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1.
Kelly PJ Fournier PE Parola P Raoult D 《The American journal of tropical medicine and hygiene》2003,69(1):58-59
Eighty-nine Amblyomma variegatum ticks were collected from the islands of St. Kitts and Nevis in the Caribbean and preserved in 70% ethanol or local rum. After being washed in sterile water, their DNA was extracted and analyzed by a polymerase chain reaction (PCR) for DNA of spotted fever group rickettsiae and ehrlichiae. None of the tested ticks was positive in a PCR assay using the primers 16S EHRD and 16S EHRR for the 16S rRNA gene of Ehrlichia spp.. Forty-one percent of the A. variegatum (36 of 89 of which 34 [47%] of 72 were adult males, 2 (13%) of 16 were adult females, and 0 (0%) of 1 were nymphs) were positive in a PCR assay using the primer pair 190-70 and 190-701 for the outer membrane protein A (ompA) gene of spotted fever group rickettsiae. All PCR amplification products obtained had 100% sequence homology with Rickettsia africae, the agent of African tick-bite fever. 相似文献
2.
Macaluso KR Davis J Alam U Korman A Rutherford JS Rosenberg R Azad AF 《The American journal of tropical medicine and hygiene》2003,68(5):551-553
We have identified for the first time Rickettsia africae, and the ticks that harbored them, in Kenya. A total of 5,325 ticks were collected from vegetation, livestock, and wild animals during two field trips to southwestern Kenya. Most were immature forms (85.2%) belonging to the genera Amblyomma or Rhipicephalus. The adults also included representatives from the genus Boophilus. Ticks were assessed for rickettsial DNA by a polymerase chain reaction (PCR) using primers for the spotted fever group (SFG)-specific rickettsial outer membrane protein A (rompA) gene, and positive amplicons were sequenced. While none of the immature ticks tested positive by PCR, 15.8% of the adult Amblyomma variegatum and less than 1% of the Rhipicephalus spp. were SFG positive. Sequences of amplified products were identified as R. africae. These findings extend the known range of R. africae. 相似文献
3.
Ndip LM Fokam EB Bouyer DH Ndip RN Titanji VP Walker DH McBride JW 《The American journal of tropical medicine and hygiene》2004,71(3):363-366
Rickettsia africae was identified in seven (6%) of 118 patients with acute fevers of unknown etiology proven not to be malaria or typhoid fever from clinics along the coastal region of Cameroon by polymerase chain reaction (PCR) amplification and sequencing of the citrate synthase (gltA) and outer membrane protein A (ompA) genes of Rickettsia. The majority (71%) of the patients were female. Clinical manifestations included fever (100%), headache (71%), myalgia (71%), arthralgia (43%), pulmonary involvement (29%), and diffuse rash (14%). Moreover, R. africae was detected by PCR amplification and sequence analysis of the gltA and ompA genes in 62 (75%) of 83 adult Amblyomma variegatum ticks collected from cattle in the same region. These results confirm the presence of a previously unrecognized infectious disease in the indigenous Cameroonian population, as well as extend the established range of R. africae. 相似文献
4.
Portillo A Pérez-Martínez L Santibáñez S Blanco JR Ibarra V Oteo JA 《The American journal of tropical medicine and hygiene》2007,77(2):376-377
A total of 53 engorged adult ticks belonging to the species Rhipicephalus (Boophilus) decoloratus (N = 9), Rhipicephalus evertsi evertsi (N = 27), Rhipicephalus appendiculatus (N = 9), Amblyomma hebraeum (N = 5), and Hyalomma marginatum turanicum (N = 3), were removed from oryx in Botswana (South Africa). They were tested for the presence of spotted fever group (SFG) Rickettsia and Anaplasma phagocytophilum using polymerase chain reaction (PCR). Seventy-seven percent of R. decoloratus as well as twenty percent of A. hebraeum were positive for ompA, gltA and 16S rRNA SFG Rickettsia PCR assays. All nucleotide sequences were homologous to Rickettsia africae, the agent of African tick-bite fever (ATBF). None of the tested ticks was positive for 16S rRNA A. phagocytophilum PCR assays. These results suggest for the first time that R. decoloratus ticks may be reservoirs of R. africae, and support the ATBF risk in this area. 相似文献
5.
