Search Our Scientific Publications & Authors

J Infect Dis 2022 Jun 23. Epub 2022 Jun 23.

Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.

Native and invasive tick species pose a serious public health concern in the United States. Range expansion of several medically important tick species has resulted in an increasing number of communities at risk for exposure to ticks and tickborne pathogens. Read More

Proc Natl Acad Sci U S A 2022 03 21;119(13):e2117770119. Epub 2022 Mar 21.

Department of Molecular Biology and Microbiology, Tufts School of Medicine, Tufts University, Boston, MA 02155.

Spirochetal pathogens, such as the causative agent of Lyme disease, Borrelia burgdorferi sensu lato, encode an abundance of lipoproteins; however, due in part to their evolutionary distance from more well-studied bacteria, such as Proteobacteria and Firmicutes, few spirochetal lipoproteins have assigned functions. Indeed, B. burgdorferi devotes almost 8% of its genome to lipoprotein genes and interacts with its environment primarily through the production of at least 80 surface-exposed lipoproteins throughout its tick vector–vertebrate host lifecycle. Read More

PLoS Pathog 2022 03 14;18(3):e1010370. Epub 2022 Mar 14.

Laboratory of Bacteriology, Gene Regulation Section, Division of Intramural Research, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, Montana, United States of America.

Borrelia species are amino acid auxotrophs that utilize di- and tri- peptides obtained through their oligopeptide transport system to supply amino acids for replicative growth during their enzootic cycles. However, Borrelia species from both the Lyme disease (LD) and relapsing fever (RF) groups harbor an amino acid transport and catabolism system, the Arginine Deiminase System (ADI), that could potentially augment intracellular L-arginine required for growth. RF spirochetes contain a "complete", four gene ADI (arcA, B, D, and C) while LD spirochetes harbor arcA, B, and sometimes D but lack arcC (encoding carbamate kinase). Read More

PLoS Pathog 2022 03 7;18(3):e1010385. Epub 2022 Mar 7.

Division of Biological Sciences, University of Montana, Missoula, Montana, United States of America.

We have identified GpsA, a predicted glycerol-3-phosphate dehydrogenase, as a virulence factor in the Lyme disease spirochete Borrelia (Borreliella) burgdorferi: GpsA is essential for murine infection and crucial for persistence of the spirochete in the tick. B. burgdorferi has a limited biosynthetic and metabolic capacity; the linchpin connecting central carbohydrate and lipid metabolism is at the interconversion of glycerol-3-phosphate and dihydroxyacetone phosphate, catalyzed by GpsA and another glycerol-3-phosphate dehydrogenase, GlpD. Read More

BMC Vet Res 2022 Mar 2;18(1):84. Epub 2022 Mar 2.

Secure Food Systems Team, University of Minnesota, Saint Paul, MN, 55108, USA.

Background: African swine fever (ASF) is a highly contagious and devastating pig disease that has caused extensive global economic losses. Understanding ASF virus (ASFV) transmission dynamics within a herd is necessary in order to prepare for and respond to an outbreak in the United States. Although the transmission parameters for the highly virulent ASF strains have been estimated in several articles, there are relatively few studies focused on moderately virulent strains. Read More

Cell Rep 2022 02;38(7):110388

Department of Molecular Microbiology and Immunology, Saint Louis University, St. Louis, MO 63104, USA. Electronic address:

Powassan virus (POWV) is a tick-borne pathogen for which humans are an incidental host. POWV infection can be fatal or result in long-term neurological sequelae; however, there are no approved vaccinations for POWV. Integral to efficacious vaccine development is the identification of correlates of protection, which we accomplished in this study by utilizing a murine model of POWV infection. Read More

Front Cell Infect Microbiol 2022 28;12:828082. Epub 2022 Jan 28.

Intracellular Pathogens Research Laboratory, Department of Clinical Sciences, The Comparative Medicine Institute, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States.

Among the -borne pathogens, , the main aetiological agent of cat scratch disease (CSD), is of increasing comparative biomedical importance. Despite the importance of as an emergent pathogen, prevention of the diseases caused by this agent in cats, dogs and humans mostly relies on the use of ectoparasiticides. A vaccine targeting both flea fitness and pathogen competence is an attractive choice requiring the identification of flea proteins/metabolites with a dual effect. Read More

Infez Med 2021 10;29(3):378-385. Epub 2021 Sep 10.

Department of Medicine, Division of Infectious Diseases, University of Colorado Denver School of Medicine, Denver, Colorado, USA.

