scholarly journals Acquisition and Subsequent Transmission of Borrelia hermsii by the Soft Tick Ornithodoros hermsi

2011 ◽  
Vol 48 (4) ◽  
pp. 891-895 ◽  
Author(s):  
Job E. Lopez ◽  
Brandi N. McCoy ◽  
Benjamin J. Krajacich ◽  
Tom G. Schwan
Keyword(s):  
Soft Tick ◽  
Borrelia Hermsii ◽  
Ornithodoros Hermsi

Transmission Of Borreua Hermsii, The Agent Of Relapsing Fever, By The Tick Vector Ornithodoros Hermsi

1999 ◽  
Vol 5 (S2) ◽  
pp. 1220-1221
Author(s):  
Elizabeth R. Fischer ◽  
Tom G. Schwan
Keyword(s):  
Salivary Glands ◽  
Soft Tick ◽  
Relapsing Fever ◽  
Tick Feeding ◽  
Infected Tick ◽  
Borrelia Hermsii ◽  
Tick Vector ◽  
Functional Relationships ◽  
Ornithodoros Hermsi ◽  
Tick Midgut

Relapsing fever, a disease characterized by recurrent episodes of high fevers, is caused by geographically distinct spirochetes of the genus Borrelia,transmitted by ticks of the genus Ornithodoros. In the Northwestern United States, the soft tick Ornithodoros hermsi has been identified as the vector for the spirochete Borrelia hermsii. The life cycle of O.hermsi includes larval and multiple nymphal stages prior to full maturation into an adult male or female (Fig.1). Progression into each stage requires a blood-meal typically provided by squirrels and chipmunks, and incidentally humans. Feeding is rapid, lasting 10-60 minutes, and during this time an infected tick can transmit the agent of relapsing fever, B. hermsii. Following ingestion, spirochetes are initially found in the tick midgut. Within 1-3 weeks, they are found in other organs, including the central ganglion and salivary glands. Since saliva is the primary mode of transmission of these bacteria during tick feeding, we assessed by electron microscopy the structural and functional relationships between the spirochetes and the salivary glands.

scholarly journals Cotransmission of Divergent Relapsing Fever Spirochetes by Artificially Infected Ornithodoros hermsi

2011 ◽  
Vol 77 (24) ◽  
pp. 8494-8499 ◽  
Author(s):  
Paul F. Policastro ◽  
Sandra J. Raffel ◽  
Tom G. Schwan
Keyword(s):  
Soft Tick ◽  
Relapsing Fever ◽  
Rodent Host ◽  
Borrelia Hermsii ◽  
Content Type ◽  
Tick Vector ◽  
Tick Infection ◽  
Group I ◽  
Ornithodoros Hermsi ◽  
Feeding Tick

ABSTRACTThe soft tickOrnithodoros hermsi, which ranges in specific arboreal zones of western North America, acts as a vector for the relapsing fever spirocheteBorrelia hermsii. Two genomic groups (genomic group I [GGI] and GGII) ofB. hermsiiare differentiated by multilocus sequence typing yet are codistributed in much of the vector's range. To test whether the tick vector can be infected via immersion, noninfected, colony-derivedO. hermsilarvae were exposed to reduced-humidity conditions before immersion in culture suspensions of several GGI and GGII isolates. We tested for spirochetes in ticks by immunofluorescence microscopy and in mouse blood by quantitative PCR of thevtplocus to differentiate spirochete genotypes. The immersed larval ticks were capable of spirochete transmission to mice at the first nymphal feeding. Tick infection with mixed cultures of isolates DAH (vtp-6) (GGI) and MTW-2 (vtp-5) (GGII) resulted in ticks that caused spirochetemias in mice consisting of MTW-2 or both DAH and MTW-2. These findings show that this soft tick species can acquireB. hermsiiby immersion in spirochete suspensions, that GGI and GGII isolates can coinfect the tick vector by this method, and that these spirochetes can be cotransmitted to a rodent host.

scholarly journals Identification of conserved antigens for early serodiagnosis of relapsing fever Borrelia

Microbiology ◽  
2009 ◽  
Vol 155 (8) ◽  
pp. 2641-2651 ◽  
Author(s):  
Job E. Lopez ◽  
Stephen F. Porcella ◽  
Merry E. Schrumpf ◽  
Sandra J. Raffel ◽  
Carl H. Hammer ◽  
...  
Keyword(s):  
Immune Evasion ◽  
Hypothetical Protein ◽  
Immune Serum ◽  
Borrelia Hermsii ◽  
Flagellar Proteins ◽  
Adhesin Protein ◽  
Shock Proteins ◽  
Argasid Tick ◽  
Ornithodoros Hermsi ◽  
Glycerophosphodiester Phosphodiesterase

