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Tom G. Schwan - One of the best experts on this subject based on the ideXlab platform.
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host competency of the multimammate rat mastomys natalensis demonstrated by prolonged spirochetemias with the african Relapsing Fever spirochete borrelia crocidurae
American Journal of Tropical Medicine and Hygiene, 2019Co-Authors: Kristin Boardman, David Safronetz, Kyle Rosenke, Heinz Feldmann, Tom G. SchwanAbstract:African multimammate rats, Mastomys natalensis, are widely distributed in sub-Saharan Africa and live in close association with humans. In West Africa, numerous field studies have shown these animals may be naturally infected with the Relapsing Fever spirochete Borrelia crocidurae, the primary cause of tick-borne Relapsing Fever in this region of the continent. However, naturally infected individual rats have never been examined over time; therefore, the true host competency of these rats for this spirochete is unknown. Therefore, using animals from an established laboratory colony of M. natalensis, rats were experimentally infected with B. crocidurae and their blood examined to 28 days postinoculation. These animals were highly susceptible to infection and displayed prolonged and cyclic spirochetemias. Our results demonstrate these peridomestic rodents are likely competent hosts for infecting argasid tick vectors and play a primary role in the enzootic cycle for B. crocidurae in West Africa.
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Tickborne Relapsing Fever, Bitterroot Valley, Montana, USA
Emerging infectious diseases, 2015Co-Authors: Joshua Christensen, Brandi N Mccoy, Sandra J Raffel, Robert J. Fischer, Tom G. SchwanAbstract:In July 2013, a resident of the Bitterroot Valley in western Montana, USA, contracted tickborne Relapsing Fever caused by an infection with the spirochete Borrelia hermsii. The patient’s travel history and activities before onset of illness indicated a possible exposure on his residential property on the eastern side of the valley. An onsite investigation of the potential exposure site found the vector, Ornithodoros hermsi ticks, and 1 chipmunk infected with spirochetes, which on the basis of multilocus sequence typing were identical to the spirochete isolated from the patient. Field studies in other locations found additional serologic evidence and an infected tick that demonstrated a wider distribution of spirochetes circulating among the small mammal populations. Our study demonstrates that this area of Montana represents a previously unrecognized focus of Relapsing Fever and poses a risk for persons of acquiring this tickborne disease.
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first isolation of the Relapsing Fever spirochete borrelia hermsii from a domestic dog
Ticks and Tick-borne Diseases, 2014Co-Authors: Ashley L Kelly, Sandra J Raffel, Robert J. Fischer, Michael Bellinghausen, Connie Stevenson, Tom G. SchwanAbstract:In North America, tick-borne Relapsing Fever of humans is most frequently caused by infection with the spirochete Borrelia hermsii. Prior to our investigation, this spirochete was not known to infect dogs although another species, Borrelia turicatae, has been isolated from domestic canids in Florida and Texas. A clinically ill dog in Washington, USA, was spirochetemic upon examination. Spirochetes were isolated from the dog's serum and examined by PCR and multi-locus sequence typing. DNA sequences for 7 loci all typed the spirochete as B. hermsii and a member of genomic group II of this species. Therefore, companion dogs that reside in rustic cabins in higher elevation forests are at risk of infection with B. hermsii.
