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Wei H, Xiong T, Wang SS, Wang BH, Du LF, Xu Q, Zheng JJ, Cui XM, Jia N, Jiang JF, Shi W, Zhao L, Cao WC. Investigating the pathogens associated with Dermacentor nuttalli and its global distribution: A study integrating metagenomic sequencing, meta-analysis and niche modeling. Int J Parasitol Parasites Wildl 2024; 23:100907. [PMID: 38283887 PMCID: PMC10810740 DOI: 10.1016/j.ijppaw.2024.100907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 01/09/2024] [Accepted: 01/10/2024] [Indexed: 01/30/2024]
Abstract
Dermacentor nuttalli, a member of family Ixodidae and genus Dermacentor, is predominantly found in North Asia. It transmits various pathogens of human and animal diseases, such as Lymphocytic choriomeningitis mammarenavirus and Brucella ovis, leading to severe symptoms in patients and posing serious hazards to livestock husbandry. To profile pathogen abundances of wild D. nuttalli, metagenomic sequencing was performed of four field-collected tick samples, revealing that Rickettsia, Streptomyces, and Pseudomonas were the most abundant bacterial genera in D. nuttalli. Specifically, four nearly complete Rickettsia genomes were assembled, closely relative to Rickettsia conorii subsp. raoultii. Then, a comprehensive meta-analysis was performed to evaluate its potential threats based on detected pathogens and geographical distribution positions reported in literature, reference books, related websites, and field surveys. At least 48 pathogens were identified, including 20 species of bacteria, seven species of eukaryota, and 21 species of virus. Notably, Rickettsia conorii subsp. raoultii, Coxiella burnetii, and Brucella ovis displayed remarkably high positivity rates, which were known to cause infectious diseases in both humans and livestock. Currently, the primary distribution of D. nuttalli spans China, Mongolia, and Russia. However, an additional 14 countries in Asia and America that may also be affected by D. nuttalli were identified in our niche model, despite no previous reports of its presence in these areas. This study provides comprehensive data and analysis on the pathogens carried by D. nuttalli, along with documented and potential distribution, suggesting an emerging threat to public health and animal husbandry. Therefore, there is a need for heightened surveillance and thorough investigation of D. nuttalli.
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Affiliation(s)
- Hua Wei
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Tao Xiong
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Shan-Shan Wang
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Bai-Hui Wang
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Li-Feng Du
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Qing Xu
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Jia-Jing Zheng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Xiao-Ming Cui
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Na Jia
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Jia-Fu Jiang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Wenqiang Shi
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
| | - Lin Zhao
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Wu-Chun Cao
- Institute of EcoHealth, School of Public Health, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
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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] [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.
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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
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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 : THE PREPRINT SERVER FOR BIOLOGY 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] [Abstract] [Key Words] [Grants] [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.
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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
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Kopsco HL, Smith RL, Halsey SJ. A Scoping Review of Species Distribution Modeling Methods for Tick Vectors. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.893016] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BackgroundGlobally, tick-borne disease is a pervasive and worsening problem that impacts human and domestic animal health, livelihoods, and numerous economies. Species distribution models are useful tools to help address these issues, but many different modeling approaches and environmental data sources exist.ObjectiveWe conducted a scoping review that examined all available research employing species distribution models to predict occurrence and map tick species to understand the diversity of model strategies, environmental predictors, tick data sources, frequency of climate projects of tick ranges, and types of model validation methods.DesignFollowing the PRISMA-ScR checklist, we searched scientific databases for eligible articles, their references, and explored related publications through a graphical tool (www.connectedpapers.com). Two independent reviewers performed article selection and characterization using a priori criteria.ResultsWe describe data collected from 107 peer-reviewed articles that met our inclusion criteria. The literature reflects that tick species distributions have been modeled predominantly in North America and Europe and have mostly modeled the habitat suitability for Ixodes ricinus (n = 23; 21.5%). A wide range of bioclimatic databases and other environmental correlates were utilized among models, but the WorldClim database and its bioclimatic variables 1–19 appeared in 60 (56%) papers. The most frequently chosen modeling approach was MaxEnt, which also appeared in 60 (56%) of papers. Despite the importance of ensemble modeling to reduce bias, only 23 papers (21.5%) employed more than one algorithm, and just six (5.6%) used an ensemble approach that incorporated at least five different modeling methods for comparison. Area under the curve/receiver operating characteristic was the most frequently reported model validation method, utilized in nearly all (98.9%) included studies. Only 21% of papers used future climate scenarios to predict tick range expansion or contraction. Regardless of the representative concentration pathway, six of seven genera were expected to both expand and retract depending on location, while Ornithodoros was predicted to only expand beyond its current range.ConclusionSpecies distribution modeling techniques are useful and widely employed tools for predicting tick habitat suitability and range movement. However, the vast array of methods, data sources, and validation strategies within the SDM literature support the need for standardized protocols for species distribution and ecological niche modeling for tick vectors.
