内蒙古大兴安岭林区人埃立克体病自然疫源地的调查

目的人粒细胞埃立克体病和人单核细胞埃立克体病都是近10年来发现的2种经蜱传播的自然疫源性疾病。这2种病的公共卫生学意义已受到了许多国家的关注。由于病原体是专性细胞内寄生菌,直接培养和纯化较为困难。我们根据这2种埃立克体的16S rRNA基因序列,构建了一系列PCR引物对,对采自我国大兴安岭等北方地区的蜱、动物脏器和人血标本进行PCR扩增,并对扩增出的产物进行DNA序列分析,以期查清有可疑蜱媒地区是否存在埃立克体感染,并通过这次调查为今后进一步开展系统研究提供参考。方法与结果本研究采用半巢式PCR检测蜱标本2种埃立克体的带菌率。结果首次从内蒙古大兴安岭采集的全沟硬蜱和森林革蜱,新疆精河采集的全沟硬蜱和草原革蜱中扩增出390bp的特异和人单核细胞埃立克体16S rRNA基因片段;同时检测的大兴安岭的嗜群血蜱和北京灵山采集的长角血蜱均未扩增出相应的片段。大兴安岭莫尔道嘎林业局采集的全沟硬蜱携带此基因的阳性率为39.06％(25/64),森林革蜱为 10.00％(7/70),2种蜱的带菌率有显著差异(x~2=15.53,P<0.01)。新疆精河采集的蜱携带EC率也是全沟硬蜱(11组/190,最小阳性率为5.79％)高于森林革蜱(1组/60,最小阳性率为1.67％),但差别不显著(x~2=1.30,P>0.25)。还从大兴安岭林区捕捉的一只大林姬鼠的脏器中检测到这一16S rRNA基因片段。对一只从莫尔道嘎采集的全沟硬蜱蜱标本进行近1500bp的人单核细胞埃立克体 16S rRNA全基因扩增与序列分析,结果扩增出的序列与美国一株人单核细胞埃立克体(GenBank注册号U23503)的相应序列完全相同。同样应用半巢式PCR和序列分析技术,从蜱标本中扩增出441bp的特异的人粒细胞埃立克体16SrRNA基因片段。内蒙古大兴安岭莫尔道嘎采集的全沟硬蜱和森林革蜱人粒细胞埃立克体的阳性率分别是 6.25%(4/64)和 2.86%(2/70);内蒙古大兴安岭乌尔旗汗采集的全沟硬蜱和嗜群血蜱的阳性率分别为3.81％(最小阳性率,8组/210)和2%(1/50);新疆精河采集的全沟硬蜱和草原革蜱最小阳性率分别为3.16％(6组/190)和1.67%(1组/60)。这是首次在亚洲从蜱标本中检测到人粒细胞埃立克体。同时检测的北京灵山采集的长角血蜱未扩增出相应的片段。对一只从莫尔道嘎采集的全沟硬蜱标本进行近1500bp的人粒细胞埃立克体 16S rRNA全基因分析,结果扩增出的序列与美国一株人粒细胞埃立克体(GenBank注册号U02125)的相应序列完全相同,一个碱基不差。另外还从内蒙古大兴安岭采集的森林工人血标本中扩增出特异的EC和人粒细胞埃立克体16SrRNA基因片段。这是首次在亚洲从人血中扩增出人埃立克体DNA。对一份人血标本进行近1500bp的人粒细胞埃立克体 16S rRNA全基因分析,结果仅在第81位与美国这株人粒细胞埃立克体差一个碱基,相差的位置正好位于高变区。结论根据检测结果,本研究建立的系列半巢式PCR扩增方法可以快速、灵敏地检测蜱、脏器、血等标本中的EC和人粒细胞埃立克体,并能较快地分析出其16S rRNA全基因。据报道,莱姆病的流行区往往也是人埃立克体病的流行区。为此我们在大兴安岭林区进行了人埃立克体病和莱姆病的流行病学调查。血样检测发现了人粒细胞埃立克体和 EC 16S rRNA基因阳性的病例共6名,病例均有近期蜱咬史,有埃立克体病的临床表现,潜伏期也相符;血清抗体检测发现检测人群中有HGE阳性抗体。2种病例的发现均为亚洲之首次。通过莱姆病螺旋体感染流行因素的单因素和多因素Logistic回归分析,发现在调查的流行因素中,职业和蜱咬史是影响该疫区人群感染莱姆病螺旋体的主要危险因素。这一调查结果也为该地区人埃立克体病和其他蜱传病的防治提供了参考。     

