Spotted fever group rickettsiae in ticks, Germany

To explore increased risk for human Rickettsia spp. infection in Germany, we investigated recreational areas and renatured brown coal surface-mining sites (also used for recreation) for the presence of spotted fever group rickettsiae in ticks. R. raoultii (56.7%), R. slovaca (13.3%), and R. helvetica (>13.4%) were detected in the respective tick species.     

湖南首次发现斑点热

目的　研究湖南是否存在斑点热感染。方法　采用间接免疫荧光抗体法（ＩＦＡ）检测两县林区工人斑点热感染阳性率。结果　两县林区工人感染阳性率为２０００％ ,其中宜章县阳性率为２０３７％ ,平江县阳性率为１９２０％ ;蜱类调查中除有二棘血蜱、越原血啤和微小牛蜱外,新发现有龟形花蜱;经鉴定鼠类有２３ 种。结论　宜章、平江两县林区工人存在斑点热今后需继续从病人、媒介昆虫、宿主动物分离病原体。     

Prevalence of antibodies to spotted fever group rickettsiae in the region of Split (southern Croatia)

The prevalence of IgG antibodies to spotted fever group rickettsiae (SFG) was investigated by the indirect immunofluorescence assay in a sample of 1207 healthy residents of the central part of southern Croatia (eastern coast of Adriatic Sea). Sera obtained from subjects living in three different places of residency (urban, suburban and rural environs of the region) were tested. Overall 528 (43.7%) persons had significant antibody titers (1:40 or higher), with a significantly higher prevalence in suburban and rural areas. The results show that inhabitants in the area are clearly being exposed to SFG rickettsiae. Risk factors significantly associated with seropositivity to SFG rickettsiae were: living in suburban and rural settlements (odds ratio [OR] = 1.81; 95% confidence interval [CI] = 1.35–2.4), contact with animals (OR: 1.52; 95% CI: 1.15–1.99), and increase of age (OR: 1.18; 95% CI: 1.09–1.26).     

Evidence of the presence of spotted fever group rickettsiae in dogs and dog ticks of the central provinces in Spain

To assess canine exposure to spotted group rickettsiae in the central provinces of Spain, ticks removed from dogs were studied by immunofluorescence (IF) staining. Twenty-eight out of 65 (43.0%) samples from ticks were positive. Sera from 58 dogs were also collected and the presence of antibodies to Rickettsia conorii studied. Thirty-four (58.6%) dogs presented significant titers by IF. Surveillance data from these provinces show the presence of Boutonneuse fever cases during recent years, evidence that dogs could serve as an indicator of rickettsial activity in these areas.Corresponding author.     

Spotted fever group rickettsiae identified in Dermacentor marginatus and Ixodes ricinus ticks in Algeria

Our study was carried out using Ixodes ricinus ticks collected from cattle from Tizi-Ouzou and Dermacentor marginatus ticks collected from the vegetation of the Blida region, a tourist site, both regions situated in northern Algeria. The results of real-time quantitative PCR (qPCR) specific for a partial sequence of the citrate synthase gene (gltA) indicate that Rickettsia spp. were present in 11/23 (48%) and 4/9 (44%) of the examined ticks from Tizi-Ouzou and Blida, respectively. The sequences of Rickettsia helvetica and Ri. monacensis were found in I. ricinus ticks using gltA primers. In addition, Ri. slovaca was detected based on the sequences of the gltA and the outer membrane protein (OmpA) genes in D. marginatus ticks. DNA sequencing to identify the species revealed for the first time the presence of Ri. helvetica in I. ricinus ticks and Ri. slovaca in D. marginatus ticks from Algeria and confirmed the presence of Ri. monacensis.     

Antibodies to spotted fever group rickettsiae in dogs in Croatia

The prevalence of IgG antibodies to spotted fever group rickettsiae was studied by the indirect immunofluorescent antibody assay in a sample of 194 canine sera from different parts of Croatia. Dogs (n=141) from urban and suburban-semirural environs from the middle part of the eastern coast of Adriatic sea, and dogs (n=53) from Zagreb, the capital of Croatia located in the northern continental part of Croatia, were tested. The total of 88 (62.4%) dogs from southern coastal Croatia had antibodies toRickettsia conorii, with a significantly higher prevalence (69.9%) in suburban-semirural areas. The prevalence rate of antibodies toRickettsia conorii in canine sera from urban environment in the north of Croatia was 20.7%. The results show that the members of spotted fever group rickettsiae are present in both coastal and continental Croatia.Abbreviations IFA indirect immunofluorescence - IgG immunoglobulin G - MSF Mediterranean spotted fever - SFG spotted fever group     

Gulf Coast ticks (Amblyomma maculatum) and Rickettsia parkeri, United States

Geographic distribution of Rickettsia parkeri in its US tick vector, Amblyomma maculatum, was evaluated by PCR. R. parkeri was detected in ticks from Florida, Georgia, Kentucky, Mississippi, Oklahoma, and South Carolina, which suggests that A. maculatum may be responsible for additional cases of R. parkeri rickettsiosis throughout much of its US range.     

