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Biological Sciences Faculty Publications

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Articles 31 - 60 of 101

Full-Text Articles in Immunology and Infectious Disease

Spatio-Temporal Modelling Of Tick Life-Stage Count Data With Spatially Varying Coefficients, Thabo Lephoto, Henry Mwambi, Oliver Bodhlyera, Holly Gaff Jan 2021

Spatio-Temporal Modelling Of Tick Life-Stage Count Data With Spatially Varying Coefficients, Thabo Lephoto, Henry Mwambi, Oliver Bodhlyera, Holly Gaff

Biological Sciences Faculty Publications

There is a vast amount of geo-referenced data in many fields of study including ecological studies. Geo-referencing is usually by point referencing; that is, latitudes and longitudes or by areal referencing, which includes districts, counties, states, provinces and other administrative units. The availability of large geo-referenced datasets for modelling has necessitated the development and application of spatial statistical methods. However, spatial varying coefficients models exploring the abundance of tick counts remain limited. In this study we used data that was collected and prepared by researchers in the Department of Biological Sciences from the Old Dominion University, Virginia, USA. We modelled …


Microbiomes Of Blood-Feeding Arthropods: Genes Coding For Essential Nutrients And Relation To Vector Fitness And Pathogenic Infections. A Review, Daniel E. Sonenshine, Philip E. Stewart Jan 2021

Microbiomes Of Blood-Feeding Arthropods: Genes Coding For Essential Nutrients And Relation To Vector Fitness And Pathogenic Infections. A Review, Daniel E. Sonenshine, Philip E. Stewart

Biological Sciences Faculty Publications

Blood-feeding arthropods support a diverse array of symbiotic microbes, some of which facilitate host growth and development whereas others are detrimental to vector-borne pathogens. We found a common core constituency among the microbiota of 16 different arthropod blood-sucking disease vectors, including Bacillaceae, Rickettsiaceae, Anaplasmataceae, Sphingomonadaceae, Enterobacteriaceae, Pseudomonadaceae, Moraxellaceae and Staphylococcaceae. By comparing 21 genomes of common bacterial symbionts in blood-feeding vectors versus non-blooding insects, we found that certain enteric bacteria benefit their hosts by upregulating numerous genes coding for essential nutrients. Bacteria of blood-sucking vectors expressed significantly more genes (p < 0.001) coding for these essential nutrients than those of non-blooding insects. Moreover, compared to endosymbionts, the genomes of enteric bacteria also contained significantly more genes (p < 0.001) that code for the synthesis of essential amino acids and proteins that detoxify reactive oxygen species. In contrast, microbes in non-blood-feeding insects expressed few gene families coding for these nutrient categories. We also discuss specific midgut bacteria essential for the normal development of pathogens (e.g., Leishmania) versus …


Complete Genome Sequence Of Rickettsia Parkeri Strain Black Gap, Sandor E. Karpathy, Christopher D. Paddock, Stephanie L. Grizzard, Dhwani Batra, Lori A. Rowe, David T. Gauthier Jan 2021

Complete Genome Sequence Of Rickettsia Parkeri Strain Black Gap, Sandor E. Karpathy, Christopher D. Paddock, Stephanie L. Grizzard, Dhwani Batra, Lori A. Rowe, David T. Gauthier

Biological Sciences Faculty Publications

A unique genotype of Rickettsia parkeri, designated R. parkeri strain Black Gap, has thus far been associated exclusively with the North American tick, Dermacentor parumapertus. The compete genome consists of a single circular chromosome with 1,329,522 bp and a G+C content of 32.5%.


Varroa Destructor Mites Vector And Transmit Pathogenic Honey Bee Viruses Acquired From An Artificial Diet, Francisco Posada-Florez, Eugene V. Ryabov, Matthew C. Heerman, Yanping Chen, Jay D. Evans, Daniel E. Sonenshine, Steven C. Cook Nov 2020

Varroa Destructor Mites Vector And Transmit Pathogenic Honey Bee Viruses Acquired From An Artificial Diet, Francisco Posada-Florez, Eugene V. Ryabov, Matthew C. Heerman, Yanping Chen, Jay D. Evans, Daniel E. Sonenshine, Steven C. Cook