Ndip LM Biswas HH Nfonsam LE LeBreton M Ndip RN Bissong MA Mpoudi-Ngole E Djoko C Tamoufe U Prosser AT Burke DS Wolfe ND 《The American journal of tropical medicine and hygiene》2011,84(4):608-613
African tick-bite fever is an emerging infectious disease caused by the spotted fever group Rickettsia, Rickettsia africae, and is transmitted by ticks of the genus Amblyomma. To determine the seroprevalence of exposure to R. africae and risk factors associated with infection, we conducted a cross-sectional study of persons in seven rural villages in distinct ecological habitats of Cameroon. We examined 903 plasma samples by using an indirect immunofluorescence assay for antibodies to R. africae and analyzed demographic and occupational data collected from questionnaires. Of the 903 persons tested, 243 (26.9%) had IgG/IgM/IgA reactive with R. africae. Persons from four of the seven village sites were significantly more likely to be seropositive (P < 0.05), and lowland forest sites tended to have higher seroprevalences. These results suggest that African tick-bite fever is common in adults in rural areas of Cameroon and that ecological factors may play a role in the acquisition of R. africae infection. 相似文献
6.
Morita C El Hussein AR Matsuda E Abdel Gabbar KM Muramatsu Y Abdel Rahman MB Eleragi AM Hassan SM Chitambo AM Ueno H 《Japanese journal of infectious diseases》2004,57(3):107-109
Ticks were collected from ruminants in various areas of Sudan in 1998 and 2000. Primer pairs of rickettsial citrate synthase gene (gltA) and a spotted fever group (SFG) rickettsial 190-kDa surface antigen gene (rompA), respectively, were used for identification. Polymerase chain reaction (PCR)-positive products were used for DNA sequencing. The gltA gene was detected in 55% of the ticks examined (57/104). Among the 57 ticks studied, 19 were positive for the rompA gene. Thus, 18% of the ticks examined were found to be infected with SFG rickettsiae. The nucleotide sequences of the amplified rompA gene fragment of Hyalomma spp. and Amblyomma spp. were similar to those of Rickettsia aeschlimannii and Rickettsia africae, respectively. In this study, we succeeded in detecting the SFG rickettsiae gene in ticks, and established that there were at least two species of SFG rickettsiae in field ticks in Sudan. 相似文献
7.
J V Lange A G el Dessouky E Manor A I Merdan A F Azad 《The American journal of tropical medicine and hygiene》1992,46(5):546-551
A field study was initiated in 1988 to investigate whether spotted fever group rickettsiae occur in geographic areas in Egypt that are adjacent to an area in the southern Israeli Negev that has a defined focus of spotted fever disease. Ticks were collected from dogs, sheep, and camels at four study sites in the northern Sinai. Tick hemolymph was processed for rickettsial detection by staining with fluorescein isothiocyanate-conjugated antibody to Rickettsia rickettsii. Of the 442 hemolymphs examined, 15 contained immunofluorescent rickettsiae. Eight hemolymph test-positive (HT+) ticks were Rhipicephalus sanguineus removed from dogs; the other HT+ ticks comprised three Hyalomma species, H. anatolicum, H. impeltatum, and H. dromedarii. Both HT+ and HT- ticks were tested for rickettsial DNA using the polymerase chain reaction (PCR). Eight of 10 HT+ field-collected ticks were PCR positive (PCR+). All laboratory colony R. rickettsii-infected ticks were PCR+. No HT- ticks from field or laboratory isolates were PCR+. 相似文献
8.
