Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-30 (of 37 Records) |
Query Trace: Eremeeva ME [original query] |
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Molecular detection of Bartonella species in ticks from Peru.
Billeter SA , Cáceres AG , Gonzales-Hidalgo J , Luna-Caypo D , Kosoy MY . J Med Entomol 2011 48 (6) 1257-60 A total of 103 ticks, collected from canines, horses, donkeys, and snakes from Peru, were screened for the presence of Bartonella DNA by polymerase chain reaction analysis. Bartonella DNA was detected in two ticks using Bartonella 16S-23S intergenic spacer region primers and in an additional two ticks using Bartonella NADH dehydrogenase gamma subunit gene (nuoG) primers. Bartonella rochalimae Eremeeva et al., B. quintana Schmincke, and B. elizabethae Daly et al. DNA was detected in a Rhipicephalus sanguineus Latreille (Acari: Ixodidae) female tick removed from a dog and B. quintana DNA was present in a Dermacentor nitens Neumann (Acari: Ixodidae) pool of five larvae, one nymph, and one adult male tick collected from donkeys. This is the first study to report the detection of B. rochalimae, B. quintana, and B. elizabethae DNA in ticks from Peru. Further investigations must be performed to decipher the role ticks may play in the transmission of Bartonella species. |
Genetic typing of isolates of Rickettsia typhi.
Kato CY , Chung IH , Robinson LK , Eremeeva ME , Dasch GA . PLoS Negl Trop Dis 2022 16 (5) e0010354 Murine typhus, which is caused by Rickettsia typhi, has a wide range of clinical manifestations. It has a low mortality rate but may result in meningoencephalitis and interstitial pneumonia in severe cases. Comparisons of complete genome sequences of R. typhi isolates from North Carolina, USA (Wilmington), Myanmar (B9991PP), and Thailand (TH1527) identified only 26 single nucleotide polymorphism (SNP) and 7 insertion-deletion (INDEL) sites in these highly syntenic genomes. Assays were developed to further define the distribution of these variant sites among 15 additional isolates of R. typhi with different histories from Asia, the USA, and Africa. Mismatch amplification mutation assays (MAMA) were validated for 22 SNP sites, while the 7 INDEL sites were analyzed directly on agarose gels. Six SNP types, 9 INDEL types, 11 total types were identified among these 18 isolates. Replicate DNA samples as well as comparisons of isolates with different passage and source histories gave consistent genetic typing profiles. Comparison of the SNP and INDEL markers to R. typhi's nearest neighbor Rickettsia prowazekii demonstrated that the majority of the SNPs represent intra-species variation that arose post divergence of these two species while several INDEL sites also exhibited intraspecies variability among the R. prowazekii genomes that have been completely sequenced. The assays for the presence of these SNP and INDEL sites, particularly the latter, comprise a low technology gel method for consistently distinguishing R. typhi and R. prowazekii as well as for differentiating genetic types of R. typhi. |
Molecular Characterization of Rickettsial Agents in Ticks (Acari: Ixodidae) from Sri Lanka.
Dasch GA , Eremeeva ME , Zambrano ML , Premaratna R , Kularatne SAM , Jayanthe Rajapakse RPV . Am J Trop Med Hyg 2022 106 (6) 1613-23 Because the majority of spotted fever group rickettsiae are transmitted to humans by tick bites, it is important to understand which ticks might play a role in transmission of rickettsial pathogens in Sri Lanka. The purpose of our study was to conduct molecular surveillance of 847 ticks collected in different locations in central Sri Lanka to determine which were infected with Rickettsia and Anaplasmataceae. Molecular methods were used to identify the ticks and the agents detected. Most ticks (Amblyomma, Haemaphysalis, and Rhipicephalus) were collected by flagging, and lower number was collected from dogs, cattle, pigs, a pangolin, and tortoises. Five spotted fever genotypes were identified: a Rickettsia africae-like agent in Amblyomma larvae, Rhipicephalus massiliae and a related genotype identified in association with the tropical type of Rhipicephalus sanguineus from dogs and Rhipicephalus haemaphysaloides from dogs and cattle, and Candidatus R. kellyi and another novel genotype (SL94) in R. haemaphysaloides. Twenty-three ticks were positive for Anaplasmataceae, including one Anaplasma and two Ehrlichia genotypes. Because the sequence database for both ticks and rickettsial agents from Sri Lanka and southern India is not extensive, additional molecular characterization of the tick species of Sri Lanka and their rickettsial agents is required to understand their pathogenic potential more completely. However, several of the agents we identified in this survey may well be pathogenic for humans and domestic animals, and should be considered as a part of epidemiological surveillance and patient management. |