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Duncan KT, Grant A, Johnson B, Sundstrom KD, Saleh MN, Little SE. Identification of Rickettsia spp. and Babesia conradae in Dermacentor spp. Collected from Dogs and Cats Across the United States. Vector Borne Zoonotic Dis 2021; 21:911-920. [PMID: 34958266 PMCID: PMC8742288 DOI: 10.1089/vbz.2021.0047] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
In the United States, Dermacentor variabilis and Dermacentor andersoni are considered key vectors for Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever. Through regional surveillance, a wide diversity of Rickettsia spp. have been documented in D. variabilis, and Dermacentor spp. has been suggested as potential vectors for various other pathogens, including Babesia spp. and Ehrlichia canis. To better define the prevalence and diversity of pathogens in Dermacentor spp. across the United States, 848 ticks collected from dogs and cats in 44/50 states in 2018–2019 were tested by PCR for Rickettsia spp.-specific 17 kDa and ompA gene fragments; a subset of Dermacentor spp. was also tested with PCR, targeting fragments of the 18S and large subunit region rRNA genes of Babesia spp. and 16S rRNA genes of E. canis. Rickettsia spp. was identified in 12.5% (106/848) of ticks. Species detected include Rickettsia montanensis (n = 64 ticks), Rickettsia bellii (n = 15 ticks), Rickettsia rhipicephali (n = 13 ticks), Rickettsia peacockii (n = 8 ticks), Rickettsia amblyommatis (n = 3 ticks), Rickettsia cooleyi (n = 1 tick), and unclassified Rickettsia spp. (n = 2 ticks). Ticks with R. montanensis and R. bellii were submitted from every U.S. region; R. rhipicephali was predominantly detected in ticks from the southern half of the United States, and all R. peacockii-positive ticks were D. andersoni that originated from the Rocky Mountain states. Ehrlichia canis was not detected in any Dermacentor spp., and Babesia conradae was detected in two Dermacentor albipictus. Because most ticks had fed on dogs or cats before submission, these findings do not implicate a given Dermacentor sp. as a primary vector of these agents, but in regard to Rickettsia spp., the data do support other published work showing D. variabilis harbors a diversity of Rickettsia species with unknown implications for animal and human health.
