1
|
White AL, Cumbie A, Brinkerhoff RJ, Hynes WL, Gaff HD. Release the hens: a study on the complexities of guinea fowl as tick control. J Med Entomol 2024; 61:410-417. [PMID: 38279688 DOI: 10.1093/jme/tjad167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 10/27/2023] [Accepted: 12/08/2023] [Indexed: 01/28/2024]
Abstract
Established tick control strategies often involve methods that can be damaging to existing environmental conditions or natural host ecology. To find more environmentally friendly methods, biological controls, like predators of ticks, have been suggested. There are natural predators of ticks, but most are generalists and not expected to control tick populations. Helmeted guinea fowl (Numida meleagris (L.) (Galliformes: Numididae)) have been suggested to be biological controls of ticks, and therefore, tick-borne pathogens, but their potential role as hosts for ticks complicates the relationship. A study was conducted to assess whether guinea fowl reduces the abundance of lone star ticks, Amblyomma americanum (L.) (Acari: Ixodidae), or whether they are hosts of ticks. Using mark-recapture techniques, painted lone star ticks were placed into 3 different treatments: penned, excluded, and free range. The recapture rates of painted ticks were compared. There was a significant difference between excluded and free-range treatments, but not between excluded and penned or between free range and penned. To investigate the role of guinea fowl as hosts of ticks, coop floors were examined for engorged ticks. Engorged lone star nymphs that had fed on guinea fowl were found. Lastly, ticks collected were tested to identify the potential reduction in risk of tick-borne pathogens. This study found no evidence that guinea fowl are an effective biological control of lone star ticks or tick-borne pathogens, but they are hosts of lone star nymphs. Future studies are needed to assess the complex ecology of a biological control of ticks that is also a host.
Collapse
Affiliation(s)
- Alexis L White
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, USA
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, USA
| | - Alexandra Cumbie
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, USA
- Department of Health Sciences, ECPI University, Newport News, VA, USA
| | | | - Wayne L Hynes
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, USA
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, USA
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban, South Africa
| |
Collapse
|
2
|
Lippi CA, Gaff HD, Nadolny RM, Ryan SJ. Newer Surveillance Data Extends our Understanding of the Niche of Rickettsia montanensis (Rickettsiales: Rickettsiaceae) Infection of the American Dog Tick (Acari: Ixodidae) in the United States. Vector Borne Zoonotic Dis 2023. [PMID: 37083463 DOI: 10.1089/vbz.2023.0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023] Open
Abstract
Background: Understanding the geographic distribution of Rickettsia montanensis infections in Dermacentor variabilis is important for tick-borne disease management in the United States, as both a tick-borne agent of interest and a potential confounder in surveillance of other rickettsial diseases. Two previous studies modeled niche suitability for D. variabilis with and without R. montanensis, from 2002 to 2012, indicating that the D. variabilis niche overestimates the infected niche. This study updates these, adding data since 2012. Methods: Newer surveillance and testing data were used to update Species Distribution Models (SDMs) of D. variabilis, and R. montanensis-infected D. variabilis, in the United States. Using random forest models, found to perform best in previous work, we updated the SDMs and compared them with prior results. Warren's I niche overlap metric was used to compare between predicted suitability for all ticks and "R. montanensis-positive niche" models across datasets. Results: Warren's I indicated <2% change in predicted niche, and there was no change in order of importance of environmental predictors, for D. variabilis or R. montanensis-positive niche. The updated D. variabilis niche model overpredicted suitability compared with the updated R. montanensis-positive niche in key peripheral parts of the range, but slightly underpredicted through the northern and midwestern parts of the range. This reinforces previous findings of a more constrained R. montanensis-positive niche than predicted by D. variabilis records alone. Conclusions: The consistency of predicted niche suitability for D. variabilis in the United States, with the addition of nearly a decade of new data, corroborates this is a species with generalist habitat requirements. Yet a slight shift in updated niche distribution, even of low suitability, included more southern areas, pointing to a need for continued and extended monitoring and surveillance. This further underscores the importance of revisiting vector and vector-borne disease distribution maps.
Collapse
Affiliation(s)
- Catherine A Lippi
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA
| | - Holly D Gaff
- Department of Biology, Old Dominion University, Norfolk, Virginia, USA
| | - Robyn M Nadolny
- Defense Centers for Public Health-Aberdeen, Aberdeen Proving Ground, Maryland, USA
| | - Sadie J Ryan
- Department of Geography and Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA
| |
Collapse
|
3
|
Lippi CA, Canfield S, Espada C, Gaff HD, Ryan SJ. Estimating the distribution of
Oryzomys palustris
, a potential key host in expanding rickettsial tick‐borne disease risk. Ecosphere 2023. [DOI: 10.1002/ecs2.4445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
Affiliation(s)
- Catherine A. Lippi
- Department of Geography and Emerging Pathogens Institute University of Florida Gainesville Florida USA
| | - Samuel Canfield
- Department of Geography and Emerging Pathogens Institute University of Florida Gainesville Florida USA
| | - Christina Espada
- Department of Biology Old Dominion University Norfolk Virginia USA
| | - Holly D. Gaff
- Department of Biology Old Dominion University Norfolk Virginia USA
| | - Sadie J. Ryan
- Department of Geography and Emerging Pathogens Institute University of Florida Gainesville Florida USA
| |
Collapse
|
4
|
Lippi CA, Gaff HD, Nadolny RM, Ryan SJ. Newer Surveillance Data Extends our Understanding of the Niche of Rickettsia montanensis (Rickettsiales: Rickettsiaceae) Infection of the American Dog Tick (Acari: Ixodidae) in the United States. bioRxiv 2023:2023.01.11.523628. [PMID: 36711596 PMCID: PMC9882046 DOI: 10.1101/2023.01.11.523628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Background Understanding the geographic distribution of Rickettsia montanensis infections in Dermacentor variabilis is important for tick-borne disease management in the United States, as both a tick-borne agent of interest and a potential confounder in surveillance of other rickettsial diseases. Two previous studies modeled niche suitability for D. variabilis with and without R. montanensis , from 2002-2012, indicating that the D. variabilis niche overestimates the infected niche. This study updates these, adding data since 2012. Methods Newer surveillance and testing data were used to update Species Distribution Models (SDMs) of D. variabilis , and R. montanensis infected D. variabilis , in the United States. Using random forest (RF) models, found to perform best in previous work, we updated the SDMs and compared them with prior results. Warren's I niche overlap metric was used to compare between predicted suitability for all ticks and 'pathogen positive niche' models across datasets. Results Warren's I indicated <2% change in predicted niche, and there was no change in order of importance of environmental predictors, for D. variabilis or R. montanensis positive niche. The updated D. variabilis niche model overpredicted suitability compared to the updated R. montanensis positive niche in key peripheral parts of the range, but slightly underpredicted through the northern and midwestern parts of the range. This reinforces previous findings of a more constrained pathogen-positive niche than predicted by D. variabilis records alone. Conclusions The consistency of predicted niche suitability for D. variabilis in the United States, with the addition of nearly a decade of new data, corroborates this is a species with generalist habitat requirements. Yet a slight shift in updated niche distribution, even of low suitability, included more southern areas, pointing to a need for continued and extended monitoring and surveillance. This further underscores the importance of revisiting vector and vector-borne disease distribution maps.