Confirmation of Rickettsia conorii subspecies indica infection by next-generation sequencing, Shandong, China
Xu N , Gai W , Zhang Y , Wang W , Wang G , Dasch GA , Eremeeva ME . Emerg Infect Dis 2021 27 (10) 2691-2694 We describe 3 similar cases of rickettsial disease that occurred after tick bites in a mountainous rural area of Shandong Province, China. Next-generation sequencing indicated the etiologic agent of 1 patient was Rickettsia conorii subspecies indica. This agent may be more widely distributed across China than previously thought. |
Molecular typing of Rickettsia akari
Eremeeva ME , Sturgeon MM , Willard JK , Karpathy SE , Madan A , Dasch GA . Rus J Infect Immun 2020 10 (3) 497-505 Rickettsia akari, an obligately intracellular bacterium, is the causative agent of the cosmopolitan urban disease rickettsialpox. R. akari is an atypical representative of spotted fever group rickettsiae (SFG) as it is associated with rodent mites rather than ticks or fleas; however, only limited information is available about the degree of genetic variability found among isolates of R. akari. We examined 13 isolates of R. akari from humans, rodents and mites in the USA, the former Soviet Union, and the former Yugoslavia made between 1946 and 2003 for diversity in their tandem repeat regions (TR) and intergenic regions (IGR). The 1.23 Mb genome of R. akari strain Hartford CWPP was analyzed using Tandem Repeat Finder software (http://tandem.bu.edu) and 374 different TRs were identified, with size variation from 1 to 483 bp and with TR copy numbers ranging between 21 and 1.9, respectively. No size polymorphisms were detected among the 11 TR regions examined from 5 open reading frames and 6 IGR. Eighteen non-TR IGR’s were amplified and sequenced for the same isolates comprising a total of 5.995 bp (0.49%) of the Hartford CWPP strain chromosome. Three single nucleotide polymorphism (SNP) sites were detected in two IGR’s which permitted separation of the five R. akari isolates from Ukraine SSR from the other eight isolates. In conclusion, this is the first study reporting genetic heterogeneity among R. akari isolates of different geographic origins. Further exploration of this genetic diversity is needed to understand better the geographic distribution of R. akari and the epidemiology of rickettsialpox. The potential of mites as hosts for other rickettsial agents also needs further investigation. |
Detection of Rickettsia asembonensis in Fleas (Siphonaptera: Pulicidae, Ceratophyllidae) Collected in Five Counties in Georgia, United States.
Eremeeva ME , Capps D , McBride CL , Williams-Newkirk AJ , Dasch GA , Salzer JS , Beati L , Durden LA . J Med Entomol 2020 57 (4) 1246-1253 We conducted a molecular survey of Rickettsia in fleas collected from opossums, road-killed and live-trapped in peridomestic and rural settings, state parks, and from pet cats and dogs in Georgia, United States during 1992-2014. The cat flea, Ctenocephalides felis (Bouche) was the predominant species collected from cats and among the archival specimens from opossums found in peridomestic settings. Polygenis gwyni (Fox) was more prevalent on opossums and a single cotton rat trapped in sylvatic settings. Trapped animals were infested infrequently with the squirrel flea, Orchopeas howardi (Baker) and C. felis. TaqMan assays targeting the BioB gene of Rickettsia felis and the OmpB gene of Rickettsia typhi were used to test 291 flea DNAs for Rickettsia. A subset of 53 C. felis collected from a cat in 2011 was tested in 18 pools which were all bioB TaqMan positive (34% minimum infection prevalence). Of 238 fleas tested individually, 140 (58.8%, 95% confidence interval [CI]: 52.5-64.9%) DNAs were bioB positive. Detection of bioB was more prevalent in individual C. felis (91%) compared to P. gwyni (13.4%). Twenty-one (7.2%) were ompB TaqMan positive, including 18 C. felis (9.5%) and 3 P. gwyni (3.2%). Most of these fleas were also positive with bioB TaqMan; however, sequencing of gltA amplicons detected only DNA of Rickettsia asembonensis. Furthermore, only the R. asembonensis genotype was identified based on NlaIV restriction analysis of a larger ompB fragment. These findings contribute to understanding the diversity of Rickettsia associated with fleas in Georgia and emphasize the need for development of more specific molecular tools for detection and field research on rickettsial pathogens. |
Detection and characterization of a novel spotted fever group Rickettsia genotype in Haemaphysalis leporispalustris from California, USA.