Biological Sciences Faculty Publications

The ectoparasitic mite Varroa destructoris one of the most destructive pests of the honey bee (Apis mellifera) and the primary biotic cause of colony collapse in many regions of the world. These mites inflict physical injury on their honey bee hosts from feeding on host hemolymph and fat body cells/cellular components, and serve as the vector for deadly honey bee viruses, including Deformed wing virus (DWV) and the related Varroa destructor virus-1 (VDV-1) (i.e., DWV-like viruses). Studies focused on elucidating the dynamics of Varroa-mediated vectoring and transmission of DWV-like viruses may be confounded by viruses present in …


Lymesim 2.0: An Updated Simulation Of Blacklegged Tick (Acari: Ixodidae) Population Dynamics And Enzootic Transmission Of Borrelia Burgdorferi (Spirochaetales: Spirochaetaceae), Holly Gaff, Rebecca J. Eisen, Lars Eisen, Robyn Nadolny, Jenna Bjork, Andrew J. Monaghan Jan 2020

Lymesim 2.0: An Updated Simulation Of Blacklegged Tick (Acari: Ixodidae) Population Dynamics And Enzootic Transmission Of Borrelia Burgdorferi (Spirochaetales: Spirochaetaceae), Holly Gaff, Rebecca J. Eisen, Lars Eisen, Robyn Nadolny, Jenna Bjork, Andrew J. Monaghan

Biological Sciences Faculty Publications

Lyme disease is the most commonly reported vector-borne disease in the United States, and the number of cases reported each year continues to rise. The complex nature of the relationships between the pathogen (Borrelia burgdorferi sensu stricto), the tick vector (Ixodes scapularis Say), multiple vertebrate hosts, and numerous environmental factors creates challenges for understanding and predicting tick population and pathogen transmission dynamics. LYMESIM is a mechanistic model developed in the late 1990s to simulate the life-history of I. scapularis and transmission dynamics of B. burgdorferi s.s. Here we present LYMESIM 2.0, a modernized version of LYMESIM, that includes …


An Efficient Microinjection Method To Generate Human Anaplasmosis Agent Anaplasma Phagocytophilum-Infected Ticks, Vikas Taank, Ellango Ramasamy, Hameeda Sultana, Girish Neelakanta Jan 2020

An Efficient Microinjection Method To Generate Human Anaplasmosis Agent Anaplasma Phagocytophilum-Infected Ticks, Vikas Taank, Ellango Ramasamy, Hameeda Sultana, Girish Neelakanta

Biological Sciences Faculty Publications

Ticks are important vectors that transmit several pathogens including human anaplasmosis agent, Anaplasma phagocytophilum. This bacterium is an obligate intracellular rickettsial pathogen. An infected reservoir animal host is often required for maintenance of this bacterial colony and as a source for blood to perform needle inoculations in naïve animals for tick feeding studies. In this study, we report an efficient microinjection method to generate A. phagocytophilum-infected ticks in laboratory conditions. The dense-core (DC) form of A. phagocytophilum was isolated from in vitro cultures and injected into the anal pore of unfed uninfected Ixodes scapularis nymphal ticks. These ticks …


Tick-Borne Flavivirus Inhibits Sphingomyelinase (Issmase), A Venomous Spider Ortholog To Increase Sphingomyelin Lipid Levels For Its Survival In Ixodes Scapularis Ticks, Pravesh Regmi, Supreet Khanal, Girish Neelakanta, Hameda Sultana Jan 2020

Tick-Borne Flavivirus Inhibits Sphingomyelinase (Issmase), A Venomous Spider Ortholog To Increase Sphingomyelin Lipid Levels For Its Survival In Ixodes Scapularis Ticks, Pravesh Regmi, Supreet Khanal, Girish Neelakanta, Hameda Sultana

Biological Sciences Faculty Publications

Our previous study showed that cells from medically important arthropods, such as ticks, secrete extracellular vesicles (EVs) including exosomes that mediate transmission of flavivirus RNA and proteins to the human cells. Understanding the molecular determinants and mechanism(s) of arthropod-borne flavivirus transmission via exosome biogenesis is very important. In this current study, we showed that in the presence of tick-borne Langat Virus (LGTV; a member of tick-borne encephalitis virus complex), the expression of arthropod IsSMase, a sphingomyelinase D (SMase D) that catalyzes the hydrolytic cleavage of substrates like sphingomyelin (SM) lipids, was significantly reduced in both Ixodes scapularis ticks (in vivo) …