Collapse
Affiliation(s)
- Catherine A. Lippi
- Department of Geography and Emerging Pathogens Institute, University Florida, Gainesville, FL 32611
| | - Holly D. Gaff
- Department of Biology, Old Dominion University, Norfolk, VA 23529
| | - Robyn M. Nadolny
- Defense Centers for Public Health-Aberdeen, Aberdeen Proving Ground, MD 21010
| | - Sadie J. Ryan
- Department of Geography and Emerging Pathogens Institute, University Florida, Gainesville, FL 32611,Correspondence to
| |
Collapse
|
5
|
Morris CN, Gaff HD, Berghaus RD, Wilson CM, Gleim ER. Tick Species Composition, Collection Rates, and Phenology Provide Insights into Tick-Borne Disease Ecology in Virginia. J Med Entomol 2022; 59:1993-2005. [PMID: 35996864 PMCID: PMC9667727 DOI: 10.1093/jme/tjac121] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Indexed: 06/12/2023]
Abstract
To better understand tick ecology in Virginia and the increasing Lyme disease incidence in western Virginia, a comparative phenological study was conducted in which monthly collections were performed at twelve sampling locations in southwestern Virginia (high Lyme disease incidence) and 18 equivalent sampling locations in southeastern Virginia (low Lyme disease incidence) for one year. In western Virginia, we also explored the effect of elevation on collection rates of Ixodes scapularis Say (Acari: Ixodidae) and Amblyomma americanum (L.) (Acari: Ixodidae). In total, 35,438 ticks were collected (33,106 A. americanum; 2,052 I. scapularis; 134 Ixodes affinis Neumann [Acari: Ixodidae]; 84 Dermacentor variabilis [Say] [Acari: Ixodidae]; 49 Dermacentor albipictus [Packard] [Acari: Ixodidae]; 10 Haemaphysalis leporispalustris [Packard] [Acari: Ixodidae]; 2 Ixodes brunneus Koch [Acari: Ixodidae]; 1 Haemaphysalis longicornis Neumann [Acari: Ixodidae]). Within southwestern Virginia, Ixodes scapularis collection rates were not influenced by elevation, unlike A. americanum which were collected more frequently at lower elevations (e.g., below 500 m). Notably, I. scapularis larvae and nymphs were commonly collected in southwestern Virginia (indicating that they were questing on or above the leaf litter) but not in southeastern Virginia. Questing on or above the leaf litter is primarily associated with northern populations of I. scapularis. These findings may support the hypothesis that I. scapularis from the northeastern United States are migrating into western Virginia and contributing to the higher incidence of Lyme disease in this region. This comparative phenological study underscores the value of these types of studies and the need for additional research to further understand the rapidly changing tick-borne disease dynamics in Virginia.
Collapse
Affiliation(s)
- Ciera N Morris
- Department of Biology, Hollins University, Roanoke, VA 24020, USA
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23508, USA
- University of KwaZulu-Natal, School of Mathematics, Statistics, and Computer Sciences, Durban, South Africa
| | - Roy D Berghaus
- Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
| | - C Morgan Wilson
- Department of Biology, Hollins University, Roanoke, VA 24020, USA
| | | |
Collapse
|
6
|
Abstract
Tick-borne diseases are a growing problem in many parts of the world, and their surveillance and control touch on challenging issues in medical entomology, agricultural health, veterinary medicine, and biosecurity. Spatial approaches can be used to synthesize the data generated by integrative One Health surveillance systems, and help stakeholders, managers, and medical geographers understand the current and future distribution of risk. Here, we performed a systematic review of over 8,000 studies and identified a total of 303 scientific publications that map tick-borne diseases using data on vectors, pathogens, and hosts (including wildlife, livestock, and human cases). We find that the field is growing rapidly, with the major Ixodes-borne diseases (Lyme disease and tick-borne encephalitis in particular) giving way to monitoring efforts that encompass a broader range of threats. We find a tremendous diversity of methods used to map tick-borne disease, but also find major gaps: data on the enzootic cycle of tick-borne pathogens is severely underutilized, and mapping efforts are mostly limited to Europe and North America. We suggest that future work can readily apply available methods to track the distributions of tick-borne diseases in Africa and Asia, following a One Health approach that combines medical and veterinary surveillance for maximum impact.
Collapse
Affiliation(s)
- Catherine A Lippi
- Quantitative Disease Ecology and Conservation (QDEC) Lab, Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
- Corresponding author, e-mail:
| | - Sadie J Ryan
- Quantitative Disease Ecology and Conservation (QDEC) Lab, Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
- College of Life Sciences, University of KwaZulu Natal, Durban, South Africa
| | - Alexis L White
- Quantitative Disease Ecology and Conservation (QDEC) Lab, Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Holly D Gaff
- Department of Biology, Old Dominion University, Norfolk, VA, USA
- School of Mathematics, Statistics and Computer Science, University of Kwa-Zulu Natal, Durban, South Africa
| | - Colin J Carlson
- Center for Global Health Science and Security, Georgetown University Medical Center, Georgetown University, Washington, DC, USA
- Department of Microbiology and Immunology, Georgetown University Medical Center, Georgetown University, Washington, DC, USA
| |
Collapse
|
7
|
Bradshaw BT, Jones KM, Westerdale-McInnis JM, Gaff HD. Orofacial Manifestations of Lyme Disease: A systematic review. J Dent Hyg 2021; 95:23-31. [PMID: 34376541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 11/18/2020] [Indexed: 06/13/2023]
Abstract
Purpose: Orofacial manifestations of Lyme disease can affect head and neck anatomical structures that are frequently examined by dental professionals. The purpose of this systematic review was to examine the literature for types and frequencies of orofacial manifestations documented in populations in the United States (US) with Lyme disease.Methods: Four electronic databases (Dentistry and Oral Sciences, PubMed, Cinahl Plus, and Medline) were systematically searched during the summer of 2019 using keywords and MeSH terms to identify relevant studies. Search term alterations and synonyms were cross-checked using the US National Library of Medicine Unified Medical Language System Metathesaurus. Full-text, English language studies were included if they reported on US populations with Centers for Disease Control and Prevention confirmed cases of Lyme disease. The review followed guidelines set forth in Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). Quality was assessed with a modified version of the Cochrane Data Collection Form for Randomized Control Trials and Non-randomized Control Trials. Extracted data was organized by themes of manifestations and the frequencies were calculated.Results: An initial search extracted 217,381 articles; 43 met the inclusion criteria and were further reviewed for quality. Twelve articles published from 1992-2017 were deemed appropriate for inclusion. All were from non-dental journals and fewer than half (n=6) reported on Lyme disease endemic states. Eight incidences of orofacial manifestations within head/neck regions were documented in Lyme disease patients (n=951) and included: headache (39.5%), facial palsy (42.5%), temporomandibular joint arthralgia (42.0%), altered taste (11.0%), stiff neck (13.6%), sore throat (3.0%), neck pain/arthralgia (7.5%), and erythema migrans rash (5.2%).Conclusion: Eight orofacial manifestations of Lyme disease were revealed by this systematic review. Future research regarding the orofacial manifestations of Lyme disease is needed so this medical condition can be better understood by oral health care providers and result in improved health outcomes for infected patients.
Collapse
Affiliation(s)
- Brenda T Bradshaw
- Assistant professor and undergraduate program director, Gene W. Hirschfeld School of Dental Hygiene from Old Dominion University, Norfolk, VA, USA.
| | - Kelsey M Jones
- Student in the Department of Biological Sciences from Old Dominion University, Norfolk, VA, USA
| | | | - Holly D Gaff
- Professor, Department of Biological Sciences and a honorary professor of Mathematics, Statistics and Computer Science at the University of KwaZulu-Natal, Durban, South Africa from Old Dominion University, Norfolk, VA, USA from Old Dominion University, Norfolk, VA, USA
| |
Collapse
|
8
|
Nadolny RM, Toliver M, Gaff HD, Snodgrass JG, Robbins RG. Focus Stacking Images of Morphological Character States for Differentiating the Adults of Ixodes affinis and Ixodes scapularis (Acari: Ixodidae) in Areas of Sympatry. J Med Entomol 2021; 58:1941-1947. [PMID: 33864374 PMCID: PMC8285092 DOI: 10.1093/jme/tjab058] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Indexed: 06/12/2023]
Abstract
Adult females and males of Ixodes affinis and Ixodes scapularis are illustrated by focus stacking image photography, and morphological character states are described that reliably differentiate the two species. In conjunction with other environmental cues, such as the questing phenology of adults, these characteristics will enable the rapid identification of adults of either sex along the southern Coastal Plain of the United States, where these species are sympatric.