Eremeeva ME , Weiner LM , Zambrano ML , Dasch GA , Hu R , Vilcins I , Castro MB , Bonilla DL , Padgett KA . Ticks Tick Borne Dis 2018 9 (4) 814-818 The rabbit tick, Haemaphysalis leporispalustris Packard, is known for its association with Rickettsia rickettsii as it harbors both virulent and avirulent strains of this pathogen. In this manuscript we report findings and preliminary characterization of a novel spotted fever group rickettsia (SFGR) in rabbit ticks from California, USA. Rickettsia sp. CA6269 (proposed "Candidatus Rickettsia lanei") is most related to known R. rickettsii isolates but belongs to its own well-supported branch different from those of all R. rickettsii including strain Hlp2 and from Rickettsia sp. 364D (also known as R. philipii) and R. peacockii. This SFGR probably exhibits both transovarial and transstadial survival since it was found in both questing larvae and nymphs. Although this rabbit tick does not frequently bite humans, its role in maintenance of other rickettsial agents and this novel SFGR warrant further investigation. |
The eco-epidemiology of Pacific Coast tick fever in California
Padgett KA , Bonilla D , Eremeeva ME , Glaser C , Lane RS , Porse CC , Castro MB , Messenger S , Espinosa A , Hacker J , Kjemtrup A , Ryan B , Scott JJ , Hu R , Yoshimizu MH , Dasch GA , Kramer V . PLoS Negl Trop Dis 2016 10 (10) e0005020 Rickettsia philipii (type strain "Rickettsia 364D"), the etiologic agent of Pacific Coast tick fever (PCTF), is transmitted to people by the Pacific Coast tick, Dermacentor occidentalis. Following the first confirmed human case of PCTF in 2008, 13 additional human cases have been reported in California, more than half of which were pediatric cases. The most common features of PCTF are the presence of at least one necrotic lesion known as an eschar (100%), fever (85%), and headache (79%); four case-patients required hospitalization and four had multiple eschars. Findings presented here implicate the nymphal or larval stages of D. occidentalis as the primary vectors of R. philipii to people. Peak transmission risk from ticks to people occurs in late summer. Rickettsia philipii DNA was detected in D. occidentalis ticks from 15 of 37 California counties. Similarly, non-pathogenic Rickettsia rhipicephali DNA was detected in D. occidentalis in 29 of 38 counties with an average prevalence of 12.0% in adult ticks. In total, 5,601 ticks tested from 2009 through 2015 yielded an overall R. philipii infection prevalence of 2.1% in adults, 0.9% in nymphs and a minimum infection prevalence of 0.4% in larval pools. Although most human cases of PCTF have been reported from northern California, acarological surveillance suggests that R. philipii may occur throughout the distribution range of D. occidentalis. |
Challenges posed by tick-borne rickettsiae: eco-epidemiology and public health implications.
Eremeeva ME , Dasch GA . Front Public Health 2015 3 55 Rickettsiae are obligately intracellular bacteria that are transmitted to vertebrates by a variety of arthropod vectors, primarily by fleas and ticks. Once transmitted or experimentally inoculated into susceptible mammals, some rickettsiae may cause febrile illness of different morbidity and mortality, and which can manifest with different types of exhanthems in humans. However, most rickettsiae circulate in diverse sylvatic or peridomestic reservoirs without having obvious impacts on their vertebrate hosts or affecting humans. We have analyzed the key features of tick-borne maintenance of rickettsiae, which may provide a deeper basis for understanding those complex invertebrate interactions and strategies that have permitted survival and circulation of divergent rickettsiae in nature. Rickettsiae are found in association with a wide range of hard and soft ticks, which feed on very different species of large and small animals. Maintenance of rickettsiae in these vector systems is driven by both vertical and horizontal transmission strategies, but some species of Rickettsia are also known to cause detrimental effects on their arthropod vectors. Contrary to common belief, the role of vertebrate animal hosts in maintenance of rickettsiae is very incompletely understood. Some clearly play only the essential role of providing a blood meal to the tick while other hosts may supply crucial supplemental functions for effective agent transmission by the vectors. This review summarizes the importance of some recent findings with known and new vectors that afford an improved understanding of the eco-epidemiology of rickettsiae; the public health implications of that information for rickettsial diseases are also described. Special attention is paid to the co-circulation of different species and genotypes of rickettsiae within the same endemic areas and how these observations may influence, correctly or incorrectly, trends, and conclusions drawn from the surveillance of rickettsial diseases in humans. |