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RESEARCH Tick-borne Relapsing Fever and
2013Co-Authors: Tom G. Schwan, Merry E Schrumpf, Larry S Webster, Robyn Spano, Ra J. Raffel, Adriana R. Marques, Michael Rood, Joe BurnsAbstract:The primary cause of tick-borne Relapsing Fever in western North America is Borrelia hermsii, a rodent-associated spirochete transmitted by the fast-feeding soft tick Ornithodoros hermsii. We describe a patient who had an illness consistent with Relapsing Fever after exposure in the mountains near Los Angeles, California, USA. The patient’s convalescent-phase serum was seropositive for B. hermsii but negative for several other vector-borne bacterial pathogens. Investigations at the exposure site showed the presence of O. hermsi ticks infected with B. hermsii and the presence of rodents that were seropositive for the spirochete. We determined that this tickborne disease is endemic to the San Gabriel Mountains near the greater Los Angeles metropolitan area. Tick-borne Relapsing Fever was first observed in California, USA, in 1921 when 2 persons were infected in a cabin in Nevada County, north of Lake Tahoe (1). Another 251 cases of Relapsing Fever were reported in this state through 1941. Most persons who became ill had exposures at high elevations in various mountain locations (2). During this time, tick-borne Relapsing Fever was found to b
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DISPATCHES Tick-borne Relapsing Fever Caused by Borrelia
2013Co-Authors: Tom G. Schwan, Paul F. Policastro, Zachary Miller, Robert L. Thompson, Todd A. Damrow, James E. KeiransAbstract:Five persons contracted tick-borne Relapsing Fever after staying in a cabin in western Montana. Borrelia hermsii was isolated from the blood of two patients, and Ornithodoros hermsi ticks were collected from the cabin, the first demonstration of this bacterium and tick in Montana. Relapsing Fever should be considered when patients who reside or have vacationed in western Montana exhibit a recurring febrile illness. Tick-borne Relapsing Fever, caused by Borrelia hermsii, is endemic in the higher elevations and coniferous forests of the western United States and southern British Columbia, Canada (1). Although many multicase outbreaks of Relapsing Fever associated with B. hermsii and its tick vector, Ornithodoros hermsi, have been reported (2–6), none has been documented in Montana. Patients usuall
Sandra J Raffel - One of the best experts on this subject based on the ideXlab platform.
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Tickborne Relapsing Fever, Bitterroot Valley, Montana, USA
Emerging infectious diseases, 2015Co-Authors: Joshua Christensen, Brandi N Mccoy, Sandra J Raffel, Robert J. Fischer, Tom G. SchwanAbstract:In July 2013, a resident of the Bitterroot Valley in western Montana, USA, contracted tickborne Relapsing Fever caused by an infection with the spirochete Borrelia hermsii. The patient’s travel history and activities before onset of illness indicated a possible exposure on his residential property on the eastern side of the valley. An onsite investigation of the potential exposure site found the vector, Ornithodoros hermsi ticks, and 1 chipmunk infected with spirochetes, which on the basis of multilocus sequence typing were identical to the spirochete isolated from the patient. Field studies in other locations found additional serologic evidence and an infected tick that demonstrated a wider distribution of spirochetes circulating among the small mammal populations. Our study demonstrates that this area of Montana represents a previously unrecognized focus of Relapsing Fever and poses a risk for persons of acquiring this tickborne disease.
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first isolation of the Relapsing Fever spirochete borrelia hermsii from a domestic dog
Ticks and Tick-borne Diseases, 2014Co-Authors: Ashley L Kelly, Sandra J Raffel, Robert J. Fischer, Michael Bellinghausen, Connie Stevenson, Tom G. SchwanAbstract:In North America, tick-borne Relapsing Fever of humans is most frequently caused by infection with the spirochete Borrelia hermsii. Prior to our investigation, this spirochete was not known to infect dogs although another species, Borrelia turicatae, has been isolated from domestic canids in Florida and Texas. A clinically ill dog in Washington, USA, was spirochetemic upon examination. Spirochetes were isolated from the dog's serum and examined by PCR and multi-locus sequence typing. DNA sequences for 7 loci all typed the spirochete as B. hermsii and a member of genomic group II of this species. Therefore, companion dogs that reside in rustic cabins in higher elevation forests are at risk of infection with B. hermsii.
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endemic foci of the tick borne Relapsing Fever spirochete borrelia crocidurae in mali west africa and the potential for human infection
PLOS Neglected Tropical Diseases, 2012Co-Authors: Jennifer M. Anderson, Brandi N Mccoy, Nafomon Sogoba, Sandra J Raffel, Job E Lopez, Robert J. Fischer, David Safronetz, Ousmane MaigaAbstract:Background Tick-borne Relapsing Fever spirochetes are maintained in endemic foci that involve a diversity of small mammals and argasid ticks in the genus Ornithodoros. Most epidemiological studies of tick-borne Relapsing Fever in West Africa caused by Borrelia crocidurae have been conducted in Senegal. The risk for humans to acquire Relapsing Fever in Mali is uncertain, as only a few human cases have been identified. Given the high incidence of malaria in Mali, and the potential to confuse the clinical diagnosis of these two diseases, we initiated studies to determine if there were endemic foci of Relapsing Fever spirochetes that could pose a risk for human infection.