Stromdahl EY Jiang J Vince M Richards AL 《Vector borne and zoonotic diseases (Larchmont, N.Y.)》2011,11(7):969-977
From 1997 to 2009, the Tick-Borne Disease Laboratory of the U.S. Army Public Health Command (USAPHC) (formerly the U.S. Army Center for Health Promotion and Preventive Medicine) screened 5286 Dermacentor variabilis ticks removed from Department of Defense (DOD) personnel, their dependents, and DOD civilian personnel for spotted fever group rickettsiae using polymerase chain reaction and restriction fragment length polymorphism analysis. Rickettsia montanensis (171/5286 = 3.2%) and Rickettsia amblyommii (7/5286 = 0.1%) were detected in a small number of samples, but no ticks were found positive for Rickettsia rickettsii, the agent of Rocky Mountain spotted fever (RMSF) until May 2009, when it was detected in one D. variabilis male removed from a child in Maryland. This result was confirmed by nucleotide sequence analysis of the rickettsial isolate and of the positive control used in the polymerase chain reaction, which was different from the isolate. Lethal effects of rickettsiostatic proteins of D. variabilis on R. rickettsii and lethal effects of R. rickettsii infection on tick hosts may account for this extremely low prevalence. Recent reports of R. rickettsii in species Rhipicephalus sanguineus and Amblyomma americanum ticks suggest their involvement in transmission of RMSF, and other pathogenic rickettsiae have been detected in Amblyomma maculatum. The areas of the U.S. endemic for RMSF are also those where D. variabilis exist in sympatry with populations of A. americanum and A. maculatum. Interactions among the sympatric species of ticks may be involved in the development of a focus of RMSF transmission. On the other hand, the overlap of foci of RMSF cases and areas of A. americanum and A. maculatum populations might indicate the misdiagnosis as RMSF of diseases actually caused by other rickettsiae vectored by these ticks. Further studies on tick vectors are needed to elucidate the etiology of RMSF. 相似文献
9.
目的对采自广东省连平县的3种硬蜱进行蜱传斑点热立克次体检测分析。方法斑点热立克次体的ompA基因片段扩增并测定扩增片段的DNA序列。结果20只蜱分为17组,其中15组PCR检测阳性。对4个测序成功的标本进行聚类分析,证实其中3个序列单独聚为一类,与引起Flinders岛蜱传斑点热的弗诺立克次体(R.honei)、非洲蜱咬热的非洲立克次体(R.africa)、未定名斑点热的斯洛伐克立克次体(R.slovaca)以及西伯利亚立克次体BJ-90株等亲缘关系较近,另一序列与我国长白山地区检测到的JL-02具有较高的同源性。结论本研究提示该地区除了已证实的西伯利亚斑点热外,还存在新的蜱传斑点热。 相似文献
10.
J F Anderson L A Magnarelli R N Philip W Burgdorfer 《The American journal of tropical medicine and hygiene》1986,35(1):187-191
Dermacentor variabilis, infected with spotted fever group rickettsiae, parasitized 8 of 70 raccoons captured in Newtown, Connecticut. The spotted fever agent, Rickettsia rickettsii, was isolated and identified from 4 adult D. variabilis and from 1 nymphal Ixodes texanus removed from raccoons. This verifies the presence of this etiologic agent in ticks in an area where 6 people had clinical signs and symptoms of Rocky Mountain spotted fever (RMSF) and antibodies to R. rickettsii. These are the first isolations of R. rickettsii from D. variabilis in southern New England and the first identified rickettsiae from I. texanus. No rickettsiae were isolated from Ixodes muris or I. cookei. Rickettsia montana was recovered in Vero cell culture from a D. variabilis collected in East Haddam, Connecticut where RMSF is not known to be prevalent. 相似文献
11.
Stenos J Graves S Popov VL Walker DH 《The American journal of tropical medicine and hygiene》2003,69(3):314-317
Rickettsia honei is the etiologic agent of Flinders Island (Australia) spotted fever. The tick Aponomma hydrosauri is associated with reptiles and is the arthropod reservoir for this rickettsia on Flinders Island. The rickettsia appears to be maintained in the tick via vertical transmission. Of 46 ticks examined, 29 (63%) were positive for spotted fever group rickettsiae by detection of the citrate synthase gene by a polymerase chain reaction (PCR). From the positive tick samples, seven were sequenced and found to be 100% homologous with R. honei. Of 17 reptiles examined, none had evidence of rickettsiae by PCR or culture of blood. 相似文献
12.
