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Musnoff BL, Cuadera MKQ, Birney MR, Zipper L, Nicholson W, Ayres B, Cervantes K, Woell D, Occi JL. The first record of an established population of Amblyomma maculatum (Acari: Ixodidae) in New Jersey, USA. JOURNAL OF MEDICAL ENTOMOLOGY 2024; 61:1081-1085. [PMID: 38712431 DOI: 10.1093/jme/tjae056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Revised: 03/26/2024] [Accepted: 04/15/2024] [Indexed: 05/08/2024]
Abstract
Amblyomma maculatum Koch, the Gulf Coast tick, is expanding northward from its original range in the southeastern United States. In 2013, its most northern collection was in Delaware. Amblyomma maculatum has since been found in Connecticut, Illinois, and New York. It is the vector of the human pathogen Rickettsia parkeri, the causative agent of R. parkeri rickettsiosis. We report the first finding of an established population of A. maculatum in Salem County, NJ, with a R. parkeri infection prevalence rate of 23.8%. Our finding of A. maculatum is consistent with other recent findings in the northeastern United States in that specimens were found in open areas devoid of tree canopy. This discovery demonstrates the importance of tick surveillance in order to identify expanding tick populations and the pathogens they may transmit.
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Affiliation(s)
- Brandon L Musnoff
- Salem County Mosquito Control, 900 RT 45, Building #4, Woodstown, NJ 08098, USA
| | | | - Matthew R Birney
- New Jersey Department of Health, Communicable Disease Service, Trenton, NJ, USA
| | - Lara Zipper
- New Jersey Department of Health, Communicable Disease Service, Trenton, NJ, USA
| | - William Nicholson
- Centers for Disease Control and Prevention, Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Mail Stop H17-3, Atlanta, GA 30333, USA
| | - Bryan Ayres
- Centers for Disease Control and Prevention, Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, National Center for Emerging and Zoonotic Infectious Diseases, Mail Stop H17-3, Atlanta, GA 30333, USA
| | - Kim Cervantes
- New Jersey Department of Health, Communicable Disease Service, Trenton, NJ, USA
| | - Dana Woell
- New Jersey Department of Health, Public Health and Environmental Labs, 3 Schwarzkopf Drive, Ewing Twp., NJ 08628, USA
| | - James L Occi
- New Jersey Department of Health, Public Health and Environmental Labs, 3 Schwarzkopf Drive, Ewing Twp., NJ 08628, USA
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Noden BH, Roselli MA, Loss SR. Factors influencing abundance of 3 tick species across a gradient of urban development intensity in the US Great Plains. JOURNAL OF MEDICAL ENTOMOLOGY 2024; 61:233-244. [PMID: 37738149 DOI: 10.1093/jme/tjad132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 08/28/2023] [Accepted: 09/07/2023] [Indexed: 09/24/2023]
Abstract
Urbanization alters abiotic conditions, vegetation, and wildlife populations in ways that affect tick abundance and tick-borne disease prevalence. Likely due to such changes, tick abundance has increased in many US urban areas. Despite growing public health importance of tick-borne diseases, little is known about how ticks are influenced by urbanization in North America, especially in the central United States where several pathogens occur at or near their highest incidences. To identify factors influencing tick abundance across a gradient of urbanization intensity, we used CO2 traps and flagging to sample ticks at 16 parks across Oklahoma City, Oklahoma, USA over 2 yr, conducted vegetation surveys, and used trail cameras to estimate a deer abundance index. Our results indicate there is a risk of encountering ticks across the entire urbanization gradient from exurban areas to the urban core, although some species (Dermacentor variabilis (Say)) appear less-common in heavily-urbanized areas. Vegetation variables were also associated with tick abundance. For example, Amblyomma maculatum Koch decreased with increasing woody plant and leaf litter cover, and there was a weak positive relationship between D. variabilis abundance and cover of understory eastern redcedar (Juniperus virginiana L.), indicating this native encroaching tree may increase tick populations in urban areas of the Great Plains. The deer abundance index was positively correlated with A. maculatum and D. variabilis abundance but unrelated to A. americanum (L.) abundance. Public health officials and land managers can use such information about parks/greenspaces and their surroundings to focus public education and land management efforts designed to reduce tick-borne disease prevalence.
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Affiliation(s)
- Bruce H Noden
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Megan A Roselli
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK 74078, USA
| | - Scott R Loss
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK 74078, USA
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3
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Bidder L, Gaff H. Survival of adult Amblyomma americanum, Amblyomma maculatum, and Dermacentor variabilis (Acari: Ixodidae) in four habitats in southeastern Virginia. JOURNAL OF MEDICAL ENTOMOLOGY 2023; 60:978-986. [PMID: 37364564 PMCID: PMC10496434 DOI: 10.1093/jme/tjad073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 04/28/2023] [Accepted: 06/09/2023] [Indexed: 06/28/2023]
Abstract
Adult, unfed Amblyomma americanum (Linnaeus), Amblyomma maculatum Koch, and Dermacentor variabilis (Say) ticks were housed inside environmental containers in situ from May through August 2015. The environmental containers were placed in 4 habitats in southeastern Virginia, United States. Two of the habitats were located in low ground and were prone to flooding; the other two consisted of a drier landscape located in a more upland habitat. A Cox Regression survival analysis indicated there was a significant difference in survival among species across all field sites. There was a 50.5-times higher risk of mortality for A. maculatum compared to A. americanum, a 4.3-times higher risk of mortality for A. maculatum compared to D. variabilis, and an 11.9-times higher risk of mortality for D. variabilis compared to A. americanum. There was also significantly higher mortality in field sites prone to flooding than in drier, upland field sites. We concluded that A. americanum was not negatively affected by increased flooding or the variable environmental conditions in southeastern Virginia. Dermacentor variabilis also was successful at remaining in the environment off-host, although increased flooding reduced survival over time. Amblyomma maculatum was more susceptible to mortality during long periods of time off-host in both environments, with high mortality rates in both dry upland and low-ground, flood-prone habitats.
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Affiliation(s)
- Lindsey Bidder
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, USA
| | - Holly Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, USA
- School of Mathematics, Statistics, and Computer Sciences, University of KwaZulu-Natal, Durban, South Africa
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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; 14:e4445. [PMID: 39211416 PMCID: PMC11359945 DOI: 10.1002/ecs2.4445] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 12/21/2022] [Indexed: 03/18/2023] Open
Abstract
Increasingly, geographic approaches to assessing the risk of tick-borne diseases are being used to inform public health decision-making and surveillance efforts. The distributions of key tick species of medical importance are often modeled as a function of environmental factors, using niche modeling approaches to capture habitat suitability. However, this is often disconnected from the potential distribution of key host species, which may play an important role in the actual transmission cycle and risk potential in expanding tick-borne disease risk. Using species distribution modeling, we explore the potential geographic range of Oryzomys palustris, the marsh rice rat, which has been implicated as a potential reservoir host of Rickettsia parkeri, a pathogen transmitted by the Gulf Coast tick (Amblyomma maculatum) in the southeastern United States. Due to recent taxonomic reclassification of O. palustris subspecies, we reclassified geolocated collections records into the newer clade definitions. We modeled the distribution of the two updated clades in the region, establishing for the first time, range maps and distributions of these two clades. The predicted distribution of both clades indicates a largely Gulf and southeastern coastal distribution. Estimated suitable habitat for O. palustris extends into the southern portion of the Mid-Atlantic region, with a discontinuous, limited area of suitability in coastal California. Broader distribution predictions suggest potential incursions along the Mississippi River. We found considerable overlap of predicted O. palustris ranges with the distribution of A. maculatum, indicating the potential need for extended surveillance efforts in those overlapping areas and attention to the role of hosts in transmission cycles.
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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
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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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Nkya TE, Fillinger U, Sangoro OP, Marubu R, Chanda E, Mutero CM. Six decades of malaria vector control in southern Africa: a review of the entomological evidence-base. Malar J 2022; 21:279. [PMID: 36184603 PMCID: PMC9526912 DOI: 10.1186/s12936-022-04292-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 09/05/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Countries in the southern Africa region have set targets for malaria elimination between 2020 and 2030. Malaria vector control is among the key strategies being implemented to achieve this goal. This paper critically reviews published entomological research over the past six decades in three frontline malaria elimination countries namely, Botswana Eswatini and Namibia, and three second-line malaria elimination countries including Mozambique, Zambia, and Zimbabwe. The objective of the review is to assess the current knowledge and highlight gaps that need further research attention to strengthen evidence-based decision-making toward malaria elimination. METHODS Publications were searched on the PubMed engine using search terms: "(malaria vector control OR vector control OR malaria vector*) AND (Botswana OR Swaziland OR Eswatini OR Zambia OR Zimbabwe OR Mozambique)". Opinions, perspectives, reports, commentaries, retrospective analysis on secondary data protocols, policy briefs, and reviews were excluded. RESULTS The search resulted in 718 publications with 145 eligible and included in this review for the six countries generated over six decades. The majority (139) were from three countries, namely Zambia (59) and Mozambique (48), and Zimbabwe (32) whilst scientific publications were relatively scanty from front-line malaria elimination countries, such as Namibia (2), Botswana (10) and Eswatini (4). Most of the research reported in the publications focused on vector bionomics generated mostly from Mozambique and Zambia, while information on insecticide resistance was mostly available from Mozambique. Extreme gaps were identified in reporting the impact of vector control interventions, both on vectors and disease outcomes. The literature is particularly scanty on important issues such as change of vector ecology over time and space, intervention costs, and uptake of control interventions as well as insecticide resistance. CONCLUSIONS The review reveals a dearth of information about malaria vectors and their control, most noticeable among the frontline elimination countries: Namibia, Eswatini and Botswana. It is of paramount importance that malaria vector research capacity and routine entomological monitoring and evaluation are strengthened to enhance decision-making, considering changing vector bionomics and insecticide resistance, among other determinants of malaria vector control.