Novel PCR exclusion assay to detect spotted fever group rickettsiae in the lone star tick (Amblyomma americanum)

The lone star tick (Amblyomma americanum) is the most common and abundant human-biting tick in the southeastern United States where spotted fever rickettsioses frequently occur. However, the role of this tick in transmitting and maintaining pathogenic and non-pathogenic spotted fever group rickettsiae (SFGR) remains poorly defined. This is partially due to the high prevalence and abundance of Rickettsia amblyommatis in most populations of A. americanum. Many molecular assays commonly employed to detect rickettsiae use PCR primers that target highly conserved regions in the SFGR so low abundance rickettsia may not be detected when R. amblyommatis is present. It is costly and inefficient to test for low abundance rickettsial agents with multiple individual specific assays even when they are multiplexed, as most samples will be negative. Real time PCR assays may also be hampered by inadequate limits of detection (LODs) for low abundance agents. We exploited the absence of an otherwise relatively SFGR-conserved genome region in R. amblyommatis to design a hemi-nested PCR-assay which has a sensitivity of 10 copies in detecting the presence of most SFGR, but not R. amblyommatis in DNA of infected lone star ticks. This deletion is conserved in 21 isolates of R. amblyommatis obtained from multiple states. We demonstrated the assay’s utility by detecting a pathogenic SFGR, Rickettsia parkeri, in 15/50 (30 %) of field collected A. americanum ticks that were previously screened with conventional assays and found to be positive for R. amblyommatis. These co-infected ticks included 1 questing female, 6 questing nymphs, and 8 attached males. The high prevalence of R. parkeri among host-attached ticks may be due to several variables and does not necessarily reflect the risk of disease transmission from attached ticks to vertebrate hosts. This novel assay can provide accurate estimates of the prevalence of less common SFGR in A. americanum and thus improve our understanding of the role of this tick in the maintenance and transmission of the SFGR commonly responsible for human rickettsioses.     

Spotted fever group rickettsiae in ticks and fleas from the Democratic Republic of the Congo

Little is known about the prevalence of spotted fever group (SFG) rickettsiae in ticks and fleas in the Democratic Republic of the Congo. In 2008, 12 Amblyomma compressum ticks were collected from 3 pangolins (Manis gigantea). Two Haemaphysalis punctaleachi ticks were collected from 2 African civets (Civettictis civetta congica), and one was collected from an antelope (Onotragus leche). A total of 111 Rhipicephalus sanguineus ticks, 23 Ctenocephalides canis fleas, 39 C. felis fleas, and 5 Trichodectes canis lice were sampled from 19 dogs. One C. canis flea was collected from a human. Six of the 12 A. compressum ticks were positive for rickettsial DNA, as determined by genus-specific qPCR. The ompA gene sequences amplified from positive samples showed 100% homology with Rickettsia africae (GenBank accession number CP001612). The detection of Ri. africae in A. compressum ticks, which are highly specialized parasites of pangolins, is consistent with our previous data showing the presence of Ri. africae in A. compressum ticks from Liberia. No other ticks contained rickettsial DNA. A total of 9 C. canis fleas (39%, 9/23) and 37 C. felis fleas (95%, 37/39) that was collected from dogs and one C. canis flea collected from a human harbored Ri. felis.     

一组长角血蜱中检出莱姆病螺旋体和斑点热群立克次体复合感染

目的 了解浙江省山区野生动物和蜱中莱姆病、斑点热、埃立克体病(无形体病)的感染情况.方法 采用巢式PCR对采集的鼠、蜱标本进行莱姆病伯氏疏螺旋体、斑点热群立克次体、埃立克体(无形体)特异性核酸片段检测分析.结果 从121份鼠标本和105组蜱标本中检出阳性结果 14份.鼠标本中检出伯氏疏螺旋体5S～23S rDNA间隔区片段1份和埃立克体(无形体)16SrDNA 5'端片段2份.蜱标本中检出阳性11份,包括伯氏疏螺旋体5S～23S rDNA间隔区片段3份和斑点热群立克次体外膜蛋白OmpA基因5'端片段8份.其中1组长角血蜱成虫标本为伯氏疏螺旋体和斑点热群立克次体复合感染,5S～23S rRNA基因间隔区和ompA基因片段均阳性,分别与伯氏疏螺旋体法雷氏基因型和马赛立克次体株等关系较近.结论 在同一组长角血蜱成虫中同时检出莱姆病疏螺旋体和斑点热群立克次体复合感染.     

Isolation of Rickettsia rickettsii in Rocky Mountain Spotted Fever Outbreak,Panama

We report new cases of Rocky Mountain spotted fever in patients from Kinkantu, Ngäbe-Bugle indigenous comarca, Panama. We isolated Rickettsia rickettsii in cell culture after intraperitoneal inoculation of guinea pigs with tissues from a deceased patient. Our results indicate that Rocky Mountain spotted fever is emerging in this region.     