Collapse
Affiliation(s)
- Robyn M Nadolny
- Army Public Health Center, Aberdeen Proving Ground, MD 21010, USA
| | - Marcée Toliver
- North Carolina Department of Health and Human Services, Raleigh, NC 27699, USA
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban 4000, South Africa
| | - John G Snodgrass
- Army Public Health Center, Aberdeen Proving Ground, MD 21010, USA
| | - Richard G Robbins
- Walter Reed Biosystematics Unit, Department of Entomology, Smithsonian Institution, MSC, MRC 534, 4210 Silver Hill Road, Suitland, MD 20746, USA
- Walter Reed Army Institute of Research, Department of Entomology, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
| |
Collapse
|
9
|
Lippi CA, Gaff HD, White AL, St. John HK, Richards AL, Ryan SJ. Exploring the Niche of Rickettsia montanensis (Rickettsiales: Rickettsiaceae) Infection of the American Dog Tick (Acari: Ixodidae), Using Multiple Species Distribution Model Approaches. J Med Entomol 2021; 58:1083-1092. [PMID: 33274379 PMCID: PMC8122238 DOI: 10.1093/jme/tjaa263] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Indexed: 05/03/2023]
Abstract
The American dog tick, Dermacentor variabilis (Say) (Acari: Ixodidae), is a vector for several human disease-causing pathogens such as tularemia, Rocky Mountain spotted fever, and the understudied spotted fever group rickettsiae (SFGR) infection caused by Rickettsia montanensis. It is important for public health planning and intervention to understand the distribution of this tick and pathogen encounter risk. Risk is often described in terms of vector distribution, but greatest risk may be concentrated where more vectors are positive for a given pathogen. When assessing species distributions, the choice of modeling framework and spatial layers used to make predictions are important. We first updated the modeled distribution of D. variabilis and R. montanensis using maximum entropy (MaxEnt), refining bioclimatic data inputs, and including soil variables. We then compared geospatial predictions from five species distribution modeling frameworks. In contrast to previous work, we additionally assessed whether the R. montanensis positive D. variabilis distribution is nested within a larger overall D. variabilis distribution, representing a fitness cost hypothesis. We found that 1) adding soil layers improved the accuracy of the MaxEnt model; 2) the predicted 'infected niche' was smaller than the overall predicted niche across all models; and 3) each model predicted different sizes of suitable niche, at different levels of probability. Importantly, the models were not directly comparable in output style, which could create confusion in interpretation when developing planning tools. The random forest (RF) model had the best measured validity and fit, suggesting it may be most appropriate to these data.
Collapse
Affiliation(s)
- Catherine A Lippi
- Quantitative Disease Ecology and Conservation (QDEC) Lab Group, Department of Geography, University of Florida, Gainesville, FL
- Emerging Pathogens Institute, University of Florida, Gainesville, FL
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban, South Africa
| | - Alexis L White
- Quantitative Disease Ecology and Conservation (QDEC) Lab Group, Department of Geography, University of Florida, Gainesville, FL
- Emerging Pathogens Institute, University of Florida, Gainesville, FL
| | - Heidi K St. John
- Viral and Rickettsial Disease Program (VRDD) Naval Medical Research Center, Silver Spring, MD
- Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Dr, Bethesda, MD
| | - Allen L Richards
- Viral and Rickettsial Disease Program (VRDD) Naval Medical Research Center, Silver Spring, MD
| | - Sadie J Ryan
- Quantitative Disease Ecology and Conservation (QDEC) Lab Group, Department of Geography, University of Florida, Gainesville, FL
- Emerging Pathogens Institute, University of Florida, Gainesville, FL
- School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
- Corresponding author, e-mail:
| |
Collapse
|
10
|
Espada C, Cummins H, Gonzales JA, Notto L, Gaff HD. A Comparison of Tick Collection Materials and Methods in Southeastern Virginia. J Med Entomol 2021; 58:692-698. [PMID: 33017464 PMCID: PMC7954099 DOI: 10.1093/jme/tjaa207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Indexed: 06/11/2023]
Abstract
In field studies of tick ecology, observed patterns may be biased by sampling methods. Results can vary by species, life stage, and habitat, and understanding these biases will improve comparisons of data across studies as well as assessment of human disease risk. A direct comparison of flagging versus dragging was conducted in southeastern Virginia. Transects were surveyed over a 6-wk period to identify differences in species and life stage collected, as well as differences between corduroy and denim material and inspection method for drags. Flagging collected more Ixodes affinis Neumann (Acari: Ixodidae) adults and Amblyomma americanum L. (Acari: Ixodidae) adults than dragging. Ground inspection was more efficient than tree inspection for collection of I. affinis adults, with no significant difference in inspection method for any other species or life stage. Corduroy was found to be more effective than denim in collecting nymphal A. americanum, although this may be an artifact of three large samples for corduroy collection of these ticks. There was no significant difference in Ixodes scapularis Say (Acari: Ixodidae) collection in any comparison. Dragging, tree inspection, and denim were not found to be more efficient in any scenario. This is the first comparison of flagging and dragging conducted in the southeastern United States. The community composition of ticks in this region greatly differs from regions where studies of these commonly used sampling techniques have been conducted. As the distributions of ticks continue to change over time, it will be important to evaluate best practices annually.
Collapse
Affiliation(s)
- Christina Espada
- Department of Biological Sciences, Old Dominion University, Norfolk, VA
| | - Hannah Cummins
- Department of Biological Sciences, Old Dominion University, Norfolk, VA
| | - Jon A Gonzales
- Department of Biological Sciences, Old Dominion University, Norfolk, VA
| | - Leo Notto
- Department of Biological Sciences, Old Dominion University, Norfolk, VA
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban, South Africa
| |
Collapse
|
11
|
Lippi CA, Gaff HD, White AL, Ryan SJ. Scoping review of distribution models for selected Amblyomma ticks and rickettsial group pathogens. PeerJ 2021; 9:e10596. [PMID: 33643699 PMCID: PMC7896504 DOI: 10.7717/peerj.10596] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 11/26/2020] [Indexed: 01/23/2023] Open
Abstract
The rising prevalence of tick-borne diseases in humans in recent decades has called attention to the need for more information on geographic risk for public health planning. Species distribution models (SDMs) are an increasingly utilized method of constructing potential geographic ranges. There are many knowledge gaps in our understanding of risk of exposure to tick-borne pathogens, particularly for those in the rickettsial group. Here, we conducted a systematic scoping review of the SDM literature for rickettsial pathogens and tick vectors in the genus Amblyomma. Of the 174 reviewed articles, only 24 studies used SDMs to estimate the potential extent of vector and/or pathogen ranges. The majority of studies (79%) estimated only tick distributions using vector presence as a proxy for pathogen exposure. Studies were conducted at different scales and across multiple continents. Few studies undertook original data collection, and SDMs were mostly built with presence-only datasets from public database or surveillance sources. The reliance on existing data sources, using ticks as a proxy for disease risk, may simply reflect a lag in new data acquisition and a thorough understanding of the tick-pathogen ecology involved.