Detection of human pathogenic Ehrlichia muris-like agent in Peromyscus leucopus
Castillo CG , Eremeeva ME , Paskewitz SM , Sloan LM , Lee X , Irwin WE , Tonsberg S , Pritt BS . Ticks Tick Borne Dis 2014 6 (2) 155-7 An Ehrlichia muris-like (EML) bacterium was recently detected in humans and Ixodes scapularis ticks in Minnesota and Wisconsin. The reservoir for this agent is unknown. To investigate the occurrence of the EML agent, groEL PCR testing and sequencing was performed on blood from small mammals and white-tailed deer that were collected in areas where human and tick infections were previously demonstrated. DNA of the EML agent was detected in two Peromyscus leucopus of 146 small mammals (1.4%); while 181 O. virginianus tested negative. This report provides the first evidence that DNA from the EML agent is found in P. leucopus, the same animal that is a reservoir for Anaplasma phagocytophilum in this region. The role of white-tailed deer remains inconclusive. Further sampling is warranted to understand the spatial and temporal distribution, transmission and maintenance of this pathogen. |
Sylvatic typhus associated with flying squirrels (Glaucomys volans) in New York State, United States
Prusinski MA , White JL , Wong SJ , Conlon MA , Egan C , Kelly-Cirino CD , Laniewicz BR , Backenson PB , Nicholson WL , Eremeeva ME , Karpathy SE , Dasch GA , White DJ . Vector Borne Zoonotic Dis 2014 14 (4) 240-4 Sylvatic typhus is an infrequent, potentially life-threatening emerging zoonotic disease. In January of 2009, the New York State Department of Health was notified of a familial cluster of two suspected cases. Due to the paucity of typhus cases in New York, epidemiologic and environmental investigations were conducted to establish rickettsial etiology and determine potential sources of infection. Patients presented with symptoms consistent with typhus, and serologic testing of each patient confirmed infection with typhus group rickettsiae. Serologic analysis of blood obtained from southern flying squirrels (Glaucomys volans) captured from the attic crawlspace above an enclosed front porch of the cases' residence indicated evidence of infection with Rickettsia prowazekii, with 100% seroprevalence (n=11). Both patients reported spending significant time on the porch and hearing animal activity above the ceiling prior to onset of illness, implicating these flying squirrels as the likely source of infection. |
The 2010 outbreak of poliomyelitis in Tajikistan: epidemiology and lessons learnt
Yakovenko M , Gmyl A , Ivanova O , Eremeeva T , Ivanov A , Prostova M , Baykova O , Isaeva O , Lipskaya G , Shakaryan A , Kew O , Deshpande J , Agol V . Euro Surveill 2014 19 (7) 20706 A large outbreak of poliomyelitis, with 463 laboratory-confirmed and 47 polio-compatible cases, took place in 2010 in Tajikistan. Phylogenetic analysis of the viral VP1 gene suggested a single importation of wild poliovirus type 1 from India in late 2009, its further circulation in Tajikistan and expansion into neighbouring countries, namely Kazakhstan, Russia, Turkmenistan and Uzbekistan. Whole-genome sequencing of 14 isolates revealed recombination events with enterovirus C with cross-overs within the P2 region. Viruses with one class of recombinant genomes co-circulated with the parental virus, and representatives of both caused paralytic poliomyelitis. Serological analysis of 327 sera from acute flaccid paralysis cases as well as from patients with other diagnoses and from healthy people demonstrated inadequate immunity against polio in the years preceding the outbreak. Evidence was obtained suggesting that vaccination against poliomyelitis, in rare cases, may not prevent the disease. Factors contributing to the peculiarities of this outbreak are discussed. The outbreak emphasises the necessity of continued vaccination against polio and the need, at least in risk areas, of quality control of this vaccination through well planned serological surveillance. |
Two pathogens and one disease: detection and identification of flea-borne Rickettsiae in areas endemic for murine typhus in California
Eremeeva ME , Karpathy SE , Krueger L , Hayes EK , Williams AM , Zaldivar Y , Bennett S , Cummings R , Tilzer A , Velten RK , Kerr N , Dasch GA , Hu R . J Med Entomol 2012 49 (6) 1485-94 Results of an environmental assessment conducted in a newly emergent focus of murine typhus in southern California are described. Opossums, Didelphis virginiana Kerr, infested with cat fleas, Ctenocephalides felis Buche, in the suburban area were abundant. Animal and flea specimens were tested for the DNA of two flea-borne rickettsiae, Rickettsia typhi and Rickettsia felis. R. felis was commonly detected in fleas collected throughout this area while R. typhi was found at a much lower prevalence in the vicinity of just 7 of 14 case-patient homes identified. DNA of R. felis, but not R. typhi, was detected in renal, hepatic, and pulmonary tissues of opossums. In contrast, there were no hematologic polymerase chain reaction findings of R. felis or R. typhi in opossums, rats, and cats within the endemic area studied. Our data suggest a significant probability of human exposure to R. felis in the area studied; however, disease caused by this agent is not recognized by the medical community and may be misdiagnosed as murine typhus using nondiscriminatory serologic methods. |