黑龙江全沟硬蜱中检测出类似人粒细胞埃利希体的病原体DNA

目的：寻找我国蜱中人粒细胞埃利希体感染存在的病原学证据。方法：应用从人粒细胞埃列希体16 rRNA基因构建的特异引物进行半套式PCR,检测蜱标本中埃利希体DNA。然后对PCR扩增产物进行克隆和序列测定,与已知序列进行同源性比较。结果：从黑龙江采集的全沟硬蜱（Ixodes persulcatus）中扩增出特异DNA片段,计算最小阳性率为0.8％。对919bp的扩增产物进行序列分析,证实为埃利希体DNA,与美国人粒细胞埃利希体分离株对应序列比较,相差4个核苷酸。结论：这是首次证明我国有类似人粒细胞埃利希体的病原体存在。表明我国北方林区可能存在人粒细胞埃利希体感染垢自然疫源地。     

福建西北林区人单核细胞埃立克体病分子流行病学调查研究

目的 了解福建西北林区人单核细胞埃立克全病的存在情况。方法 评价以查菲埃立克体16S rRNA基因序列高变区构建引物进行的半套式PCR的敏感性和特异性，并用此种半套式PCR技术检测从福建武夷山市和宁化县采集的蜱类、野生动物内脏和血液及人群血液标本中的查菲埃立克体DNA，对有代表性的阳性标本的扩增产物进行克隆和序列测定，并与GenBank中注册的核苷酸序列进行同源性比较。应用以16S rRNA基因构建的特异和通用引物进行PCR，从越原血蜱及黄毛鼠标本中分段扩增查菲埃立克体DNA，进行克隆和序列测定，分别将其连成完整序列，与已知所有埃立克体及近缘菌的16SrRNA基因序列进行最大同源性比较，用Clustal X(1.8)软件对同源位碱基作聚类分析，应用“Tree View”程序得出遗传发育树图。结果 这种半套式PCR检测方法具有很高的特异性，仅能扩增查菲埃立克体DNA，而对其它蜱媒病病原体，如斑点热立克次体、菜姆病螺旋体的DNA及人粒细胞埃立克体病病原体的16S rRNA基因都不能扩增，同时，用有限稀释法以含EC 16S rRNA基因的质粒为模板评价其敏感度，结果显示：最低能检测到4个拷贝的查菲埃立克体DNA。用此半套式PCR法从该地区的越原血蜱、粒形硬蜱，鼠类（褐家鼠、黄毛鼠、黄胸鼠、神鼠、小家鼠）和野兔的脾脏和/或血块中均扩增出了查菲埃立克体的特异DNA片段。检测越原血蜱成蜱283组（659只），25组阳性，最小阳性率为3.8%。粒形硬蜱4只，1只阳性。野鼠脾脏、血块及野兔血块的阳性率分别为56.4%（22/39）、38.7%(12/31)和18.2%(2/11）。同时检测的其它蜱种、狐狸血块、野猪血块及人血块中均未发现查菲埃立克体DNA。越原血蜱和野鼠代表性标本的390bp的PCR产物经克隆、测序后，发现其DNA序列与美国查菲埃立克体分离株对应位置分别一致和相差一个核苷酸。从越原血蜱和黄毛鼠扩增来的全序列与美国查菲埃立克体分离株的16S rRNA基因序列分别相差6个和2个核苷酸，同源性分别为99.6%和99.9%；与犬埃立克体（E.cn-is）、 尤菌氏埃立克体（E.ewingii）、鼠埃立克体（E.muris）之间的同源性为97.6%～98.0%，属于近缘种；与其它埃立克体种的同源性在83.0%～92.4%之间。结论 上述研究结果提示福建西北部地区可能存在人单核细胞埃立克体病的自然疫源地。越原血蜱和粒形硬埤为其潜在传播媒介，鼠和野兔可能为其贮存宿主。实践证明，半套式PCR及序列分析技术可作为检测蜱和动物标本中查菲埃立克体的一种敏感、特异的方法，适用于现场流行病学调查。本研究首次测定我国南方蜱及啮齿动物中埃立克体的16S rRNA全基因序列，为进一步开展疫源地调查奠定了基础。     