Ticks are remarkable vectors of a diverse and growing list of infectious agents of importance to both medical and veterinary disciplines. The tick is one of the most frequently identified ticks in the United States with an expanding spectrum of human disease given its vast geographic range. The recently described Bourbon and Heartland viruses are likely transmitted by the Lone Star tick and are just two of the several novel tick-borne pathogens discovered in recent decades. Read More

Sci Rep 2022 01 27;12(1):1478. Epub 2022 Jan 27.

Department of Computer Science, Colorado State University, Fort Collins, CO, 80523, USA.

We provide a pipeline for data preprocessing, biomarker selection, and classification of liquid chromatography-mass spectrometry (LCMS) serum samples to generate a prospective diagnostic test for Lyme disease. We utilize tools of machine learning (ML), e.g. Read More

Zoonoses Public Health 2022 03 27;69(2):143-148. Epub 2021 Dec 27.

Division of Vector-Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.

The Asian longhorned tick, Haemaphysalis longicornis, an invasive species associated with human pathogens, has spread rapidly across the eastern USA. Questing H. longicornis ticks recovered from active surveillance conducted from 1 May to 6 September, 2019 throughout Pennsylvania were tested for rickettsial pathogens. Read More

Diseases 2021 Dec 17;9(4). Epub 2021 Dec 17.

Arboviral Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80521, USA.

The type species of the genus , Colorado tick fever virus (CTFV), was discovered in 1943 and is the most common tick-borne viral infection in the Western US. Despite its long history, very little is known about the molecular diversity of viruses classified within the species Previous studies have suggested genetic variants and potential serotypes of CTFV, but limited genetic sequence information is available for CTFV strains. To address this knowledge gap, we report herein the full-length genomes of five strains of CTFV, including Salmon River virus and California hare coltivirus (CTFV-Ca). Read More

Vaccine 2022 01 8;40(2):298-305. Epub 2021 Dec 8.

Centers for Disease Control and Prevention, Division of Vector-borne Diseases, 3156 Rampart Rd., Fort Collins, CO 80521, USA. Electronic address:

Background: Lyme disease incidence is increasing, despite current prevention options. New Lyme disease vaccine candidates are in development, however, investigation of the acceptability of a Lyme disease vaccine among potential consumers is needed prior to any vaccine coming to market. We conducted a population-based, cross-sectional study to estimate willingness to receive a potential Lyme disease vaccine and factors associated with willingness. Read More

Wilderness Environ Med 2021 Dec 9;32(4):474-494. Epub 2021 Oct 9.

Department of Emergency Medicine, University of Colorado School of Medicine, Denver, Colorado.

The Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for the prevention and management of tick-borne illness (TBI). Recommendations are graded based on quality of supporting evidence according to criteria put forth by the American College of Chest Physicians. The guidelines include a brief review of the clinical presentation, epidemiology, prevention, and management of TBI in the United States, with a primary focus on interventions that are appropriate for resource-limited settings. Read More

mSphere 2021 10 29;6(5):e0068221. Epub 2021 Sep 29.

Colorado State Universitygrid.47894.36, Fort Collins, Colorado, USA.

Tick-borne diseases have expanded over the last 2 decades as a result of shifts in tick and pathogen distributions. These shifts have significantly increased the need for accurate portrayal of real-time pathogen distributions and prevalence in hopes of stemming increases in human morbidity. Traditionally, pathogen distribution and prevalence have been monitored through case reports or scientific collections of ticks or reservoir hosts, both of which have challenges that impact the extent, availability, and accuracy of these data. Read More

Parasit Vectors 2021 Sep 14;14(1):467. Epub 2021 Sep 14.

Experimental and Clinical Research Center, A Cooperation Between the Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association and the Charité-Universitätsmedizin Berlin, Berlin, Germany.

Background: Hepatozoon canis is a protozoan transmitted to dogs and other wild carnivores by the ingestion of ticks containing mature oocysts and is considered the principal cause of canine hepatozoonosis in the world. Here, we examined ribosomal RNA 18S gene sequence variation to determine the genetic differences and phylogeographic diversity of H. canis from various geographical areas around the world. Read More

Vector Borne Zoonotic Dis 2021 11 31;21(11):843-853. Epub 2021 Aug 31.

USDA, ARS, Invasive Insect Biocontrol and Behavior Laboratory, Beltsville, Maryland, USA.

Three tick species that can transmit pathogen causing disease are commonly found parasitizing people and animals in the mid-Atlantic United States: the blacklegged tick ( Say), the American dog tick ( [Say]), and the lone star tick ( [L.]) (Acari: Ixodidae). The potential risk of pathogen transmission from tick bites acquired at schools in tick-endemic areas is a concern, as school-aged children are a high-risk group for tick-borne disease. Read More

PLoS Negl Trop Dis 2021 08 16;15(8):e0009642. Epub 2021 Aug 16.