Investigation of an outbreak of rickettsial febrile illness in Guatemala, 2007
Eremeeva ME , Berganza E , Suarez G , Gobern L , Dueger E , Castillo L , Reyes L , Wikswo ME , Abramowicz KF , Dasch GA , Lindblade KA . Int J Infect Dis 2012 17 (5) e304-11 OBJECTIVES: We describe an outbreak of spotted fever group (SFG) rickettsiosis that occurred in 2007 in a farming community in southeastern Guatemala. We identified 17 cases of an acute febrile illness, among which 10, including two fatalities, were confirmed or probable cases of rickettsial disease (case-fatality proportion 12%). METHODS: PCR, a microimmunofluorescence assay (IFA), and Western blotting were performed on patient samples, and PCR was performed on ticks. RESULTS: Using an indirect IFA, seven of 16 (44%) ill persons tested had both IgM and IgG antibodies reacting with one or more Rickettsia spp antigens; the other nine (56%) had only IgM titers or were seronegative. Antibodies to SFG protein and lipopolysaccharide were detected by Western blotting with antigens of Rickettsia typhi, Rickettsia rickettsii, and Rickettsia akari. Only one sample, from an ill person who died, tested positive by PCR for a SFG Rickettsia. PCR analysis of Amblyomma cajennense ticks from domestic animals in the area detected the presence of SFG Rickettsia DNA in one of 12 ticks collected. CONCLUSIONS: Further studies in Guatemala are warranted to establish the prevalence of rickettsioses and to fully characterize the identity of the etiologic agents and vectors. |
Rickettsia felis in cat fleas, Ctenocephalides felis parasitizing opossums, San Bernardino County, California
Abramowicz KF , Wekesa JW , Nwadike CN , Zambrano ML , Karpathy SE , Cecil D , Burns J , Hu R , Eremeeva ME . Med Vet Entomol 2012 26 (4) 458-62 Los Angeles and Orange Counties are known endemic areas for murine typhus in California; however, no recent reports of flea-borne rickettsioses are known from adjacent San Bernardino County. Sixty-five opossums (Didelphis virginiana) were trapped in the suburban residential and industrial zones of the southwestern part of San Bernardino County in 2007. Sixty out of 65 opossums were infested with fleas, primarily cat fleas, Ctenocephalides felis (Bouche, 1835) . The flea minimum infection rate with Rickettsia felis was 13.3% in pooled samples and the prevalence was 23.7% in single fleas, with two gltA genotypes detected. In spite of historic records of murine typhus in this area, no evidence for circulation of R. typhi in fleas was found during the present study. Factors contributing to the absence of R. typhi in these cat fleas in contrast to its presence in cat fleas from Orange and Los Angeles Counties are unknown and need to be investigated further in San Bernardino County. |
Rickettsia felis in Ctenocephalides felis from Guatemala and Costa Rica
Troyo A , Alvarez D , Taylor L , Abdalla G , Calderon-Arguedas O , Zambrano ML , Dasch GA , Lindblade K , Hun L , Eremeeva ME , Estevez A . Am J Trop Med Hyg 2012 86 (6) 1054-1056 Rickettsia felis is an emerging human pathogen associated primarily with the cat flea Ctenocephalides felis. In this study, we investigated the presence of Rickettsia felis in C. felis from Guatemala and Costa Rica. Ctenocephalides felis were collected directly from dogs and cats, and analyzed by polymerase chain reaction for Rickettsia-specific fragments of 17-kDa protein, OmpA, and citrate synthase genes. Rickettsia DNA was detected in 64% (55 of 86) and 58% (47 of 81) of flea pools in Guatemala and Costa Rica, respectively. Sequencing of gltA fragments identified R. felis genotype URRWXCal(2) in samples from both countries, and genotype Rf2125 in Costa Rica. This is the first report of R. felis in Guatemala and of genotype Rf2125 in Costa Rica. The extensive presence of this pathogen in countries of Central America stresses the need for increased awareness and diagnosis. |
Bartonella and Bartonella infections in China: from the clinic to the laboratory