用半套式PCR检测蜱和啮齿动物中查菲埃立克体

目的　了解福建西北部林区查菲埃立克体 (Ehrlichiachaffeensis)的存在情况。方法　用 16SrRNA基因特异引物进行半套式PCR ,检测从福建武夷山和宁化采集的蜱类及野生动物中的查菲埃立克体DNA ,然后对有代表性的标本的扩增产物进行克隆和序列测定 ,并与GenBank中注册的核苷酸序列进行同源性比较。结果　从该地区的越原血蜱 ,野鼠(褐家鼠、黄毛鼠、黄胸鼠、社鼠、小家鼠 )和野兔的脾脏和 /或血块中均扩增出了查菲埃立克体的特异片段。越原血蜱成蜱 2 40组 (6 16只 ) ,31组阳性 ,最小阳性率 5 0 %。野鼠脾脏标本 39份 ,2 2份阳性。野鼠和野兔血块标本共 35份 ,14份阳性。 390bp的PCR产物经克隆、测序后分析发现其DNA序列与美国查菲埃立克体分离株对应位置一致。结论　福建西北部林区可能存在人单核细胞埃立克体病的自然疫源地。     

从西藏微小牛蜱检出类查菲埃立克体和边缘无形体16S rDNA

目的　鉴定微小牛蜱 (Boophilusmicroplus)所携带的埃立克体病原体。方法　依据蜱传埃立克体 16SrDNA序列设计引物 ,建立埃立克体属特异性套式PCR检测微小牛蜱DNA样本 (每份DNA由 2个蜱提取 ) ;克隆DNA样本中的埃立克体 16SrDNA的 5′末端片段并测定其序列。结果　西藏某地的 4 3份蜱DNA样本中有 16份 (37% )经套式PCR扩得阳性片段 ,而四川某地的 2 7份蜱DNA样本扩增结果均为阴性。测定 16SrDNA的 5′末端片段 (～ 4 5 0bp)的序列 ,发现两种序列 ,一种与边缘无形体 16SrDNA完全一致 ,另一种与查菲埃立克体 16SrDNA最相关 ,但它们之间有 7个碱基 (～ 1 6 % )的不同。结论　西藏某地的微小牛蜱中携带有类查菲埃立克体和边缘无形体 ,该类查菲埃立克体可能是一个埃立克体新种     

我国南方蜱样本中发现犬埃立克体DNA

目的 调查我国南方蜱样本埃立克体感染情况。方法 用已发表的埃立克体１６ＳｒＲＮＡ基因的属特异引物和自行设计的犬埃立克全种特异引物，对广东，广西和海南部分地区采集的蜱样本进行ＰＣＲ检测，并将阳性ＰＣＲ产物克隆测序，结果通过Ｉｎｔｅｒｎｔ提交到美国国立医学图书馆／国家健康研究所的站点，利用ＢＬＡＳＴ对核酸数据库进行同源性检索。结果 从广东采集的血红扇头蜱和广西要的微小牛蜱样本中扩增出埃立克体４２５ｂｐ     

云南临沧地区蜱种分子生物学鉴定及埃立克体基因序列分析

目的 了解云南临沧地区蜱虫种类及其自然感染埃立克体的情况。方法 采集耕牛体表寄生的蜱虫,经形态学鉴定和分组后,从蜱虫中提取DNA,应用PCR扩增蜱虫COI基因以及埃立克体16S rRNA和groEL基因,并测序分析。结果 共采集到蜱虫42只,其中微小牛蜱38只占90.48%、血蜱4只占9.52%。将每种蜱的2只为1组,在21组样本中,检出COI片断21份(检出率100%);在相同的4组样本中均检出埃立克体16S rRNA片断和groEL片断4份(检出率19.05%)。基因序列分析,检出的COI片断序列中有2份与澳大利亚pava血蜱(JX573136)的同源性最高(89.3%),其余19份序列与马来西亚微小牛蜱B3的同源性最高(99.5%);检出的4份16S rRNA片断序列完全一致,与美国查菲埃立克体Arkansas和埃文埃立克体Aa2FT349及中国北京查菲埃立克体BY-YQ-HME-O18株的同源性均为100%;检出的4份groEL片断序列也完全一致,与日本埃立克体Yonaguni206 株的同源性最高均为93.9%。结论 经分子检测证实云南临沧地区耕牛体表微小牛蜱中存在一种类似日本Yonaguni206株的埃立克体感染,耕牛体表还可能寄生一种新的血蜱。     