Collapse
Affiliation(s)
- Catherine A. Lippi
- Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Holly D. Gaff
- Department of Biology, Old Dominion University, Norfolk, VA, USA
- School of Mathematics, Statistics and Computer Science, University of Kwa-Zulu Natal, Durban, South Africa
| | - Alexis L. White
- Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| | - Sadie J. Ryan
- Department of Geography, University of Florida, Gainesville, FL, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, FL, USA
| |
Collapse
|
12
|
Cumbie AN, Espada CD, Nadolny RM, Rose RK, Dueser RD, Hynes WL, Gaff HD. Survey of Rickettsia parkeri and Amblyomma maculatum associated with small mammals in southeastern Virginia. Ticks Tick Borne Dis 2020; 11:101550. [PMID: 32993923 PMCID: PMC7534852 DOI: 10.1016/j.ttbdis.2020.101550] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/02/2020] [Accepted: 08/27/2020] [Indexed: 11/29/2022]
Abstract
Small mammals are often parasitized by the immature stages of hard-bodied ticks (family Ixodidae) and may serve as reservoir hosts of tick-borne pathogens. Amblyomma maculatum, the Gulf Coast tick, is the primary vector of Rickettsia parkeri, the causative agent of R. parkeri rickettsiosis. This hard-bodied tick species is expanding its historical range from the Gulf Coast of the U.S. up the Mid-Atlantic coast. In Mid-Atlantic states, such as Virginia, R. parkeri prevalence is higher in these ticks than those found in its historical range. This high prevalence may be explained in part by small mammal populations. In this study, small mammals were trapped and checked for the presence of immature A. maculatum. The ticks as well as tissue samples from these mammals were tested for the presence of R. parkeri. This study found six rodent species acting as hosts to immature A. maculatum and three species that may play a role in the enzootic cycle of R. parkeri in Virginia.
Collapse
Affiliation(s)
- Alexandra N Cumbie
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA
| | - Christina D Espada
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA
| | - Robyn M Nadolny
- Army Public Health Center, Aberdeen Proving Ground, MD, 21010, USA
| | - Robert K Rose
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA
| | - Raymond D Dueser
- Department of Environmental Sciences, University of Virginia, Charlottesville, VA, 22901, USA
| | - Wayne L Hynes
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA.
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA; School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban, South Africa
| |
Collapse
|
13
|
Benham SA, Gaff HD, Bement ZJ, Blaise C, Cummins HK, Ferrara R, Moreno J, Parker E, Phan A, Rose T, Azher S, Price D, Gauthier DT. Comparative population genetics of Amblyomma maculatum and Amblyomma americanum in the mid-Atlantic United States. Ticks Tick Borne Dis 2020; 12:101600. [PMID: 33181442 DOI: 10.1016/j.ttbdis.2020.101600] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 10/07/2020] [Accepted: 10/16/2020] [Indexed: 12/21/2022]
Abstract
The Gulf Coast tick, Amblyomma maculatum, is undergoing a northward expansion along the United States East Coast, most recently establishing populations in Virginia, Maryland, and Delaware. This expansion has human health implications, as A. maculatum is the primary natural vector of the bacterium Rickettsia parkeri, which causes a spotted fever-type rickettsiosis. Newly established populations of A. maculatum in Virginia tend to have high prevalence of R. parkeri, compared to lower infection rates in the historical range. The factors contributing to high R. parkeri prevalence in Virginia are not known. Investigating connectivity between sites colonized with A. maculatum can help determine whether sites with higher prevalence are isolated or well-connected through migration, thus serving as a source of infected individuals. We characterized 16S rRNA haplotypes of A. maculatum and, for comparison, the congeneric Amblyomma americanum collected from sites where these species co-occur. We then explored connectivity and genetic structure among Virginia populations using pairwise ΦST and AMOVA analyses. Our study identified one recently restored native grassland site with low A. maculatum haplotype diversity and strong evidence of a founder effect, whereas most sites are haplotypically diverse but with no clear genetic structure or connectivity between sites. These findings contrast with high connectivity and a slight mainland/island structure among A. americanum populations. Our results suggest that A. maculatum populations occasionally arise following long-distance drop-offs of few individual ticks in suitable habitat, but no clear migration patterns were observed. The distinct population genetic patterns between species might result from differences in host utilization.
Collapse
Affiliation(s)
- Sara A Benham
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States; School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban, South Africa
| | - Zachary J Bement
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
| | - Christian Blaise
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
| | - Hannah K Cummins
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
| | - Rebecca Ferrara
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
| | - Joshua Moreno
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
| | - Erika Parker
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
| | - Anna Phan
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
| | - Tori Rose
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
| | - Sarah Azher
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
| | - Delonta Price
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States
| | - David T Gauthier
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States.
| |
Collapse
|
14
|
Cumbie AN, Walters EL, Gaff HD, Hynes WL. First report of Candidatus Rickettsia mendelii in Ixodes brunneus from the United States. Ticks Tick Borne Dis 2019; 11:101309. [PMID: 31591070 DOI: 10.1016/j.ttbdis.2019.101309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 08/02/2019] [Accepted: 09/26/2019] [Indexed: 11/17/2022]
Abstract
Candidatus Rickettsia mendelii is a novel rickettsial species recently identified in Ixodes ricinus. In this study, Ixodes brunneus collected from wild birds (n = 77 ticks) or vegetation (n = 4 ticks) in southeastern Virginia were surveyed for rickettsial agents. Candidatus Rickettsia mendelii was confirmed in I. brunneus through sequencing of the gltA and 16S rRNA genes. This is the first report of this rickettsial species in Ixodes ticks in North America.
Collapse
Affiliation(s)
- Alexandra N Cumbie
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA
| | - Eric L Walters
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA
| | - Wayne L Hynes
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA.
| |
Collapse
|
15
|
Affiliation(s)
- Erin L. Heller
- Department of Biological SciencesOld Dominion UniversityNorfolkVA23529USA
| | - Holly D. Gaff
- Department of Biological SciencesOld Dominion UniversityNorfolkVA23529USA
| | | | - Eric L. Walters
- Department of Biological SciencesOld Dominion UniversityNorfolkVA23529USA
| |
Collapse
|
16
|
Hecht JA, Allerdice MEJ, Dykstra EA, Mastel L, Eisen RJ, Johnson TL, Gaff HD, Varela-Stokes AS, Goddard J, Pagac BB, Paddock CD, Karpathy SE. Multistate Survey of American Dog Ticks ( Dermacentor variabilis) for Rickettsia Species. Vector Borne Zoonotic Dis 2019; 19:652-657. [PMID: 30942664 DOI: 10.1089/vbz.2018.2415] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
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 assay. Sequencing of ompA gene amplicons generated using a seminested PCR assay was used to determine the rickettsial species present in positive samples not already identified by species-specific real-time assays. A total of 87 (9.9%) tick extracts contained R. bellii DNA and 203 (23%) contained DNA of other rickettsial species, including 47 (5.3%) with Rickettsia montanensis, 11 (1.2%) with Rickettsia amblyommatis, 2 (0.2%) with Rickettsia rhipicephali, and 3 (0.3%) with Rickettsia parkeri. Only 1 (0.1%) tick extract contained DNA of R. rickettsii. These data support multiple other contemporary studies that indicate infrequent detection of R. rickettsii in D. variabilis in North America.