Liu Q , Eremeeva ME , Li D . Comp Immunol Microbiol Infect Dis 2012 35 (2) 93-102 The current status of Bartonella studies in mainland China is reviewed including both laboratory and ecological data and limited clinical data. Detection and isolation of Bartonella species from arthropods, pets and small wild animals is commonplace; this includes a variety of known and emerging Bartonella pathogens. In contrast, the medical literature analyzed from 1980 to 2010 consists of 31 reports of only of cat scratch disease (CSD). Most cases are from the East and South-Eastern provinces, the most populated areas with best access to medical care. Disease typically is described as febrile illness with symptoms traditionally reported for CSD elsewhere in the world. Clinical observations and anamnesis are the primary bases for diagnosis, since specialized serologic and molecular diagnosis is not widely available. Seroprevalence of healthy populations determined using Bartonella henselae antigen varies from 9.6 to 19.6%. The apparent discordance postulated between possible environmental exposure to diverse Bartonella agents and restricted B. henselae case etiologies suggests a need to determine whether other Bartonella species may also be etiologic agents of human illness and emphasizes the importance of applying modern diagnostic tools widely in clinical practice in mainland China. |
Rocky Mountain spotted fever in Panama: a cluster description
Tribaldos M , Zaldivar Y , Bermudez S , Samudio F , Mendoza Y , Martinez AA , Villalobos R , Eremeeva ME , Paddock CD , Page K , Smith RE , Pascale JM . J Infect Dev Ctries 2011 5 (10) 737-41 Rocky Mountain spotted fever (RMSF) is a tick-borne infection caused by Rickettsia rickettsii. We report a cluster of fatal cases of RMSF in 2007 in Panama, involving a pregnant woman and two children from the same family. The woman presented with a fever followed by respiratory distress, maculopapular rash, and an eschar at the site from which a tick had been removed. She died four days after disease onset. This is the second published report of an eschar in a patient confirmed by PCR to be infected with R. rickettsii. One month later, the children presented within days of one another with fever and rash and died three and four days after disease onset. The diagnosis was confirmed by immunohistochemistry, PCR and sequencing of the genes of R. rickettsii in tissues obtained at autopsy. |
Spotted fever group rickettsiae in ticks collected from wild animals in Israel
Keysary A , Eremeeva ME , Leitner M , Din AB , Wikswo ME , Mumcuoglu KY , Inbar M , Wallach AD , Shanas U , King R , Waner T . Am J Trop Med Hyg 2011 85 (5) 919-23 We report molecular evidence for the presence of spotted fever group rickettsiae (SFGR) in ticks collected from roe deer, addax, red foxes, and wild boars in Israel. Rickettsia aeschlimannii was detected in Hyalomma marginatum and Hyalomma detritum while Rickettsia massiliae was present in Rhipicephalus turanicus ticks. Furthermore, a novel uncultured SFGR was detected in Haemaphysalis adleri and Haemaphysalis parva ticks from golden jackals. The pathogenicity of the novel SFGR for humans is unknown; however, the presence of multiple SFGR agents should be considered when serological surveillance data from Israel are interpreted because of significant antigenic cross-reactivity among Rickettsia. The epidemiology and ecology of SFGR in Israel appear to be more complicated than was previously believed. |
Beta interferon-mediated activation of signal transducer and activator of transcription protein 1 interferes with Rickettsia conorii replication in human endothelial cells
Colonne PM , Eremeeva ME , Sahni SK . Infect Immun 2011 79 (9) 3733-43 Infection of the endothelial cell lining of blood vessels with Rickettsia conorii, the causative agent of Mediterranean spotted fever, results in endothelial activation. We investigated the effects of R. conorii infection on the status of the Janus kinase (JAK)-signal transducer and activator of transcription protein (STAT) signaling pathway in human microvascular endothelial cells (HMECs), the most relevant host cell type, in light of rickettsial tropism for microvascular endothelium in vivo. R. conorii infection induced phosphorylation of STAT1 on tyrosine 701 and serine 727 at 24, 48, and 72 h postinfection in HMECs. Employing transcription profile analysis and neutralizing antibodies, we further determined that beta interferon (IFN-beta) production and secretion are critical for STAT1 activation. Secreted IFN-beta further amplified its own expression via a positive-feedback mechanism, while expression of transcription factors interferon regulatory factor 7 (IRF7) and IRF9, implicated in the IFN-beta-STAT1 feedback loop, was also induced. Metabolic activity of rickettsiae was essential for the IFN-beta-mediated response(s) because tetracycline treatment inhibited R. conorii replication, IFN-beta expression, and STAT1 phosphorylation. Inclusion of IFN-beta-neutralizing antibody during infection resulted in significantly enhanced R. conorii replication, whereas addition of exogenous IFN-beta had the opposite inhibitory effect. Finally, small interfering RNA-mediated knockdown further confirmed a protective role for STAT1 against intracellular R. conorii replication. In concert, these findings implicate an important role for IFN-beta-mediated STAT1 activation in innate immune responses of vascular endothelium to R. conorii infection. |
Emergence of a new pathogenic Ehrlichia species, Wisconsin and Minnesota, 2009.