Discovery Of Exosomes From Tick Saliva And Salivary Glands Reveals Therapeutic Roles For Cxcl12 And Il-8 In Wound Healing At The Tick-Human Skin Interface, Wenshuo Zhou, Faizan Tahir, Joseph Che-Yen Wang, Michael Woodson, Michael B. Sherman, Shahid Karim, Girish Neelakanta, Hameeda Sultana Jan 2020

Discovery Of Exosomes From Tick Saliva And Salivary Glands Reveals Therapeutic Roles For Cxcl12 And Il-8 In Wound Healing At The Tick-Human Skin Interface, Wenshuo Zhou, Faizan Tahir, Joseph Che-Yen Wang, Michael Woodson, Michael B. Sherman, Shahid Karim, Girish Neelakanta, Hameeda Sultana

Biological Sciences Faculty Publications

Ticks secrete various anti-coagulatory, anti-vasoconstrictory, anti-inflammatory, and anti-platelet aggregation factors in their saliva at the bite site during feeding to evade host immunological surveillance and responses. For the first time, we report successful isolation of exosomes (small membrane-bound extracellular signaling vesicles) from saliva and salivary glands of partially fed or unfed ixodid ticks. Our data showed a novel role of these in vivo exosomes in the inhibition of wound healing via downregulation of C-X-C motif chemokine ligand 12 (CXCL12) and upregulation of interleukin-8 (IL-8). Cryo-electron microscopy (cryo-EM) analysis revealed that tick saliva and salivary glands are composed of heterogeneous populations …


A Simple, Inexpensive Method For Mark-Recapture Of Ixodid Ticks, Alexis White, Robin Minch, Lindsey Bidder, Holly Gaff Jan 2020

A Simple, Inexpensive Method For Mark-Recapture Of Ixodid Ticks, Alexis White, Robin Minch, Lindsey Bidder, Holly Gaff

Biological Sciences Faculty Publications

Mark-recapture techniques have been widely used and specialized to study organisms throughout the field of biology. To mark-recapture ticks (Ixodida), we have created a simple method to mark ticks using nail polish applied with an insect pin secured in a pencil that allows for a variety of questions to be answered. For measuring tick control efficacy, estimating population estimates, or measuring movement of ticks, this inexpensive mark-recapture method has been easily applied in the field and in the lab to provide useful data to answer a variety of questions about ticks.


Molecular Investigation And Phylogeny Of Species Of The Anaplasmataceae Infecting Animals And Ticks In Senegal, Mustapha Dahmani, Bernard Davoust, Masse Sambou, Hubert Bassene, Pierre Scandola, Tinhinene Ameur, Didier Raoult, Florence Feenollar, Oleg Mediannikov Oct 2019

Molecular Investigation And Phylogeny Of Species Of The Anaplasmataceae Infecting Animals And Ticks In Senegal, Mustapha Dahmani, Bernard Davoust, Masse Sambou, Hubert Bassene, Pierre Scandola, Tinhinene Ameur, Didier Raoult, Florence Feenollar, Oleg Mediannikov

Biological Sciences Faculty Publications

Background: Our study aimed to assess the diversity of the species of Anaplasmataceae in Senegal that infect animals and ticks in three areas: near Keur Momar Sarr (northern region), Dielmo and Diop (Sine Saloum, central region of Senegal), and in Casamance (southern region of Senegal).

Methods: A total of 204 ticks and 433 blood samples were collected from ruminants, horses, donkeys and dogs. Ticks were identified morphologically and by molecular characterization targeting the 12S rRNA gene. Molecular characterization of species of Anaplasmataceae infecting Senegalese ticks and animals was conducted using the 23S rRNA, 16S rRNA, rpoB and groEL genes.

Results: …


Diagnosis Of Schistosoma Mansoni Infections: What Are The Choices In Brazilian Low-Endemic Areas?, Vanessa Silva-Moraes, Lisa M. Shollenberger, Liliane Maria Vidal Siqueira, William Castro-Borges, Donald A. Harn, Rafaella Fortini Queiroz E. Grenfell, Ana Lucia Teles Rabello, Paulo Marcos Zech Coelho Jan 2019

Diagnosis Of Schistosoma Mansoni Infections: What Are The Choices In Brazilian Low-Endemic Areas?, Vanessa Silva-Moraes, Lisa M. Shollenberger, Liliane Maria Vidal Siqueira, William Castro-Borges, Donald A. Harn, Rafaella Fortini Queiroz E. Grenfell, Ana Lucia Teles Rabello, Paulo Marcos Zech Coelho