Borrelia hermsii is a blood-borne pathogen transmitted by the argasid tick Ornithodoros hermsi. Since spirochaete clearance in mice is associated with an IgM-mediated response, an immunoproteomic analysis was used to identify proteins reactive with IgM. We report that IgM from both mice and human patients infected with B. hermsii not only reacted with the previously identified variable membrane proteins but also identified candidate antigens including heat-shock proteins, an adhesin protein, ABC transporter proteins, flagellar proteins, housekeeping proteins, an immune evasion protein, and proteins with unknown function. Furthermore, IgM reactivity to recombinant glycerophosphodiester phosphodiesterase was detected during early spirochaete infection and prior to a detectable IgG response. Lastly, a conserved hypothetical protein was produced in Escherichia coli and tested with immune serum against B. hermsii and Borrelia recurrentis. These results identify a much larger set of immunoreactive proteins, and could help in the early serodiagnosis of this tick-borne infection.

scholarly journals Borrelia hermsii Acquisition Order in Superinfected Ticks Determines Transmission Efficiency

2013 ◽  
Vol 81 (8) ◽  
pp. 2899-2908 ◽  
Author(s):  
Paul F. Policastro ◽  
Sandra J. Raffel ◽  
Tom G. Schwan
Keyword(s):  
Dna Sequences ◽  
Transmission Efficiency ◽  
Infection Cycle ◽  
Chromosomal Dna ◽  
Borrelia Hermsii ◽  
Content Type ◽  
Tick Vector ◽  
Acquisition Order ◽  
Host Infection ◽  
Ornithodoros Hermsi

ABSTRACTMultilocus sequence typing ofBorrelia hermsiiisolates reveals its divergence into two major genomic groups (GG), but no differences in transmission efficiency or host pathogenicity are associated with these genotypes. To compare GGI and GGII in the tick-host infection cycle, we first determined if spirochetes from the two groups could superinfect the tick vectorOrnithodoros hermsi. We infected mice with isolates from each group and fed ticks sequentially on these mice. We then fed the infected ticks on naive mice and measured GGI and GGII spirochete densities in vector and host, using quantitative PCR of genotype-specific chromosomal DNA sequences. Sequential feedings resulted in dual tick infections, showing that GGI or GGII primary acquisition did not block superinfection by a secondary agent. On transmission to naive mice at short intervals after acquisition, ticks with primary GGI and secondary GGII spirochete infections caused mixed GGI and GGII infections in mice. However, ticks with primary GGII and secondary GGI spirochete infections caused only GGII infections with all isolate pairs examined. At longer intervals after acquisition, the exclusion of GGI by GGII spirochetes declined and cotransmission predominated. We then examined GGI and GGII spirochetemia in mice following single inoculation and coinoculation by needle and found that GGI spirochete densities were reduced on multiple days when coinoculated with GGII. These findings indicate that dual GGI-GGII spirochete infections can persist in ticks and that transmission to a vertebrate host is dependent on the order of tick acquisition and the interval between acquisition and transmission events.

scholarly journals Transovarial Transmission of Borrelia hermsii by Its Tick Vector and Reservoir Host Ornithodoros hermsi

2021 ◽  
Vol 9 (9) ◽  
pp. 1978
Author(s):  
Tom G. Schwan ◽  
Sandra J. Raffel
Keyword(s):  
Reservoir Host ◽  
Transovarial Transmission ◽  
Borrelia Hermsii ◽  
Infected Female ◽  
Vertical Inheritance ◽  
The North ◽  
Laboratory Colony ◽  
High Prevalence ◽  
Widespread Phenomenon ◽  
Ornithodoros Hermsi

Transovarial passage of relapsing fever spirochetes (Borrelia species) by infected female argasid ticks to their progeny is a widespread phenomenon. Yet this form of vertical inheritance has been considered rare for the North American tick Ornithodoros hermsi infected with Borrelia hermsii. A laboratory colony of O. hermsi was established from a single infected female and two infected males that produced a population of ticks with a high prevalence of transovarial transmission based on infection assays of single and pooled ticks feeding on mice and immunofluorescence microscopy of eggs and larvae. Thirty-eight of forty-five (84.4%) larval cohorts (groups of larvae originating from the same egg clutch) transmitted B. hermsii to mice over four and a half years, and one hundred and three single and one hundred and fifty-three pooled nymphal and adult ticks transmitted spirochetes during two hundred and fourteen of two hundred and fifty-six (83.6%) feedings on mice over seven and a half years. The perpetuation of B. hermsii for many years by infected ticks only (without acquisition of spirochetes from vertebrate hosts) demonstrates the reservoir competence of O. hermsi. B. hermsii produced the variable tick protein in eggs and unfed larvae infected by transovarial transmission, leading to speculation of the possible steps in the evolution of borreliae from a tick-borne symbiont to a tick-transmitted parasite of vertebrates.

scholarly journals Vector Specificity of the Relapsing Fever Spirochete Borrelia hermsii (Spirochaetales: Borreliaceae) for the Tick Ornithodoros hermsi (Acari: Argasidae) Involves Persistent Infection of the Salivary Glands

2021 ◽  
Author(s):  
Tom G Schwan
Keyword(s):  
Salivary Glands ◽  
Persistent Infection ◽  
Relapsing Fever ◽  
Borrelia Hermsii ◽  
Time Points ◽  
Vector Specificity ◽  
Biochemical Mechanisms ◽  
Tick Vectors ◽  
Vector Competency ◽  
Ornithodoros Hermsi