Pritt BS , Sloan LM , Johnson DK , Munderloh UG , Paskewitz SM , McElroy KM , McFadden JD , Binnicker MJ , Neitzel DF , Liu G , Nicholson WL , Nelson CM , Franson JJ , Martin SA , Cunningham SA , Steward CR , Bogumill K , Bjorgaard ME , Davis JP , McQuiston JH , Warshauer DM , Wilhelm MP , Patel R , Trivedi VA , Eremeeva ME . N Engl J Med 2011 365 (5) 422-9 BACKGROUND: Ehrlichiosis is a clinically important, emerging zoonosis. Only Ehrlichia chaffeensis and E. ewingii have been thought to cause ehrlichiosis in humans in the United States. Patients with suspected ehrlichiosis routinely undergo testing to ensure proper diagnosis and to ascertain the cause. METHODS: We used molecular methods, culturing, and serologic testing to diagnose and ascertain the cause of cases of ehrlichiosis. RESULTS: On testing, four cases of ehrlichiosis in Minnesota or Wisconsin were found not to be from E. chaffeensis or E. ewingii and instead to be caused by a newly discovered ehrlichia species. All patients had fever, malaise, headache, and lymphopenia; three had thrombocytopenia; and two had elevated liver-enzyme levels. All recovered after receiving doxycycline treatment. At least 17 of 697 Ixodes scapularis ticks collected in Minnesota or Wisconsin were positive for the same ehrlichia species on polymerase-chain-reaction testing. Genetic analyses revealed that this new ehrlichia species is closely related to E. muris. CONCLUSIONS: We report a new ehrlichia species in Minnesota and Wisconsin and provide supportive clinical, epidemiologic, culture, DNA-sequence, and vector data. Physicians need to be aware of this newly discovered close relative of E. muris to ensure appropriate testing, treatment, and regional surveillance. (Funded by the National Institutes of Health and the Centers for Disease Control and Prevention.). |
Rickettsia rickettsii in Rhipicephalus ticks, Mexicali, Mexico
Eremeeva ME , Zambrano ML , Anaya L , Beati L , Karpathy SE , Santos-Silva MM , Salceda B , MacBeth D , Olguin H , Dasch GA , Aranda CA . J Med Entomol 2011 48 (2) 418-21 Circulation of a unique genetic type of Rickettsia rickettsii in ticks of the Rhipicephalus sanguineus complex was detected in Mexicali, Baja California, Mexico. The Mexican R. rickettsii differed from all isolates previously characterized from the endemic regions of Rocky Mountain spotted fever in northern, central, and southern Americas. Rhipicephalus ticks in Mexicali are genetically different from Rh. sanguineus found in the United States. |
Eschar-associated spotted fever rickettsiosis, Bahia, Brazil
Silva N , Eremeeva ME , Rozental T , Ribeiro GS , Paddock CD , Ramos EAG , Favacho AR , Reis MG , Dasch GA , de Lemos ER , Ko AI . Emerg Infect Dis 2011 17 (2) 275-8 In Brazil, Brazilian spotted fever was once considered the only tick-borne rickettsial disease. We report eschar-associated rickettsial disease that occurred after a tick bite. The etiologic agent is most related to Rickettsia parkeri, R. africae, and R. sibirica and probably widely distributed from Sao Paulo to Bahia in the Atlantic Forest. |
A focus of dogs and Rickettsia massiliae-infected Rhipicephalus sanguineus in California
Beeler E , Abramowicz KF , Zambrano ML , Sturgeon MM , Khalaf N , Hu R , Dasch GA , Eremeeva ME . Am J Trop Med Hyg 2011 84 (2) 244-9 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. |
New spotted fever group Rickettsia in a Rhipicephalus turanicus tick removed from a child in eastern Sicily, Italy
Eremeeva ME , Stromdahl EY . Am J Trop Med Hyg 2011 84 (1) 99-101 A new genotype of spotted fever group Rickettsia (SFGR) was identified in Rhipicephalus turanicus from eastern Sicily. On the basis of current molecular criteria, the genetic characteristics obtained from multiple locus sequence typing satisfy the requirements for Candidatus status of this SFGR. Further detection and identification of this SFGR during entomological and clinical surveys will be required to establish the prevalence of this Rickettsia and its potential pathogenicity for humans. |
Urban focus of Rickettsia typhi and Rickettsia felis in Los Angeles, California
Abramowicz KF , Rood MP , Krueger L , Eremeeva ME . Vector Borne Zoonotic Dis 2010 11 (7) 979-84 Classic murine typhus, caused by Rickettsia typhi, is endemic in the continental United States in areas of Texas and southern California. We conducted an environmental investigation in an urban area of Los Angeles identified as the probable exposure site for a case of murine typhus. Four Rattus norvegicus heavily infested with Xenopsylla cheopis (average 32.5 fleas per animal, range 20-42) were trapped, and fleas, blood, and tissues were collected. DNAs from all specimens were tested for R. typhi and Rickettsia felis using a TaqMan assay targeting the rickettsial citrate synthase gene. Although rickettsiemia was not detected, DNA of R. felis was detected in at least one tissue from each rat. Tissues from 3 rats were also positive for R. typhi DNA. R. typhi and R. felis DNAs were detected in fleas collected from each animal with average minimal infection rates of 10% and 32.3%, respectively. Although R. typhi still circulates in urban Los Angeles in the classic Oriental flea-rat cycle, R. felis is more prevalent, even in this association. |