Biological Sciences Faculty Publications

The population of Brazil is currently characterised by many individuals harbouring low-intensity Schistosoma mansoni infections. The Kato-Katz technique is the diagnostic method recommended by the World Health Organization (WHO) to assess these infections, but this method is not sensitive enough in the context of low egg excretion. In this regard, potential alternatives are being employed to overcome the limits of the Kato-Katz technique. In the present review, we evaluated the performance of parasitological and immunological approaches adopted in Brazilian areas. Currently, the diagnostic choices involve a combination of strategies, including the utilisation of antibody methods to screen individuals and then …


Dynamics Of Two Pathogens In A Single Tick Population, Alexis White, Elsa Schaefer, Chelsea Wright-Thompson, Christopher M. Kribs, Holly Gaff Jan 2019

Dynamics Of Two Pathogens In A Single Tick Population, Alexis White, Elsa Schaefer, Chelsea Wright-Thompson, Christopher M. Kribs, Holly Gaff

Biological Sciences Faculty Publications

A mathematical model for a two-pathogen, one-tick, one-host system is presented and explored. The goal of this model is to determine how long an invading pathogen persists within a tick population in which a resident pathogen is already established. The numerical simulations of the model demonstrate the parameter ranges that allow for coexistence of the two pathogens. Sensitivity analysis highlights the importance of vector-borne, tick-to-host, transmission rates on the invasion reproductive number and persistence of the pathogens over time. The model is then applied to a case study based on a reclaimed swampland field site in southeastern Virginia using field …


Multistate Survey Of American Dog Ticks (Dermacentor Variabilis) For Rickettsia Species, Joy A. Hecht, Michelle E.J. Allerdice, Elizabeth A. Dykstra, Laura Mastel, Rebecca J. Eisen, Tammi L. Johnson, Holly D. Gaff, Andrea S. Varela-Stokes, Jerome Goddard, Benedict B. Pagac, Christopher D. Paddock, Sandor E. Karpathy Jan 2019

Multistate Survey Of American Dog Ticks (Dermacentor Variabilis) For Rickettsia Species, Joy A. Hecht, Michelle E.J. Allerdice, Elizabeth A. Dykstra, Laura Mastel, Rebecca J. Eisen, Tammi L. Johnson, Holly D. Gaff, Andrea S. Varela-Stokes, Jerome Goddard, Benedict B. Pagac, Christopher D. Paddock, Sandor E. Karpathy

Biological Sciences Faculty Publications

Dermacentor variabilis, a common human-biting tick found throughout the eastern half and along the west coast of the United States, is a vector of multiple bacterial pathogens. Historically, D. variabilis has been considered a primary vector of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever. A total of 883 adult D. variabilis, collected between 2012 and 2017 from various locations in 12 states across the United States, were screened for rickettsial DNA. Tick extracts were evaluated using three real-time PCR assays; an R. rickettsii-specific assay, a Rickettsia bellii-specific assay, and a Rickettsia genus-specific …


Serological Proteomic Screening And Evaluation Of A Recombinant Egg Antigen For The Diagnosis Of Low-Intensity Schistosoma Mansoni Infections In Endemic Area In Brazil, Vanessa Silva-Moraes, Lisa Marie Shollenberger, William Castro-Borges, Ana Lucia Teles Rabello, Donald A. Harn, Lia Carolina Soares Medeiros, Wander De Jesus Jeremias, Liliane Maria Vidal Siqueira, Caroline Stephane Salviano Pereira, Maria Luysa Camargos Pedrosa, Nathalie Bonatti Franco Almeida, Aureo Almeida, Jose Roberto Lambertucci, Nidia Francisca De Figueiredo Carneiro, Paulo Marcos Zech Coelho, Refaella Fortini Queiroz Grenfell Jan 2019

Serological Proteomic Screening And Evaluation Of A Recombinant Egg Antigen For The Diagnosis Of Low-Intensity Schistosoma Mansoni Infections In Endemic Area In Brazil, Vanessa Silva-Moraes, Lisa Marie Shollenberger, William Castro-Borges, Ana Lucia Teles Rabello, Donald A. Harn, Lia Carolina Soares Medeiros, Wander De Jesus Jeremias, Liliane Maria Vidal Siqueira, Caroline Stephane Salviano Pereira, Maria Luysa Camargos Pedrosa, Nathalie Bonatti Franco Almeida, Aureo Almeida, Jose Roberto Lambertucci, Nidia Francisca De Figueiredo Carneiro, Paulo Marcos Zech Coelho, Refaella Fortini Queiroz Grenfell

