If this happens, remove mouthparts with tweezers. Consult your health care provider if illness occurs.)

● After removing the tick, thoroughly disinfect the bite site and wash your hands with soap and water.

● Do not squeeze, crush, or puncture the body of the tick because its fluids may contain infectious organisms. Skin accidentally exposed to tick fluids can be disinfected with iodine scrub, rubbing alcohol, or water containing detergents.

● Save the tick for identification in case you become ill. This may help your doctor to make an accurate diagnosis. Place the tick in a sealable plastic bag and put it in your freezer. Write the date of the bite on a piece of paper with a pencil and place it in the bag.

10、Do folklore remedies work?

No. Folklore remedies, such as the use of petroleum jelly or hot matches, do little to encourage a tick to detach from skin. In fact, they may make matters worse by irritating the tick and stimulating it to release additional saliva or regurgitate gut contents, increasing the chances of transmitting the pathogen. These methods of tick removal should be avoided.

11、 can ticks be controlled?

Strategies to reduce vector tick densities through area-wide application of acaricides (chemicals that will kill ticks and mites) and control of tick habitats (e.g., leaf litter and brush) have been effective in small-scale trials. New methods being developed include applying acaricides to animal hosts by using baited tubes, boxes, and feeding stations in areas where infected ticks are endemic. Biological control with fungi, parasitic nematodes, and parasitic wasps may play supportive roles in integrated tick control efforts. Community-based integrated tick management strategies may prove to be an effective public health response to reduce the incidence of tick-borne infections. However, limiting exposure to ticks is presently the most effective method of prevention of tick-transmitted diseases.

SOURCE: Centers for Disease Control and Prevention

Last Editorial Review: 10/26/2007

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Lyme Disease

Lyme disease is often associated with heavily wooded or grassy areas where mice and deer live. It's most common in the Northeast, the Pacific Northwest, and the northern Midwest states.

1、About Lyme Disease

Lyme disease is an infection caused by the bacterium Borrelia burgdorferi. This bacterium is usually found in small animals like mice. It can be carried to people from these animals by Ixodes ticks (known as black-legged or deer ticks). These ticks pick up Borrelia burgdorferi when they bite infected animals and then infect humans by biting them and passing the bacteria into the person's bloodstream.

Ticks are small and can be hard to see. Immature ticks, or nymphs, are about the size of a poppy seed. Adult ticks are about the size of a sesame seed.

It's important to know and watch for symptoms of Lyme disease because ticks are hard to find and it's easy to overlook a tick bite — in fact, many people who get Lyme disease don't remember being bitten. The good news is that most tick bites don't result in Lyme disease.

2、Signs and Symptoms

Lyme disease can affect different body systems, such as the nervous system, joints, skin, and heart. The symptoms of Lyme disease are often described as happening in three stages (although not everyone experiences all of these stages):

Lyme disease_illustration

● Usually, the first sign of infection is a circular rash. This rash appears within 1–2 weeks of infection but may develop up to 30 days after the tick bite. The rash often has a characteristic "bull's-eye" appearance, with a central red spot surrounded by clear skin that is ringed by an expanding red rash. It may also appear as an expanding ring of solid redness. It may be warm to the touch and is usually not painful or itchy. The bull's-eye rash may be more difficult to see on people with darker skin tones, where it may take on a bruise-like appearance.

The rash usually resolves in about a month. Although this rash is considered typical of Lyme disease, many people never develop it.

● Along with the rash, a person may experience flu-like symptoms such as swollen lymph nodes, fatigue, headache, and muscle aches. Left untreated, symptoms of the initial illness may go away on their own. But in some people, the infection can spread to other parts of the body. Symptoms of this stage of Lyme disease usually appear within several weeks after the tick bite, even in someone who has not developed the initial rash. The person may feel very tired and unwell, or may have more areas of rash that aren't at the site of the bite.

Lyme disease can affect the heart, leading to an irregular heart rhythm or chest pain. It can spread to the nervous system, causing facial paralysis (Bell's palsy) or tingling and numbness in the arms and legs. It can start to cause headaches and neck stiffness, which may be a sign of meningitis. Swelling and pain in the large joints also can occur.