Department of Pediatrics, The National School of Tropical Medicine, Baylor College of Medicine, Houston, Texas, United States of America.

Tick-borne relapsing fever (TBRF) spirochetes are likely an overlooked cause of disease in Latin America. In Panama, the pathogens were first reported to cause human disease in the early 1900s. Recent collections of Ornithodoros puertoricensis from human dwellings in Panama prompted our interest to determine whether spirochetes still circulate in the country. Read More

Infect Immun 2021 09 12;89(10):e0030721. Epub 2021 Jul 12.

Department of Microbiology, UT Southwestern Medical Center, Dallas, Texas, USA.

Riboflavin is an essential micronutrient, but its transport and utilization have remained largely understudied among pathogenic spirochetes. Here, we show that Borrelia burgdorferi, the zoonotic spirochete that causes Lyme disease, is able to import riboflavin via products of its -like operon as well as synthesize flavin mononucleotide and flavin adenine dinucleotide despite lacking canonical genes for their synthesis. Additionally, a mutant deficient in the -like operon is resistant to the antimicrobial effect of roseoflavin, a natural riboflavin analog, and is attenuated in a murine model of Lyme borreliosis. Read More

Curr Trop Med Rep 2021 Jun 12;8(2):99-103. Epub 2021 Feb 12.

Department of Medicine, Section of Infectious Diseases, University of Oklahoma Health Science Center, Oklahoma, OK, USA.

Purpose Of Review: International and domestic travelers may acquire a wide variety of infectious diseases transmitted by exposure to insects. Exposure to ticks may be associated with systemic infections clinically suspected through skin and soft tissue manifestations along with fever, myalgia, headache, and other related symptoms. Cutaneous lesions may include eschars at the site of initial contact, maculopapular rashes, or others as the result of systemic dissemination of viral, Rickettsial, parasitic, and protozoan infections acquired by exposure to different types of ticks. Read More

Ticks Tick Borne Dis 2021 09 13;12(5):101789. Epub 2021 Jul 13.

University of California Division of Agriculture and Natural Resources, University of California, Berkeley, 130 Hilgard Way, Berkeley, CA 95449 USA. Electronic address:

In the western United States, Ixodes pacificus Cooley & Kohls (Acari: Ixodidae) is the primary vector of the agents causing Lyme disease and granulocytic anaplasmosis in humans. The geographic distribution of the tick is associated with climatic variables that include temperature, precipitation, and humidity, and biotic factors such as the spatial distribution of its primary vertebrate hosts. Here, we explore (1) how climate change may alter the geographic distribution of I. Read More

PLoS One 2021 1;16(6):e0252214. Epub 2021 Jun 1.

Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, United States of America.

Borrelia burgdorferi (Bb), the etiological agent of Lyme disease, produces a series of simple glycolipids where diacylglycerol and cholesterol serve as the precursor. The cholesterol-based glycolipids, cholesteryl 6-O-acyl-β-D-galactopyranoside (ACGal) and cholesteryl-β-D-galactopyranoside (CGal) are immunogenic and proposed to contribute to the pathogenesis of Lyme disease. Detailed studies of CGal and ACGal in Bb have been hampered by a lack of knowledge of their underlying biosynthetic processes. Read More

J Clin Microbiol 2021 06 18;59(7):e0298120. Epub 2021 Jun 18.

Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA.

Bacterial vector-borne diseases, including species, present a significant diagnostic, clinical, and public health challenge due to their overlapping symptoms and the breadth of causative agents and arthropod vectors. The relapsing fever (RF) borreliae encompass both established and emerging pathogens and are transmitted to humans by soft ticks, hard ticks, or lice. We developed a real-time semimultiplex PCR assay that detects multiple RF borreliae causing human illness and classifies them into one of three groups. Read More

Appl Environ Microbiol 2021 06 11;87(13):e0031921. Epub 2021 Jun 11.

Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA.

Tick-borne diseases in California include Lyme disease (caused by Borrelia burgdorferi), infections with Borrelia miyamotoi, and human granulocytic anaplasmosis (caused by Anaplasma phagocytophilum). We surveyed multiple sites and habitats (woodland, grassland, and coastal chaparral) in California to describe spatial patterns of tick-borne pathogen prevalence in western black-legged ticks (Ixodes pacificus). We found that several species of B. Read More

mBio 2021 04 13;12(2). Epub 2021 Apr 13.