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Affiliation(s)
- Kathryn T Duncan
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Amber Grant
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Britny Johnson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA.,Rickettsial Zoonoses Branch, Division of Vector-Borne Disease, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Kellee D Sundstrom
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Meriam N Saleh
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, USA
| | - Susan E Little
- Department of Veterinary Pathobiology, College of Veterinary Medicine, Oklahoma State University, Stillwater, Oklahoma, USA
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Models for Studying the Distribution of Ticks and Tick-Borne Diseases in Animals: A Systematic Review and a Meta-Analysis with a Focus on Africa. Pathogens 2021; 10:pathogens10070893. [PMID: 34358043 PMCID: PMC8308717 DOI: 10.3390/pathogens10070893] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/30/2021] [Accepted: 07/12/2021] [Indexed: 11/17/2022] Open
Abstract
Ticks and tick-borne diseases (TTBD) are constraints to the development of livestock and induce potential human health problems. The worldwide distribution of ticks is not homogenous. Some places are ecologically suitable for ticks but they are not introduced in these areas yet. The absence or low density of hosts is a factor affecting the dissemination of the parasite. To understand the process of introduction and spread of TTBD in different areas, and forecast their presence, scientists developed different models (e.g., predictive models and explicative models). This study aimed to identify models developed by researchers to analyze the TTBD distribution and to assess the performance of these various models with a meta-analysis. A literature search was implemented with PRISMA protocol in two online databases (Scopus and PubMed). The selected articles were classified according to country, type of models and the objective of the modeling. Sensitivity, specificity and accuracy available data of these models were used to evaluate their performance using a meta-analysis. One hundred studies were identified in which seven tick genera were modeled, with Ixodes the most frequently modeled. Additionally, 13 genera of tick-borne pathogens were also modeled, with Borrelia the most frequently modeled. Twenty-three different models were identified and the most frequently used are the generalized linear model representing 26.67% and the maximum entropy model representing 24.17%. A focus on TTBD modeling in Africa showed that, respectively, genus Rhipicephalus and Theileria parva were the most modeled. A meta-analysis on the quality of 20 models revealed that maximum entropy, linear discriminant analysis, and the ecological niche factor analysis models had, respectively, the highest sensitivity, specificity, and area under the curve effect size among all the selected models. Modeling TTBD is highly relevant for predicting their distribution and preventing their adverse effect on animal and human health and the economy. Related results of such analyses are useful to build prevention and/or control programs by veterinary and public health authorities.
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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. JOURNAL OF MEDICAL ENTOMOLOGY 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] [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.
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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:
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Moo-Llanes DA, de Oca-Aguilar ACM, Romero-Salas D, Sánchez-Montes S. Inferring the Potential Distribution of an Emerging Rickettsiosis in America: The Case of Rickettsia parkeri. Pathogens 2021; 10:592. [PMID: 34068132 PMCID: PMC8152739 DOI: 10.3390/pathogens10050592] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/11/2021] [Accepted: 05/11/2021] [Indexed: 02/06/2023] Open
Abstract
Tick-borne rickettsioses represent a severe public health problem that has increased in recent decades by several activities that place human populations in contact with a wide range of vectors. In particular, Rickettsia parkeri, an eschar-associated spotted fever agent, represents an emerging pathogen that has been gradually identified throughout America. In the present work, we compiled an occurrence database of these bacteria, as well as its vectors, in order to identify the potential distribution of these bacteria and to detect the risk areas where this emerging pathogen may be circulating. The results show the at-risk areas to be broad regions in Central America, on the coast of Venezuela, Colombia, Ecuador, Peru, and Chile, part of Brazil and Argentina, and the greater part of Bolivia, Paraguay, and Uruguay. Particularly, in Mexico, conditions exist for widespread dissemination. Our results must be considered for the establishment of active acarological surveillance in previously unsampled areas, as well as the establishment of prevention measures for vulnerable populations and risk groups participating in outdoor activities that can place them in contact with this pathogen.
