Marina Eremeeva | Georgia Southern University (original) (raw)

Papers by Marina Eremeeva

The American Journal of Tropical Medicine and Hygiene

ABSTRACT. Because the majority of spotted fever group rickettsiae are transmitted to humans by ti... more ABSTRACT. 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...

Journal of clinical microbiology, 1995

Strain S, a spotted fever group (SFG) rickettsia isolated from Rhipicephalus sanguineus ticks col... more Strain S, a spotted fever group (SFG) rickettsia isolated from Rhipicephalus sanguineus ticks collected in Armenia, was identified. Microimmunofluorescence, sodium dodecyl sulfate-polyacrylamide gel protein electrophoresis and Western immunoblotting, PCR and then restriction fragment length polymorphism analysis, pulsed-field gel electrophoresis, and 16S rRNA gene sequencing were used to compare strain S with reference isolates. Strain S was found to possess proteinic, antigenic, and genomic patterns which were unique among SFG rickettsiae. Strain S is characterized by its high degree of pathogenicity for experimental animals, but its role as a potential human pathogen should be determined. The role of R. sanguineus ticks in the epidemiology of SFG rickettsiae is discussed.

Journal of Clinical Microbiology, 1993

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), restriction fragment length... more Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), restriction fragment length polymorphism of polymerase chain reaction-amplified genes (RFLP-PCR), and pulsed-field gel electrophoresis (PFGE) were used to identify 25 isolates of spotted fever group rickettsia collected in the former USSR. Six Rickettsia akari isolates which were identical to the MK reference strain from the American Type Culture Collection were found. Also, 14 isolates were found to be Rickettsia sibirica and identical to reference strain 246. Two of three isolates previously considered as atypical, low-pathogenic strains of R. sibirica, were found to be strains of Rickettsia slovaca. The third, strain S, was similar in its RFLP-PCR profile to "R. africae" sp. nov. (proposed name for a rickettsia pathogenic for human beings in southern Africa) but in its SDS-PAGE and PFGE profiles was unique among spotted fever group rickettsiae. Strain M-1 was confirmed as a genetic variant of Ricketts...

Journal of Clinical Microbiology, 1994

Restriction fragment length polymorphism (RFLP) analysis of PCR-amplified genes was used to study... more Restriction fragment length polymorphism (RFLP) analysis of PCR-amplified genes was used to study spotted fever group (SFG) rickettsiae, extending the previous work of Regnery et al. (R.L. Regnery, C.L. Spruill, and B.D. Plikaytis, J. Bacteriol. 173:1576-1589, 1991). Twenty-six strains of SFG rickettsia were studied, including several recognized species which have never been studied (R. parkeri, R. helvetica, and R. japonica) as well as strains which are not currently classified. Two previously used primer pairs derived from the R. prowazekii citrate syntase gene and the R. rickettsii 190-kDa protein antigen gene were studied, as were primer pairs obtained from the R. rickettsii 120-kDa protein antigen gene. By using three amplifications and three enzyme digestions, it was possible to differentiate between almost all of the known SFG rickettsia species and to differentiate between several strains of the R. conorii complex. Two human pathogens, "R. africae" and the Israeli ...

PLOS Neglected Tropical Diseases, 2016

Rickettsia philipii (type strain "Rickettsia 364D"), the etiologic agent of Pacific Coast tick fe... more 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.

Frontiers in Public Health, 2015

Rickettsiae are obligately intracellular bacteria that are transmitted to vertebrates by a variet... more 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.

BMC microbiology, Jan 14, 2005

Rickettsiae closely related to the Malish strain, the reference Rickettsia conorii strain, includ... more Rickettsiae closely related to the Malish strain, the reference Rickettsia conorii strain, include Indian tick typhus rickettsia (ITTR), Israeli spotted fever rickettsia (ISFR), and Astrakhan fever rickettsia (AFR). Although closely related genotypically, they are distinct serotypically. Using multilocus sequence typing (MLST), we have recently found that distinct serotypes may not always represent distinct species within the Rickettsia genus. We investigated the possibility of classifying rickettsiae closely related to R. conorii as R. conorii subspecies as proposed by the ad hoc committee on reconciliation of approaches to bacterial systematics. For this, we first estimated their genotypic variability by using MLST including the sequencing of 5 genes, of 31 rickettsial isolates closely related to R. conorii strain Malish, 1 ITTR isolate, 2 isolates and 3 tick amplicons of AFR, and 2 ISFR isolates. Then, we selected a representative of each MLST genotype and used multi-spacer typin...