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a novel surface antigen of Relapsing Fever spirochetes can discriminate between Relapsing Fever and lyme borreliosis
Clinical and Vaccine Immunology, 2010Co-Authors: Job E Lopez, Brandi N Mccoy, Sandra J Raffel, Merry E Schrumpf, Vijayaraj Nagarajan, Tom G. SchwanAbstract:In a previous immunoproteome analysis of Borrelia hermsii, candidate antigens that bound IgM antibodies from mice and patients infected with Relapsing Fever spirochetes were identified. One candidate that was identified is a hypothetical protein with a molecular mass of 57 kDa that we have designated Borrelia immunogenic protein A (BipA). This protein was further investigated as a potential diagnostic antigen for B. hermsii given that it is absent from the Borrelia burgdorferi genome. The bipA locus was amplified and sequenced from 39 isolates of B. hermsii that had been acquired from western North America. bipA was also expressed as a recombinant fusion protein. Serum samples from mice and patients infected with B. hermsii or B. burgdorferi were used to confirm the immunogenicity of the recombinant protein in patients infected with Relapsing Fever spirochetes. Lastly, in silico and experimental analysis indicated that BipA is a surface-exposed lipoprotein in B. hermsii. These findings enhance the capabilities of diagnosing infection with Relapsing Fever spirochetes.
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characterization of a novel Relapsing Fever spirochete in the midgut coxal fluid and salivary glands of the bat tick carios kelleyi
Vector-borne and Zoonotic Diseases, 2009Co-Authors: Tom G. Schwan, Sandra J Raffel, Merry E Schrumpf, James S Gill, Joseph PiesmanAbstract:Bat ticks, Carios kelleyi, from Iowa were examined for the presence of Relapsing Fever group borreliae. A novel spirochete was characterized by DNA sequence analysis of polymerase chain reaction amplicons for the 16S rRNA, flaB, and glpQ genes in either triturated tick pools or single ticks. All loci and the concatenated DNA sequence of 3,289 bases identified the Carios bacterium as a Relapsing Fever spirochete most closely related to, but distinct from, Borrelia turicatae. Spirochetes reactive with a Borrelia-specific monoclonal antibody were observed microscopically in the coxal fluid and salivary glands from one tick. These data confirm the presence of a novel species of Relapsing Fever spirochete in bat ticks and the potential for new enzootic foci for endemic Relapsing Fever that warrants further investigation. The name Borrelia johnsonii is proposed for this novel spirochete in honor of Dr. Russell C. Johnson.
Sally J Cutler - One of the best experts on this subject based on the ideXlab platform.
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Relapsing Fever borreliae a global review
Clinics in Laboratory Medicine, 2015Co-Authors: Sally J CutlerAbstract:Relapsing Fever borreliae were notorious and feared infectious agents that earned their place in history through their devastating impact as causes of both epidemic and endemic infection. They are now considered more as an oddity, and their burden of infection is largely overshadowed by other infections such as malaria, which presents in a similar clinical way. Despite this, they remain the most common bacterial infection in some developing countries. Transmitted by soft ticks or lice, these fascinating spirochetes have evolved a myriad of mechanisms to survive within their diverse environments.