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Affiliation(s)
- David A. Moo-Llanes
- Centro Regional de Investigación en Salud Pública (CRISP), Instituto Nacional de Salud Pública (INSP), Tapachula, Chiapas 30700, Mexico;
| | | | - Dora Romero-Salas
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Veracruzana, Veracruz 91710, Mexico
| | - Sokani Sánchez-Montes
- Facultad de Ciencias Biológicas y Agropecuarias, Región Tuxpan, Universidad Veracruzana, Tuxpan de Rodríguez Cano, Veracruz 92870, Mexico
- Centro de Medicina Tropical, División de Investigación, Facultad de Medicina, Universidad Nacional Autónoma de Mexico, Ciudad de Mexico 06726, Mexico
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Luker HA, Rodriguez S, Kandel Y, Vulcan J, Hansen IA. A novel Tick Carousel Assay for testing efficacy of repellents on Amblyomma americanum L.. PeerJ 2021; 9:e11138. [PMID: 33976963 PMCID: PMC8067905 DOI: 10.7717/peerj.11138] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 03/01/2021] [Indexed: 11/23/2022] Open
Abstract
Ticks are important vectors of human and veterinary diseases. A primary way ticks gain access to human hosts is by engaging to clothing. Repellents or acaricides sprayed onto fabric are used to deter ticks’ access to human hosts. However, there are a limited amount of standardized laboratory assays that can determine the potency and efficacy of repellents. We present a novel fabric-engagement assay referred to as the ‘Tick Carousel Assay’. This assay utilizes fabric brushing past ticks located on an artificial grass patch and measures tick engagements to fabric over time. After screening a variety of tick species, we used the lone star tick (Amblyomma americanum) to test the efficacy of four commonly used active ingredients in repellents: DEET, Picaridin, IR3535, and Oil of Lemon Eucalyptus. Repellency was tested immediately, after three hours, and six hours post application to fabric. Our data show that each repellent we tested significantly reduced the number of tick engagements to fabric for at least 6 hours. We did not find significant differences in repellent efficacy between the four active ingredients tested directly and three hours after application. After six hours, Oil of Lemon Eucalyptus repelled ticks more than the other active ingredients. We show that our Tick Carousel Assay provides an affordable, repeatable, and standardized way to compare and test repellent efficacy on treated fabrics. Our results confirm that commonly used repellents applied to fabric are an effective way to reduce tick engagement.
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Affiliation(s)
- Hailey A Luker
- Department of Biology, New Mexico State University, Las Cruces, NM, United States of America
| | - Stacy Rodriguez
- Department of Biology, New Mexico State University, Las Cruces, NM, United States of America
| | - Yashoda Kandel
- Department of Biology, New Mexico State University, Las Cruces, NM, United States of America
| | - Julia Vulcan
- Department of Biology, New Mexico State University, Las Cruces, NM, United States of America
| | - Immo A Hansen
- Department of Biology, New Mexico State University, Las Cruces, NM, United States of America
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Snellgrove AN, Krapiunaya I, Scott P, Levin ML. Assessment of the Pathogenicity of Rickettsia amblyommatis, Rickettsia bellii, and Rickettsia montanensis in a Guinea Pig Model. Vector Borne Zoonotic Dis 2021; 21:232-241. [PMID: 33600263 DOI: 10.1089/vbz.2020.2695] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Members of the genus Rickettsia range from nonpathogenic endosymbionts to virulent pathogens such as Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever. Many rickettsiae are considered nonpathogenic because they have been isolated from ticks but not vertebrate hosts. We assessed the ability of three presumed endosymbionts: Rickettsia amblyommatis, Rickettsia bellii, and Rickettsia montanensis, to infect a guinea pig animal model. These species were chosen because of their high prevalence in respective tick vectors or published reports suggestive of human or animal pathogenicity. Following intraperitoneal (IP) inoculation of cell culture suspensions of R. rickettsii, R. amblyommatis, R. bellii, or R. montanensis into guinea pigs, animals were monitored for signs of clinical illness for 13 days. Ear biopsies and blood samples were taken at 2- to 3-day intervals for detection of rickettsial DNA by PCR. Animals were necropsied and internal organ samples were also tested using PCR assays. Among the six guinea pigs inoculated with R. amblyommatis, fever, orchitis, and dermatitis were observed in one, one, and three animals respectively. In R. bellii-exposed animals, we noted fever in one of six animals, orchitis in one, and dermatitis in two. No PCR-positive tissues were present in either the R. amblyommatis- or R. bellii-exposed groups. In the R. montanensis-exposed group, two of six animals became febrile, two had orchitis, and three developed dermatitis in ears or footpads. R. montanensis DNA was detected in ear skin biopsies collected on multiple days from three animals. Also, a liver specimen from one animal and spleen specimens of two animals were PCR positive. The course and severity of disease in the three experimental groups were significantly milder than that of R. rickettsii. This study suggests that the three rickettsiae considered nonpathogenic can cause either subclinical or mild infections in guinea pigs when introduced via IP inoculation.