Biological Sciences Faculty Publications

Background

Despite decades of use of control programs, schistosomiasis remains a global public health problem. To further reduce prevalence and intensity of infection, or to achieve the goal of elimination in low-endemic areas, there needs to be better diagnostic tools to detect low-intensity infections in low-endemic areas in Brazil. The rationale for development of new diagnostic tools is that the current standard test Kato-Katz (KK) is not sensitive enough to detect low-intensity infections in low-endemic areas. In order to develop new diagnostic tools, we employed a proteomics approach to identify biomarkers associated with schistosome-specific immune responses in hopes of developing …


Prime-Boost Vaccine Regimen For Sjtpl And Sjc23 Schistosome Vaccines, Increases Efficacy In Water Buffalo In A Field Trial In China, Akram A. Da'dara, Changlin Li, Xinling Yu, Mao Zheng, Jie Zhou, Lisa M. Shollenberger, Yue-Sheng Li, Donald A. Ham Jan 2019

Prime-Boost Vaccine Regimen For Sjtpl And Sjc23 Schistosome Vaccines, Increases Efficacy In Water Buffalo In A Field Trial In China, Akram A. Da'dara, Changlin Li, Xinling Yu, Mao Zheng, Jie Zhou, Lisa M. Shollenberger, Yue-Sheng Li, Donald A. Ham

Biological Sciences Faculty Publications

Schistosomiasis remains a serious zoonotic disease in China and the Philippines. Water buffalo and cattle account for the majority of transmission. Vaccination of water buffalo is considered a key strategy to reduce disease prevalence. Previously, we showed that vaccination of water buffalo with SjC23 or SjCTPI plasmid DNA vaccines, induced 50% efficacy to challenge infection. Here, we evaluated several parameters to determine if we can develop a two dose vaccine that maintains the efficacy of the three dose vaccine. We performed four trials evaluating: (1) lab produced vs. GLP grade vaccines, (2) varying the time between prime and boost, (3) …


Parasitic Dinoflagellate Hematodinium Perezi Prevalence In Larval And Juvenile Blue Crabs Callinectes Sapidus From Coastal Bays Of Virginia, H. J. Small, J. P. Huchin-Mian, K. S. Reece, K. M. Pagenkopp Lohan, Mark J. Butler Iv, J. D. Shields Jan 2019

Parasitic Dinoflagellate Hematodinium Perezi Prevalence In Larval And Juvenile Blue Crabs Callinectes Sapidus From Coastal Bays Of Virginia, H. J. Small, J. P. Huchin-Mian, K. S. Reece, K. M. Pagenkopp Lohan, Mark J. Butler Iv, J. D. Shields

Biological Sciences Faculty Publications

The parasitic dinoflagellate Hematodinium perezi infects the American blue crab Callinectes sapidus and other decapods along the Eastern seaboard and Gulf of Mexico coast of the USA. Large juvenile and adult blue crabs experience high mortality during seasonal outbreaks of H. perezi, but less is known about its presence in the early life history stages of this host. We determined the prevalence of H. perezi in megalopae and early benthic juvenile crabs from multiple locations along the Virginia portion of the Delmarva Peninsula. The DNA of H. perezi was not detected in any megalopae collected from several locations within …


Characterization Of Tick Organic Anion Transporting Polypeptides (Oatps) Upon Bacterial And Viral Infections, Vikas Taank, Wenshou Zhou, Xuran Zhuang, John F. Anderson, Utpal Pal, Hameeda Sultana, Girish Neelakanta Nov 2018

Characterization Of Tick Organic Anion Transporting Polypeptides (Oatps) Upon Bacterial And Viral Infections, Vikas Taank, Wenshou Zhou, Xuran Zhuang, John F. Anderson, Utpal Pal, Hameeda Sultana, Girish Neelakanta

Biological Sciences Faculty Publications

Background: Ixodes scapularis organic anion transporting polypeptides (OATPs) play important roles in tickrickettsial pathogen interactions. In this report, we characterized the role of these conserved molecules in ticks infected with either Lyme disease agent Borrelia burgdorferi or tick-borne Langat virus (LGTV), a pathogen closely related to tick-borne encephalitis virus (TBEV).

