A Contribution to the Biology of Ornithodoros hermsi Wheeler, Herms and Meyer

1943 ◽  
Vol 29 (1) ◽  
pp. 33 ◽  
Author(s):  
Charles M. Wheeler
Keyword(s):  
Ornithodoros Hermsi

Ornithodoros hermsi Wheeler as a Vector of Relapsing Fever in California

1936 ◽  
Vol 22 (3) ◽  
pp. 276 ◽  
Author(s):  
W. B. Herms ◽  
C. M. Wheeler
Keyword(s):  
Relapsing Fever ◽  
Ornithodoros Hermsi

scholarly journals Bloodmeal Size and Spirochete Acquisition of Ornithodoros hermsi (Acari: Argasidae) During Feeding

2010 ◽  
Vol 47 (6) ◽  
pp. 1164-1172 ◽  
Author(s):  
Brandi N. McCoy ◽  
Sandra J. Raffel ◽  
Job E. Lopez ◽  
Tom G. Schwan
Keyword(s):  
Ornithodoros Hermsi

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.

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.

An Atypical Ornithodoros hermsi from Utah (Ixodoidea, Argasidae)

1956 ◽  
Vol 42 (3) ◽  
pp. 293 ◽  
Author(s):  
Gordon E. Davis ◽  
Anthony J. Mavros
Keyword(s):  
Ornithodoros Hermsi

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.

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