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Affiliation(s)
- Alyssa N Snellgrove
- Division of Vector Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Inna Krapiunaya
- Division of Vector Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | | | - Michael L Levin
- Division of Vector Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
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Xin H, Fu P, Sun J, Lai S, Hu W, Clements ACA, Sun J, Cui J, Hay SI, Li X, Li Z. Risk mapping of scrub typhus infections in Qingdao city, China. PLoS Negl Trop Dis 2020; 14:e0008757. [PMID: 33264282 PMCID: PMC7735632 DOI: 10.1371/journal.pntd.0008757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 12/14/2020] [Accepted: 08/28/2020] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The emergence and re-emergence of scrub typhus has been reported in the past decade in many global regions. In this study, we aim to identify potential scrub typhus infection risk zones with high spatial resolution in Qingdao city, in which scrub typhus is endemic, to guide local prevention and control strategies. METHODOLOGY/PRINCIPAL FINDINGS Scrub typhus cases in Qingdao city during 2006-2018 were retrieved from the Chinese National Infectious Diseases Reporting System. We divided Qingdao city into 1,101 gridded squares and classified them into two categories: areas with and without recorded scrub typhus cases. A boosted regression tree model was used to explore environmental and socioeconomic covariates associated with scrub typhus occurrence and predict the risk of scrub typhus infection across the whole area of Qingdao city. A total of 989 scrub typhus cases were reported in Qingdao from 2006-2018, with most cases located in rural and suburban areas. The predicted risk map generated by the boosted regression tree models indicated that the highest infection risk areas were mainly concentrated in the mid-east and northeast regions of Qingdao, with gross domestic product (20.9%±1.8% standard error) and annual cumulative precipitation (20.3%±1.1%) contributing the most to the variation in the models. By using a threshold environmental suitability value of 0.26, we identified 757 squares (68.7% of the total) with a favourable environment for scrub typhus infection; 66.2% (501/757) of the squares had not yet recorded cases. It is estimated that 6.32 million people (72.5% of the total population) reside in areas with a high risk of scrub typhus infection. CONCLUSIONS/SIGNIFICANCE Many locations in Qingdao city with no recorded scrub typhus cases were identified as being at risk for scrub typhus occurrence. In these at-risk areas, awareness and capacity for case diagnosis and treatment should be enhanced in the local medical service institutes.
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Affiliation(s)
- Hualei Xin
- Division of Infectious Disease, Qingdao City Center for Disease Control and Prevention, Qingdao, Shandong, China
- Key Laboratory of Surveillance and Early Warning on Infectious Disease, Division of Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
- World Health Organization (WHO) Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Peng Fu
- Department of Anesthesiology, Qingdao Fuwai Cardiovascular Hospital, Qingdao, Shandong, China
| | - Junling Sun
- Key Laboratory of Surveillance and Early Warning on Infectious Disease, Division of Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Shengjie Lai
- Key Laboratory of Surveillance and Early Warning on Infectious Disease, Division of Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
- School of Geography and Environmental Science, University of Southampton, Southampton 1BJ, United Kingdom
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, China
| | - Wenbiao Hu
- School of Public Health and Social Work, Institute of Health and Biomedical Innovation, Queensland University of Technology, Queensland, Australia
| | - Archie C. A. Clements
- Faculty of Health Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Jianping Sun
- Division of Infectious Disease, Qingdao City Center for Disease Control and Prevention, Qingdao, Shandong, China
| | - Jing Cui
- Division of Infectious Disease, Qingdao City Center for Disease Control and Prevention, Qingdao, Shandong, China
| | - Simon I. Hay
- Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, United States of America
| | - Xiaojing Li
- Division of Infectious Disease, Qingdao City Center for Disease Control and Prevention, Qingdao, Shandong, China
- * E-mail: (XL); (ZL)
| | - Zhongjie Li