The expanding spectrum of eschar-associated rickettsioses in the United States
Cragun WC , Bartlett BL , Ellis MW , Hoover AZ , Tyring SK , Mendoza N , Vento TJ , Nicholson WL , Eremeeva ME , Olano JP , Rapini RP , Paddock CD . Arch Dermatol 2010 146 (6) 641-8 BACKGROUND: Until recently, Rickettsia rickettsii was the only substantiated cause of tick-borne spotted fever group (SFG) rickettsiosis in humans in the United States. Rickettsia parkeri, originally thought to be nonpathogenic in humans, was recently proved to be another cause of tick-borne SFG rickettsiosis. OBSERVATIONS: We report 3 cases of SFG rickettsiosis and discuss the epidemiology, clinical presentation, histopathologic features, and laboratory findings that support confirmed or probable diagnoses of R parkeri infection and describe the expanding list of eschar-associated SFG rickettsioses recognized in US patients. CONCLUSIONS: The SFG rickettsioses share many clinical manifestations and extensive antigenic cross-reactivity that may hamper specific confirmation of the causative agent. Published online April 19, 2010 (doi:10.1001/archdermatol.2010.48). |
Murine typhus in Austin, Texas, USA, 2008
Adjemian J , Parks S , McElroy K , Campbell J , Eremeeva ME , Nicholson WL , McQuiston J , Taylor J . Emerg Infect Dis 2010 16 (3) 412-7 In August 2008, Texas authorities and the Centers for Disease Control and Prevention investigated reports of increased numbers of febrile rash illnesses in Austin to confirm the causative agent as Rickettsia typhi, to assess the outbreak magnitude and illness severity, and to identify potential animal reservoirs and peridomestic factors that may have contributed to disease emergence. Thirty-three human cases of confirmed murine typhus were identified. Illness onset was reported from March to October. No patients died, but 23 (70%) were hospitalized. The case-patients clustered geographically in central Austin; 12 (36%) resided in a single ZIP code area. Specimens from wildlife and domestic animals near case-patient homes were assessed; 18% of cats, 44% of dogs, and 71% of opossums had antibodies reactive to R. typhi. No evidence of R. typhi was detected in the whole blood, tissue, or arthropod specimens tested. These findings suggest that an R. typhi cycle involving opossums and domestic animals may be present in Austin. |
Rickettsia felis, West Indies
Kelly PJ , Lucas H , Eremeeva ME , Dirks KG , Rolain JM , Yowell C , Thomas R , Douglas T , Dasch GA , Raoult D . Emerg Infect Dis 2010 16 (3) 570-1 To the Editor: A spay-neuter (sterilization) program for feral cats from Basseterre, the capital of the Caribbean Island St. Kitts, found that most (45/58; 66%) cats had antibodies to spotted fever group rickettsiae (SFGR). The antibodies were detected with Rickettsia rickettsii antigen in a standard microimmunofluorescence assay (1). Titers for 13 (20%) cats were ≥320. |
Incongruent effects of two isolates of Rickettsia conorii on the survival of Rhipicephalus sanguineus ticks
Levin ML , Killmaster L , Zemtsova G , Grant D , Mumcuoglu KY , Eremeeva ME , Dasch GA . Exp Appl Acarol 2009 49 (4) 347-59 Rickettsia conorii, the etiologic agent of Mediterranean spotted fever is widely distributed in Southern Europe, the Middle East, Africa, India and the Caspian region. In the Mediterranean region, the brown dog tick, Rhipicephalus sanguineus, is the recognized vector of R. conorii. To study tick-pathogen relationships and pathogenesis of infection caused in model animals by the bite of an infected tick, we attempted to establish a laboratory colony of Rh. sanguineus persistently infected with R. conorii. Rhipicephalus sanguineus ticks of North American and Mediterranean origin were exposed to R. conorii isolates of African (R. conorii conorii strain Malish) and Mediterranean (R. conorii israelensis strain ISTT) origin. Feeding of ticks upon infected mice and dogs, intra-hemocoel inoculation, and submersion in suspensions of purified rickettsiae were used to introduce the pathogen into uninfected ticks. Feeding success, molting success and the longevity of molted ticks were measured to assess the effects of R. conorii on the survival of Rh. sanguineus. In concordance with previously published results, Rh. sanguineus larvae and nymphs from both North American and Mediterranean colonies exposed to R. conorii conorii Malish experienced high mortality during feeding and molting or immediately after. The prevalence of infection in surviving ticks did not exceed 5%. On the other hand, exposure to ISTT strain had lesser effect on tick survival and resulted in 35-66% prevalence of infection. Rh. sanguineus of Mediterranean origin were more susceptible to infection with either strain of R. conorii than those from North America. Previous experimental studies had demonstrated transovarial and transstadial transmission of R. conorii in Rh. sanguineus; however, our data suggest that different strains of R. conorii may employ different means of maintenance in nature. The vertebrate host may be a more important reservoir than previously thought, or co-feeding transmission between different generations of ticks may obviate or lessen the requirement for transovarial maintenance of R. conorii. |
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