Collapse
Affiliation(s)
- Joy A Hecht
- Rickettsial Zoonoses Branch, National Center for Emerging and Zoonotic Infectious Disease, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Michelle E J Allerdice
- Rickettsial Zoonoses Branch, National Center for Emerging and Zoonotic Infectious Disease, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Elizabeth A Dykstra
- Zoonotic Disease Program, Washington State Department of Health, Olympia, Washington
| | - Laura Mastel
- Division of Microbiology Lab Services, North Dakota Department of Health, Bismarck, North Dakota
| | - Rebecca J Eisen
- Bacterial Diseases Branch, National Center for Emerging and Zoonotic Infectious Disease, Centers for Disease Control and Prevention, Ft. Collins, Colorado
| | - Tammi L Johnson
- Bacterial Diseases Branch, National Center for Emerging and Zoonotic Infectious Disease, Centers for Disease Control and Prevention, Ft. Collins, Colorado
| | | | - Andrea S Varela-Stokes
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, Mississippi
| | - Jerome Goddard
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Mississippi State, Mississippi
| | | | - Christopher D Paddock
- Rickettsial Zoonoses Branch, National Center for Emerging and Zoonotic Infectious Disease, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Sandor E Karpathy
- Rickettsial Zoonoses Branch, National Center for Emerging and Zoonotic Infectious Disease, Centers for Disease Control and Prevention, Atlanta, Georgia
| |
Collapse
|
17
|
Bidder LA, Asmussen KM, Campbell SE, Goffigan KA, Gaff HD. Assessing the underwater survival of two tick species, Amblyomma americanum and Amblyomma maculatum. Ticks Tick Borne Dis 2018; 10:18-22. [PMID: 30181095 DOI: 10.1016/j.ttbdis.2018.08.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 08/19/2018] [Accepted: 08/27/2018] [Indexed: 10/28/2022]
Abstract
The hard (ixodid) ticks Amblyomma americanum and Amblyomma maculatum are found throughout the southeastern United States. To study the effects of water inundation, which is an increasingly common phenomenon in many coastal areas, unfed adult A. americanum and A. maculatum ticks were tested for survival by submergence in three water conditions: freshwater, brackish water, and saltwater. The results demonstrated a significant difference in survival between the two species in all three water conditions, with A. maculatum ticks surviving a shorter time underwater than A. americanum ticks. There is also a significant difference in A. americanum survival among the different water conditions, with the highest mortality in saltwater and the lowest in freshwater. Amblyomma americanum ticks survived the longest in freshwater (70 d), followed by brackish water (64 d), and the shortest survival was in saltwater (46 d), while the longest any A. maculatum tick survived was 24 d in freshwater. These findings demonstrate that any short-term flooding events, e.g., less than a week, would not likely eliminate these species of ticks in the flooded area.
Collapse
Affiliation(s)
- Lindsey A Bidder
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| | - Kristine M Asmussen
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| | - Sean E Campbell
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| | - Katerina A Goffigan
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| | - Holly D Gaff
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA.
| |
Collapse
|
18
|
Abstract
The Gulf Coast tick Amblyomma maculatum Koch is increasingly relevant to medical and veterinary communities as human infection rates of Rickettsia parkeri rise, the risk of introduction of Ehrlichia ruminantium increases, and the range of this tick expands into the densely populated Mid-Atlantic region of the United States. We report on the results of five years of field surveillance to better describe the ecology of A. maculatum in newly established populations in southeastern Virginia. We document habitat preferences, host preferences, and the phenology of the adult human-biting life stage. We discuss key ecological factors needed for A. maculatum establishment and the influence of the successional process and anthropogenic activities on the persistence of A. maculatum populations in Virginia.
Collapse
Affiliation(s)
- Robyn M Nadolny
- Old Dominion University, Department of Biological Sciences, Norfolk, VA USA; U.S. Army Public Health Center Tick-Borne Disease Laboratory, Aberdeen Proving Ground, MD USA.
| | - Holly D Gaff
- Old Dominion University, Department of Biological Sciences, Norfolk, VA USA; University of KwaZulu-Natal, School of Mathematics, Statistics, and Computer Sciences, Durban, South Africa
| |
Collapse
|
19
|
Nadolny RM, Gaff HD. Natural history of Ixodes affinis in Virginia. Ticks Tick Borne Dis 2018; 9:109-119. [DOI: 10.1016/j.ttbdis.2017.09.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 09/13/2017] [Accepted: 09/28/2017] [Indexed: 10/18/2022]
|
20
|
Shannon AB, Rucinsky R, Gaff HD, Brinkerhoff RJ. Borrelia miyamotoi, Other Vector-Borne Agents in Cat Blood and Ticks in Eastern Maryland. Ecohealth 2017; 14:816-820. [PMID: 28879619 DOI: 10.1007/s10393-017-1268-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 05/25/2017] [Accepted: 07/01/2017] [Indexed: 06/07/2023]
Abstract
We collected blood and tick samples in eastern Maryland to quantify vector-borne pathogen exposure and infection in healthy cats and to assess occupational disease risk to veterinary professionals and others who regularly interact with household pets. Thirty-six percent of healthy cats parasitized by ticks at time of examination (9/25) were exposed to, and 14% of bloods (7/49) tested PCR-positive for, at least one vector-borne pathogen including several bloods and ticks with Borrelia miyamotoi, a recently recognized tick-borne zoonotic bacterium. There was no indication that high tick burdens were associated with exposure to vector-borne pathogens. Our results underscore the potential importance of cats to human vector-borne disease risk.
Collapse
Affiliation(s)
- Avery B Shannon
- Department of Biology, University of Richmond, Richmond, VA, 23173, USA
| | | | - Holly D Gaff
- Department of Biology, Old Dominion University, Norfolk, VA, USA
- School of Mathematics, Statistics, and Computer Science, University of KwaZulu-Natal, Durban, South Africa
| | - R Jory Brinkerhoff
- Department of Biology, University of Richmond, Richmond, VA, 23173, USA.
- School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa.
| |
Collapse
|
21
|
Maliyoni M, Chirove F, Gaff HD, Govinder KS. A Stochastic Tick-Borne Disease Model: Exploring the Probability of Pathogen Persistence. Bull Math Biol 2017; 79:1999-2021. [PMID: 28707219 DOI: 10.1007/s11538-017-0317-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 07/03/2017] [Indexed: 11/25/2022]
Abstract
We formulate and analyse a stochastic epidemic model for the transmission dynamics of a tick-borne disease in a single population using a continuous-time Markov chain approach. The stochastic model is based on an existing deterministic metapopulation tick-borne disease model. We compare the disease dynamics of the deterministic and stochastic models in order to determine the effect of randomness in tick-borne disease dynamics. The probability of disease extinction and that of a major outbreak are computed and approximated using the multitype Galton-Watson branching process and numerical simulations, respectively. Analytical and numerical results show some significant differences in model predictions between the stochastic and deterministic models. In particular, we find that a disease outbreak is more likely if the disease is introduced by infected deer as opposed to infected ticks. These insights demonstrate the importance of host movement in the expansion of tick-borne diseases into new geographic areas.
Collapse
Affiliation(s)
- Milliward Maliyoni
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Pietermaritzburg, 3201, South Africa.
| | - Faraimunashe Chirove
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Pietermaritzburg, 3201, South Africa
| | - Holly D Gaff
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Pietermaritzburg, 3201, South Africa.,Department of Biological Sciences, Old Dominion University, Norfolk, VA, 23529, USA
| | - Keshlan S Govinder
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Pietermaritzburg, 3201, South Africa
| |
Collapse
|
22
|
Walter KS, Pepin KM, Webb CT, Gaff HD, Krause PJ, Pitzer VE, Diuk-Wasser MA. Invasion of two tick-borne diseases across New England: harnessing human surveillance data to capture underlying ecological invasion processes. Proc Biol Sci 2016; 283:20160834. [PMID: 27252022 PMCID: PMC4920326 DOI: 10.1098/rspb.2016.0834] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 05/09/2016] [Indexed: 11/12/2022] Open
Abstract
Modelling the spatial spread of vector-borne zoonotic pathogens maintained in enzootic transmission cycles remains a major challenge. The best available spatio-temporal data on pathogen spread often take the form of human disease surveillance data. By applying a classic ecological approach-occupancy modelling-to an epidemiological question of disease spread, we used surveillance data to examine the latent ecological invasion of tick-borne pathogens. Over the last half-century, previously undescribed tick-borne pathogens including the agents of Lyme disease and human babesiosis have rapidly spread across the northeast United States. Despite their epidemiological importance, the mechanisms of tick-borne pathogen invasion and drivers underlying the distinct invasion trajectories of the co-vectored pathogens remain unresolved. Our approach allowed us to estimate the unobserved ecological processes underlying pathogen spread while accounting for imperfect detection of human cases. Our model predicts that tick-borne diseases spread in a diffusion-like manner with occasional long-distance dispersal and that babesiosis spread exhibits strong dependence on Lyme disease.