Results: Quantitative real-time polymerase chain reaction analysis revealed no significant changes in oatps gene expression upon infection with B. burgdorferi in unfed ticks. Synchronous infection of unfed nymphal ticks with LGTV in vitro revealed no significant changes in oatps gene expression. However, expression of specific oatps was significantly downregulated upon …


The Mechanisms Shaping The Repertoire Of Cd4(+)Foxp3(+) Regulatory T Cells, Piotr Kraj, Leszek Ignatowicz Jan 2018

The Mechanisms Shaping The Repertoire Of Cd4(+)Foxp3(+) Regulatory T Cells, Piotr Kraj, Leszek Ignatowicz

Biological Sciences Faculty Publications

Regulatory T (Treg) cells expressing Foxp3 transcription factor control homeostasis of the immune system, antigenic responses to commensal and pathogenic microbiota, and immune responses to self and tumour antigens. The Treg cells differentiate in the thymus, along with conventional CD4+ T cells, in processes of positive and negative selection. Another class of Treg cells is generated in peripheral tissues by inducing Foxp3 expression in conventional CD4+ T cells in response to antigenic stimulation. Both thymic and peripheral generation of Treg cells depends on recognition of peptide/MHC ligands by the T-cell receptors (TCR) expressed on thymic Treg precursors or …


Range Expansion Of Tick Disease Vectors In North America: Implications For Spread Of Tick-Borne Disease, Daniel E. Sonenshine Jan 2018

Range Expansion Of Tick Disease Vectors In North America: Implications For Spread Of Tick-Borne Disease, Daniel E. Sonenshine

Biological Sciences Faculty Publications

Ticks are the major vectors of most disease-causing agents to humans, companion animals and wildlife. Moreover, ticks transmit a greater variety of pathogenic agents than any other blood-feeding arthropod. Ticks have been expanding their geographic ranges in recent decades largely due to climate change. Furthermore, tick populations in many areas of their past and even newly established localities have increased in abundance. These dynamic changes present new and increasing severe public health threats to humans, livestock and companion animals in areas where they were previously unknown or were considered to be of minor importance. Here in this review, the geographic …


Using An In Vitro System For Maintaining Varroa Destructor Mites On Apis Mellifera Pupae As Hosts: Studies Of Mite Longevity And Feeding Behavior, Noble I. Egekwu, Francisco Posada, Daniel E. Sonenshine, Steven Cook Jan 2018

Using An In Vitro System For Maintaining Varroa Destructor Mites On Apis Mellifera Pupae As Hosts: Studies Of Mite Longevity And Feeding Behavior, Noble I. Egekwu, Francisco Posada, Daniel E. Sonenshine, Steven Cook

Biological Sciences Faculty Publications

Varroa destructor mites (varroa) are ectoparasites of Apis mellifera honey bees, and the damage they inflict on hosts is likely a causative factor of recent poor honey bee colony performance. Research has produced an arsenal of control agents against varroa mites, which have become resistant to many chemical means of their control, and other means have uncertain efficacy. Novel means of control will result from a thorough understanding of varroa physiology and behavior. However, robust knowledge of varroa biology is lacking; mites have very low survivability and reproduction away from their natural environment and host, and few tested protocols of …


Do Avian Blood Parasites Influence Hypoxia Physiology In A High Elevation Environment?, Farah Ishtiaq, Sahas Barve Jan 2018

Do Avian Blood Parasites Influence Hypoxia Physiology In A High Elevation Environment?, Farah Ishtiaq, Sahas Barve

Biological Sciences Faculty Publications

BACKGROUND: Montane birds which engage in elevational movements have evolved to cope with fluctuations in environmental hypoxia, through changes in physiological parameters associated with blood oxygen-carrying capacity such as haemoglobin concentration (Hb) and haematocrit (Hct). In particular, elevational migrants which winter at low elevations, encounter varying intensities of avian haemosporidian parasites as they traverse heterogeneous environments. Whilst high intensity parasite infections lead to anaemia, one can expect that the ability to cope with haemosporidian infections should be a key trait for elevational migrants that must be balanced against reducing the oxygen-carrying capacity of blood in response to high elevation. In …


Modelling The Effects Of Habitat And Hosts On Tick Invasions, Robyn M. Nadolny, Holly D. Gaff Jan 2018

Modelling The Effects Of Habitat And Hosts On Tick Invasions, Robyn M. Nadolny, Holly D. Gaff