- Key Laboratory of Surveillance and Early Warning on Infectious Disease, Division of Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
- * E-mail: (XL); (ZL)
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12
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Occi J, Egizi AM, Goncalves A, Fonseca DM. New Jersey-Wide Survey of Spotted Fever Group Rickettsia (Proteobacteria: Rickettsiaceae) in Dermacentor variabilis and Amblyomma americanum (Acari: Ixodida: Ixodidae). Am J Trop Med Hyg 2020; 103:1009-1016. [PMID: 32588804 DOI: 10.4269/ajtmh.20-0145] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
For the last decade, the New Jersey (NJ) Department of Health has reported between 42 and 144 new cases each year of "spotted fever group rickettsiosis" (SFGR), a statistic that reflects uncertainty regarding which rickettsial agents (Proteobacteria: Rickettsiaceae: Rickettsia) are infecting NJ residents. To identify the Rickettsia circulating in NJ ticks, we used a combination of conventional and real time PCR approaches to screen 560 Dermacentor variabilis Say and 245 Amblyomma americanum L. obtained from a 1-day state-wide surveillance in May 2018 and an additional 394 D. variabilis collected across NJ in 2013-2018. We found zero D. variabilis infected with Rickettsia rickettsii, the agent of Rocky Mountain spotted fever and, on average, 1.3% infected with presumed nonpathogenic Rickettsia montanensis. We also found zero A. americanum infected with R. rickettsii, and 20% infected with Rickettsia amblyommatis, a prevalence somewhat lower than in more southern states. Overall, we conclude that it is unlikely that R. rickettsii vectored by D. variabilis is a primary cause of SFGR cases in NJ and discuss our findings in the context of known facts and current limitations. We conclude that understanding the causes of SFGR east of the Mississippi will require collaboration among medical doctors, public health authorities, and medical entomologists to follow up presumptive human cases of SFGR with detailed histories of exposure, species-specific molecular assays, and active surveillance of putative vectors and the pathogens they may carry.
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Affiliation(s)
- James Occi
- Department of Entomology, Center for Vector Biology, Rutgers University, New Brunswick, New Jersey
| | - Andrea M Egizi
- Monmouth County Mosquito Control Division, Tick-borne Diseases Laboratory, Tinton Falls, New Jersey.,Department of Entomology, Center for Vector Biology, Rutgers University, New Brunswick, New Jersey
| | - Ashley Goncalves
- Department of Entomology, Center for Vector Biology, Rutgers University, New Brunswick, New Jersey
| | - Dina M Fonseca
- Department of Entomology, Center for Vector Biology, Rutgers University, New Brunswick, New Jersey
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13
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Polo G, Luz HR, Regolin AL, Martins TF, Winck GR, da Silva HR, Onofrio VC, Labruna MB, Faccini JLH. Distribution modeling of Amblyomma rotundatum and Amblyomma dissimile in Brazil: estimates of environmental suitability. Parasitol Res 2020; 120:797-806. [PMID: 33068151 DOI: 10.1007/s00436-020-06924-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 10/07/2020] [Indexed: 12/26/2022]
Abstract
The number of reports of tick parasitism in amphibians and reptiles has increased over the past few years, including new host and location records for Amblyomma rotundatum and Amblyomma dissimile. However, knowledge of the geographical distribution remains incomplete, and in many regions of Brazil, the presence of these vectors has not been investigated. Several candidate models were built using a correlative maximum entropy approach, and best-fitting models were selected based on statistical significance, predictive ability, and complexity based on current climatic trends and future projected climate changes. Final models showed a good ability to discriminate A. rotundatum and A. dissimile current and future potential distributions. The entire country had higher predicted suitability for A. rotundatum while A. dissimile was mainly restricted to the Amazon and Pantanal biomes. A. rotundatum is a species with enormous potential for dissemination in the next decades, potentially through the legal and illegal transport of reptiles and amphibians. The proposed model is useful for targeting surveillance efforts increasing the efficiency and accuracy of future ecological research and tick management efforts.
