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Full-Text Articles in Tropical Medicine

Human Exposure To Spirochete-Infected Ornithodoros Turicata In A Residential Setting In The Austin, Texas Metropolitan Area, Serhii Filatov, Bonny Mayes, Sarah M Gunter, Alexander R Kneubehl, Job E Lopez Jul 2026

Human Exposure To Spirochete-Infected Ornithodoros Turicata In A Residential Setting In The Austin, Texas Metropolitan Area, Serhii Filatov, Bonny Mayes, Sarah M Gunter, Alexander R Kneubehl, Job E Lopez

Faculty, Staff and Students Publications

A central Texas resident found an engorged Ornithodoros turicata tick attached to their ankle while at home. The tick tested positive for Borrelia turicatae, an agent for soft tick-borne relapsing fever. Three weeks earlier, the patient started experiencing febrile episodes, rash, and nausea, yet the etiological agent went undiagnosed.


Genome Report: Whole-Genome Assembly Of The Relapsing Fever Tick Ornithodoros Turicata Dugès (Acari: Argasidae), Mackenzie Tietjen, Amanda R Stahlke, David Luecke, Perot Saelao, Sheina B Sim, Scott M Geib, Brian E Scheffler, Anna K Childers, Alexander R Kneubehl, Pete D Teel, Job E Lopez Jul 2025

Genome Report: Whole-Genome Assembly Of The Relapsing Fever Tick Ornithodoros Turicata Dugès (Acari: Argasidae), Mackenzie Tietjen, Amanda R Stahlke, David Luecke, Perot Saelao, Sheina B Sim, Scott M Geib, Brian E Scheffler, Anna K Childers, Alexander R Kneubehl, Pete D Teel, Job E Lopez

Faculty, Staff and Students Publications

The soft tick family Argasidae contains vectors of medical and veterinary importance, but few molecular resources are available compared to hard ticks (Ixodidae). One example is Ornithodoros turicata, a recognized vector of Borrelia turicatae, causal agent of human relapsing fever, and a putative vector of African swine fever virus. To address the current lack of molecular resources for the Argasidae, we generated a chromosome-level genome assembly for O. turicata using PacBio sequencing in conjunction with an Illumina Hi-C library. The resulting reference genome has a total of 1.1 Gb in length and was assembled into 10 chromosomes and 368 unplaced …


Use Of A Mouse Model For The Isolation Of Borrelia Puertoricensis From Soft Ticks, Edwin Vázquez-Guerrero, Alexander R Kneubehl, Guadalupe C Reyes-Solís, Carlos Machain-Williams, Aparna Krishnavajhala, Paulina Estrada-De Los Santos, Job E Lopez, José Antonio Ibarra Jan 2025

Use Of A Mouse Model For The Isolation Of Borrelia Puertoricensis From Soft Ticks, Edwin Vázquez-Guerrero, Alexander R Kneubehl, Guadalupe C Reyes-Solís, Carlos Machain-Williams, Aparna Krishnavajhala, Paulina Estrada-De Los Santos, Job E Lopez, José Antonio Ibarra

Faculty, Staff and Students Publications

The isolation of tick-borne relapsing fever (TBRF) spirochetes has proven to be a useful tool to understand their distribution in geographic areas where the tick vectors inhabit. However, their isolation and culture are not easy and in general an animal model is needed to achieve this task. Here, argasid ticks were collected from a neighborhood in Ciudad Caucel, and they were identified as Ornithodoros (Alectorobius) puertoricensis. To determine whether these were infected with TBRF bacteria they were fed with healthy mice but only a low burden of spirochetes was observed. An immunosuppressed mouse model was used to feed the ticks …


Autogenous Reproduction By Ornithodoros Turicata (Ixodida: Argasidae) Females And Vertical Transmission Of The Tick-Borne Pathogen Borrelia Turicatae (Spirochaetales: Borreliaceae), Serhii Filatov, Aparna Krishnavajhala, Job E Lopez Nov 2023