African tick bite fever 总被引:1,自引:0,他引:1
Jensenius M Fournier PE Kelly P Myrvang B Raoult D 《The Lancet infectious diseases》2003,3(9):557-564
African tick bite fever is an acute febrile illness that is frequently accompanied by headache, prominent neck muscle myalgia, inoculation eschars, and regional lymphadenitis. The disease is caused by Rickettsia africae, a recently identified spotted fever group rickettsia, which is transmitted by ungulate ticks of the Amblyomma genus in rural sub-Saharan Africa and the French West Indies. Whereas reports on African tick bite fever in indigenous populations are scarce, the number of reported cases in travellers from Europe and elsewhere has recently increased significantly. Treatment with doxycycline is associated with rapid recovery in most patients.An immunofluorescence assay is recommended for the diagnosis but seroconversion is commonly delayed and this limits the usefulness of the test. Travellers to endemic areas should be informed of the risk of contracting African tick bite fever and be encouraged to take personal protective measures against tick bites. 相似文献
13.
Beeler E Abramowicz KF Zambrano ML Sturgeon MM Khalaf N Hu R Dasch GA Eremeeva ME 《The American journal of tropical medicine and hygiene》2011,84(2):244-249
A recurrent focus of Rhipicephalus sanguineus infestation was investigated in a suburban area of southern California after reports of suspected Rocky Mountain spotted fever in two dogs on the same property. Abundant quantities of Rh. sanguineus were collected on the property and repeatedly from each dog, and Rickettsia massiliae DNA was detected by polymerase chain reaction (PCR). Whole blood and serum samples from four dogs were tested by using PCR and microimmunofluorescent assay for antibodies against spotted fever group rickettsiae. Serum samples from all four dogs contained antibodies reactive with R. massiliae, R. rhipicephali, R. rickettsii, and 364D Rickettsia but no rickettsial DNA was detected by PCR of blood samples. Serum cross-absorption and Western blot assays implicated R. massiliae as the most likely spotted fever group rickettsiae responsible for seropositivity. To our knowledge, this is the first detection of R. massiliae in ticks in California. 相似文献
14.
我国南方媒介蜱中首次检出黑龙江立克次体(R.heilongjiangii)及马赛立克次体(R.massilliae)近缘菌 总被引:1,自引:0,他引:1
目的研究我国南方媒介蜱斑点热群立克次体带菌状况。方法采用斑点热群立克次体外膜蛋白ompA基因特异引物,对我国广东省连平县采集的长角血蜱进行检测分析。结果15组蜱标本中,14组检测阳性,阳性率为93.3%。通过测序分析,发现当地长角血蜱携带黑龙江立克次体及马赛立克次体近缘菌。结论我国南方地区除已证实的北亚蜱传斑点热外,还应加强当地其他斑点热的监测及临床鉴别诊断。 相似文献
15.
J C Gordon S W Gordon E Peterson R N Philip 《The American journal of tropical medicine and hygiene》1984,33(5):1026-1031
A survey for the prevalence of Rocky Mountain spotted fever (RMSF) antibodies in dogs associated with confirmed human cases in Ohio was conducted during 1981. Twelve of 14 confirmed cases (85%) had a history of dog association prior to onset of RMSF. A total of 29 dogs were included in the study, with 16 dogs providing serum samples for antibody testing and the remainder providing tick samples. Serum samples tested by indirect microimmunofluorescence techniques revealed 12/16 dogs (75%) to be seropositive for Rickettsia rickettsii. A total of 310 ticks were collected from study dogs and the vegetation surrounding RMSF case exposure sites. Twenty-two (7.1%) of these ticks (all Dermacentor variabilis) were found to be infected with spotted fever group rickettsiae. Four ticks (1.3%) were infected with R. rickettsii, 13 (4.2%) with Rickettsia montana, and four (1.3%) with Rickettsia bellii. R. montana, a nonpathogen, was the only rickettsia found in dogs (antibodies) and ticks (isolation) associated with human cases in Southern Ohio. 相似文献
16.