● The last stage of Lyme disease can occur if the early stages of the disease were not detected or appropriately treated. Symptoms of late Lyme disease can appear any time from weeks to years after an infectious tick bite. They may include arthritis, particularly in the knees, and memory lapses (this last symptom happens mainly to adults and is rare in kids and teens).

Having such a wide range of symptoms can make Lyme disease difficult for doctors to diagnose. Fortunately, there's a blood test that looks for evidence of the body's reaction to Lyme disease.

3、When to Call the Doctor

If you think your child may be at risk for Lyme disease or has been bitten by a tick, contact your doctor. Although conditions other than Lyme disease can cause similar symptoms, it's always wise to discuss symptoms with your doctor (especially if your child develops a red-ringed rash, prolonged flu-like symptoms, joint pain or a swollen joint, or facial paralysis). That way your child can get further evaluation and treatment, if necessary, before the disease progresses too far.

4、Prevention

There's no surefire way to avoid getting Lyme disease. But you can minimize your family's risk.

Be aware of ticks in high-risk areas like shady, moist ground cover or areas with tall grass, brush, shrubs, and low tree branches. Lawns and gardens may harbor ticks, too, especially at the edges of woods and forests and around old stone walls (areas where deer and mice, the primary hosts of the deer tick, thrive).

If you or your kids spend a lot of time outdoors, take precautions:

● Wear enclosed shoes or boots, long-sleeved shirts, and long pants. Tuck pant legs into shoes or boots to prevent ticks from crawling up legs.
● Use an insect repellant containing 20% to 30% DEET (N,N-diethyl-meta-toluamide).
● Wear light-colored clothing to help you see ticks more easily.
● Keep long hair pulled back or tucked in a cap for protection.
● Don't sit on the ground outside.
● Check for ticks regularly — both indoors and outdoors. Wash clothes and hair after leaving tick-infested areas.

If you use an insect repellent containing DEET, always follow the recommendations on the product's label and don't overapply it. Place DEET on shirt collars and sleeves and pant cuffs, and only use it directly on exposed areas of skin. Be sure to wash it off when you go back indoors.

There is no vaccine for Lyme disease currently on the market in the United States.

5、Treatment

Lyme disease is usually treated with a 2- to 4-week course of antibiotics. Cases of Lyme disease that are diagnosed quickly and treated with antibiotics almost always have a good outcome. A person should be feeling back to normal within several weeks after beginning treatment.

6、Contagiousness

Lyme disease is not contagious, so it can't be transmitted from person to person. But a person can get it more than once from ticks that live on deer, in the woods, or travel on your pets. So continue to practice caution even if you or your child has already had Lyme disease.

7、If You Find a Tick

You should know how to remove a tick just in case one lands on you or your child. First, don't panic. The risk of developing Lyme disease after being bitten by a tick is only about 1% to 3%. On top of that, it takes at least 24 to 48 hours for the tick to transmit the bacteria that cause Lyme disease. (To be safe, though, you'll want to remove the tick as soon as possible.) This is why a daily tick check is a good idea for people who live in high-risk areas.

If you find a tick:

● Call your doctor, who might want you to save the tick after removal so it can be determined if it's the type that can carry Lyme disease. Put the tick in a sealed container to kill it.
● Use tweezers to grasp the tick firmly at its head or mouth, next to the skin.
● Pull firmly and steadily on the tick until it lets go of the skin. If part of the tick stays in the skin, don't worry. It will eventually come out — although you should call your doctor if you notice any irritation in the area or symptoms of Lyme disease.
● Swab the bite site with alcohol.
One note of caution: Don't use "folk remedies" like petroleum jelly or a lit match to kill and remove a tick.

Tick bites don't generally hurt — that's part of the difficulty in knowing whether someone has Lyme disease because pain usually helps to call attention to problems. So be on the lookout for ticks and rashes, and call your doctor if you're at all concerned.

Rocky Mountain spotted fever
From Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Rocky_Mountain_spotted_fever

落磯山斑點熱
维基百科,自由的百科全书
http://zh.wikipedia.org/wiki/%E8%90%BD%E7%A3%AF%E5%B1%B1%E6%96%91%E9%BB%9E%E7%86%B1

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