Autogenous Reproduction By Ornithodoros Turicata (Ixodida: Argasidae) Females And Vertical Transmission Of The Tick-Borne Pathogen Borrelia Turicatae (Spirochaetales: Borreliaceae), Serhii Filatov, Aparna Krishnavajhala, Job E Lopez

Faculty, Staff and Students Publications

Ornithodoros turicata is a vector of relapsing fever spirochetes in North America and transmits Borrelia turicatae to a variety of vertebrate hosts. The remarkably long lifespan of O. turicata and its ability to maintain spirochetes horizontally (between life stages) and vertically (to progeny) promote the perpetuation of B. turicatae in nature. Nevertheless, the reproductive biology of O. turicata is poorly understood. In this report, we collected ticks from a park within a neighborhood of Austin, TX. They were reared to adulthood, and male ticks were individually housed with females. We observed autogenous reproduction, which is the ability to produce eggs …


Comparative Genomics Analysis Of Three Conserved Plasmid Families In The Western Hemisphere Soft Tick-Borne Relapsing Fever Borreliae Provides Insight Into Variation In Genome Structure And Antigenic Variation Systems, Alexander R Kneubehl, Job E Lopez Sep 2023

Comparative Genomics Analysis Of Three Conserved Plasmid Families In The Western Hemisphere Soft Tick-Borne Relapsing Fever Borreliae Provides Insight Into Variation In Genome Structure And Antigenic Variation Systems, Alexander R Kneubehl, Job E Lopez

Faculty, Staff and Students Publications

Borrelia spirochetes, causative agents of Lyme disease and relapsing fever (RF), have uniquely complex genomes, consisting of a linear chromosome and both circular and linear plasmids. The plasmids harbor genes important for the vector-host life cycle of these tick-borne bacteria. The role of plasmids from Lyme disease causing spirochetes is more refined compared to RF Borrelia because of limited plasmid-resolved genome assemblies for the latter. We recently addressed this limitation and found that three linear plasmid families (F6, F27, and F28) were syntenic across all the RF Borrelia species that we examined. Given this conservation, we further investigated the three …


New Records Of Ornithodoros Turicata (Ixodida: Argasidae) In Rural And Urban Sites In The Mexican States Of Aguascalientes And Zacatecas Indicate The Potential For Tick-Borne Relapsing Fever, Edwin Vázquez-Guerrero, José Luis González-Quiroz, María Lilia Domínguez-López, Alexander R Kneubehl, Aparna Krishnavajhala, Michael W Curtis, Alejandro Ponce-Mendoza, Paulina Estrada-De Los Santos, Job E Lopez, J Antonio Ibarra Sep 2023

New Records Of Ornithodoros Turicata (Ixodida: Argasidae) In Rural And Urban Sites In The Mexican States Of Aguascalientes And Zacatecas Indicate The Potential For Tick-Borne Relapsing Fever, Edwin Vázquez-Guerrero, José Luis González-Quiroz, María Lilia Domínguez-López, Alexander R Kneubehl, Aparna Krishnavajhala, Michael W Curtis, Alejandro Ponce-Mendoza, Paulina Estrada-De Los Santos, Job E Lopez, J Antonio Ibarra

Faculty, Staff and Students Publications

Soft ticks from the Ornithodoros genus are vectors of relapsing fever (RF) spirochetes around the world. In Mexico, they were originally described in the 19th century. However, few recent surveillance studies have been conducted in Mexico, and regions where RF spirochetes circulate remain vague. Here, the presence of soft ticks in populated areas was assessed in two sites from the Mexican states of Aguascalientes and Zacatecas. Argasidae ticks were collected, identified by morphology and mitochondrial 16S rDNA gene sequencing, and tested for RF borreliae. The specimens in both sites were identified as Ornithodoros turicata but no RF spirochetes were detected. …