Ecological relationships between ticks and rickettsiae

Ticks play important roles as vectors and sometimes as reservoirs in the ecology of rickettsiae. The obligate association between ticks and rickettsiae has been elucidated in studies concerning the maintenance of rickettsiae in ticks, agent dissemination in various tick organs, rickettsial developmental cycles in the tick organism, transfer among various developmental stages in tick hosts, the effect of rickettsiae on the tick organism, the interaction between microorganisms other than rickettsiae and rickettsiae is a tick body, as well as the release of rickettsiae from ticks into the environment.Presented at the 4th European Congress of Clinical Microbiology, Nice, 177-20 April, 1989.     

Spotted fever group and typhus group rickettsioses in humans, South Korea

The presence of the nucleic acid of the spotted fever group (SPG) and typhus group (TG) rickettsiae was investigated in 200 serum specimens seropositive for SFG rickettsiae by multiplex-nested polymerase chain reaction with primers derived from the rickettsial outer membrane protein B gene. The DNA of SFG, TG, or both rickettsiae was amplified in the 24 serum specimens, and sequence analysis showed Rickettsia conorii, R. japonica, and R. felis in the specimens. R. conorii and R. typhi were found in 7 serum specimens, which indicated the possibility of dual infection in these patients. These findings suggest that several kinds of rickettsial diseases, including boutonneuse fever, rickettsialpox, R. felis infection, and Japanese spotted fever, as well as scrub typhus and murine typhus, are occurring in Korea.     

Serosurvey of wild rodents for Rickettsioses (spotted fever, murine typhus and Q fever) in Java Island, Indonesia

The prevalence of antibodies against spotted fever group rickettsia (SFGR), murine typhus and Q fever were investigated in wild rats captured in Indonesia. Sera of 327 rats were collected from Jakarta and Boyolali on Java Island. The prevalences of antibodies against SFGR and murine typhus were 128 (39.1%) and 48 (14.7%), respectively. Antibodies against Q fever were not detected in these serum samples. Antibodies against SFGR were found in all species of rats (20.8–51.9%). The antibody positive rate against murine typhus in Rattus norvegicus (38.0%) was significantly higher than that in other rat species (0–4.8%, p < 0.01). The antibody positive rates against SFGR and murine typhus in rats captured in Jakarta were significantly higher than those in rats captured in Boyolali (p < 0.01). In this survey, all species of rats had antibodies against SFGR, indicating that the 4 species of tested rats (R. norvegicus, R. rattus, R. exulans, R. tiomanicus) were infected with SFGR and that SFGR may infest the whole of Java Island. Most of the rats that were antibody-positive against murine typhus were captured in Jakarta. Therefore, R. norvegicus and R. rattus are likely to be important hosts of murine typhus in Jakarta. The antibody-positive rates against SFGR and murine typhus in rats captured in the dry season were significantly higher than those in rats captured in the rainy season. This may coincide with the active periods of ticks and fleas in Indonesia.     

浙江省蜱标本中斑点热群立克次体rOmpA和gltA基因检测

目的了解浙江省部分山区蜱中感染斑点热群立克次体的状况,探讨以外膜蛋白A（rOmpA）和柠檬酸合成酶基因（gltA）为靶基因的PCR方法可行性。方法利用PCR方法,检测天台县左溪镇和临安县西天目地区共46组蜱类标本中rOmpA和gltA基因特异片段。对所检测到的阳性结果进行克隆与序列测定,并进行聚类分析。结果从46组蜱标本中检测发现2组长角血蜱中斑点热群立克次体的rOmpA和gltA基因片段均为阳性,核酸序列基本一致,但推测斑点热群立克次体种的进化位置存在差异。结论浙江省部分山区存在蜱中感染斑点热群立克次体的状况。利用rOmpA和gltA基因能从标本中检测到斑点热群立克次体,但从2个结果推测立克次体的分类位置存在差异。     

部分省区啮齿动物中斑点热群立克次体的检测

目的了解我国部分省区啮齿动物中斑点热群立克次体的自然感染情况，比较南北地区不同鼠种带菌率的差异。方法在黑龙江、内蒙古、新疆、浙江和贵州5省（自治区）共捕获鼠473只，用聚合酶链反应检测鼠脾脏中的斑点热群立克次体DNA序列片段。结果共检测鼠473只，69只阳性，阳性率为14．6％；在黑龙江、内蒙古、新疆、浙江和贵州省（自治区）都检测出阳性标本，阳性率分别为3．1％、21．6％、30．0％、10．8％和21．4％。结论我国黑龙江、内蒙古、新疆、浙江和贵州省（自治区）的鼠中都存在斑点热群立克次体的感染，南北地区鼠的带菌率差异无统计学意义（P〉0．05）。