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Affiliation(s)
- Theresia Estomih Nkya
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- University of Dar es Salaam, Mbeya College of Health and Allied Sciences, Mbeya, Tanzania
| | - Ulrike Fillinger
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | | | - Rose Marubu
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Emmanuel Chanda
- World Health Organization-Regional Office for Africa, Brazzaville, Republic of Congo
| | - Clifford Maina Mutero
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- School of Health Systems and Public Health, University of Pretoria, Pretoria, South Africa
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7
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Bajwa WI, Tsynman L, Egizi AM, Tokarz R, Maestas LP, Fonseca DM. The Gulf Coast Tick, Amblyomma maculatum (Ixodida: Ixodidae), and Spotted Fever Group Rickettsia in the Highly Urbanized Northeastern United States. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:1434-1442. [PMID: 35639921 DOI: 10.1093/jme/tjac053] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Indexed: 06/15/2023]
Abstract
We report the multi-year collection of the Gulf Coast tick, Amblyomma maculatum Koch (Acaridae: Ixodida: Ixodidae) in Staten Island, New York City (NYC) as well as their detection in Brooklyn, NYC, and in Atlantic and Cumberland counties in southern New Jersey, USA. The first and most common detections were of adults, however in Freshkills Park on Staten Island larvae were also collected in a following year. The presence of larvae indicates that adults are successfully finding hosts in Staten Island. While it is still unknown how A. americanum reached Staten Island, immatures of this species often parasitize migratory birds, which are now often seen in Freshkills Park. We describe the landscape features of the area in Staten Island where populations were highest and larvae were detected, which could have facilitated the establishment of A. maculatum. Notably, we also report the presence of human pathogens Rickettsia parkeri in 5/10 (50%) of adults tested and R. felis in 1/24 (4.17%) of larvae tested. In addition to established populations in Staten Island we found evidence of A. maculatum in NJ and other NYC boroughs, suggesting current or future establishment is possible. The failure thus far to detect established populations in these areas may be due to inherent difficulties in detecting low density, spatially heterogeneous incipient populations, which could require targeted surveillance efforts for this species. We discuss the consequences to public health of the establishment of A. maculatum and detection of two additional rickettsial pathogens in the densely populated northeastern United States.
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Affiliation(s)
- Waheed I Bajwa
- New York City Department of Health and Mental Hygiene, 125 Worth Street, New York, NY 10013, USA
| | - Leonid Tsynman
- New York City Department of Health and Mental Hygiene, 125 Worth Street, New York, NY 10013, USA
| | - Andrea M Egizi
- Tick-Borne Disease Program, Monmouth County Mosquito Control Division, 1901 Wayside Road, Tinton Falls, NJ 07724, USA
- Center for Vector Biology, Rutgers University, 180 Jones Avenue, New Brunswick, NJ 08901, USA
| | - Rafal Tokarz
- Center for Infection and Immunity, Columbia University, 722 West 168th Street, New York, NY 10032, USA
| | - Lauren P Maestas
- Delaware Division of Fish and Wildlife, Mosquito Control Section, 2430 Old County Road, Newark, DE 19702, USA
| | - Dina M Fonseca
- Center for Vector Biology, Rutgers University, 180 Jones Avenue, New Brunswick, NJ 08901, USA
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Johnson CR, Ponnusamy L, Richards AL, Apperson CS. Analyses of Bloodmeal Hosts and Prevalence of Rickettsia parkeri in the Gulf Coast Tick Amblyomma maculatum (Acari: Ixodidae) From a Reconstructed Piedmont Prairie Ecosystem, North Carolina. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:1382-1393. [PMID: 35489062 DOI: 10.1093/jme/tjac033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Indexed: 06/14/2023]
Abstract
Host feeding patterns and the prevalence of infection with Rickettsia parkeri were determined for the primary vector, Amblyomma maculatum Koch as well as sympatric tick species A. americanum (Linnaeus) and Dermacentor variabilis (Say) collected from a reconstructed prairie in the Piedmont region of North Carolina during 2011 and 2012. The occurrence of R. parkeri among A. maculatum adults and nymphs was 36.9% (45/122) and 33.3% (2/6), respectively. Rickettsia parkeri was detected in a single male A. americanum 2.3% (1/43). A PCR-reverse line blot hybridization assay of a 12S rDNA fragment amplified from remnant larval and nymphal bloodmeals of host-seeking ticks was used to identify bloodmeal hosts. Of the tick samples tested, bloodmeal host identification was successful for 29.3% (12/41) of adult A. americanum and 39.2% (20/51) of adult D. variabilis. For A. maculatum, bloodmeal host identification was successful for 50% (61/122) of adults collected from vegetation and 100% (4/4) of nymphs removed from cotton rats (Sigmodon hispidus Say and Ord). The cotton rat was the most common bloodmeal host with 59.0% (36/61) identified for adult A. maculatum. No statistically significant association was observed, however, between bloodmeal host and pathogen prevalence for any tick species. While the cotton rat was an important bloodmeal host for A. maculatum nymphs, this vertebrate did not appear to be the primary source of R. parkeri infection for A. maculatum.
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Affiliation(s)
- Connie R Johnson
- Department of Entomology and Plath Pathology, North Carolina State University, Raleigh, NC 27695, USA
| | - Loganathan Ponnusamy
- Department of Entomology and Plath Pathology, North Carolina State University, Raleigh, NC 27695, USA
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27695USA
| | - Allen L Richards
- Department of Preventive Medicine and Biostatistics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Charles S Apperson
- Department of Entomology and Plath Pathology, North Carolina State University, Raleigh, NC 27695, USA
- Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27695USA
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Ross AML, Stokes JV, Cross CE, Alugubelly N, Varela-Stokes AS. Multiplex TaqMan® Quantitative PCR Assays for Host-Tick-Pathogen Studies Using the Guinea Pig-Tick-Rickettsia System. Pathogens 2022; 11:pathogens11050594. [PMID: 35631115 PMCID: PMC9147651 DOI: 10.3390/pathogens11050594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/10/2022] [Accepted: 05/16/2022] [Indexed: 12/04/2022] Open
Abstract
Spotted Fever Rickettsiosis (SFR) is caused by spotted fever group Rickettsia spp. (SFGR), and is associated with symptoms common to other illnesses, making it challenging to diagnose before detecting SFGR-specific antibodies. The guinea pig is a valuable biomedical model for studying Spotted Fever Rickettsiosis (SFR); its immune system is more like the human immune system than that of the murine model, and guinea pigs develop characteristic clinical signs. Thus, we have a compelling interest in developing, expanding, and optimizing tools for use in our guinea pig-Amblyomma-Rickettsia system for understanding host-tick-pathogen interactions. With the design and optimization of the three multiplex TaqMan® qPCR assays described here, we can detect the two SFGR, their respective primary Amblyomma sp. vectors, and the guinea pig model as part of controlled experimental studies using tick-transmission of SFGR to guinea pigs. We developed qPCR assays that reliably detect each specific target down to 10 copies by producing plasmid standards for each assay target, optimizing the individual primer-probe sets, and optimizing the final multiplex reactions in a methodical, stepwise fashion. We anticipate that these assays, currently designed for in vivo studies, will serve as a foundation for optimal SFGR detection in other systems, including fieldwork.
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Affiliation(s)
| | - John V. Stokes
- Correspondence: (J.V.S.); (A.S.V.-S.); Tel.: +1-662-769-7191 (J.V.S.); +1-662-769-7192 (A.S.V.-S.)
| | | | | | - Andrea S. Varela-Stokes
- Correspondence: (J.V.S.); (A.S.V.-S.); Tel.: +1-662-769-7191 (J.V.S.); +1-662-769-7192 (A.S.V.-S.)
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10
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Noden BH, Roselli MA, Loss SR. Effect of Urbanization on Presence, Abundance, and Coinfection of Bacteria and Protozoa in Ticks in the US Great Plains. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:957-968. [PMID: 35024846 DOI: 10.1093/jme/tjab228] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Indexed: 06/14/2023]
Abstract
Urbanization alters components of natural ecosystems which can affect tick abundance and tick-borne disease prevalence. Likely due to these changes, tick-borne pathogen prevalence has increased in many U.S. urban areas. Despite the growing public health importance of tick-borne diseases, little is known about how they are influenced by urbanization in North America, especially in the central U.S. where several pathogens occur at or near their highest levels of incidence nationally. To determine whether urban development influences tick infection with bacteria and protozoa, we collected ticks at 16 parks across a gradient of urbanization intensity in Oklahoma City, Oklahoma, USA and tested them using a variety of PCR assays. Adult ticks tested positive for Rickettsia parkeri, R. amblyommatis, R. rhiphicephali, 'Candidatus R. andeanae', Ehrlichia chaffeensis, E. ewingii, Panola Mountain Ehrlichia, 'Borrelia lonestari', Theileria cervi, Babesia spp. Coco, and Cytauxzoon felis. These results indicate the presence of a high diversity of tick-borne bacteria and protozoa across an expanding urban area in the U.S. Great Plains. Although there appeared to be some risk of encountering tick-borne microorganisms across the entire urbanization gradient, E. chaffeensis, E. ewingii, and T. cervi-infected ticks and microbe diversity decreased with increasing urbanization intensity. We identified a low rate of coinfection between different microorganisms, with coinfected ticks mainly collected from sites in the least-urbanized areas. This study suggests the need for awareness of tick-borne disease risk throughout urban areas in the central U.S., and highlights a need for studies of tick host habitat use and movement in cities.