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Affiliation(s)
- Gina Polo
- Department of Preventive Veterinary Medicine and Animal Heath, University of São Paulo, São Paulo, SP, Brazil. .,Grupo de Investigación en Epidemiología y Salud Pública, Universidad de La Salle, Bogotá, Colombia.
| | - Hermes R Luz
- Programa de Pós Graduação em Biotecnologia do Renorbio, Ponto Focal Maranhão, Universidade Federal do Maranhão, São Luís, MA, Brazil
| | - André Luis Regolin
- Department of Biodiversity, Spatial Ecology and Conservation Lab (LEEC), Institute of Biosciences, Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Campus Rio Claro, São Paulo, Brazil.,Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO, USA
| | - Thiago F Martins
- Department of Preventive Veterinary Medicine and Animal Heath, University of São Paulo, São Paulo, SP, Brazil
| | - Gisele R Winck
- Department of Ecology, Institute of Biology, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Hélio R da Silva
- Department of Animal Biology, Federal Rural University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Valeria C Onofrio
- Special Laboratory of Zoological Collections, Butantan Institute, São Paulo, Brazil.,Master's Program in Veterinary Medicine and Animal Welfare, Santo Amaro University, São Paulo, SP, Brazil
| | - Marcelo B Labruna
- Department of Preventive Veterinary Medicine and Animal Heath, University of São Paulo, São Paulo, SP, Brazil
| | - João L H Faccini
- Department of Animal Parasitology, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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14
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Luedtke BE, Shaffer JJ, Monrroy E, Willicott CW, Bourret TJ. Molecular Detection of Spotted Fever Group Rickettsiae (Rickettsiales: Rickettsiaceae) in Dermacentor variabilis (Acari: Ixodidae) Collected Along the Platte River in South Central Nebraska. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:519-523. [PMID: 31576408 PMCID: PMC7530562 DOI: 10.1093/jme/tjz167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Indexed: 05/03/2023]
Abstract
Dermacentor variabilis is the predominant tick species in Nebraska and is presumed to be the primary vector of Rickettsia rickettsii associated with cases of Rocky Mountain spotted fever (RMSF). Interestingly, RMSF cases in Nebraska have increased on a year-to-year basis, yet the prevalence of R. rickettsii in D. variabilis ticks has not been established for Nebraska. Here we sought to set a baseline for the prevalence of R. rickettsii and other spotted fever group (SFG) rickettsiae harbored by D. variabilis ticks. Over a 3-yr period, D. variabilis were collected along the Platte River in south central Nebraska. Individual tick DNA was analyzed using endpoint PCR to identify ticks carrying SFG rickettsiae. In total, 927 D. variabilis were analyzed by PCR and 38 (4.1%) ticks tested positive for SFG rickettsiae. Presumptive positives were sequenced to identify the Rickettsia species, of which 29 (76%) were R. montanensis, 5 (13%) were R. amblyommatis, 4 (11%) were R. bellii, and R. rickettsii was not detected. These data indicate that R. rickettsii is likely at a low prevalence in south central Nebraska and spillover of R. amblyommatis into D. variabilis is likely occurring due to the invasive lone star tick (Amblyomma americanum). In addition, our data suggest that R. montanensis and R. amblyommatis could be associated with the increase in SFG rickettsiae infections in Nebraska. This information will be of value to clinicians and the general public for evaluating diagnosis of disease- and risk-associated environmental exposure, respectively.
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Affiliation(s)
| | - Julie J Shaffer
- Biology Department, University of Nebraska at Kearney, Kearney, NE
| | - Estrella Monrroy
- Biology Department, University of Nebraska at Kearney, Kearney, NE
| | | | - Travis J Bourret
- Department of Medical Microbiology and Immunology, Creighton University School of Medicine, Omaha, NE
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15
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Luce-Fedrow A, Lehman ML, Kelly DJ, Mullins K, Maina AN, Stewart RL, Ge H, John HS, Jiang J, Richards AL. A Review of Scrub Typhus (Orientia tsutsugamushi and Related Organisms): Then, Now, and Tomorrow. Trop Med Infect Dis 2018; 3:E8. [PMID: 30274407 PMCID: PMC6136631 DOI: 10.3390/tropicalmed3010008] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 01/09/2018] [Accepted: 01/10/2018] [Indexed: 12/26/2022] Open
Abstract
Scrub typhus and the rickettsial diseases represent some of the oldest recognized vector-transmitted diseases, fraught with a rich historical aspect, particularly as applied to military/wartime situations. The vectors of Orientia tsutsugamushi were once thought to be confined to an area designated as the Tsutsugamushi Triangle. However, recent reports of scrub typhus caused by Orientia species other than O. tsutsugamushi well beyond the limits of the Tsutsugamushi Triangle have triggered concerns about the worldwide presence of scrub typhus. It is not known whether the vectors of O. tsutsugamushi will be the same for the new Orientia species, and this should be a consideration during outbreak/surveillance investigations. Additionally, concerns surrounding the antibiotic resistance of O. tsutsugamushi have led to considerations for the amendment of treatment protocols, and the need for enhanced public health awareness in both the civilian and medical professional communities. In this review, we discuss the history, outbreaks, antibiotic resistance, and burgeoning genomic advances associated with one of the world's oldest recognized vector-borne pathogens, O. tsutsugamushi.