塞罕坝自然保护区硬蜱调查及分子鉴定

目的掌握河北省承德市塞罕坝自然保护区内硬蜱种类及其分子特征,明确该地区蜱类的分类地位,为相关蜱媒传染病的防控制提供参考。方法 2018年4-9月间,采用布旗法捕捉该地区森林、草地、灌丛3种生境内自由生活的蜱类;提取蜱基因组,PCR扩增2种硬蜱的线粒体16S rDNA和COⅠ基因片段,并进行同源性分析。基于邻接法和最大简约法,用Mega 7.0软件分别构建系统发生树,进行遗传进化分析。结果在植被上共采集蜱231头,分为1科2属2种,其中全沟硬蜱212头,嗜群血蜱19头。PCR扩增嗜群血蜱标本(QS11)16S rDNA和COⅠ扩增基因片段长度分别是434 bp和712 bp,全沟硬蜱标本(QG13)16S rDNA、COⅠ基因片段长度是445 bp、735 bp。嗜群血蜱标本和全沟硬蜱标本的16S rDNA序列、COⅠ序列与GenBank中已登录的2种硬蜱对应基因聚类,且在一个进化分支上;嗜群血蜱标本16S rDNA、COⅠ序列与已登录嗜群血蜱相同基因序列的同源性分别为98.2%和98.1%,遗传距离分别为0.035和0.028;全沟硬蜱2个基因与已登录基因的同源性分别为98.3%和97.4%,遗传距离分别为0.067和0.104。结论塞罕坝自然保护区内优势蜱种是全沟硬蜱且存在嗜群血蜱。两蜱种16S rDNA、COⅠ与序列存在多样性和地域差异性。     

福建厦门微小牛蜱中埃立克体的检测与鉴定

目的 检测福建厦门微小牛蜱携带的埃立克体，进行分类鉴定。方法 采用套式PCR方法检测埃立克体，然后对阳性标本中的埃立克体进行16SrRNA全基因序列测定并分析。结果 共检测吸血微小牛蜱标本299份，27份阳性，阳性率为9．0％。选择其中的1份阳性样本扩增16SrRNA的全基因序列，全长1458bp，序列对比显示与泰缅边境和越南的埃立克体同源性为99．9％，相差2个碱基；与西藏埃立克体同源性为99．7％，相差4个碱基；与非洲埃立克体同源性为99．6％，相差7个碱基；与中国南方的查菲埃立克体同源性为98．9％，相差17个碱基。结论 从福建厦门微小牛蜱中检测到埃立克体，可能是一个埃立克体新的亚种。     

吉林省林区蜱粒细胞无形体感染的调查

目的调查吉林省蜱粒细胞无形体感染。方法运用聚合酶链反应方法对吉林延边地区采集的蜱标本粒细胞无形体16S rRNA和gltA基因片段进行扩增及序列分析,将扩增序列与GenBank注册的基因序列进行比较,构建粒细胞无形体gltA基因进化树。结果共检测游离蜱427只,其中全沟硬蜱100只,森林革蜱327只,粒细胞无形体感染阳性率分别为4.00%和0.00%。寄生蜱感染阳性率2.9%。寄生蜱与游离蜱感染率差别无显著性。16S rRNA序列与我国已在GenBank注册的AF205140序列一致,与国外粒细胞无形体16S rRNA序列存在不同程度的差异,相似性为97%～99%;gltA基因与GenBank的粒细胞无形体gltA基因片段比较,相似性为87%～97%,推导的氨基酸序列相似性为84%～99%。结论我国吉林省林区存在蜱粒细胞无形体感染。     

New evidence for the detection of ehrlichia and anaplasma in ixodes ticks in Russia and Kazakhstan