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Affiliation(s)
- Bruce H Noden
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, USA
| | - Megan A Roselli
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, USA
| | - Scott R Loss
- Department of Natural Resource Ecology and Management, Oklahoma State University, Stillwater, OK, USA
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11
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Ramírez-Garofalo JR, Curley SR, Field CE, Hart CE, Thangamani S. Established Populations of Rickettsia parkeri-Infected Amblyomma maculatum Ticks in New York City, New York, USA. Vector Borne Zoonotic Dis 2021; 22:184-187. [PMID: 34958248 DOI: 10.1089/vbz.2021.0085] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Objectives: We sought to determine the habitat associations and pathogen status of Amblyomma maculatum ticks in New York City (NYC), New York, USA, a newly expanded portion of their range. Methods: We collected 88 ticks from two NYC parks on Staten Island, one of the five boroughs of NYC, and compared our findings with similar habitat in Brooklyn, New York during the same time period (April 30-September 1). We tested 76 for pathogens. Results: We found adult and immature ticks in native and invasive grasses at Freshkills and Brookfield parks on Staten Island. No A. maculatum ticks were found in Brooklyn. 52.6% of ticks tested were infected with Rickettsia parkeri-the etiological agent of R. parkeri rickettsiosis. Conclusions: This high rate of R. parkeri in a dense urban center is of concern to the medical community, who should be aware of this species' presence and the symptoms of R. parkeri rickettsiosis.
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Affiliation(s)
- José R Ramírez-Garofalo
- Biology Department, The College of Staten Island, City University of New York, Staten Island, New York, USA
| | - Shannon R Curley
- Biology Department, The College of Staten Island, City University of New York, Staten Island, New York, USA.,New York City Department of Parks and Recreation, New York, New York, USA
| | - Caitlin E Field
- New York City Department of Parks and Recreation, New York, New York, USA
| | - Charles E Hart
- Department of Microbiology and Immunology, SUNY Center for Vector-Borne Diseases, Syracuse, New York, USA.,Institute for Global Health and Translational Science, Upstate Medical University, State University of New York, Syracuse, New York, USA
| | - Saravanan Thangamani
- Department of Microbiology and Immunology, SUNY Center for Vector-Borne Diseases, Syracuse, New York, USA.,Institute for Global Health and Translational Science, Upstate Medical University, State University of New York, Syracuse, New York, USA
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12
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Phylogenetic Differentiation of Rickettsia parkeri Reveals Broad Dispersal and Distinct Clustering within North American Strains. Microbiol Spectr 2021; 9:e0141721. [PMID: 34643451 PMCID: PMC8515929 DOI: 10.1128/spectrum.01417-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The tick-borne pathogen Rickettsia parkeri causes a mild rickettsiosis, with cases reported from several countries to its known distribution in the Americas. Molecular analyses have identified a clear distinction between strains of R. parkeri sensu stricto (s. s.) and R. parkeri sensu lato (s. l.) as well as separation between North American and South American R. parkeri s. s. strains. To expand on this previous work, we developed a multilocus sequence typing analysis with two aims: first, to investigate the genetic diversity within strains of North American R. parkeri s. s., and second, to further the understanding of the genetic relationships between R. parkeri s. s. and R. parkeri s. l. Sixty-four R. parkeri isolates and 12 R. parkeri-positive tick lysates were analyzed using a novel typing scheme consisting of four coding regions and two intergenic regions. A concatenated Bayesian phylogeny that identified eight clades was constructed: three represent the R. parkeri s. l. strains, and five represent the R. parkeri s. s. strains. The clades appear to be generally phylogeographically organized and associated with specific tick vectors. However, while one of the four R. parkeri s. s. North American clades appears to be limited to the southwestern United States, the other North American clades exhibit broad dispersal, most notably seen in the largest group, which includes representative samples extending from northern Mexico to Delaware. This work highlights the increasingly recognized geographic range of R. parkeri in the Americas and suggests a potential public health risk for these areas. IMPORTANCE Since 1937, when Rickettsia parkeri was originally identified in Amblyomma maculatum group ticks, the recognized range and associated vectors for this pathogen have expanded significantly. In recent years, R. parkeri has been identified in 12 tick species from seven countries in the Americas. Herein, we provide evidence that the greatest genetic diversity within R. parkeri exists in North America, where one R. parkeri sensu lato and four R. parkeri sensu stricto genotypes are present. While one distinct R. parkeri sensu stricto genotype exists only in the southwestern United States, three genotypes are broadly distributed in the eastern United States, with the largest of these found across the known range of R. parkeri in North America. In contrast, the South American R. parkeri sensu stricto samples represent a single genotype and are completely clonal at the loci analyzed, irrespective of their country of origin.
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Allerdice MEJ, Snellgrove AN, Hecht JA, Hartzer K, Jones ES, Biggerstaff BJ, Ford SL, Karpathy SE, Delgado-de la Mora J, Delgado-de la Mora D, Licona-Enriquez JD, Goddard J, Levin ML, Paddock CD. Reproductive incompatibility between Amblyomma maculatum (Acari: Ixodidae) group ticks from two disjunct geographical regions within the USA. EXPERIMENTAL & APPLIED ACAROLOGY 2020; 82:543-557. [PMID: 33091146 PMCID: PMC11008682 DOI: 10.1007/s10493-020-00557-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/05/2020] [Indexed: 06/11/2023]
Abstract
The Amblyomma maculatum Koch group of ixodid ticks consists of three species: A. maculatum, A. triste, and A. tigrinum. However, since Koch described this group in 1844, the systematics of its members has been the subject of ongoing debate. This is especially true of A. maculatum and A. triste; recent molecular analyses reveal insufficient genetic divergence to separate these as distinct species. Further confounding this issue is the discovery in 2014 of A. maculatum group ticks in southern Arizona (AZ), USA, that share morphological characteristics with both A. triste and A. maculatum. To biologically evaluate the identity of A. maculatum group ticks from southern Arizona, we analyzed the reproductive compatibility between specimens of A. maculatum group ticks collected from Georgia (GA), USA, and southern Arizona. Female ticks from both Arizona and Georgia were mated with males from both the Georgia and Arizona Amblyomma populations, creating two homologous and two heterologous F1 cohorts of ticks: GA ♀/GA ♂, AZ ♀/AZ ♂, GA ♀/AZ ♂, and AZ ♀/GA ♂. Each cohort was maintained separately into the F2 generation with F1 females mating only with F1 males from their same cohort. Survival and fecundity parameters were measured for all developmental stages. The observed survival parameters for heterologous cohorts were comparable to those of the homologous cohorts through the F1 generation. However, the F1 heterologous females produced F2 egg clutches that did not hatch, thus indicating that the Arizona and Georgia populations of A. maculatum group ticks tested here represent different biological species.
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Affiliation(s)
- Michelle E J Allerdice
- Division of Vector-Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA.
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS, USA.
| | - Alyssa N Snellgrove
- Division of Vector-Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Joy A Hecht
- Division of Vector-Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Kris Hartzer
- Division of Vector-Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Emma S Jones
- Division of Vector-Borne Diseases, Office of the Director, Centers for Disease Control and Prevention, Fort Collins, CO, USA
| | - Brad J Biggerstaff
- Division of Vector-Borne Diseases, Office of the Director, Centers for Disease Control and Prevention, Fort Collins, CO, USA
| | - Shelby L Ford
- Division of Vector-Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
- Division of Vector-Borne Diseases, Bacterial Diseases Branch, Centers for Disease Control and Prevention, Fort Collins, CO, USA
| | - Sandor E Karpathy
- Division of Vector-Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Jesus Delgado-de la Mora
- Departamento de Anatomía Patológica, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Mexico, Mexico
| | - David Delgado-de la Mora
- Departamento de Anatomía Patológica, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Mexico, Mexico
| | | | - Jerome Goddard
- Department of Biochemistry, Molecular Biology, Entomology, and Plant Pathology, Mississippi State University, Starkville, MS, USA
| | - Michael L Levin
- Division of Vector-Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
| | - Christopher D Paddock
- Division of Vector-Borne Diseases, Rickettsial Zoonoses Branch, Centers for Disease Control and Prevention, Atlanta, GA, USA
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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: 1.8] [Reference Citation Analysis] [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.
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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
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Torres-Chable OM, Jimenez-Delgadillo BG, Alvarado-Kantún YN, Zaragoza-Vera CV, Arjona-Jimenez G, Zaragoza-Vera M, Baak-Baak CM, Cigarroa-Toledo N, Brito-Argaez LG, Machain-Williams C, Garcia-Rejon JE. Rickettsia parkeri (Rickettsiales: Rickettsiaceae) detected in Amblyomma maculatum ticks collected on dogs in Tabasco, Mexico. EXPERIMENTAL & APPLIED ACAROLOGY 2020; 82:431-440. [PMID: 33025238 DOI: 10.1007/s10493-020-00524-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 07/04/2020] [Indexed: 06/11/2023]
Abstract
The present study was carried out to identify Rickettsia species with zoonotic potential in ticks collected from dogs in a rural area in Tabasco, Mexico. In total 197 Amblyomma maculatum ticks were collected from 40 domestic dogs. The collected specimens were pooled and subjected to DNA extraction. A fragment (380 bp) of citrate synthase gene (gltA) was amplified by polymerase chain reaction (PCR) using universal primers for Rickettsia. A second PCR was later performed to amplify a fragment (420 bp) of the outer membrane protein B gene (ompB). The PCR products were purified, sequenced and compared using the basic local alignment search tool (BLAST). Twenty out of 40 (50%) tick pools assayed were positive for rickettsial DNA using both primer pairs. The consensus sequence obtained from the ompB gene fragments showed 99.5-100% of identity with strains of Rickettsia parkeri. This study provides the first molecular evidence of the presence of R. parkeri in A. maculatum ticks infesting domestic dogs from southeastern Mexico. Close contact between dogs and humans should lead to consider the infection caused by this species of Rickettsia among the differential diagnoses for people of Tabasco, Mexico, who show acute febrile syndrome associated to inoculation eschar and have a clinical history of tick exposure.