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multispacer sequence typing Relapsing Fever borreliae in africa
PLOS Neglected Tropical Diseases, 2012Co-Authors: Elbir Haitham, Gregory Gimenez, Cheikh Sokhna, Kassahun Desalegn Bilcha, Stephen C Barker, Sally J Cutler, Didier Raoult, Michel DrancourtAbstract:In Africa, Relapsing Fevers are caused by four cultured species: Borrelia crocidurae, Borrelia duttonii, Borrelia hispanica and Borrelia recurrentis. These borreliae are transmitted by the bite of Ornithodoros soft ticks except for B. recurrentis which is transmitted by louse Pediculus humanus. They cause potentially undifferentiated Fever infection and co-infection with malaria could also occur. The exact prevalence of each Borrelia is unknown and overlaps between B. duttonii and B. crocidurae have been reported. The lack of tools for genotyping these borreliae limits knowledge concerning their epidemiology. We developed multispacer sequence typing (MST) and applied it to blood specimens infected by B. recurrentis (30 specimens), B. duttonii (18 specimens) and B. crocidurae (13 specimens), delineating these 60 strains and the 3 type strains into 13 species-specific spacer types. B. crocidurae strains were classified into 8 spacer types, B. duttonii into 3 spacer types and B. recurrentis into 2 spacer types. These findings provide the proof-of-concept that that MST is a reliable tool for identification and genotyping Relapsing Fever borreliae in Africa.
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population structure of east african Relapsing Fever borrelia spp
Emerging Infectious Diseases, 2010Co-Authors: Sally J Cutler, Margarita E Bonilla, Rajbir J SinghAbstract:Differentiation of endemic East African tick-borne Relapsing Fever Borrelia duttonii spirochetes from epidemic louse-borne Relapsing Fever (LBRF) B. recurrentis spirochetes into different species has been questioned. We assessed a noncoding intragenic spacer (IGS) region to compare genotypes found in clinical samples from Relapsing Fever patients. Although IGS typing was highly discriminatory and resolved 4 East African tick-borne Relapsing Fever groups from a disease-endemic region in Tanzania, 2 IGS clades were found among LBRF patients in Ethiopia. The 2 IGS sequence types for B. recurrentis overlapped with 2 of the 4 groups found among B. duttonii. All cultivable isolates of B. duttonii fell into a single IGS cluster, which suggests their analysis might introduce selective bias. We provide further support that B. recurrentis is a subset of B. duttonii and represents an ecotype rather than a species. These observations have disease control implications and suggest LBRF Borrelia spp. could reemerge from its tick-borne reservoirs where vectors coexist.
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Relapsing Fever a forgotten disease revealed
Journal of Applied Microbiology, 2010Co-Authors: Sally J CutlerAbstract:Borrelial Relapsing Fever was once a major worldwide epidemic disease that made a significant impact on Livingstone during his epic travels through Africa and throughout Europe. Indeed, the term 'Relapsing Fever' was first used to describe clinical cases of this disease in Edinburgh. During the last century, we have witnessed the demise of the louse-borne infection, largely through improving standards of living resulting in a reduction in body lice, the vector for Borrelia recurrentis [louse-borne Relapsing Fever (LBRF)]. The tick-borne zoonotic form of the disease persists in endemic foci around the world [tick-borne Relapsing Fever (TBRF)]. Indeed, TBRF is reportedly the most common bacterial infection from Senegal and listed within the top ten causes of mortality in children under five in Tanzania. In Ethiopia, LBRF is again within the top ten causes of hospital admission, associated with significant morbidity and mortality. Despite these figures, many now regard Relapsing Fever as an unusual tropical disease. Certainly, recent cases have been imported following travel from endemic zones. More surprisingly, cases have been reported following family reunions in Colorado, USA. A further case was reported from the Mt Wilson observatory in Los Angeles, USA. In many regions, the infection is zoonotic with natural reservoirs in several vertebrate species. In West Africa, infection is again primarily zoonotic. Whether those species found predominantly in East Africa are zoonoses or are infections of humans alone is still debated, however, the life cycle may be determined by the feeding preferences of their arthropod vectors.
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new concepts for the old challenge of african Relapsing Fever borreliosis
Clinical Microbiology and Infection, 2009Co-Authors: Sally J Cutler, Alemseged Abdissa, Jean-françois TrapeAbstract:Relapsing Fever, caused by spirochaetes belonging to the genus Borrelia, was once the cause of worldwide epidemic disease. This was largely through infection with the louse-borne form of the disease, caused by Borrelia recurrentis (louse-borne Relapsing Fever (LBRF)). During the last century, we have witnessed the demise of this infection, largely owing to improved standards of living and the introduction of the insecticide DDT, resulting in a reduction in the incidence of the body louse, the vector for Relapsing Fever. In areas of extreme poverty this disease persists, causing a significant burden of disease. It is now looking probable that this infection is caused by a louse-adapted variant of Borrelia duttonii, transmitted by Ornithodoros moubata ‘soft’ ticks in East Africa. Like LBRF, infection still causes impact, particularly affecting young children and pregnant women. Over recent years, the true burden of Relapsing Fever caused by infection with the closely related Borrelia crocidurae, transmitted by Ornithodoros sonrai ticks, has only just begun to emerge. Here, the current state of knowledge concerning Relapsing Fever in Africa is reviewed.