Polymerase chain reaction and sequence analysis were used to screen Ehrlichia and Anaplasma DNA in 900 specimens of Ixodes ticks of four genera (Dermacetor, Haemaphysalis, Ixodes, and Hyalomma) collected on 14 administrative territories of Russia and Kazakhstan. Anaplasma phagocytophilia DNA was detected and identified in Ixodes persulcatus ticks gathered in the Altai and Primorye Territories. Ehrlichia muris DNA was genotyped in the I. persulcatus ticks collected in the Tyumen, Omsk, and Novosibirsk Regions and the Altai Territory. Examining the Haemaphysalis concinna collected in the Primorye Territory revealed A. bovis DNA. The I. persulcatus ticks gathered in the Omsk Region were found to have "Ehrlichia-like "Schotti variant" DNA, Studying the ticks of the genera Dermatocentor and Hyalomma gathered in Russia and Kazakhstan failed to detect the representatives of the genera Anaplasma and Ehrlichia. The detection of A. phagocytophilia DNA in the I. persulcatus ticks in the Altai and Primorye territories and the serological verification of cases of human granulocytic anaplasmosis among patients with tick-borne infections in these territories lead to the conclusion that there are natural loci of this disease in West Siberia and the Far East of Russia.     

Prevalence of Anaplasma phagocytophila and Borrelia burgdorferi in Ixodes persulcatus ticks from northeastern China

A total of 1,345 Ixodes persulcatus ticks collected from northeastern China were investigated for the presence of Anaplasma phagocytophila and Borrelia burgdorferi by a nested polymerase chain reaction (PCR). Sixty-two (4.6%) ticks were positive for A. phagocytophila and 454 (33.8%) were positive for B. burgdorferi. Seven (0.5%) were coinfected with both agents. Sequence analysis of 919-basepair PCR amplicons revealed three types of A. phagocytophila. Type 1 was identical to the published sequences of A. phagocytophilas responsible for human granulocytic ehrlichiosis (HGE). The other two variants differed from the HGE agent sequence at one and four positions, respectively. These findings imply that infection with A. phagocytophila poses a potential health threat to both humans and animals in northeastern China, and that ehrlichiosis should be considered in the differential diagnosis of febrile patients with a history of tick bite, particularly when clinical manifestations are atypical for Lyme disease.     

Detection of the genotypic heterogeneity of Ixodes persulcatus Schulze (Acari: Ixodidae) of the North-West region of Russia and characteristics of distribution of tick-borne pathogens causing Lyme disease and Ehrlichia infections in various genotypes]

The heterogeneity of the Ixodes persulcatus population in the vicinity of Saint Petersburg was estimated by using malate dehydrogenase (MDH) isoenzyme. There are six MDH genotypes carrying 3 alleles in the Ixodes persulcatus population. The prevalence of Borrelia and Ehrlichia species in the study genotypes was analyzed. There was a difference in the prevalence and intensity of infection. The greatest abundance of Borrelia was described in the genotypes to Genogroup 1 (with allele 1). Among them, heterozygous ticks were most intensively infected. Polymerase chain reaction identified species pathogenic for man. These included 3 species of Borrelia: B. afzelii, B. garinii, and B. burgdorferi sensu stricto and 2 species of Ehrlichia muris and HGE agent. The author are the first to describe HGE agent and B. burgdorfei ss encountered in Russia.     

Detection and identification of bacterial agents in Ixodes persulcatus Schulze ticks from the north western region of Russia

Ixodes persulcatus Schultze ticks are traditionally associated with transmission of Lyme disease, babesiosis, and tick-borne encephalitis. Here we compared the prevalence of infection with Borrelia burgdorferi, and rickettsial and ehrlichial agents in I. persulcatus ticks collected in different locations of the North Western administrative region of Russia. Altogether, 27.7% of ticks were infected with at least one organism, while the DNA of two or more bacteria was found in 11.8% of ticks tested. The highest average prevalence of Anaplasmataceae (20.8%) was detected in ticks from Arkhangel'sk province, while the prevalence in ticks from Novgorod province and St. Petersburg, respectively, was 7.3% and 12.2%. Only Ehrlichia muris DNA was identified by DNA sequencing. In comparison, the prevalence of B. burdorferi DNA was 16.6%, 5.8%, and 24.5% in the respective locations. The 382-bp amplicon of gltA from Candidatus Rickettsia tarasevichiae was detected in 2.75% and 1.6%, respectively, of ticks from Arkhangel'sk and Novgorod provinces, extending further west and north the area where this rickettsia is known to be present. DNA of the rickettsia-like endosymbiont Montezuma was primarily associated with female ticks, 8-28% of which were infected. Since I. persulcatus is so commonly infected with multiple agents that may cause human diseases, exposure to these ticks poses significant risk to human health in this region.     