Collapse
Affiliation(s)
- Katharine S Walter
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT 06520, USA
| | - Kim M Pepin
- United States Department of Agriculture Animal and Plant Health Inspection Service, National Wildlife Research Center, 4101 LaPorte Avenue, Fort Collins, CO 80521, USA Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Colleen T Webb
- Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA Department of Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, 302a Mills Godwin Building, Norfolk, VA 23529, USA
| | - Peter J Krause
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT 06520, USA
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT 06520, USA Fogarty International Center, National Institutes of Health, Bethesda, MD 20892, USA
| | - Maria A Diuk-Wasser
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College Street, New Haven, CT 06520, USA Department of Ecology, Evolution, and Environmental Biology, Columbia University, 1200 Amsterdam Avenue, New York, NY 10027, USA
| |
Collapse
|
23
|
Springer YP, Hoekman D, Johnson PTJ, Duffy PA, Hufft RA, Barnett DT, Allan BF, Amman BR, Barker CM, Barrera R, Beard CB, Beati L, Begon M, Blackmore MS, Bradshaw WE, Brisson D, Calisher CH, Childs JE, Diuk‐Wasser M, Douglass RJ, Eisen RJ, Foley DH, Foley JE, Gaff HD, Gardner SL, Ginsberg HS, Glass GE, Hamer SA, Hayden MH, Hjelle B, Holzapfel CM, Juliano SA, Kramer LD, Kuenzi AJ, LaDeau SL, Livdahl TP, Mills JN, Moore CG, Morand S, Nasci RS, Ogden NH, Ostfeld RS, Parmenter RR, Piesman J, Reisen WK, Savage HM, Sonenshine DE, Swei A, Yabsley MJ. Tick‐, mosquito‐, and rodent‐borne parasite sampling designs for the National Ecological Observatory Network. Ecosphere 2016. [DOI: 10.1002/ecs2.1271] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
|
24
|
Campana MG, Hawkins MTR, Henson LH, Stewardson K, Young HS, Card LR, Lock J, Agwanda B, Brinkerhoff J, Gaff HD, Helgen KM, Maldonado JE, McShea WJ, Fleischer RC. Simultaneous identification of host, ectoparasite and pathogen DNA via in-solution capture. Mol Ecol Resour 2016; 16:1224-39. [DOI: 10.1111/1755-0998.12524] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 01/08/2016] [Accepted: 01/19/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Michael G. Campana
- Center for Conservation and Evolutionary Genetics; Smithsonian Conservation Biology Institute; 3001 Connecticut Avenue NW Washington DC 20008 USA
| | - Melissa T. R. Hawkins
- Center for Conservation and Evolutionary Genetics; Smithsonian Conservation Biology Institute; 3001 Connecticut Avenue NW Washington DC 20008 USA
- Division of Mammals; National Museum of Natural History; Smithsonian Institution; MRC 108, P.O. Box 37012 Washington DC 20013-7012 USA
| | - Lauren H. Henson
- Center for Conservation and Evolutionary Genetics; Smithsonian Conservation Biology Institute; 3001 Connecticut Avenue NW Washington DC 20008 USA
| | - Kristin Stewardson
- Center for Conservation and Evolutionary Genetics; Smithsonian Conservation Biology Institute; 3001 Connecticut Avenue NW Washington DC 20008 USA
| | - Hillary S. Young
- Department of Ecology, Evolution and Marine Biology; University of California Santa Barbara; Santa Barbara CA 93106 USA
| | - Leah R. Card
- Smithsonian Conservation Biology Institute; National Zoological Park; 1500 Remount Rd. Front Royal VA 22630 USA
| | - Justin Lock
- Center for Conservation and Evolutionary Genetics; Smithsonian Conservation Biology Institute; 3001 Connecticut Avenue NW Washington DC 20008 USA
| | | | - Jory Brinkerhoff
- Department of Biology; B322 Gottwald Center for the Sciences; University of Richmond; 28 Westhampton Way Richmond VA 23173 USA
| | - Holly D. Gaff
- Department of Biological Sciences; Old Dominion University; Norfolk VA 23529 USA
| | - Kristofer M. Helgen
- Division of Mammals; National Museum of Natural History; Smithsonian Institution; MRC 108, P.O. Box 37012 Washington DC 20013-7012 USA
| | - Jesús E. Maldonado
- Center for Conservation and Evolutionary Genetics; Smithsonian Conservation Biology Institute; 3001 Connecticut Avenue NW Washington DC 20008 USA
- Division of Mammals; National Museum of Natural History; Smithsonian Institution; MRC 108, P.O. Box 37012 Washington DC 20013-7012 USA
| | - William J. McShea
- Smithsonian Conservation Biology Institute; National Zoological Park; 1500 Remount Rd. Front Royal VA 22630 USA
| | - Robert C. Fleischer
- Center for Conservation and Evolutionary Genetics; Smithsonian Conservation Biology Institute; 3001 Connecticut Avenue NW Washington DC 20008 USA
| |
Collapse
|
25
|
Heller EL, Wright CL, Nadolny RM, Hynes WL, Gaff HD, Walters EL. New Records of Ixodes affinis (Acari: Ixodidae) Parasitizing Avian Hosts in Southeastern Virginia. J Med Entomol 2016; 53:441-445. [PMID: 26586535 DOI: 10.1093/jme/tjv175] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Ixodes affinis Neumann (Acari: Ixodidae) is a hard-bodied tick species distributed throughout much of the southeastern United States. Although I. affinis does not parasitize humans, it is a competent vector of Borrelia burgdorferi sensu stricto, the causative-agent of Lyme disease, and thus contributes to the enzootic maintenance of this pathogen. This study presents evidence of I. affinis parasitizing five new host passerine species. During 2012-2014, 1,888 birds were captured and examined for ticks, and 18 immature I. affinis were collected from 12 birds-six Carolina Wrens (Thyrothorus ludovicianus); two Brown Thrashers (Toxostoma rufum); and one American Robin (Turdus migratorius), Eastern Towhee (Pipilo erythrophthalmus), Northern Cardinal (Cardinalis cardinalis), and White-throated Sparrow (Zonotrichia albicollis). Of 15 larvae and 3 nymphs collected, one nymph tested positive for B. burgdorferi DNA. I. affinis was found co-feeding on birds with immature Amblyomma americanum (L.), Ixodes brunneus Koch, Ixodes dentatus Marx, Ixodes scapularis Say, and Haemaphysalis leporispalustris Packard. The results of this research provide a better understanding of I. affinis hosts and identify avian taxa that may play a role in the maintenance and dispersal of this tick species.
Collapse
|
26
|
Wright CL, Sonenshine DE, Gaff HD, Hynes WL. Rickettsia parkeri Transmission to Amblyomma americanum by Cofeeding with Amblyomma maculatum (Acari: Ixodidae) and Potential for Spillover. J Med Entomol 2015; 52:1090-1095. [PMID: 26336226 DOI: 10.1093/jme/tjv086] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 06/08/2015] [Indexed: 06/05/2023]
Abstract
Amblyomma americanum (L.) is a human-biting ixodid tick distributed throughout much of the southeastern United States. Rickettsia parkeri is a member of the spotted fever group rickettsiae and causes a febrile illness in humans commonly referred to as "Tidewater spotted fever" or "R. parkeri rickettsiosis." Although the Gulf Coast tick, Amblyomma maculatum Koch, is the primary vector of R. parkeri, a small proportion of A. americanum have also been shown to harbor R. parkeri. The purpose of this investigation was to determine whether R. parkeri is spilling over into A. americanum in eastern Virginia and also to determine through laboratory experiments, whether A. americanum can acquire R. parkeri by cofeeding alongside infected ticks. Of 317 wild-caught, flat adult A. americanum tested from 29 counties and independent cities in coastal Virginia, a single female A. americanum was positive for R. parkeri, suggesting that R. parkeri is spilling over into this species, but at very low rates (<1.0%). Laboratory studies using guinea pigs indicated that nymphal A. americanum were able to acquire R. parkeri while feeding alongside infected A. maculatum and then transstadially maintain the infection. Nymphal A. americanum infected with Rickettsia amblyommii, however, were less likely to acquire R. parkeri, suggesting that infection with R. amblyommii may prevent R. parkeri from establishing infection in A. americanum.