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Affiliation(s)
- Oswaldo M Torres-Chable
- Laboratorio de Enfermedades Tropicales y Transmitidas por Vector, División Académica de Ciencias Agropecuarias, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico.
| | - Bertha G Jimenez-Delgadillo
- Laboratorio de Enfermedades Infecciosas y Parasitarias 1, Facultad de Medicina, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - Yessenia N Alvarado-Kantún
- Laboratorio de Arbovirología, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - Claudia V Zaragoza-Vera
- Laboratorio de Enfermedades Tropicales y Transmitidas por Vector, División Académica de Ciencias Agropecuarias, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico
| | - Guadalupe Arjona-Jimenez
- Laboratorio de Enfermedades Tropicales y Transmitidas por Vector, División Académica de Ciencias Agropecuarias, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico
| | - Maritza Zaragoza-Vera
- Laboratorio de Enfermedades Tropicales y Transmitidas por Vector, División Académica de Ciencias Agropecuarias, Universidad Juárez Autónoma de Tabasco, Villahermosa, Tabasco, Mexico
| | - Carlos M Baak-Baak
- Laboratorio de Arbovirología, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - Nohemi Cigarroa-Toledo
- Laboratorio de Biología Celular, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, 97000, Mérida, Mexico
| | - Ligia Guadalupe Brito-Argaez
- Laboratorio de Bioquímica y Biología Molecular, Centro de Investigaciones Científicas de Yucatán (CICY), Mérida, Yucatán, Mexico
| | - Carlos Machain-Williams
- Laboratorio de Arbovirología, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - Julián E Garcia-Rejon
- Laboratorio de Arbovirología, Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
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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: 0.8] [Reference Citation Analysis] [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.
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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.
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Maestas LP, Reeser SR, McGay PJ, Buoni MH. Surveillance for Amblyomma maculatum (Acari: Ixodidae) and Rickettsia parkeri (Rickettsiales: Rickettsiaceae) in the State of Delaware, and Their Public Health Implications. JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:979-983. [PMID: 31917445 DOI: 10.1093/jme/tjz255] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Indexed: 06/10/2023]
Abstract
Amblyomma maculatum Koch is the primary vector of Rickettsia parkeri, the etiologic agent of tidewater spotted fever, and can also carry and transmit a variety of other pathogens. This tick historically has been a costly nuisance to livestock owners in the southeastern United States. Over the past 6 yr, A. maculatum has been collected in numbers sufficient to demonstrate their establishment in Kent County, Delaware, and the presence of R. parkeri has been documented. Our goals were to determine the geographic distribution of A. maculatum and R. parkeri in Delaware, and to equate this to relative risk to the public of encountering R. parkeri-infected ticks. We surveyed for ticks in four locations throughout the state from May to August 2019, and found established A. maculatum populations in all three counties. Laboratory analysis of collected specimens by quantitative polymerase chain reaction detected R. parkeri in A. maculatum populations across the state. These results indicate that A. maculatum could present a health risk to inhabitants of the state, and they also historically have posed a risk to the livestock industry, making them an important consideration in the development and implementation of continued tick surveillance efforts and future policies regarding tick management.
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Affiliation(s)
- Lauren P Maestas
- Delaware Division of Fish and Wildlife, Mosquito Control Section, Newark, DE
| | - Sean R Reeser
- Delaware Division of Fish and Wildlife, Mosquito Control Section, Newark, DE
| | - Patrick J McGay
- Delaware Division of Fish and Wildlife, Mosquito Control Section, Newark, DE
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Novel PCR exclusion assay to detect spotted fever group rickettsiae in the lone star tick (Amblyomma americanum). Ticks Tick Borne Dis 2020; 11:101453. [PMID: 32439385 DOI: 10.1016/j.ttbdis.2020.101453] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 04/10/2020] [Accepted: 04/19/2020] [Indexed: 01/22/2023]
Abstract
The lone star tick (Amblyomma americanum) is the most common and abundant human-biting tick in the southeastern United States where spotted fever rickettsioses frequently occur. However, the role of this tick in transmitting and maintaining pathogenic and non-pathogenic spotted fever group rickettsiae (SFGR) remains poorly defined. This is partially due to the high prevalence and abundance of Rickettsia amblyommatis in most populations of A. americanum. Many molecular assays commonly employed to detect rickettsiae use PCR primers that target highly conserved regions in the SFGR so low abundance rickettsia may not be detected when R. amblyommatis is present. It is costly and inefficient to test for low abundance rickettsial agents with multiple individual specific assays even when they are multiplexed, as most samples will be negative. Real time PCR assays may also be hampered by inadequate limits of detection (LODs) for low abundance agents. We exploited the absence of an otherwise relatively SFGR-conserved genome region in R. amblyommatis to design a hemi-nested PCR-assay which has a sensitivity of 10 copies in detecting the presence of most SFGR, but not R. amblyommatis in DNA of infected lone star ticks. This deletion is conserved in 21 isolates of R. amblyommatis obtained from multiple states. We demonstrated the assay's utility by detecting a pathogenic SFGR, Rickettsia parkeri, in 15/50 (30 %) of field collected A. americanum ticks that were previously screened with conventional assays and found to be positive for R. amblyommatis. These co-infected ticks included 1 questing female, 6 questing nymphs, and 8 attached males. The high prevalence of R. parkeri among host-attached ticks may be due to several variables and does not necessarily reflect the risk of disease transmission from attached ticks to vertebrate hosts. This novel assay can provide accurate estimates of the prevalence of less common SFGR in A. americanum and thus improve our understanding of the role of this tick in the maintenance and transmission of the SFGR commonly responsible for human rickettsioses.
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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 2019; 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] [Abstract] [Key Words] [MESH Headings] [Grants] [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.
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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.
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White A, Schaefer E, Thompson CW, Kribs CM, Gaff H. Dynamics of two pathogens in a single tick population. LETTERS IN BIOMATHEMATICS 2019; 6:50-66. [PMID: 33015353 PMCID: PMC7531760 DOI: 10.1080/23737867.2019.1682473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A mathematical model for a two-pathogen, one-tick, one-host system is presented and explored. The model system is based on the dynamics of Amblyomma americanum, Rickettsia parkeri, and Rickettsia amblyommatis. The goal of this model is to determine how long an invading pathogen, R. parkeri, persists within a tick population, A. americanum, in which a resident pathogen, R. amblyommatis, is already established. The numerical simulations of the model demonstrate the parameter ranges that allow for coexistence of the two pathogens. Sensitivity analysis highlights the importance of vector-borne, tick-to-host, transmission rates on the invasion reproductive number and persistence of the pathogens over time. The model is then applied to a case study based on a reclaimed swampland field site in south-eastern Virginia using field and laboratory data. The results pinpoint the thresholds required for persistence of both pathogens in the local tick population. However, R. parkeri, is not predicted to persist beyond 3 years. Understanding the persistence and coexistence of tick-borne pathogens will allow public health officials increased insight into tick-borne disease dynamics.
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Affiliation(s)
- Alexis White
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA
| | - Elsa Schaefer
- Department of Mathematics, Marymount University, Arlington, Virginia, USA
| | | | - Christopher M. Kribs
- Department of Mathematics, University of Texas at Arlington, Arlington, Texas, USA
| | - Holly Gaff
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA
- School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, South Africa
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Kelman P, Thompson CW, Hynes W, Bergman C, Lenahan C, Brenner JS, Brenner MG, Goodman B, Borges D, Filak M, Gaff H. Rickettsia parkeri infections diagnosed by eschar biopsy, Virginia, USA. Infection 2018; 46:559-563. [PMID: 29383651 DOI: 10.1007/s15010-018-1120-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 01/23/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND Infection with Rickettsia parkeri is an emerging tick-borne illness, often accompanied by fever and an eschar at the site of tick attachment. We present three cases of R. parkeri in Virginia residents. CASE PRESENTATIONS Case 1 presented initially afebrile, failed to seroconvert to rickettsial antigens, and was diagnosed by DNA testing of the eschar. Case 2 presented febrile with eschar, no serologies were performed, and was diagnosed by DNA testing of the eschar. Case 3 presented febrile with eschar, serologies were negative for rickettsial antigens, and was diagnosed by DNA testing of the eschar. CONCLUSION DNA testing of eschars represents an under-utilized diagnostic test and may aid in cases where the diagnosis is not made clinically.
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Affiliation(s)
| | | | | | | | | | - Joel S Brenner
- Eastern Virginia Medical School, Norfolk, VA, USA
- Children's Hospital of The King's Daughters, Norfolk, VA, USA
| | - Michelle G Brenner
- Eastern Virginia Medical School, Norfolk, VA, USA
- Children's Hospital of The King's Daughters, Norfolk, VA, USA
| | | | | | - Michael Filak
- Family Medicine Clifton/Centreville, Centreville, VA, USA
| | - Holly Gaff
- Old Dominion University, Norfolk, VA, USA.
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Lee JK, Stokes JV, Moraru GM, Harper AB, Smith CL, Wills RW, Varela-Stokes AS. Transmission of Amblyomma maculatum-Associated Rickettsia spp. During Cofeeding on Cattle. Vector Borne Zoonotic Dis 2018; 18:511-518. [PMID: 30063189 DOI: 10.1089/vbz.2017.2228] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Amblyomma maculatum is the primary vector for the spotted fever group rickettsiae, Rickettsia parkeri, a known pathogen, and "Candidatus Rickettsia andeanae," currently considered nonpathogenic. Spotted fever group rickettsiae are typically endothelial cell associated and rarely circulate in the blood. Horizontal transmission to naïve ticks through blood feeding from an infected host is likely rare. Cofeeding provides an opportunity for rickettsial transmission to naïve ticks in the absence of circulating rickettsiae. We evaluated R. parkeri transmission through cofeeding between A. maculatum adults and nymphs on beef calves. Six calves in each of two trials were infested with A. maculatum that had been capillary fed R. parkeri. Four days later, calves each received recipient A. maculatum that were either capillary fed "Ca. R. andeanae" or not capillary fed before infestation. Trials differed by whether we included a barrier to minimize adjacent feeding between recipient and donor ticks. After cofeeding, we detected R. parkeri in 27% of "Ca. R. andeanae"-free recipient ticks, whereas R. parkeri was not detected in any recipient ticks that were capillary fed "Ca. R. andeanae." Rickettsia parkeri transmission efficiency to naïve ticks was greater when ticks freely cofed in proximity. No rickettsial DNA was detected in calf blood. Results confirm cofeeding as a method of horizontal transmission of R. parkeri in the absence of host rickettsemia and suggest no evidence of transmission by cofeeding when recipient ticks are first exposed to "Ca. R. andeanae" through capillary feeding. While cofeeding may provide an opportunity for maintaining the pathogen, R. parkeri, the mechanisms driving any potential effect of "Ca. R. andeanae" on R. parkeri transmission are unclear.