Biological Sciences Faculty Publications

Many tick species are invading new areas because of anthropogenic changes in the landscape, shifting climatic variables and increasing populations of suitable host species and tick habitat. However, the relative influences of habitat and hosts in tick dispersal and tick population establishment remain in question. A spatially explicit agent-based model was developed to explore the spatio-temporal dynamics of a generic tick population in the years immediately following the introduction of ticks into a novel environment. The general model was then adapted to investigate a case study of two recent tick species invasions into the Mid-Atlantic United States. The recent simultaneous …


Towards Understanding The Role Of Small Mammals In The Transmission Of Lyme Disease In Virginia, Usa, Robert K. Rose, Laura Bitzer, Wayne Hynes, Holly D. Gaff, Robyn Nadolny, Jory Brinkerhoff Jan 2018

Towards Understanding The Role Of Small Mammals In The Transmission Of Lyme Disease In Virginia, Usa, Robert K. Rose, Laura Bitzer, Wayne Hynes, Holly D. Gaff, Robyn Nadolny, Jory Brinkerhoff

Biological Sciences Faculty Publications

Larvae and nymphs of many species of ticks select small mammals, reptiles, and birds as hosts. Since 2011, we have examined more than 1,000 small mammals of 10 species and collected a small tissue sample as well as all visible ticks; rates of infestation range from 18% in harvest mice to 53% in meadow voles. Identification of immature ticks is challenging and requires molecular or genetic methods beyond classification as being from the genus Ixodes or another genus. Ixodes ticks include Ixodes scapularis, the species that transmits the Lyme disease-causing bacterium Borrelia burgdorferi to humans. Of the approximately 2,300 ticks …


Ticks, Ixodes Scapularis, Feed Repeatedly On White-Footed Mice Despite Strong Inflammatory Response: An Expanding Paradigm For Understanding Tick-Host Interactions, Jennifer M. Anderson, Ian N. Moore, Bianca M. Nagata, José M.C. Ribeiro, Jesus G. Valenzuela, Daniel E. Sonenshine Dec 2017

Ticks, Ixodes Scapularis, Feed Repeatedly On White-Footed Mice Despite Strong Inflammatory Response: An Expanding Paradigm For Understanding Tick-Host Interactions, Jennifer M. Anderson, Ian N. Moore, Bianca M. Nagata, José M.C. Ribeiro, Jesus G. Valenzuela, Daniel E. Sonenshine

Biological Sciences Faculty Publications

Ticks transmit infectious agents including bacteria, viruses and protozoa. However, their transmission may be compromised by host resistance to repeated tick feeding. Increasing host resistance to repeated tick bites is well known in laboratory animals, including intense inflammation at the bite sites. However, it is not known whether this also occurs in wild rodents such as white-footed mice, Peromyscus leucopus, and other wildlife, or if it occurs at all. According to the "host immune incompetence" hypothesis, if these mice do not have a strong inflammatory response, they would not reject repeated tick bites by Ixodes scapularis. To test …


Microbial Invasion Vs. Tick Immune Regulation, Daniel E. Sonenshine, Kevin R. Macaluso Sep 2017

Microbial Invasion Vs. Tick Immune Regulation, Daniel E. Sonenshine, Kevin R. Macaluso

Biological Sciences Faculty Publications

Ticks transmit a greater variety of pathogenic agents that cause disease in humans and animals than any other haematophagous arthropod, including Lyme disease, Rocky Mountain spotted fever, human granulocytic anaplasmosis, babesiosis, tick-borne encephalitis, Crimean Congo haemorhagic fever, and many others (Gulia-Nuss et al., 2016). Although diverse explanations have been proposed to explain their remarkable vectorial capacity, among the most important are their blood feeding habit, their long term off-host survival, the diverse array of bioactive molecules that disrupt the host's natural hemostatic mechanisms, facilitate blood flow, pain inhibitors, and minimize inflammation to prevent immune rejection (Hajdušek et al., 2013). Moreover, …


Defining The Risk Of Zika And Chikungunya Virus Transmission In Human Population Centers Of The Eastern United States, Carrie A. Manore, Richard S. Ostfeld, Folashade B. Agusto, Holly Gaff, Shannon L. Ladeau Jan 2017

Defining The Risk Of Zika And Chikungunya Virus Transmission In Human Population Centers Of The Eastern United States, Carrie A. Manore, Richard S. Ostfeld, Folashade B. Agusto, Holly Gaff, Shannon L. Ladeau