Collapse
Affiliation(s)
- Chelsea L Wright
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529
| | - Daniel E Sonenshine
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529. School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, University Road, Westville, Durban 4000, South Africa
| | - Wayne L Hynes
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529. Corresponding author, e-mail:
| |
Collapse
|
27
|
Nadolny RM, Feldman KA, Pagac B, Stromdahl EY, Rutz H, Wee SB, Richards AL, Smith J, Armolt M, Gaff HD. Review of the Mid-Atlantic Tick Summit III: A model for regional information sharing. Ticks Tick Borne Dis 2015; 6:435-8. [PMID: 25920376 DOI: 10.1016/j.ttbdis.2015.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 03/31/2015] [Accepted: 04/02/2015] [Indexed: 11/16/2022]
Abstract
Ticks are the most significant vectors of infectious diseases in the United States, inspiring many researchers to study aspects of their biology, ecology, and their effects on public health. However, regional differences in tick abundance and pathogen infection prevalence result in the inability to assume results from one area are relevant in another. Current local information on tick ranges, infection rates, and human cases is needed to assess tick-borne disease risk in any given region. The Mid-Atlantic Tick Summit III brought together over 100 area experts and researchers to share regional updates on ticks and their associated pathogens. We report some meeting highlights here. Regional meetings foster cross-disciplinary collaborations that benefit the community, and open novel lines of inquiry so that tick-bite risk can be reduced and tick-borne diseases can be treated effectively.
Collapse
Affiliation(s)
- Robyn M Nadolny
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States; U.S. Army Public Health Command, Aberdeen Proving Ground, MD, United States
| | - Katherine A Feldman
- Center for Zoonotic and Vector-borne Diseases, Maryland Department of Health and Mental Hygiene, Baltimore, MD, United States
| | - Benedict Pagac
- U.S. Army Public Health Command, Aberdeen Proving Ground, MD, United States
| | - Ellen Y Stromdahl
- U.S. Army Public Health Command, Aberdeen Proving Ground, MD, United States
| | - Heather Rutz
- Center for Zoonotic and Vector-borne Diseases, Maryland Department of Health and Mental Hygiene, Baltimore, MD, United States
| | - Siok-Bi Wee
- Center for Zoonotic and Vector-borne Diseases, Maryland Department of Health and Mental Hygiene, Baltimore, MD, United States
| | - Allen L Richards
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD, United States
| | - Joshua Smith
- Fairfax County Health Department, Fairfax, VA, United States
| | - Mary Armolt
- Center for Zoonotic and Vector-borne Diseases, Maryland Department of Health and Mental Hygiene, Baltimore, MD, United States
| | - Holly D Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, United States.
| |
Collapse
|
28
|
Wright CL, Gaff HD, Hynes WL. Prevalence of Ehrlichia chaffeensis and Ehrlichia ewingii in Amblyomma americanum and Dermacentor variabilis collected from southeastern Virginia, 2010-2011. Ticks Tick Borne Dis 2014; 5:978-82. [PMID: 25155340 DOI: 10.1016/j.ttbdis.2014.07.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 07/21/2014] [Accepted: 07/31/2014] [Indexed: 11/29/2022]
Abstract
Amblyomma americanum is the most commonly encountered tick species in southeastern Virginia, representing approximately 95% of the human-biting tick population in this area. Here we investigated the prevalence of Ehrlichia chaffeensis and Ehrlichia ewingii in questing Amblyomma americanum and Dermacentor variabilis ticks collected from multiple sites in southeastern Virginia from 2010 to 2011. Although both Ehrlichia species were detected in Amblyomma americanum, no evidence of either pathogen was found in Dermacentor variabilis. Prevalence of E. chaffeensis varied by location, ranging from 0 to 5.08% among Amblyomma americanum populations. Ehrlichia ewingii prevalence was slightly higher, ranging from 0 to 8.20% among A. americanum populations. We conclude that both pathogens are established in southeastern Virginia A. americanum populations, and that although there are no apparent temporal trends in Ehrlichia prevalence, there is variation among locations, suggesting the potential for disease hotspots.
Collapse
Affiliation(s)
- Chelsea L Wright
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| | - Holly D Gaff
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| | - Wayne L Hynes
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA.
| |
Collapse
|
29
|
Tracy JK, Schluterman NH, Greene C, Sow SO, Gaff HD. Planning for human papillomavirus (HPV) vaccination in sub-Saharan Africa: A modeling-based approach. Vaccine 2014; 32:3316-22. [DOI: 10.1016/j.vaccine.2014.03.067] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 03/12/2014] [Accepted: 03/17/2014] [Indexed: 11/15/2022]
|
30
|
Nadolny RM, Wright CL, Sonenshine DE, Hynes WL, Gaff HD. Ticks and spotted fever group rickettsiae of southeastern Virginia. Ticks Tick Borne Dis 2013; 5:53-7. [PMID: 24201057 DOI: 10.1016/j.ttbdis.2013.09.001] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 09/04/2013] [Accepted: 09/06/2013] [Indexed: 10/26/2022]
Abstract
The incidence of tick-borne rickettsial disease in the southeastern United States has been rising steadily through the past decade, and the range expansions of tick species and tick-borne infectious agents, new and old, has resulted in an unprecedented mix of vectors and pathogens. The results of an ongoing 4-year surveillance project describe the relative abundance of questing tick populations in southeastern Virginia. Since 2009, more than 66,000 questing ticks of 7 species have been collected from vegetation in a variety of habitats, with Amblyomma americanum constituting over 95% of ticks collected. Other species represented included Ixodes scapularis, Dermacentor variabilis, Amblyomma maculatum, Ixodes affinis, Haemaphysalis leporispalustris, and Ixodes brunneus. We found that 26.9-54.9% of A. americanum ticks tested were positive for Rickettsia amblyommii, a non-pathogenic symbiont of this tick species. We also found no evidence of R. rickettsii in D. variabilis ticks, although they did show low infection rates of R. montanensis (1.5-2.0%). Rickettsia parkeri and Candidatus R. andeanae were found in 41.8-55.7% and 0-1.5% A. maculatum ticks, respectively. The rate of R. parkeri in A. maculatum ticks is among the highest in the literature and has increased in the 2 years since R. parkeri and A. maculatum were first reported in southeastern Virginia. We conclude that tick populations in southeastern Virginia have recently undergone dramatic changes in species and abundance and that these populations support a variety of rickettsial agents with the potential for increased risk to human health.
Collapse
Affiliation(s)
- Robyn M Nadolny
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| | - Chelsea L Wright
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| | - Daniel E Sonenshine
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| | - Wayne L Hynes
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| | - Holly D Gaff
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| |
Collapse
|
31
|
Wright CL, Hynes WL, White BT, Marshall MN, Gaff HD, Gauthier DT. Single-tube real-time PCR assay for differentiation of Ixodes affinis and Ixodes scapularis. Ticks Tick Borne Dis 2013; 5:48-52. [PMID: 24192510 DOI: 10.1016/j.ttbdis.2013.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Revised: 07/31/2013] [Accepted: 08/08/2013] [Indexed: 10/26/2022]
Abstract
Ixodes affinis Neumann (1899) and Ixodes scapularis Say (1821) are tick vectors of the etiologic agent of Lyme disease, Borrelia burgdorferi sensu stricto. Ixodes affinis and I. scapularis are morphologically very similar, and as they are sympatric in the mid- and south-Atlantic U.S. coastal states, their accurate identification is crucial to studies of disease and vector ecology in this area. This work describes a rapid, single-tube SYBR(®) Green-based real-time PCR assay for differentiation of I. affinis and I. scapularis at all life stages. The assay employs 2 pairs of species-specific primers directed against the internal transcribed spacer 2 (ITS2) region of the nuclear rRNA operon. Amplification products for these primer pairs differ in size and may be differentiated with a melt curve analysis. This tool is intended as a supplement to morphological methods for accurate identification of these ticks.