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Affiliation(s)
- Jung Keun Lee
- 1 Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University , Mississippi State, Mississippi
| | - John V Stokes
- 1 Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University , Mississippi State, Mississippi
| | - Gail M Moraru
- 1 Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University , Mississippi State, Mississippi
| | - Amanda B Harper
- 1 Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University , Mississippi State, Mississippi
| | - Catherine L Smith
- 1 Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University , Mississippi State, Mississippi
| | - Robert W Wills
- 2 Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University , Mississippi State, Mississippi
| | - Andrea S Varela-Stokes
- 1 Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University , Mississippi State, Mississippi
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Phylogenetic Evidence for the Existence of Multiple Strains of Rickettsia parkeri in the New World. Appl Environ Microbiol 2018; 84:AEM.02872-17. [PMID: 29439989 DOI: 10.1128/aem.02872-17] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 02/05/2018] [Indexed: 11/20/2022] Open
Abstract
The bacterium Rickettsia parkeri has been reported to infect ticks of the "Amblyomma maculatum species complex" in the New World, where it causes spotted fever illness in humans. In South America, three additional rickettsial strains, namely, Atlantic rainforest, NOD, and Parvitarsum, have been isolated from the ticks Amblyomma ovale, Amblyomma nodosum, and Amblyomma parvitarsum, respectively. These three strains are phylogenetically closely related to R. parkeri, Rickettsia africae, and Rickettsia sibirica Herein, we performed a robust phylogenetic analysis encompassing 5 genes (gltA, ompA, virB4, dnaA, and dnaK) and 3 intergenic spacers (mppE-pur, rrl-rrf-ITS, and rpmE-tRNAfMet) from 41 rickettsial isolates, including different isolates of R. parkeri, R. africae, R. sibirica, Rickettsia conorii, and strains Atlantic rainforest, NOD, and Parvitarsum. In our phylogenetic analyses, all New World isolates grouped in a major clade distinct from the Old World Rickettsia species (R. conorii, R. sibirica, and R. africae). This New World clade was subdivided into the following 4 clades: the R. parkerisensu stricto clade, comprising the type strain Maculatum 20 and all other isolates of R. parkeri from North and South America, associated with ticks of the A. maculatum species complex; the strain NOD clade, comprising two South American isolates from A. nodosum ticks; the Parvitarsum clade, comprising two South American isolates from A. parvitarsum ticks; and the strain Atlantic rainforest clade, comprising six South American isolates from the A. ovale species complex (A. ovale or Amblyomma aureolatum). Under such evidences, we propose that strains Atlantic rainforest, NOD, and Parvitarsum are South American strains of R. parkeriIMPORTANCE Since the description of Rickettsia parkeri infecting ticks of the "Amblyomma maculatum species complex" and humans in the New World, three novel phylogenetic close-related rickettsial isolates were reported in South America. Herein, we provide genetic evidence that these novel isolates, namely, strains Atlantic rainforest, NOD, and Parvitarsum, are South American strains of R. parkeri. Interestingly, each of these R. parkeri strains seems to be primarily associated with a tick species group, namely, R. parkerisensu stricto with the "Amblyomma maculatum species group," R. parkeri strain NOD with Amblyomma nodosum, R. parkeri strain Parvitarsum with Amblyomma parvitarsum, and R. parkeri strain Atlantic rainforest with the "Amblyomma ovale species group." Such rickettsial strain-tick species specificity suggests a coevolution of each tick-strain association. Finally, because R. parkerisensu stricto and R. parkeri strain Atlantic rainforest are human pathogens, the potential of R. parkeri strains NOD and Parvitarsum to be human pathogens cannot be discarded.
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24
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Nadolny RM, Gaff HD. Natural history of Amblyomma maculatum in Virginia. Ticks Tick Borne Dis 2018; 9:188-195. [PMID: 28958704 PMCID: PMC5803413 DOI: 10.1016/j.ttbdis.2017.09.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 08/23/2017] [Accepted: 09/01/2017] [Indexed: 11/18/2022]
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.
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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
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25
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Allerdice MEJ, Beati L, Yaglom H, Lash RR, Delgado-de la Mora J, Licona-Enriquez JD, Delgado-de la Mora D, Paddock CD. Rickettsia parkeri (Rickettsiales: Rickettsiaceae) Detected in Ticks of the Amblyomma maculatum (Acari: Ixodidae) Group Collected from Multiple Locations in Southern Arizona. JOURNAL OF MEDICAL ENTOMOLOGY 2017; 54:1743-1749. [PMID: 28981813 DOI: 10.1093/jme/tjx138] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Indexed: 06/07/2023]
Abstract
Rickettsia parkeri is an emerging human pathogen transmitted by Amblyomma ticks in predominately tropical and subtropical regions of the western hemisphere. In 2014 and 2015, one confirmed case and one probable case of R. parkeri rickettsiosis were reported from the Pajarita Wilderness Area, a semi-arid mountainous region in southern Arizona. To examine more closely the potential public health risk of R. parkeri in this region, a study was initiated to investigate the pervasiveness of Amblyomma maculatum Koch group ticks in mountainous areas of southern Arizona and to ascertain the infection frequencies of R. parkeri in these ticks. During July 2016, a total of 182 adult ticks were collected and evaluated from the Pajarita Wilderness Area in Santa Cruz County and two additional sites in Cochise and Santa Cruz counties in southern Arizona. DNA of R. parkeri was detected in a total of 44 (24%) of these ticks. DNA of "Candidatus Rickettsia andeanae" and Rickettsia rhipicephali was detected in three (2%) and one (0.5%) of the samples, respectively. These observations corroborate previous collection records and indicate that established populations of A. maculatum group ticks exist in multiple foci in southern Arizona. The high frequency of R. parkeri in these tick populations suggests a public health risk as well as the need to increase education of R. parkeri rickettsiosis for those residing, working in, or visiting this area.
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Affiliation(s)
- Michelle E J Allerdice
- Rickettsial Zoonoses Branch, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA
| | - Lorenza Beati
- United States National Tick Collection, Institute for Coastal Plain Science, Georgia Southern University, Statesboro, GA
| | - Hayley Yaglom
- Office of Infectious Disease Services | Bureau of Epidemiology & Disease Control, Arizona Department of Health Services, Phoenix, AZ
| | - R Ryan Lash
- Travelers' Health Branch, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Diseases Control and Prevention, Atlanta, GA
| | | | | | - David Delgado-de la Mora
- Department of Agronomic and Veterinary Sciences, Technologic Institute of Sonora, Sonora, Mexico
| | - Christopher D Paddock
- Rickettsial Zoonoses Branch, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA
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26
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Harris EK, Verhoeve VI, Banajee KH, Macaluso JA, Azad AF, Macaluso KR. Comparative vertical transmission of Rickettsia by Dermacentor variabilis and Amblyomma maculatum. Ticks Tick Borne Dis 2017; 8:598-604. [PMID: 28433729 PMCID: PMC5702269 DOI: 10.1016/j.ttbdis.2017.04.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 02/18/2017] [Accepted: 04/04/2017] [Indexed: 11/26/2022]
Abstract
The geographical overlap of multiple Rickettsia and tick species coincides with the molecular detection of a variety of rickettsial agents in what may be novel tick hosts. However, little is known concerning transmissibility of rickettsial species by various tick hosts. To examine the vertical transmission potential between select tick and rickettsial species, two sympatric species of ticks, Dermacentor variabilis and Amblyomma maculatum, were exposed to five different rickettsial species, including Rickettsia rickettsii, Rickettsia parkeri, Rickettsia montanensis, Rickettsia amblyommatis, or flea-borne Rickettsia felis. Fitness-related metrics including engorgement weight, egg production index, nutrient index, and egg hatch percentage were then assessed. Subsamples of egg clutches and unfed larvae, nymphs, and adults for each cohort were assessed for transovarial and transstadial transmission of rickettsiae by qPCR. Rickettsial exposure had a minimal fitness effect in D. variabilis and transovarial transmission was observed for all groups except R. rickettsii. In contrast, rickettsial exposure negatively influenced A. maculatum fitness and transovarial transmission of rickettsiae was demonstrated only for R. amblyommatis- and R. parkeri-exposed ticks. Sustained maintenance of rickettsiae via transstadial transmission was diminished from F1 larvae to F1 adults in both tick species. The findings of this study suggest transovarial transmission specificity may not be tick species dependent, and sustained vertical transmission is not common.
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Affiliation(s)
- Emma K Harris
- Vector-Borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Dr., SVM-3213, Baton Rouge, LA, 70803, USA
| | - Victoria I Verhoeve
- Vector-Borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Dr., SVM-3213, Baton Rouge, LA, 70803, USA
| | - Kaikhushroo H Banajee
- Vector-Borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Dr., SVM-3213, Baton Rouge, LA, 70803, USA
| | - Jacqueline A Macaluso
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD, 21201, USA
| | - Abdu F Azad
- Department of Microbiology and Immunology, School of Medicine, University of Maryland, 685 W. Baltimore St., HSF I Suite 380, Baltimore, MD, 21201, USA
| | - Kevin R Macaluso
- Vector-Borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Skip Bertman Dr., SVM-3213, Baton Rouge, LA, 70803, USA.