Abstract The relapsing fever spirochetes Borrelia hermsii and Borrelia turicatae are each maintained and transmitted in nature by their specific tick vectors, Ornithodoros hermsi Wheeler (Acari: Argasidae) and Ornithodoros turicata (Duges), respectively. The basis for this spirochete and vector specificity is not known, but persistent colonization of spirochetes in the tick’s salivary glands is presumed to be essential for transmission by these long-lived ticks that feed in only minutes on their warm-blooded hosts. To examine this hypothesis further, cohorts of O. hermsi and O. turicata were infected with B. hermsii and examined 7–260 d later for infection in their midgut, salivary glands, and synganglion. While the midgut from all ticks of both species at all time points examined were infected with spirochetes, the salivary glands of only O. hermsi remained persistently infected. The salivary glands of O. turicata were susceptible to an early transient infection. However, no spirochetes were observed in these tissues beyond the first 32 d after acquisition. Ticks of both species were fed on mice 112 d after they acquired spirochetes and only those mice fed upon by O. hermsi became infected. Thus, the vector competency for B. hermsii displayed by O. hermsi but not O. turicata lies, in part, in the persistent infection of the salivary glands of the former but not the latter species of tick. The genetic and biochemical mechanisms supporting this spirochete and vector specificity remain to be identified.

A review of the Afrotropical sand tampan, Ornithodoros savignyi: a complex species.

2021 ◽  
Vol 16 (036) ◽  
Author(s):  
Roxanne Albertha Charles
Keyword(s):  
Species Complex ◽  
Single Species ◽  
Biological Molecules ◽  
Soft Tick ◽  
Complex Species ◽  
Lake Chad ◽  
Ornithodoros Savignyi ◽  
Morphological Studies ◽  
Biological Studies ◽  
Wide Range

Abstract The sand tampan, Ornithodoros savignyi (Audouin, 1827), is an economically important soft tick of the Afrotropics parasitising a wide range of livestock and humans. These ticks are known to inflict painful bites which may be fatal in susceptible hosts. Historically thought to be a single species, Ornithodoros savignyi is now considered to be a complex of four tick subspecies based on molecular and morphological studies. They include Ornithodoros (Ornithodoros) kalahariensis, O. (O.) pavimentosus, O. (O.) noorsveldensis and O. (O.) savignyi. As such there may be significant implications for previous biological studies conducted on this tick. Therefore, for the purposes of this review, sand tampan toxicosis and potentially useful biological molecules have been discussed for O. (O.) savignyi sensu lato since most reported work was based on ticks collected from the Kalahari and Lake Chad region. An overview of the host range and vector biology for the O. (O.) savignyi species complex will also be examined.

Assembly Pheromone(s) in the Soft Tick Argas persicus (Oken)

Nature ◽  
1973 ◽  
Vol 246 (5434) ◽  
pp. 515-517 ◽  
Author(s):  
M. G. LEAHY ◽  
R. VANDEHEY ◽  
R. GALUN
Keyword(s):  
Soft Tick ◽  
Assembly Pheromone ◽  
Argas Persicus

scholarly journals The Relapsing Fever Spirochete Borrelia hermsiiContains Multiple, Antigen-Encoding Circular Plasmids That Are Homologous to the cp32 Plasmids of Lyme Disease Spirochetes

2000 ◽  
Vol 68 (7) ◽  
pp. 3900-3908 ◽  
Author(s):  
Brian Stevenson ◽  
Stephen F. Porcella ◽  
Katrina L. Oie ◽  
Cecily A. Fitzpatrick ◽  
Sandra J. Raffel ◽  
...  
Keyword(s):  
Lyme Disease ◽  
Direct Detection ◽  
Human Infection ◽  
Relapsing Fever ◽  
Borrelia Hermsii ◽  
Functional Studies ◽  
Dna Library ◽  
Multiple Antigen ◽  
Antigenic Proteins

ABSTRACT Borrelia hermsii, an agent of tick-borne relapsing fever, was found to contain multiple circular plasmids approximately 30 kb in size. Sequencing of a DNA library constructed from circular plasmid fragments enabled assembly of a composite DNA sequence that is homologous to the cp32 plasmid family of the Lyme disease spirochete,B. burgdorferi. Analysis of another relapsing fever bacterium, B. parkeri, indicated that it contains linear homologs of the B. hermsii and B. burgdorfericp32 plasmids. The B. hermsii cp32 plasmids encode homologs of the B. burgdorferi Mlp and Bdr antigenic proteins and BlyA/BlyB putative hemolysins, but homologs of B. burgdorferi erp genes were absent. Immunoblot analyses demonstrated that relapsing fever patients produced antibodies to Mlp proteins, indicating that those proteins are synthesized by the spirochetes during human infection. Conservation of cp32-encoded genes in differentBorrelia species suggests that their protein products serve functions essential to both relapsing fever and Lyme disease spirochetes. Relapsing fever borreliae replicate to high levels in the blood of infected animals, permitting direct detection and possible functional studies of Mlp, Bdr, BlyA/BlyB, and other cp32-encoded proteins in vivo.

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