Tsui PY Tsai KH Weng MH Hung YW Liu YT Hu KY Lien JC Lin PR Shaio MF Wang HC Wang HC Ji DD 《The American journal of tropical medicine and hygiene》2007,77(5):883-890
Rickettsioses are emerging infectious diseases caused by rickettsiae in association with arthropods. We report the detection of spotted fever group rickettsiae (SFGR) in Taiwan using molecular methods. Phylogenetic analyses of the 17-kd protein and citrate synthase (gltA) genes showed that SFGR TwKM01 detected in Rhipicephalus haemaphysaloides ticks was most similar to Rickettsia rhipicephali. Three TwKM01 isolates were obtained from three individual R. haemaphysaloides ticks. Small, intracellular, coccobacillary bacteria were found in infected L929 cells using immunofluorescence antibody testing and transmission electron microscopy. Two other SFGRs, TwKM02 and TwKM03, identified in Leptotrombidium chigger mites, were closely related to R. australis and R. felis URRWXCal(2), respectively. The TwKM03 strain was also detected in Ixodes granulatus ticks and widely distributed in Hualien, Kinmen, and Lienchiang counties in Taiwan. The endonucleases MaeII and HhaI selected for restriction fragment length polymorphism analysis of the gltA and 17-kd polymerase chain reaction products, respectively, were useful for genotyping Rickettsia species TwKM01, TwKM02, TwKM03, and other SFGRs. Although their infectivity and pathogenicity for vertebrates are unknown, the finding of SFGRs raises the possibility that bacteria other than Orientia tsutsugamushi, Coxiella burnetii, and R. typhi may be involved in rickettsial diseases in Taiwan. 相似文献
17.
Endemicity of spotted fever group rickettsiae in Connecticut 总被引:4,自引:0,他引:4
L A Magnarelli J F Anderson R N Philip W Burgdorfer E A Casper 《The American journal of tropical medicine and hygiene》1981,30(3):715-721
To compare rickettsial infectivity and seropositivity rates against spotted fever group (SFG) rickettsiae, ticks and wild mammals were collected from three areas where Rickettsia rickettsii was thought to be enzootic in Connecticut during 1978-1979, and from four additional sites (with no reported human cases) between 1976 and 1979. Of the 1,001 Dermacentor variabilis examined by the hemolymph test, 59 (5.9%) contained rickettsia-like organisms; direct immunofluorescence tests verified the presence of SFT rickettsiae in 14 specimens. Prevalence of rickettsiae-infected ticks at Newtown, an area where human cases of Rocky Mountain spotted fever probably originated, was 2.2%. Rates for six other areas ranged between 0 and 6.3%. Isolations included Rickettsia montana from four ticks collected at Branford and Woodbridge, and R. rickettsii (R-like strain) from the blood of an acutely ill person. Microagglutination (MA) tests indicated that 15 (14.9%) of 101 Peromyscus leucopus (white-footed mice) from Newtown had agglutinins in titers greater than or equal to 1:8 against R. rickettsii, whereas five of 92 white-footed mice (5.4%) from Brandord, West Hartford, Woodbridge, and Sharon were considered MA-positive. Indirect microimmunofluorescence tests of Procyon lotor (raccoon) sera revealed antibodies to R. rickettsii in 33 of 69 (47.8%) samples from Newtown and in two of 60 (3.3%) from Guilford. Additionally, 17 raccoons had sera specific to R. montana (n = 8) or to the 369-C rickettsia strain (n = 9). Since rickettsia-positive ticks are high-titered seropositive mammals occurred at widely separated sites in Connecticut there are probably several foci of SFG rickettsiae distributed throughout the D. variabilis range. 相似文献
18.