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27
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Lee JK, Moraru GM, Stokes JV, Wills RW, Mitchell E, Unz E, Moore-Henderson B, Harper AB, Varela-Stokes AS. Rickettsia parkeri and "Candidatus Rickettsia andeanae" in Questing Amblyomma maculatum (Acari: Ixodidae) From Mississippi. JOURNAL OF MEDICAL ENTOMOLOGY 2017; 54:476-480. [PMID: 27773866 PMCID: PMC5850715 DOI: 10.1093/jme/tjw175] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 09/22/2016] [Indexed: 05/27/2023]
Abstract
Amblyomma maculatum Koch (Acari: Ixodidae), the primary vector for Rickettsia parkeri, may also be infected with a rickettsia of unknown pathogenicity, "Candidatus Rickettsia andeanae." Infection rates with these rickettsiae vary geographically, and coinfected ticks have been reported. In this study, infection rates of R. parkeri and "Ca. R. andeanae" were evaluated, and rickettsial DNA levels quantified, in 335 questing adult A. maculatum collected in 2013 (n = 95), 2014 (n = 139), and 2015 (n = 101) from Oktibbeha County, MS. Overall infection rates of R. parkeri and "Ca. R. andeanae" were 28.7% and 9.3%, respectively, with three additional A. maculatum (0.9%) coinfected. While R. parkeri-infected ticks were detected all three years (34.7% in 2013; 13.7% in 2014; 43.6% in 2015), "Ca. R. andeanae" was not detected in 2013, and was detected at rates of 10.8% in 2014, and 15.8% in 2015. Interestingly, rickettsial DNA levels in singly-infected ticks were significantly lower in "Ca. R. andeanae"-infected ticks compared to R. parkeri-infected ticks (P < 0.0001). Thus, both infection rates and rickettsial DNA levels were higher for R. parkeri than "Ca. R. andeanae." Infection rates of R. parkeri were also higher, and "Ca. R. andeanae" lower, here compared to A. maculatum reported previously in Kansas and Oklahoma. As we continue to monitor infection rates and levels, we anticipate that understanding temporal changes will improve our awareness of human risk for spotted fever rickettsioses. Further, these data may lead to additional studies to evaluate potential interactions among sympatric Rickettsia species in A. maculatum at the population level.
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Affiliation(s)
- J K Lee
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr., Mississippi State, MS 39762 (; ; ; ; ; ; ; )
| | - G M Moraru
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr., Mississippi State, MS 39762 (; ; ; ; ; ; ; )
| | - J V Stokes
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr., Mississippi State, MS 39762 (; ; ; ; ; ; ; )
| | - R W Wills
- Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr., Mississippi State, MS 39762
| | - E Mitchell
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr., Mississippi State, MS 39762 (; ; ; ; ; ; ; )
| | - E Unz
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr., Mississippi State, MS 39762 (; ; ; ; ; ; ; )
| | - B Moore-Henderson
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr., Mississippi State, MS 39762 (; ; ; ; ; ; ; )
| | - A B Harper
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr., Mississippi State, MS 39762 (; ; ; ; ; ; ; )
| | - A S Varela-Stokes
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr., Mississippi State, MS 39762 (; ; ; ; ; ; ; )
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28
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Mays SE, Houston AE, Trout Fryxell RT. Specifying Pathogen Associations of Amblyomma maculatum (Acari: Ixodidae) in Western Tennessee. JOURNAL OF MEDICAL ENTOMOLOGY 2016; 53:435-440. [PMID: 26744464 DOI: 10.1093/jme/tjv238] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Amblyomma maculatum Koch (Acari: Ixodidae) is established in western Tennessee, a region with increased risk for Rocky Mountain spotted fever and ehrlichiosis. This tick transmits Rickettsia parkeri to humans, likely contributing to cases of rickettsiosis in the region. The objective was to determine pathogen associations within questing and host-collected A. maculatum, and identify ecological factors associated with pathogen infection that may increase the effectiveness of surveillance methods. Of 265 ticks tested, 60 (22.6%) were infected with R. parkeri, and 15 (5.7%) with Candidatus Rickettsia andeanae, a Rickettsia of unknown pathogenicity. Two deer-collected ticks tested positive for Ehrlichia ewingii. No ticks were positive for Anaplasma or Borrelia species. None of the ecological factors tested (collection month, collection source, sex, and habitat type) were associated with R. parkeri infection. This project developed baseline prevalence and incidence data for monitoring pathogen prevalence in A. maculatum populations, and identified an inexpensive method for distinguishing R. parkeri from Ca. R. andeanae.
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29
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Henning TC, Orr JM, Smith JD, Arias JR, Rasgon JL, Norris DE. Discovery of filarial nematode DNA in Amblyomma americanum in Northern Virginia. Ticks Tick Borne Dis 2015; 7:315-8. [PMID: 26707835 DOI: 10.1016/j.ttbdis.2015.11.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 11/24/2015] [Accepted: 11/24/2015] [Indexed: 11/30/2022]
Abstract
Ticks collected in 2011 were screened for the presence of filarial nematode genetic material, and positive samples were sequenced for analysis. Monanema-like filarial nematode DNA was recently discovered in Amblyomma americanum in northern Virginia, marking the first time genetic material from this parasite has been discovered in ticks in the state. Phylogenetic analysis revealed that this material was directly related to a previously discovered filarial nematode in A. americanum populations in Maryland as well as recently identified parasites in Ixodes scapularis from southern Connecticut. Further study is warranted to visually confirm the presence of these nematodes, characterize their distribution, and determine if these ticks are intermediate hosts.
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Affiliation(s)
- Tyler C Henning
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St E5132, Baltimore, MD 21205, USA.
| | - John M Orr
- Fair County Health Department, Disease Carrying Insects Program, 10777 Main Street, Fairfax, VA 22030, USA.
| | - Joshua D Smith
- Fair County Health Department, Disease Carrying Insects Program, 10777 Main Street, Fairfax, VA 22030, USA.
| | - Jorge R Arias
- Fair County Health Department, Disease Carrying Insects Program, 10777 Main Street, Fairfax, VA 22030, USA.
| | - Jason L Rasgon
- Department of Entomology, the Center for Infectious Disease Dynamics and the Huck Institutes of the Life Sciences, Pennsylvania State University, W127 Millennium Sci Complex, University Park, PA 16802, USA.
| | - Douglas E Norris
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St E5132, Baltimore, MD 21205, USA.
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30
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Dahlgren FS, Paddock CD, Springer YP, Eisen RJ, Behravesh CB. Expanding Range of Amblyomma americanum and Simultaneous Changes in the Epidemiology of Spotted Fever Group Rickettsiosis in the United States. Am J Trop Med Hyg 2015; 94:35-42. [PMID: 26503270 DOI: 10.4269/ajtmh.15-0580] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 09/09/2015] [Indexed: 11/07/2022] Open
Abstract
Spotted fever group (SFG) Rickettsia species are etiologic agents of a wide range of human infections from asymptomatic or mild infections to severe, life-threatening disease. In the United States, recent passive surveillance for SFG rickettsiosis shows an increased incidence and decreased severity of reported cases. The reasons for this are not well understood; however, we hypothesize that less pathogenic rickettsiae are causing more human infections, while the incidence of disease caused by more pathogenic rickettsiae, particularly Rickettsia rickettsii, is relatively stable. During the same period, the range of Amblyomma americanum has expanded. Amblyomma americanum is frequently infected with "Candidatus Rickettsia amblyommii", a SFG Rickettsia of unknown pathogenicity. We tested our hypothesis by modeling incidence rates from 1993 to 2013, hospitalization rates from 1981 to 2013, and case fatality rates from 1981 to 2013 regressed against the presence of A. americanum, the decade of onset of symptoms, and the county of residence. Our results support the hypothesis, and we show that the expanding range of A. americanum is associated with changes in epidemiology reported through passive surveillance. We believe epidemiological and acarological data collected on individual cases from enhanced surveillance may further elucidate the reasons for the changing epidemiology of SFG rickettsiosis.
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Affiliation(s)
- F Scott Dahlgren
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia; Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado
| | - Christopher D Paddock
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia; Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado
| | - Yuri P Springer
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia; Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado
| | - Rebecca J Eisen
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia; Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado
| | - Casey Barton Behravesh
- Rickettsial Zoonoses Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia; Bacterial Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado
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31
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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. JOURNAL OF MEDICAL ENTOMOLOGY 2015; 52:1090-5. [PMID: 26336226 DOI: 10.1093/jme/tjv086] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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.
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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:
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32
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Banajee KH, Embers ME, Langohr IM, Doyle LA, Hasenkampf NR, Macaluso KR. Amblyomma maculatum Feeding Augments Rickettsia parkeri Infection in a Rhesus Macaque Model: A Pilot Study. PLoS One 2015; 10:e0135175. [PMID: 26244337 PMCID: PMC4526656 DOI: 10.1371/journal.pone.0135175] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 07/17/2015] [Indexed: 11/19/2022] Open
Abstract
Rickettsia parkeri is an emerging eschar-causing human pathogen in the spotted fever group of Rickettsia and is transmitted by the Gulf coast tick, Amblyomma maculatum. Tick saliva has been shown to alter both the cellular and humoral components of the innate and adaptive immune systems. However, the effect of this immunomodulation on Rickettsia transmission and pathology in an immunocompetent vertebrate host has not been fully examined. We hypothesize that, by modifying the host immune response, tick feeding enhances infection and pathology of pathogenic spotted fever group Rickettsia sp. In order to assess this interaction in vivo, a pilot study was conducted using five rhesus macaques that were divided into three groups. One group was intradermally inoculated with low passage R. parkeri (Portsmouth strain) alone (n = 2) and another group was inoculated during infestation by adult, R. parkeri-free A. maculatum (n = 2). The final macaque was infested with ticks alone (tick feeding control group). Blood, lymph node and skin biopsies were collected at several time points post-inoculation/infestation to assess pathology and quantify rickettsial DNA. As opposed to the tick-only animal, all Rickettsia-inoculated macaques developed inflammatory leukograms, elevated C-reactive protein concentrations, and elevated TH1 (interferon-γ, interleukin-15) and acute phase inflammatory cytokines (interleukin-6) post-inoculation, with greater neutrophilia and interleukin-6 concentrations in the tick plus R. parkeri group. While eschars formed at all R. parkeri inoculation sites, larger and slower healing eschars were observed in the tick feeding plus R. parkeri group. Furthermore, dissemination of R. parkeri to draining lymph nodes early in infection and increased persistence at the inoculation site were observed in the tick plus R. parkeri group. This study indicates that rhesus macaques can be used to model R. parkeri rickettsiosis, and suggests that immunomodulatory factors introduced during tick feeding may enhance the pathogenicity of spotted fever group Rickettsia.