Department of Microbiology & Molecular Genetics, School of Medicine, University of California Irvine, Irvine, California, USA

Animals that are competent reservoirs of zoonotic pathogens commonly suffer little morbidity from the infections. To investigate mechanisms of this tolerance of infection, we used single-dose lipopolysaccharide (LPS) as an experimental model of inflammation and compared the responses of two rodents: , the white-footed deermouse and reservoir for the agents of Lyme disease and other zoonoses, and the house mouse Four hours after injection with LPS or saline, blood, spleen, and liver samples were collected and subjected to transcriptome sequencing (RNA-seq), metabolomics, and specific reverse transcriptase quantitative PCR (RT-qPCR). Differential expression analysis was at the gene, pathway, and network levels. Read More

Insects 2021 Mar 5;12(3). Epub 2021 Mar 5.

Biodiversity Institute, University of Kansas, Lawrence, KS 66045, USA.

Ticks rank high among arthropod vectors in terms of numbers of infectious agents that they transmit to humans, including Lyme disease, Rocky Mountain spotted fever, Colorado tick fever, human monocytic ehrlichiosis, tularemia, and human granulocytic anaplasmosis. Increasing temperature is suspected to affect tick biting rates and pathogen developmental rates, thereby potentially increasing risk for disease incidence. Tick distributions respond to climate change, but how their geographic ranges will shift in future decades and how those shifts may translate into changes in disease incidence remain unclear. Read More

Microorganisms 2021 Mar 23;9(3). Epub 2021 Mar 23.

Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1G6, Canada.

Tick-borne infectious diseases can affect many tissues and organs including bone, one of the most multifunctional structures in the human body. There is a scarcity of data regarding the impact of tick-borne pathogens on bone. The aim of this review was to survey existing research literature on this topic. Read More

J Public Health Manag Pract 2022 Jan-Feb 01;28(1):E37-E42

Connecticut Emerging Infections Program, Yale School of Public Health, New Haven, Connecticut (Ms Niesobecki and Dr Niccolai); Maryland Department of Health, Baltimore, Maryland (Ms Rutz); Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado (Ms Hook and Dr Hinckley); and Maryland Department of Health, Baltimore, Maryland (Dr Feldman).

Tick-borne diseases (TBDs) are increasing despite prevention recommendations. We explored whether cost is a barrier to prevention use in Connecticut and Maryland, using a cross-sectional survey. Respondents were queried regarding their willingness to pay for chemical, natural, and rodent-targeted yard pesticide treatments and permethrin-treated clothing. Read More

Ticks Tick Borne Dis 2021 07 20;12(4):101688. Epub 2021 Feb 20.

Department of Parasitology, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, Queensland 4072, Australia. Electronic address:

Argasid systematics remains controversial with widespread adherence to the Hoogstraal (1985) classification scheme, even though it does not reflect evolutionary relationships and results in paraphyly for the main genera of soft ticks (Argasidae), namely Argas and Ornithodoros. The alternative classification scheme, proposed by Klompen and Oliver (1993), has problems of its own: most notably paraphyly of the subgenus Pavlovskyella and the controversial grouping together of the subgenera Alectorobius, Antricola, Carios, Chiropterargas, Nothoaspis, Parantricola, Reticulinasus and Subparmatus into the genus Carios. Recent phylogenetic analyses of 18S/28S rRNA sequences and mitochondrial genomes agree with the scheme of Klompen and Oliver (1993), with regard to the paraphyly of Pavlovskyella, placement of Alveonasus, Ogadenus, Proknekalia and Secretargas in the Argasinae and placement of Carios and Chiropterargas in the Ornithodorinae (Mans et al. Read More

J Clin Microbiol 2021 04 20;59(5). Epub 2021 Apr 20.

Division of Clinical Microbiology, Mayo Clinic, Rochester, Minnesota, USA

Reported cases of tick-borne diseases have steadily increased for more than a decade. In the United States, a majority of tick-borne infections are caused by bacteria. Clinical diagnosis may be challenging, as tick-borne diseases can present with similar symptoms. Read More

Am J Trop Med Hyg 2021 01 18;104(3):1048-1054. Epub 2021 Jan 18.

4Department of Biomedical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado.

Powassan virus (POWV) is a tick-borne virus maintained in sylvatic cycles between mammalian wildlife hosts and ticks (primarily Ixodes spp.). There are two currently recognized lineages, POWV-lineage 1 (POWV-L1) and deer tick virus (DTV; lineage 2), both of which can cause fatal neurologic disease in humans. Read More