New England Journal of Medicine, 2005

background Rocky Mountain spotted fever is a life-threatening, tick-borne disease caused by Ricke... more background Rocky Mountain spotted fever is a life-threatening, tick-borne disease caused by Rickettsia rickettsii. This disease is rarely reported in Arizona, and the principal vectors, Dermacentor species ticks, are uncommon in the state. From 2002 through 2004, a focus of Rocky Mountain spotted fever was investigated in rural eastern Arizona. methods We obtained blood and tissue specimens from patients with suspected Rocky Mountain spotted fever and ticks from patients' homesites. Serologic, molecular, immunohistochemical, and culture assays were performed to identify the causative agent. On the basis of specific laboratory criteria, patients were classified as having confirmed or probable Rocky Mountain spotted fever infection. results A total of 16 patients with Rocky Mountain spotted fever infection (11 with confirmed and 5 with probable infection) were identified. Of these patients, 13 (81 percent) were children 12 years of age or younger, 15 (94 percent) were hospitalized, and 2 (12 percent) died. Dense populations of Rhipicephalus sanguineus ticks were found on dogs and in the yards of patients' homesites. All patients with confirmed Rocky Mountain spotted fever had contact with tick-infested dogs, and four had a reported history of tick bite preceding the illness. R. rickettsii DNA was detected in nonengorged R. sanguineus ticks collected at one home, and R. rickettsii isolates were cultured from these ticks. conclusions This investigation documents the presence of Rocky Mountain spotted fever in eastern Arizona, with common brown dog ticks (R. sanguineus) implicated as a vector of R. rickettsii. The broad distribution of this common tick raises concern about its potential to transmit R. rickettsii in other settings.

Journal of Medical Entomology, 2007

Sixty-two questing adult Rhipicephalus sanguineus (Latreille) ticks were collected by direct remo... more Sixty-two questing adult Rhipicephalus sanguineus (Latreille) ticks were collected by direct removal from blades of turfgrass and adjacent concrete walkways at a suburban home in Riverside County, CA, and tested for the presence of Rickettsia, Bartonella, and Ehrlichia DNA. Polymerase chain reaction (PCR) was used to amplify fragments of the 17-kDa antigen gene and the rOmpA gene of the spotted fever group rickettsiae. One male tick contained R. rickettsii DNA; its genotype differed from R. rickettsii isolates found in Montana and Arizona that cause Rocky Mountain spotted fever and from Hlp#2 and 364D serotypes. One male tick and one female tick contained B. henselae DNA. No Ehrlichia platys or Ehrlichia canis DNAs were detected using nested PCR for their 16S rRNA genes. These Þndings extend the area where Rickettsia rickettsii may be vectored by Rh. sanguineus. Rh. sanguineus also may be infected with Bartonella henselae, a human pathogen that is typically associated with ßeas and causes cat scratch disease. KEY WORDS Rocky Mountain spotted fever, Rhipicephalus sanguineus, Rickettsia rickettsii, Bartonella henselae, California Rhipicephalus sanguineus (Latreille), the brown dog tick, is distributed worldwide, with a predominantly urban distribution. Domestic dogs are the preferred hosts, although Rh. sanguineus can be found on a variety of domestic and wild animals, including cattle, sheep, cats, rodents, wild canids, wild boar, and rarely humans (Carpenter et al. 1990, Walker et al. 2000, Dantas-Torres et al. 2005, Foata et al. 2006) Rh. sanguineus also has been known to cause infestations in homes and may persist there for years (Lord 2001). In California, adult Rh. sanguineus ticks have been collected year-round and encountered mostly in areas where dogs are maintained (Furman and Loomis 1984). Rh. sanguineus is important mainly as a bloodsucking nuisance of dogs, but it also has great potential for carrying disease-causing agents. In parts of southern Europe, Asia, and Africa, Rh. sanguineus is the classic vector of Rickettsia conorii, the causative agent of Mediterranean spotted fever, and Rickettsia massiliae, which has recently been implicated as a cause of human disease (Parola et al. 2005, Vitale et al. 2006). New World Rh. sanguineus are commonly associated with Rickettsia rhipicephali;

Journal of Clinical Microbiology, 2007

ABSTRACTRickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, is found thro... more ABSTRACTRickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, is found throughout the Americas, where it is associated with different animal reservoirs and tick vectors. No molecular typing system currently exists to allow for the robust differentiation of isolates ofR. rickettsii. Analysis of eight completed genome sequences of rickettsial species revealed a high degree of sequence conservation within the coding regions of chromosomes in the genus. Intergenic regions between coding sequences should be under less selective pressure to maintain this conservation and thus should exhibit greater nucleotide polymorphisms. Utilizing these polymorphisms, we developed a molecular typing system that allows for the genetic differentiation of isolates ofR. rickettsii. This typing system was applied to a collection of 38 different isolates collected from humans, animals, and tick vectors from different geographic locations. Serotypes 364D, fromDermacentor occidentalistick...

International Journal of Infectious Diseases, 2013

We describe an outbreak of spotted fever group (SFG) rickettsiosis that occurred in 2007 in a far... more 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.