Collapse
Affiliation(s)
- Chelsea L Wright
- Old Dominion University, Department of Biological Sciences, Norfolk, VA 23529, USA
| | | | | | | | | | | |
Collapse
|
32
|
Hartley DM, Barker CM, Le Menach A, Niu T, Gaff HD, Reisen WK. Effects of temperature on emergence and seasonality of West Nile virus in California. Am J Trop Med Hyg 2012; 86:884-94. [PMID: 22556092 PMCID: PMC3335698 DOI: 10.4269/ajtmh.2012.11-0342] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 02/04/2012] [Indexed: 11/07/2022] Open
Abstract
Temperature has played a critical role in the spatiotemporal dynamics of West Nile virus transmission throughout California from its introduction in 2003 through establishment by 2009. We compared two novel mechanistic measures of transmission risk, the temperature-dependent ratio of virus extrinsic incubation period to the mosquito gonotrophic period (BT), and the fundamental reproductive ratio (R(0)) based on a mathematical model, to analyze spatiotemporal patterns of receptivity to viral amplification. Maps of BT and R(0) were created at 20-km scale and compared throughout California to seroconversions in sentinel chicken flocks at half-month intervals. Overall, estimates of BT and R(0) agreed with intensity of transmission measured by the frequency of sentinel chicken seroconversions. Mechanistic measures such as these are important for understanding how temperature affects the spatiotemporal dynamics of West Nile virus transmission and for delineating risk estimates useful to inform vector control agency intervention decisions and communicate outbreak potential.
Collapse
Affiliation(s)
- David M Hartley
- Georgetown University Medical Center, Washington, District of Columbia 20057, USA.
| | | | | | | | | | | |
Collapse
|
33
|
Luce-Fedrow A, Wright C, Gaff HD, Sonenshine DE, Hynes WL, Richards AL. In vitropropagation ofCandidatusRickettsia andeanae isolated fromAmblyomma maculatum. ACTA ACUST UNITED AC 2012; 64:74-81. [DOI: 10.1111/j.1574-695x.2011.00905.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Revised: 11/02/2011] [Accepted: 11/04/2011] [Indexed: 11/29/2022]
|
34
|
Nadolny RM, Wright CL, Hynes WL, Sonenshine DE, Gaff HD. Ixodes affinis (Acari: Ixodidae) in southeastern Virginia and implications for the spread of Borrelia burgdorferi, the agent of Lyme disease. J Vector Ecol 2011; 36:464-467. [PMID: 22129422 DOI: 10.1111/j.1948-7134.2011.00191.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Affiliation(s)
- Robyn M Nadolny
- Department of Biological Sciences, Old Dominion University, Norfolk, VA 23529, USA
| | | | | | | | | |
Collapse
|
35
|
Wright CL, Nadolny RM, Jiang J, Richards AL, Sonenshine DE, Gaff HD, Hynes WL. Rickettsia parkeri in gulf coast ticks, southeastern Virginia, USA. Emerg Infect Dis 2011; 17:896-8. [PMID: 21529406 PMCID: PMC3321792 DOI: 10.3201/eid1705.101836] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
We report evidence that Amblyomma maculatum tick populations are well established in southeastern Virginia. We found that 43.1% of the adult Gulf Coast ticks collected in the summer of 2010 carried Rickettsia parkeri, suggesting that persons living in or visiting southeastern Virginia are at risk for infection with this pathogen.
Collapse
Affiliation(s)
- Chelsea L Wright
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia 23529, USA
| | | | | | | | | | | | | |
Collapse
|
36
|
Tracy L, Gaff HD, Burgess C, Sow S, Gravitt PE, Tracy JK. Estimating the impact of human papillomavirus (HPV) vaccination on HPV prevalence and cervical cancer incidence in Mali. Clin Infect Dis 2011; 52:641-5. [PMID: 21252142 DOI: 10.1093/cid/ciq190] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Human papillomavirus vaccines have potential to reduce cervical cancer incidence and mortality; however, cultural and economic barriers may hinder success in developing countries. We assessed impact of a single vaccine campaign in Mali with use of mathematical modeling. Our model shows that decreases in the prevalence of Human papillomavirus infection are proportional to achieved vaccination coverage.
Collapse
Affiliation(s)
- LaRee Tracy
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, Maryland, USA.
| | | | | | | | | | | |
Collapse
|
37
|
Jungck JR, Gaff HD, Fagen AP, Labov JB. "Beyond BIO2010: Celebration and Opportunities" at the intersection of mathematics and biology. CBE Life Sci Educ 2010; 9:143-7. [PMID: 20810941 PMCID: PMC2931655 DOI: 10.1187/cbe.10-06-0079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Affiliation(s)
- John R Jungck
- Department of Biology, Beloit College, Beloit, WI 53511, USA.
| | | | | | | |
Collapse
|
38
|
Furuno JP, Harris AD, Wright MO, Hartley DM, McGregor JC, Gaff HD, Hebden JN, Standiford HC, Perencevich EN. Value of performing active surveillance cultures on intensive care unit discharge for detection of methicillin-resistant Staphylococcus aureus. Infect Control Hosp Epidemiol 2007; 28:666-70. [PMID: 17520538 DOI: 10.1086/518348] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2006] [Accepted: 11/08/2006] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To quantify the value of performing active surveillance cultures for detection of methicillin-resistant Staphylococcus aureus (MRSA) on intensive care unit (ICU) discharge. DESIGN Prospective cohort study. SETTING Medical ICU (MICU) and surgical ICU (SICU) of a tertiary care hospital. PARTICIPANTS We analyzed data on adult patients who were admitted to the MICU or SICU between January 17, 2001, and December 31, 2004. All participants had a length of ICU stay of at least 48 hours and had surveillance cultures of anterior nares specimens performed on ICU admission and discharge. Patients who had MRSA-positive clinical cultures in the ICU were excluded. RESULTS Of 2,918 eligible patients, 178 (6%) were colonized with MRSA on ICU admission, and 65 (2%) acquired MRSA in the ICU and were identified by results of discharge surveillance cultures. Patients with MRSA colonization confirmed by results of discharge cultures spent 853 days in non-ICU wards after ICU discharge, which represented 27% of the total number of MRSA colonization-days during hospitalization in non-ICU wards for patients discharged from the ICU. CONCLUSIONS Surveillance cultures of nares specimens collected at ICU discharge identified a large percentage of MRSA-colonized patients who would not have been identified on the basis of results of clinical cultures or admission surveillance cultures alone. Furthermore, these patients were responsible for a large percentage of the total number of MRSA colonization-days during hospitalization in non-ICU wards for patients discharged from the ICU.
Collapse
Affiliation(s)
- Jon P Furuno
- Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Abstract
Recent increases in reported outbreaks of tick-borne diseases have led to increased interest in understanding and controlling epidemics involving these transmission vectors. Mathematical disease models typically assume constant population size and spatial homogeneity. For tick-borne diseases, these assumptions are not always valid. The disease model presented here incorporates non-constant population sizes and spatial heterogeneity utilizing a system of differential equations that may be applied to a variety of spatial patches. We present analytical results for the one patch version and find parameter restrictions under which the populations and infected densities reach equilibrium. We then numerically explore disease dynamics when parameters are allowed to vary spatially and temporally and consider the effectiveness of various tick-control strategies.
Collapse
Affiliation(s)
- Holly D Gaff
- Department of Epidemiology and Preventive Medicine, School of Medicine, University of Maryland, 660 West Redwood Street, Howard Hall, Room 140D, Baltimore, MD 21201, USA.
| | | |
Collapse
|