Venzal JM Estrada-Peña A Portillo A Mangold AJ Castro O De Souza CG Félix ML Pérez-Martínez L Santibánez S Oteo JA 《Revista do Instituto de Medicina Tropical de S?o Paulo》2012,54(3):131-134
At first Rickettsia conorii was implicated as the causative agent of spotted fever in Uruguay diagnosed by serological assays. Later Rickettsia parkeri was detected in human-biting Amblyomma triste ticks using molecular tests. The natural vector of R. conorii, Rhipicephalus sanguineus, has not been studied for the presence of rickettsial organisms in Uruguay. To address this question, 180 R. sanguineus from dogs and 245 A. triste from vegetation (flagging) collected in three endemic localities were screened for spotted fever group (SFG) rickettsiosis in southern Uruguay. Tick extracted DNA pools were subjected to PCR using primers which amplify a fragment of the rickettsial gltA gene. Positive tick DNA pools with these primers were subjected to a second PCR round with primers targeting a fragment of the ompA gene, which is only present in SFG rickettsiae. No rickettsial DNA was detected in R. sanguineus. However, DNA pools of A. triste were found to be positive for a rickettsial organism in two of the three localities, with prevalences of 11.8% to 37.5% positive pools. DNA sequences generated from these PCR-positive ticks corresponded to R. parkeri. These findings, joint with the aggressiveness shown by A. triste towards humans, support previous data on the involvement of A. triste as vector of human infections caused by R. parkeri in Uruguay. 相似文献
19.
E M Gross R A Goldwasser J E Bearman I Sarov B Sarov V Torok L Naggan 《The American journal of tropical medicine and hygiene》1983,32(6):1387-1391
A retrospective serological survey was carried out using sera obtained from women at childbirth in the southern desert region of Israel to determine exposure experience to three rickettsial agents: Coxiella burnetii, Rickettsia typhi, and spotted fever group rickettsiae. Using the indirect fluorescent antibody method for determining IgG antibodies, it was found that about 40% of all sera examined demonstrated antibodies to one or more rickettsiae. Bedouin women appeared to be at greater risk of having antibodies to C. burnetii and spotted fever group rickettsiae than did Jewish residents of Beersheba, agricultural settlements, and development towns. The residents of development towns appeared to be at lower risk of developing antibodies to spotted fever group rickettsiae than did other populations sampled. Possible reasons for these differences are discussed. 相似文献
20.
Jensenius M Hoel T Raoult D Fournier PE Kjelshus H Bruu AL Myrvang B 《Scandinavian journal of infectious diseases》2002,34(2):93-96
Rickettsia africae is the causative agent of African tick bite fever (ATBF), an acute febrile illness frequently accompanied by inoculation eschars, regional lymphadenitis, myalgia and severe headache. Recently, ATBF has been recognized as an emerging health problem for international travellers to rural sub-Saharan Africa. To estimate the incidence, risk factors for and proportion of symptomatic cases of travel-associated R. africae infection, we performed a seroepidemiological study of 152 first-time Norwegian travellers to rural areas in sub-Equatorial Africa. Seropositivity was based on the detection of specific antibodies to R. africae in microimmunofluorescence and/or Western blotting assays. Thirteen (8.6%) travellers were seropositive to R. africae. Eight (62%) seropositive travellers reported symptoms consistent with ATBF; of these, 2 had received antirickettsial therapy. Using multiple logistic regression, the following factors were found to be significantly associated with seropositivity: hunting as the purpose of travel [odds ratio (OR) 10.1; 95% confidence interval (CI) 1.5-69; p=0.019] and stay in rural areas of > 7 d (OR 6.0; 95% CI 1.5-24; p=0.012). This first seroepidemiological study on travel-associated R. africae infection suggests that the infection may be common in international travellers to rural sub-Saharan Africa but that most cases are asymptomatic or clinically mild and self-limited. 相似文献