Emerging Infectious Diseases, 2011

Clinical Infectious Diseases, 2010

Background. Four spotted fever group rickettsiae (SFGR) are known to infect humans in the United ... more Background. Four spotted fever group rickettsiae (SFGR) are known to infect humans in the United States. A member of the SFGR designated 364D and detected in Dermacentor occidentalis ticks has not previously been identified as a human pathogen. Methods. An 80-year-old man from a rural northern California community presented with an eschar on his forearm. A skin punch biopsy of the lesion was evaluated by immunohistochemistry and molecular analysis. Serum specimens obtained from the patient and 3 other area residents with similar illnesses were tested by immunofluorescence and Western immunoblot for antibodies to SFGR. Ticks were collected near the patient's residence and tested for SFGR. Results. Abundant intracellular rickettsiae and fragmented rickettsial antigens were observed in the mononuclear inflammatory infiltrates of the biopsy. Nucleotide sequences of DNA fragments amplified from the biopsy were identical to those of 364D. Convalescent sera from all four patients exhibited high immunoglobulin G titers to Rickettsia rickettsii, Rickettsia rhipicephali, and 364D antigens. Three adult D. occidentalis were positive for 364D, R. rhipicephali, and an unidentified Rickettsia species. Conclusions. This is the first confirmation of human disease associated with the SFGR 364D, which was likely transmitted by D. occidentalis. Although the patients described here presented with a single cutaneous eschar as the principal manifestation, the full spectrum of illness associated with 364D has yet to be determined. Possible infection with 364D or other SFGR should be confirmed through molecular techniques in patients who present with "spotless" Rocky Mountain spotted fever or have serum antibodies to R. rickettsii with group-specific assays. Four species of spotted fever group rickettsiae (SFGR)-Rickettsia rickettsii, Rickettsia parkeri, Rickettsia felis, and Rickettsia akari-are well-documented causes of infections in humans in the United States [1-4]. Rocky Mountain spotted fever (RMSF), which is caused by R. rickettsii, is most frequently reported in the Mississippi River Valley and southern Atlantic states but is rarely reported west of the Rocky Mountains [5,

Clinical Infectious Diseases, 2008

Background. Rickettsia parkeri rickettsiosis, a recently identified spotted fever transmitted by ... more Background. Rickettsia parkeri rickettsiosis, a recently identified spotted fever transmitted by the Gulf Coast tick (Amblyomma maculatum), was first described in 2004. We summarize the clinical and epidemiological features of 12 patients in the United States with confirmed or probable disease attributable to R. parkeri and comment on distinctions between R. parkeri rickettsiosis and other United States rickettsioses. Methods. Clinical specimens from patients in the United States who reside within the range of A. maculatum for whom an eschar or vesicular rash was described were evaluated by у1 laboratory assays at the Centers for Disease Control and Prevention (Atlanta, GA) to identify probable or confirmed infection with R. parkeri. Results. During 1998-2007, clinical samples from 12 patients with illnesses epidemiologically and clinically compatible with R. parkeri rickettsiosis were submitted for diagnostic evaluation. Using indirect immunofluorescence antibody assays, immunohistochemistry, polymerase chain reaction assays, and cell culture isolation, we identified 6 confirmed and 6 probable cases of infection with R. parkeri. The aggregate clinical characteristics of these patients revealed a disease similar to but less severe than classically described Rocky Mountain spotted fever. Conclusions. Closer attention to the distinct clinical features of the various spotted fever syndromes that exist in the United States and other countries of the Western hemisphere, coupled with more frequent use of specific confirmatory assays, may unveil several unique diseases that have been identified collectively as Rocky Mountain spotted fever during the past century. Accurate assessments of these distinct infections will ultimately provide a more valid description of the currently recognized distribution, incidence, and case-fatality rate of Rocky Mountain spotted fever. An unnamed, apparently new rickettsia has been repeatedly isolated at the Rocky Mountain Laboratory during the past nine years from specimens of Amblyomma maculatum, a tick of wide distribution in the Southern States…the presumptive evidence from animal experimentation suggests that human infection might be confusingly similar to spotted fever.

Archives of Dermatology, 2010

Background: Until recently, Rickettsia rickettsii was the only substantiated cause of tick-borne ... more 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 tickborne 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.

Applied and Environmental Microbiology, 2006

ABSTRACTTwentyRhipicephalus sanguineusticks collected in eastern Arizona were tested by PCR assay... more ABSTRACTTwentyRhipicephalus sanguineusticks collected in eastern Arizona were tested by PCR assay to establish their infection rate with spotted fever group rickettsiae. With a nested PCR assay which detects a fragment of theRickettsiagenus-specific 17-kDa antigen gene (htrA), five ticks (25%) were found to contain rickettsial DNA. One rickettsial isolate was obtained from these ticks by inoculating a suspension of a triturated tick into monolayers of Vero E6 monkey kidney cells and XTC-2 clawed toad cells, and its cell culture and genotypic characteristics were determined. Fragments of the 16S rRNA, GltA, rOmpA, rOmpB, and Sca4 genes had 100%, 100%, 99%, 99%, and 99%, respectively, nucleotide similarity toRickettsia massiliaestrain Bar29, previously isolated fromR. sanguineusin Catalonia, Spain (L. Beati et al., J. Clin. Microbiol.34:2688-2694, 1996). The new isolate, AZT80, does not elicit cytotoxic effects in Vero cells and causes a persistent infection in XTC-2 cells. The AZT80 ...

The American Journal of Tropical Medicine and Hygiene, 2014

The American Journal of Tropical Medicine and Hygiene, 2011

International Journal of Systematic Bacteriology, 1997

Clinical Microbiology and Infection, 2009