Molecular survey of Anaplasma and Ehrlichia infections of feral raccoons (Procyon lotor) in Hokkaido, Japan

Infection by Anaplasma and Ehrlichia in feral raccoons (Procyon lotor) in Hokkaido, Japan, was examined by molecular methods. A polymerase chain reaction (PCR) screen for Anaplasmataceae, based on 16S rRNA, showed that 38 (5.4%) of 699 raccoons examined were positive. These 38 positive samples were examined for Anaplasma phagocytophilum, Anaplasma bovis, Ehrlichia chaffeensis, and Ehrlichia canis infection by species-specific nested PCR. Nested PCR results indicated that 36 of the 38 samples were positive for A. bovis. All 38 samples were PCR negative for A. phagocytophilum, E. chaffeensis, and E. canis. This is the first report of the detection of A. bovis in the peripheral blood of raccoons. A total of 124 raccoons were infested with ticks, including Ixodes ovatus, Ixodes persulcatus, and Haemaphysalis spp. The rate of A. bovis infection in raccoons infested with Haemaphysalis spp. (46.7%, 7/15) was significantly higher than that in raccoons without Haemaphysalis spp. infestation (3.7%, 4/109, p?相似文献   

The biodiversity dynamics of the causative agents of diseases transmitted by ticks in the genus Ixodes: an analysis of multiyear data

Fauna of pathogen's met in the organism of the primary tick-borne disease vectors--Ixodes persulcatus Schulze and Ixodes ricinus (L.) was observed. Prevalence of Borrelia mono- and poly-infection in the I. persulcatus ticks within a season of the vector activity was analyzed and increase of the number of the dual infected specimens during the season was demonstrated. The first determination of Ehrlichia infected I. ricinus and I. persulcatus collected in the Baltic region of Russia was stated. The triple infection of Ixodes ticks in was proved: infection by the two species of Borrelia and Ehrlichia; infection by the three species of Borrelia and infection by the tick-borne encephalitis virus and two species of Borrelia. The first determination of the tick-borne encephalitis virus in I. ricinus in the recreational zone of Kaliningrad Province (Courland [correction of Curonian] Spit) was described. Dipetalonema sp. was detected in the St. Petersburg population of I. persulcatus. The prevalence of poly-infection among I. persulcatus ticks was stated.     

Participation of Ixodes ricinus developmental stages in transmission of Anaplasma (Ehrlichia) phagocytophila

The present study constitutes a survey on the prevalence of human granulocytic ehrlichiosis agent, Anaplasma (Ehrlichia) phagocytophila, infecting ticks, Ixodes ricinus. I. ricinus were collected in the spring and autumn of the years 2000-2002 in western Pomerania (Poland), on vegetation using cloth drags. In all, 3340 individuals of I. ricinus were collected from the sampling sites. This total comprised of 511 females, 525 males, and 1998 nymphs. The prevalence of this pathogen in ticks was assessed using the PCR technique (a fragment of 16S rDNA gene amplified with EHR 521 and EHR 747 primers). The overall prevalence of A. phagocytophila in I. ricinus was 3 % in adults but only 1.6% in nymphs.     

Tickborne infections as a cause of nonspecific febrile illness in Wisconsin.

Lyme disease, human granulocytic ehrlichiosis (HGE), and babesiosis are tickborne infections that are indigenous to Wisconsin. To assess their importance as a cause of nonspecific fever, we recruited patients with febrile illness at 10 clinics in northwestern Wisconsin from May through August of both 1997 and 1998. Eligible patients had a temperature >38.0 degrees C but no rash or other localizing source. Acute and convalescent serological tests were performed for Borrelia burgdorferi, Babesia microti, and Ehrlichia equi; polymerase chain reaction was performed to detect granulocytic Ehrlichia rDNA. Seventeen (27%) of 62 eligible patients had laboratory evidence of tickborne infection, including 7 (11%) with probable Lyme disease only, 8 (13%) with HGE only, and 2 (3%) with apparent coinfection. No patients with Babesia infection were identified. Patients with and without tickborne infection were similar with regard to age, sex, symptoms, history of tick bite, and outdoor exposure. The results suggest that tickborne infections are an important cause of nonspecific febrile illness during the tick season in northwestern Wisconsin.