Merry E Schrumpf - One of the best experts on this subject based on the ideXlab platform.
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RESEARCH Tick-borne Relapsing Fever and
2013Co-Authors: Tom G. Schwan, Merry E Schrumpf, Larry S Webster, Robyn Spano, Ra J. Raffel, Adriana R. Marques, Michael Rood, Joe BurnsAbstract:The primary cause of tick-borne Relapsing Fever in western North America is Borrelia hermsii, a rodent-associated spirochete transmitted by the fast-feeding soft tick Ornithodoros hermsii. We describe a patient who had an illness consistent with Relapsing Fever after exposure in the mountains near Los Angeles, California, USA. The patient’s convalescent-phase serum was seropositive for B. hermsii but negative for several other vector-borne bacterial pathogens. Investigations at the exposure site showed the presence of O. hermsi ticks infected with B. hermsii and the presence of rodents that were seropositive for the spirochete. We determined that this tickborne disease is endemic to the San Gabriel Mountains near the greater Los Angeles metropolitan area. Tick-borne Relapsing Fever was first observed in California, USA, in 1921 when 2 persons were infected in a cabin in Nevada County, north of Lake Tahoe (1). Another 251 cases of Relapsing Fever were reported in this state through 1941. Most persons who became ill had exposures at high elevations in various mountain locations (2). During this time, tick-borne Relapsing Fever was found to b
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a novel surface antigen of Relapsing Fever spirochetes can discriminate between Relapsing Fever and lyme borreliosis
Clinical and Vaccine Immunology, 2010Co-Authors: Job E Lopez, Brandi N Mccoy, Sandra J Raffel, Merry E Schrumpf, Vijayaraj Nagarajan, Tom G. SchwanAbstract:In a previous immunoproteome analysis of Borrelia hermsii, candidate antigens that bound IgM antibodies from mice and patients infected with Relapsing Fever spirochetes were identified. One candidate that was identified is a hypothetical protein with a molecular mass of 57 kDa that we have designated Borrelia immunogenic protein A (BipA). This protein was further investigated as a potential diagnostic antigen for B. hermsii given that it is absent from the Borrelia burgdorferi genome. The bipA locus was amplified and sequenced from 39 isolates of B. hermsii that had been acquired from western North America. bipA was also expressed as a recombinant fusion protein. Serum samples from mice and patients infected with B. hermsii or B. burgdorferi were used to confirm the immunogenicity of the recombinant protein in patients infected with Relapsing Fever spirochetes. Lastly, in silico and experimental analysis indicated that BipA is a surface-exposed lipoprotein in B. hermsii. These findings enhance the capabilities of diagnosing infection with Relapsing Fever spirochetes.
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characterization of a novel Relapsing Fever spirochete in the midgut coxal fluid and salivary glands of the bat tick carios kelleyi
Vector-borne and Zoonotic Diseases, 2009Co-Authors: Tom G. Schwan, Sandra J Raffel, Merry E Schrumpf, James S Gill, Joseph PiesmanAbstract:Bat ticks, Carios kelleyi, from Iowa were examined for the presence of Relapsing Fever group borreliae. A novel spirochete was characterized by DNA sequence analysis of polymerase chain reaction amplicons for the 16S rRNA, flaB, and glpQ genes in either triturated tick pools or single ticks. All loci and the concatenated DNA sequence of 3,289 bases identified the Carios bacterium as a Relapsing Fever spirochete most closely related to, but distinct from, Borrelia turicatae. Spirochetes reactive with a Borrelia-specific monoclonal antibody were observed microscopically in the coxal fluid and salivary glands from one tick. These data confirm the presence of a novel species of Relapsing Fever spirochete in bat ticks and the potential for new enzootic foci for endemic Relapsing Fever that warrants further investigation. The name Borrelia johnsonii is proposed for this novel spirochete in honor of Dr. Russell C. Johnson.