A Serological Assay To Detect And Differentiate Rodent Exposure To Soft Tick And Hard Tick Relapsing Fever Infections In The United States, Christina M Parise, Ying Bai, Kevin S Brandt, Shelby L Ford, Sarah Maes, Adam J Replogle, Alexander R Kneubehl, Job E Lopez, Rebecca J Eisen, Andrias Hojgaard Jul 2023

A Serological Assay To Detect And Differentiate Rodent Exposure To Soft Tick And Hard Tick Relapsing Fever Infections In The United States, Christina M Parise, Ying Bai, Kevin S Brandt, Shelby L Ford, Sarah Maes, Adam J Replogle, Alexander R Kneubehl, Job E Lopez, Rebecca J Eisen, Andrias Hojgaard

Faculty, Staff and Students Publications

Human cases of relapsing fever (RF) in North America are caused primarily by Borrelia hermsii and Borrelia turicatae, which are spread by argasid (soft) ticks, and by Borrelia miyamotoi, which is transmitted by ixodid (hard) ticks. In some regions of the United States, the ranges of the hard and soft tick RF species are known to overlap; in many areas, recorded ranges of RF spirochetes overlap with Lyme disease (LD) group Borrelia spirochetes. Identification of RF clusters or cases detected in unusual geographic localities might prompt public health agencies to investigate environmental exposures, enabling prevention of additional cases through locally …


Case Report: Exposure To Relapsing Fever Group Borreliae In Patients With Undifferentiated Febrile Illness In Mexico, Edwin Vázquez-Guerrero, Guadalupe Gordillo-Pérez, Nora Ríos-Sarabia, Job E Lopez, J Antonio Ibarra Mar 2023

Case Report: Exposure To Relapsing Fever Group Borreliae In Patients With Undifferentiated Febrile Illness In Mexico, Edwin Vázquez-Guerrero, Guadalupe Gordillo-Pérez, Nora Ríos-Sarabia, Job E Lopez, J Antonio Ibarra

Faculty, Staff and Students Publications

Relapsing fever (RF) borreliosis is a neglected disease in Mexico. A retrospective serological survey using diagnostic antigens GlpQ and BipA from Borrelia turicatae was performed to evaluate human exposure to RF borreliae. Seventy serum samples were used from a cohort of patients with undifferentiated febrile illness in Mexico. Four samples were positive to GlpQ and three to BipA. Results indicate that RF borreliae continue to circulate in regions of Mexico and pose a risk to human health.


Analysis Of Variable Major Protein Antigenic Variation In The Relapsing Fever Spirochete, Borrelia Miyamotoi, In Response To Polyclonal Antibody Selection Pressure, Robert D Gilmore, Brittany A Armstrong, Kevin S Brandt, Taylor J Van Gundy, Andrias Hojgaard, Job E Lopez, Alexander R Kneubehl Jan 2023

Analysis Of Variable Major Protein Antigenic Variation In The Relapsing Fever Spirochete, Borrelia Miyamotoi, In Response To Polyclonal Antibody Selection Pressure, Robert D Gilmore, Brittany A Armstrong, Kevin S Brandt, Taylor J Van Gundy, Andrias Hojgaard, Job E Lopez, Alexander R Kneubehl

Faculty, Staff and Students Publications

Borrelia miyamotoi is a tick-transmitted spirochete that is genetically grouped with relapsing fever Borrelia and possesses multiple archived pseudogenes that encode variable major proteins (Vmps). Vmps are divided into two groups based on molecular size; variable large proteins (Vlps) and variable small proteins (Vsps). Relapsing fever Borrelia undergo Vmp gene conversion at a single expression locus to generate new serotypes by antigenic switching which is the basis for immune evasion that causes relapsing fever in patients. This study focused on B. miyamotoi vmp expression when spirochetes were subjected to antibody killing selection pressure. We incubated a low passage parent …