Biological Sciences Faculty Publications

The recent spread of mosquito-transmitted viruses and associated disease to the Americas motivates a new, data-driven evaluation of risk in temperate population centers. Temperate regions are generally expected to pose low risk for significant mosquito-borne disease; however, the spread of the Asian tiger mosquito (Aedes albopictus) across densely populated urban areas has established a new landscape of risk. We use a model informed by field data to assess the conditions likely to facilitate local transmission of chikungunya and Zika viruses from an infected traveler to Ae. albopictus and then to other humans in USA cities with variable human …


Genomic Insights Into The Ixodes Scapularis Tick Vector Of Lyme Disease, Monika Gulia-Nuss, Andrew B. Nuss, Jason M. Meyer, Daniel E. Sonenshine, R. Michael Roe, Robert M. Waterhouse, David B. Sattelle, Jose De La Fuente, Jose M. Ribeiro, Karine Megy Jan 2016

Genomic Insights Into The Ixodes Scapularis Tick Vector Of Lyme Disease, Monika Gulia-Nuss, Andrew B. Nuss, Jason M. Meyer, Daniel E. Sonenshine, R. Michael Roe, Robert M. Waterhouse, David B. Sattelle, Jose De La Fuente, Jose M. Ribeiro, Karine Megy

Biological Sciences Faculty Publications

Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing ~57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick-host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host 'questing', prolonged feeding, cuticle …


Investigating Cholera Using An Sir Model With Age-Class Structure And Optimal Control, K. Renee Fister, Holly Gaff, Elsa Schaefer, Glenna Buford, Bryce C. Norris Jan 2016

Investigating Cholera Using An Sir Model With Age-Class Structure And Optimal Control, K. Renee Fister, Holly Gaff, Elsa Schaefer, Glenna Buford, Bryce C. Norris

Biological Sciences Faculty Publications

The use of systems of differential equations in mathematical modeling in conjunction with epidemiology continues to be an area of focused research. This paper briefly acquaints readers with epidemiology, cholera, and the need for effective control strategies; discusses cholera dynamics through a variation on the SIR epidemiological model in which two separate age classes exist in a population; finds the numeric value for R₀ to be approximately 1.54 using estimated parameters for Bangladesh; and employs an optimal control resulting in a suggestion that a protection control be implemented at the end of the monsoon season.


Colonization Of Lutzomyia Verrucarum And Lutzomyia Longipalpis Sand Flies (Diptera: Psychodidae) By Bartonella Bacilliformis, The Etiologic Agent Of Carrion's Disease, James M. Battisti, Phillip G. Lawyer, Michael F. Minnick Oct 2015

Colonization Of Lutzomyia Verrucarum And Lutzomyia Longipalpis Sand Flies (Diptera: Psychodidae) By Bartonella Bacilliformis, The Etiologic Agent Of Carrion's Disease, James M. Battisti, Phillip G. Lawyer, Michael F. Minnick

Biological Sciences Faculty Publications

Bartonella bacilliformis is a pathogenic bacterium transmitted to humans presumably by bites of phlebotomine sand flies, infection with which results in a bi-phasic syndrome termed Carrion's disease. After constructing a low-passage GFP-labeled strain of B. bacilliformis, we artificially infected Lutzomyia verrucarum and L. longipalpis populations, and subsequently monitored colonization of sand flies by fluorescence microscopy. Initially, colonization of the two fly species was indistinguishable, with bacteria exhibiting a high degree of motility, yet still confined to the abdominal midgut. After 48h, B. bacilliformis transitioned from bacillus-shape to a non-motile, small coccoid form and appeared to be digested along with …


Proteins Of Bartonella Bacilliformis:Candidates For Vaccine Development, Cesar Henriquez-Camocho, Palmira Ventosilla, Michael F. Minnick, Joaquim Ruiz, Ciro Maguina Aug 2015

Proteins Of Bartonella Bacilliformis:Candidates For Vaccine Development, Cesar Henriquez-Camocho, Palmira Ventosilla, Michael F. Minnick, Joaquim Ruiz, Ciro Maguina

Biological Sciences Faculty Publications

Bartonella bacilliformis is the etiologic agent of Carrion's disease suggest complex adaptations by the bacterium to the human host, with the overall objectives of persistence, maintenance of a reservoir state for vectorial transmission, and immune evasion. These events include a multitude of biochemical and genetic mechanisms involving both bacterial and host proteins. This review focuses on proteins involved in interactions between B. bacilliformis and human host. Some of them (e.g., flagellin, Brps, IalB, FtsZ, Hbp/Pap31, and other outer membrane proteins) are potential protein antigen candidates for a synthetic vaccine.