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tick borne Relapsing Fever and borrelia hermsii los angeles county california usa
Emerging Infectious Diseases, 2009Co-Authors: Tom G. Schwan, Sandra J Raffel, Merry E Schrumpf, Larry S Webster, Adriana Marques, Robyn Spano, Michael P Rood, Joseph E BurnsAbstract:The primary cause of tick-borne Relapsing Fever in western North America is Borrelia hermsii, a rodent-associated spirochete transmitted by the fast-feeding soft tick Ornithodoros hermsi. We describe a patient who had an illness consistent with Relapsing Fever after exposure in the mountains near Los Angeles, California, USA. The patient’s convalescent-phase serum was seropositive for B. hermsii but negative for several other vector-borne bacterial pathogens. Investigations at the exposure site showed the presence of O. hermsi ticks infected with B. hermsii and the presence of rodents that were seropositive for the spirochete. We determined that this tick-borne disease is endemic to the San Gabriel Mountains near the greater Los Angeles metropolitan area.
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Relapsing Fever spirochetes retain infectivity after prolonged in vitro cultivation
Vector-borne and Zoonotic Diseases, 2008Co-Authors: Job E Lopez, Sandra J Raffel, Paul F. Policastro, Merry E Schrumpf, Stephen F. Porcella, Tom G. SchwanAbstract:Borrelia hermsii and Borrelia burgdorferi, two closely related spirochetes, are the etiological agents of tick-borne Relapsing Fever and Lyme disease, respectively. Previous studies have shown the loss of infectivity of B. burgdorferi is associated with in vitro cultivation. This diminished infectivity of B. burgdorferi has occurred as early as three in vitro passages, and the loss of plasmids have been observed with these less virulent to noninfective cultures. The effects of long-term in vitro cultivation on B. hermsii have not been investigated. However, understanding the degree of genomic degradation during in vitro cultivation is important for investigating pathogenic mechanisms of spirochetes. In this study, we analyzed the effects of continuous in vitro cultivation on the genomic composition and infectivity of B. hermsii and B. turicatae. We report that all seven isolates of B. hermsii and the one isolate of B. turicatae examined retained infectivity in mice after 1 year of continuous in vitro cultivation. Furthermore, there were few apparent differences in the plasmid profiles after long-term cultivation. Two isolates of B. hermsii remained infective after high passage despite losing a portion of the 200-kb linear plasmid containing the fhbA gene encoding the factor H binding protein. Also, sequence analysis of multiple B. hermsii isolates demonstrated two types of fhbA with complete congruence with the two genomic groups of B. hermsii spirochetes. Therefore, these results suggest that Relapsing Fever spirochetes are genetically stable during in vitro cultivation, and the fhbA-containing segment of DNA that is lost during cultivation is not required for infection.
Job E Lopez - One of the best experts on this subject based on the ideXlab platform.
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detection of tickborne Relapsing Fever spirochete austin texas usa
Emerging Infectious Diseases, 2018Co-Authors: Jack D. Bissett, Martin E. Schriefer, Suzanne Ledet, Aparna Krishnavajhala, Brittany A. Armstrong, Anna Klioueva, Christopher Sexton, Adam Replogle, Job E LopezAbstract:In March 2017, a patient became febrile within 4 days after visiting a rustic conference center in Austin, Texas, USA, where Austin Public Health suspected an outbreak of tickborne Relapsing Fever a month earlier. Evaluation of a patient blood smear and molecular diagnostic assays identified Borrelia turicatae as the causative agent. We could not gain access to the property to collect ticks. Thus, we focused efforts at a nearby public park, <1 mile from the suspected exposure site. We trapped Ornithodoros turicata ticks from 2 locations in the park, and laboratory evaluation resulted in cultivation of 3 B. turicatae isolates. Multilocus sequencing of 3 chromosomal loci (flaB, rrs, and gyrB) indicated that the isolates were identical to those of B. turicatae 91E135 (a tick isolate) and BTE5EL (a human isolate). We identified the endemicity of O. turicata ticks and likely emergence of B. turicatae in this city.