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Affiliation(s)
- Kaikhushroo H. Banajee
- Vector-borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
| | - Monica E. Embers
- Division of Bacteriology and Parasitology, Tulane National Primate Research Center, Tulane University Health Sciences, Covington, Louisiana, United States of America
| | - Ingeborg M. Langohr
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Lara A. Doyle
- Division of Veterinary Medicine, Tulane National Primate Research Center, Tulane University Health Sciences Center, Covington, Louisiana, United States of America
| | - Nicole R. Hasenkampf
- Division of Bacteriology and Parasitology, Tulane National Primate Research Center, Tulane University Health Sciences, Covington, Louisiana, United States of America
| | - Kevin R. Macaluso
- Vector-borne Disease Laboratories, Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, 70803, United States of America
- * E-mail:
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Nadolny R, Gaff H, Carlsson J, Gauthier D. Comparative population genetics of two invading ticks: Evidence of the ecological mechanisms underlying tick range expansions. INFECTION GENETICS AND EVOLUTION 2015; 35:153-62. [PMID: 26254575 DOI: 10.1016/j.meegid.2015.08.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 07/29/2015] [Accepted: 08/04/2015] [Indexed: 11/18/2022]
Abstract
Two species of ixodid tick, Ixodes affinis Neumann and Amblyomma maculatum Koch, are simultaneously expanding their ranges throughout the mid-Atlantic region of the US. Although we have some understanding of the ecology and life history of these species, the ecological mechanisms governing where and how new populations establish and persist are unclear. To assess population connectivity and ancestry, we sequenced a fragment of the 16S mitochondrial rRNA gene from a representative sample of individuals of both species from populations throughout the eastern US. We found that despite overlapping host preferences throughout ontogeny, each species exhibited very different genetic and geographic patterns of population establishment and connectivity. I. affinis was of two distinct mitochondrial clades, with a clear geographic break separating northern and southern populations. Both I. affinis populations showed evidence of recent expansion, although the southern population was more genetically diverse, indicating a longer history of establishment. A. maculatum exhibited diverse haplotypes that showed no significant relationship with geographic patterns and little apparent connectivity between sites. Heteroplasmy was also observed in the 16S mitochondrial rRNA gene in 3.5% of A. maculatum individuals. Genetic evidence suggests that these species rely on different key life stages to successfully disperse into novel environments, and that host vagility, habitat stability and habitat connectivity all play critical roles in the establishment of new tick populations.
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Affiliation(s)
- Robyn Nadolny
- Old Dominion University, Dept. of Biological Sciences, Norfolk, VA, USA.
| | - Holly Gaff
- Old Dominion University, Dept. of Biological Sciences, Norfolk, VA, USA; University of KwaZulu-Natal, School of Mathematics, Statistics and Computer Science, South Africa
| | - Jens Carlsson
- Area 52 Research Group, School of Biology & Environment Science and Earth Institute, University College Dublin, Belfield, Dublin, Ireland
| | - David Gauthier
- Old Dominion University, Dept. of Biological Sciences, Norfolk, VA, USA
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Immunoproteomic profiling of Rickettsia parkeri and Rickettsia amblyommii. Ticks Tick Borne Dis 2015; 6:829-35. [PMID: 26234571 DOI: 10.1016/j.ttbdis.2015.07.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/16/2015] [Accepted: 07/20/2015] [Indexed: 11/22/2022]
Abstract
Rickettsia parkeri is an Amblyomma-associated, spotted fever group Rickettsia species that causes an eschar-associated, febrile illness in multiple countries throughout the Western Hemisphere. Many other rickettsial species of known or uncertain pathogenicity have been detected in Amblyomma spp. ticks in the Americas, including Rickettsia amblyommii, "Candidatus Rickettsia andeanae" and Rickettsia rickettsii. In this study, we utilized an immunoproteomic approach to compare antigenic profiles of low-passage isolates of R. parkeri and R. amblyommii with serum specimens from patients with PCR- and culture-confirmed infections with R. parkeri. Five immunoreactive proteins of R. amblyommii and nine immunoreactive proteins of R. parkeri were identified by matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry. Four of these, including the outer membrane protein (Omp) A, OmpB, translation initiation factor IF-2, and cell division protein FtsZ, were antigens common to both rickettsiae. Serum specimens from patients with R. parkeri rickettsiosis reacted specifically with cysteinyl-tRNA synthetase, DNA-directed RNA polymerase subunit alpha, putative sigma (54) modulation protein, chaperonin GroEL, and elongation factor Tu of R. parkeri which have been reported as virulence factors in other bacterial species. Unique antigens identified in this study may be useful for further development of the better serological assays for diagnosing infection caused by R. parkeri.
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Wright CL, Gaff HD, Sonenshine DE, Hynes WL. Experimental vertical transmission of Rickettsia parkeri in the Gulf Coast tick, Amblyomma maculatum. Ticks Tick Borne Dis 2015; 6:568-73. [PMID: 25958197 DOI: 10.1016/j.ttbdis.2015.04.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 04/16/2015] [Accepted: 04/21/2015] [Indexed: 11/24/2022]
Abstract
Rickettsia parkeri, an obligate intracellular bacterium, is a member of the spotted fever group of rickettsiae (SFGR), and is transmitted to humans and other animals by invertebrate vectors. In the United States, the primary vector of R. parkeri is the Gulf Coast tick, Amblyomma maculatum Koch. This study investigates the vertical transmission dynamics of R. parkeri within a field-derived, naturally infected colony of A. maculatum. Transovarial and transstadial transmission of the pathogen was observed over three generations, with transovarial transmission efficiency averaging 83.7% and transstadial transmission rates approaching 100%. Fitness costs were determined by comparing reproduction values of the R. parkeri-infected A. maculatum colony to values from a R. parkeri-free colony. No significant reproductive fitness costs to the host ticks were detected in the R. parkeri-infected A. maculatum colony. Significantly fewer engorged F1 nymphs and F2 larvae of the R. parkeri-free colony succeeded in molting, suggesting that there may be some advantage to survival conferred by R. parkeri. The results of this study indicate that R. parkeri is maintained in A. maculatum populations efficiently by transovarial and transstadial transmission without any noticeable effects on tick reproduction or survival.
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Affiliation(s)
- Chelsea L Wright
- Biological Sciences Department, Old Dominion University, Norfolk, VA, USA
| | - Holly D Gaff
- Biological Sciences Department, Old Dominion University, Norfolk, VA, USA; University of KwaZulu-Natal, Durban, South Africa
| | | | - Wayne L Hynes
- Biological Sciences Department, Old Dominion University, Norfolk, VA, USA.
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High prevalence of "Candidatus Rickettsia andeanae" and apparent exclusion of Rickettsia parkeri in adult Amblyomma maculatum (Acari: Ixodidae) from Kansas and Oklahoma. Ticks Tick Borne Dis 2015; 6:297-302. [PMID: 25773931 DOI: 10.1016/j.ttbdis.2015.02.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 01/29/2015] [Accepted: 02/03/2015] [Indexed: 11/23/2022]
Abstract
Amblyomma maculatum (the Gulf Coast tick), an aggressive, human-biting, Nearctic and Neotropical tick, is the principal vector of Rickettsia parkeri in the United States. This pathogenic spotted fever group Rickettsia species has been identified in 8-52% of questing adult Gulf Coast ticks in the southeastern United States. To our knowledge, R. parkeri has not been reported previously from adult specimens of A. maculatum collected in Kansas or Oklahoma. A total of 216 adult A. maculatum ticks were collected from 18 counties in Kansas and Oklahoma during 2011-2014 and evaluated by molecular methods for evidence of infection with R. parkeri. No infections with this agent were identified; however, 47% of 94 ticks collected from Kansas and 73% of 122 ticks from Oklahoma were infected with "Candidatus Rickettsia andeanae" a spotted fever group Rickettsia species of undetermined pathogenicity. These preliminary data suggest that "Ca. R. andeanae" is well-adapted to survival in populations of A. maculatum in Kansas and Oklahoma, and that its ubiquity in Gulf Coast ticks in these states may effectively exclude R. parkeri from their shared arthropod host, which could diminish markedly or preclude entirely the occurrence of R. parkeri rickettsiosis in this region of the United States.
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Henning TC, Orr JM, Smith JD, Arias JR, Norris DE. Spotted fever group rickettsiae in multiple hard tick species from Fairfax County, Virginia. Vector Borne Zoonotic Dis 2014; 14:482-5. [PMID: 24978651 DOI: 10.1089/vbz.2013.1534] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Spotted fever group rickettsiosis (SFGR) is a potentially fatal disease that has displayed increasing incidence in the United States in recent years. The most well-known and severe type of this disease is Rocky Mountain spotted fever, but there are other mild forms that occur. Recently, human infection with Rickettsia parkeri has been reported and linked with the tick Amblyomma maculatum. In 2010, a population of R. parkeri-infected A. maculatum was discovered in Fairfax County, Virginia, leading to increased surveillance of tick species. In this study, we report the presence of R. parkeri in Rhipicephalus sanguineus, Haemaphysalis leporispalustris, and Dermacentor variabilis in Fairfax County. R. parkeri was discovered in two Rh. sanguineus, one H. leporispalustris, and 17 D. variabilis. These findings suggest that spillover infections of R. parkeri may be occurring in tick species not typically associated with this pathogen; however, vector competence studies need to be conducted to determine if these tick species can serve as potential vectors for human SFGR.