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Affiliation(s)
- Alison Luce-Fedrow
- Department of Biology, Shippensburg University, Shippensburg, PA 17202, USA.
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Marcie L Lehman
- Department of Biology, Shippensburg University, Shippensburg, PA 17202, USA.
| | - Daryl J Kelly
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH 43210, USA.
| | - Kristin Mullins
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Alice N Maina
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Richard L Stewart
- Department of Biology, Shippensburg University, Shippensburg, PA 17202, USA.
| | - Hong Ge
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Heidi St John
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Ju Jiang
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
| | - Allen L Richards
- Viral and Rickettsial Diseases Department, Naval Medical Research Center, Silver Spring, MD 20910, USA.
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
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16
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Suspected and Confirmed Vector-Borne Rickettsioses of North America Associated with Human Diseases. Trop Med Infect Dis 2018; 3:tropicalmed3010002. [PMID: 30274401 PMCID: PMC6136625 DOI: 10.3390/tropicalmed3010002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Revised: 12/18/2017] [Accepted: 12/19/2017] [Indexed: 11/27/2022] Open
Abstract
The identification of pathogenic rickettsial agents has expanded over the last two decades. In North America, the majority of human cases are caused by tick-borne rickettsioses but rickettsiae transmitted by lice, fleas, mites and other arthropods are also responsible for clinical disease. Symptoms are generally nonspecific or mimic other infectious diseases; therefore, diagnosis and treatment may be delayed. While infection with most rickettsioses is relatively mild, delayed diagnosis and treatment may lead to increased morbidity and mortality. This review will discuss the ecology, epidemiology and public health importance of suspected and confirmed vector-transmitted Rickettsia species of North America associated with human diseases.
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17
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Current and potential future distribution of the American dog tick (Dermacentor variabilis, Say) in North America. Ticks Tick Borne Dis 2017; 9:354-362. [PMID: 29275873 DOI: 10.1016/j.ttbdis.2017.11.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 11/14/2017] [Accepted: 11/21/2017] [Indexed: 01/01/2023]
Abstract
The American dog tick (Dermacentor variabilis) is medically and economically important in North America. This species is found across central and eastern North America from the Gulf Coast of Mexico through southern Canada. In parts of this region, D. variabilis is a vector for pathogens that cause diseases in humans and animals. Our aim was to determine whether climate change would affect the distribution of the climatically suitable area for D. variabilis in North America, to aid monitoring for potential future spread of tick-borne pathogens. We developed a species distribution model for D. variabilis to project where climate will likely be suitable for the tick in North America using a maximum entropy method, occurrence records from museum and laboratory archives, and 10 environmental variables relevant to climate requirements for the tick. We used four emissions scenarios from the Intergovernmental Panel on Climate Change's Fifth Assessment Report and 10 climate models from the Coupled Model Intercomparison Project (phase 5) to estimate potential future climate suitability and determine how the tick's distribution could change. Our consensus model projected that the area of suitable climate in North America could increase from present by approximately 50% by 2070. In areas beyond the current northern limit of D. variabilis, climate could become more suitable for the tick than at present, possibly resulting in a northward expansion in Canada, but the potential suitability of the southern range of D. variabilis could decrease, depending on the region and climate model. Due to the ability of D. variabilis to harbor and transmit pathogens, a change in the distribution of this species could also affect the risk of human and animal diseases throughout North America, particularly in the northern range of the tick.
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