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Detection of Tickborne Relapsing Fever Spirochete, Austin, Texas, USA
Centers for Disease Control and Prevention, 2018Co-Authors: Jack D. Bissett, Martin E. Schriefer, Suzanne Ledet, Aparna Krishnavajhala, Brittany A. Armstrong, Anna Klioueva, Christopher Sexton, Adam Replogle, Job E LopezAbstract:In March 2017, a patient became febrile within 4 days after visiting a rustic conference center in Austin, Texas, USA, where Austin Public Health suspected an outbreak of tickborne Relapsing Fever a month earlier. Evaluation of a patient blood smear and molecular diagnostic assays identified Borrelia turicatae as the causative agent. We could not gain access to the property to collect ticks. Thus, we focused efforts at a nearby public park,
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Tick-Borne Relapsing Fever Spirochetes in the Americas.
Veterinary sciences, 2016Co-Authors: Job E Lopez, Aparna Krishnavahjala, Melissa N. Garcia, Sergio E. BermúdezAbstract:Relapsing Fever spirochetes are tick- and louse-borne pathogens that primarily afflict those in impoverished countries. Historically the pathogens have had a significant impact on public health, yet currently they are often overlooked because of the nonspecific display of disease. In this review, we discuss aspects of Relapsing Fever (RF) spirochete pathogenesis including the: (1) clinical manifestation of disease; (2) ability to diagnose pathogen exposure; (3) the pathogen’s life cycle in the tick and mammal; and (4) ecological factors contributing to the maintenance of RF spirochetes in nature.
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endemic foci of the tick borne Relapsing Fever spirochete borrelia crocidurae in mali west africa and the potential for human infection
PLOS Neglected Tropical Diseases, 2012Co-Authors: Jennifer M. Anderson, Brandi N Mccoy, Nafomon Sogoba, Sandra J Raffel, Job E Lopez, Robert J. Fischer, David Safronetz, Ousmane MaigaAbstract:Background Tick-borne Relapsing Fever spirochetes are maintained in endemic foci that involve a diversity of small mammals and argasid ticks in the genus Ornithodoros. Most epidemiological studies of tick-borne Relapsing Fever in West Africa caused by Borrelia crocidurae have been conducted in Senegal. The risk for humans to acquire Relapsing Fever in Mali is uncertain, as only a few human cases have been identified. Given the high incidence of malaria in Mali, and the potential to confuse the clinical diagnosis of these two diseases, we initiated studies to determine if there were endemic foci of Relapsing Fever spirochetes that could pose a risk for human infection.
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a novel surface antigen of Relapsing Fever spirochetes can discriminate between Relapsing Fever and lyme borreliosis
Clinical and Vaccine Immunology, 2010Co-Authors: Job E Lopez, Brandi N Mccoy, Sandra J Raffel, Merry E Schrumpf, Vijayaraj Nagarajan, Tom G. SchwanAbstract:In a previous immunoproteome analysis of Borrelia hermsii, candidate antigens that bound IgM antibodies from mice and patients infected with Relapsing Fever spirochetes were identified. One candidate that was identified is a hypothetical protein with a molecular mass of 57 kDa that we have designated Borrelia immunogenic protein A (BipA). This protein was further investigated as a potential diagnostic antigen for B. hermsii given that it is absent from the Borrelia burgdorferi genome. The bipA locus was amplified and sequenced from 39 isolates of B. hermsii that had been acquired from western North America. bipA was also expressed as a recombinant fusion protein. Serum samples from mice and patients infected with B. hermsii or B. burgdorferi were used to confirm the immunogenicity of the recombinant protein in patients infected with Relapsing Fever spirochetes. Lastly, in silico and experimental analysis indicated that BipA is a surface-exposed lipoprotein in B. hermsii. These findings enhance the capabilities of diagnosing infection with Relapsing Fever spirochetes.