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Affiliation(s)
- Tyler C Henning
- 1 The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland
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Gaines DN, Operario DJ, Stroup S, Stromdahl E, Wright C, Gaff H, Broyhill J, Smith J, Norris DE, Henning T, Lucas A, Houpt E. Ehrlichia and spotted fever group Rickettsiae surveillance in Amblyomma americanum in Virginia through use of a novel six-plex real-time PCR assay. Vector Borne Zoonotic Dis 2014; 14:307-16. [PMID: 24746145 DOI: 10.1089/vbz.2013.1509] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The population of the lone star tick Amblyomma americanum has expanded in North America over the last several decades. It is known to be an aggressive and nondiscriminatory biter and is by far the most common human-biting tick encountered in Virginia. Few studies of human pathogen prevalence in ticks have been conducted in our state since the mid-twentieth century. We developed a six-plex real-time PCR assay to detect three Ehrlichia species (E. chaffeensis, E. ewingii, and Panola Mountain Ehrlichia) and three spotted fever group Rickettsiae (SFGR; R. amblyommii, R. parkeri, and R. rickettsii) and used it to test A. americanum from around the state. Our studies revealed a presence of all three Ehrlichia species (0-24.5%) and a high prevalence (50-80%) of R. amblyommii, a presumptively nonpathogenic SFGR, in all regions surveyed. R. parkeri, previously only detected in Virginia's Amblyomma maculatum ticks, was found in A. americanum in several surveyed areas within two regions having established A. maculatum populations. R. rickettsii was not found in any sample tested. Our study provides the first state-wide screening of A. americanum ticks in recent history and indicates that human exposure to R. amblyommii and to Ehrlichiae may be common. The high prevalence of R. amblyommii, serological cross-reactivity of all SFGR members, and the apparent rarity of R. rickettsii in human biting ticks across the eastern United States suggest that clinical cases of tick-borne disease, including ehrlichiosis, may be commonly misdiagnosed as Rocky Mountain spotted fever, and that suspicion of other SFGR as well as Ehrlichia should be increased. These data may be of relevance to other regions where A. americanum is prevalent.
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Cortinas R, Spomer SM. Occurrence and county-level distribution of ticks (Acari: Ixodoidea) in Nebraska using passive surveillance. JOURNAL OF MEDICAL ENTOMOLOGY 2014; 51:352-359. [PMID: 24724283 DOI: 10.1603/me13122] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A 100 yr (1911-2011) examination of tick submissions was compiled from the U.S. National Tick Collection and three state databases to determine tick species occurrence in Nebraska Sixteen tick species were identified including Amblyomma americanum (L.), Dermacentor variabilis (Say), Dermacentor albipictus (Packard), Dermacentor andersoni Stiles, Haemaphysalis leporispalustris (Packard), Rhipicephalus sanguineus (Latreille), and Otobius megrini (Dughs). Amblyomma maculatum Koch and Ixodes scapularis Say were identified in only two and four submissions, respectively, but all identifications have occurred after 1990. County submissions were associated with county population, forested area, and number of recreation areas.
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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: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [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.
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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
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Parola P, Paddock CD, Socolovschi C, Labruna MB, Mediannikov O, Kernif T, Abdad MY, Stenos J, Bitam I, Fournier PE, Raoult D. Update on tick-borne rickettsioses around the world: a geographic approach. Clin Microbiol Rev 2013; 26:657-702. [PMID: 24092850 PMCID: PMC3811236 DOI: 10.1128/cmr.00032-13] [Citation(s) in RCA: 986] [Impact Index Per Article: 82.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia. These zoonoses are among the oldest known vector-borne diseases. However, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. Several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections, and novel Rickettsia species of undetermined pathogenicity continue to be detected in or isolated from ticks around the world. This remarkable expansion of information has been driven largely by the use of molecular techniques that have facilitated the identification of novel and previously recognized rickettsiae in ticks. New approaches, such as swabbing of eschars to obtain material to be tested by PCR, have emerged in recent years and have played a role in describing emerging tick-borne rickettsioses. Here, we present the current knowledge on tick-borne rickettsiae and rickettsioses using a geographic approach toward the epidemiology of these diseases.
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Affiliation(s)
- Philippe Parola
- Aix Marseille Université, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), UM63, CNRS 7278, IRD 198, Inserm 1095, WHO Collaborative Center for Rickettsioses and Other Arthropod-Borne Bacterial Diseases, Faculté de Médecine, Marseille, France
| | | | - Cristina Socolovschi
- Aix Marseille Université, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), UM63, CNRS 7278, IRD 198, Inserm 1095, WHO Collaborative Center for Rickettsioses and Other Arthropod-Borne Bacterial Diseases, Faculté de Médecine, Marseille, France
| | - Marcelo B. Labruna
- Departamento de Medicina Veterinária Preventiva e Saúde Animal, Faculdade de Medicina Veterinária e Zootecnia Universidade de São Paulo, Cidade Universitária, São Paulo, SP, Brazil
| | - Oleg Mediannikov
- Aix Marseille Université, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), UM63, CNRS 7278, IRD 198, Inserm 1095, WHO Collaborative Center for Rickettsioses and Other Arthropod-Borne Bacterial Diseases, Faculté de Médecine, Marseille, France
| | - Tahar Kernif
- Service d'Ecologie des Systèmes Vectoriels, Institut Pasteur d'Algérie, Algiers, Algeria
| | - Mohammad Yazid Abdad
- Division of Veterinary and Biomedical Science, Murdoch University, Australian Rickettsial Reference Laboratory, Barwon Health, Geelong, Victoria, Australia
| | - John Stenos
- Division of Veterinary and Biomedical Science, Murdoch University, Australian Rickettsial Reference Laboratory, Barwon Health, Geelong, Victoria, Australia
| | - Idir Bitam
- University of Boumerdes, Boumerdes, Algeria
| | - Pierre-Edouard Fournier
- Aix Marseille Université, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), UM63, CNRS 7278, IRD 198, Inserm 1095, WHO Collaborative Center for Rickettsioses and Other Arthropod-Borne Bacterial Diseases, Faculté de Médecine, Marseille, France
| | - Didier Raoult
- Aix Marseille Université, Unité de Recherche en Maladies Infectieuses et Tropicales Emergentes (URMITE), UM63, CNRS 7278, IRD 198, Inserm 1095, WHO Collaborative Center for Rickettsioses and Other Arthropod-Borne Bacterial Diseases, Faculté de Médecine, Marseille, France
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Ferrari FAG, Goddard J, Moraru GM, Smith WEC, Varela-Stokes AS. Isolation of "Candidatus Rickettsia andeanae" (Rickettsiales: Rickettsiaceae) in embryonic cells of naturally infected Amblyomma maculatum (Ixodida: Ixodidae). JOURNAL OF MEDICAL ENTOMOLOGY 2013; 50:1118-1125. [PMID: 24180118 DOI: 10.1603/me13010] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The Gulf Coast tick, Amblyomma maculatum Koch, has become increasingly important in public health for its role as a vector of the recently recognized human pathogen, Rickettsia parkeri. More recently, these ticks were also found to harbor a novel spotted fever group rickettsia, "Candidatus Rickettsia andeanae." First identified in Peru, and subsequently reported in ticks collected in the United States, Chile, and Argentina, "Ca. R. andeanae" remains largely uncharacterized, in part because of the lack of a stable isolate. Although the isolation of "Ca. R. andeanae" was recently described in DH82, Vero, and Drosophila S2 cells, its stability in these cell lines was not shown. To evaluate "Ca. R. andeanae" transmission and pathogenicity in vertebrates, as well as further describe biological characteristics of this candidate species to fulfill criteria for its establishment as a new species, availability of a stable isolate is essential. Here we describe the propagation of "Ca. R. andeanae" by using a primary culture derived from naturally infected A. maculatum embryos. Subsequent passage of the "Ca. R. andeanae" isolate to ISE6 (Ixodes scapularis embryonic) and Vero (African green monkey kidney epithelial) cell lines demonstrated limited propagation of the rickettsiae. Treatment of the infected primary cells with tetracycline resulted in cultures negative for "Ca. R. andeanae" by polymerase chain reaction and microscopy. Establishment of an isolate of "Ca. R. andeanae" will promote further investigation into the significance of this tick-associated rickettsia, including its role in spotted fever and interactions with the sympatric species, R. parkeri in A.
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Affiliation(s)
- F A G Ferrari
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, 240 Wise Center Dr., Mississippi State, MS 39762, USA
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Moraru GM, Goddard J, Paddock CD, Varela-Stokes A. Experimental infection of cotton rats and bobwhite quail with Rickettsia parkeri. Parasit Vectors 2013; 6:70. [PMID: 23497681 PMCID: PMC3606396 DOI: 10.1186/1756-3305-6-70] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Accepted: 02/19/2013] [Indexed: 11/10/2022] Open
Abstract
Background Amblyomma maculatum is the primary vector for Rickettsia parkeri, a spotted fever group rickettsia (SFGR) and human pathogen. Cotton rats and quail are known hosts for larval and nymphal A. maculatum; however, the role of these hosts in the ecology of R. parkeri is unknown. Methods Cotton rats and quail were inoculated with low or high doses of R. parkeri (strain Portsmouth) grown in Vero cells to evaluate infection by R. parkeri in these two hosts species. Animals were euthanized 2, 4, 7, 10, and 14 days post-injection (dpi) and blood, skin, and spleen samples were collected to analyze by Vero cell culture and polymerase chain reaction (PCR). In a second trial, cotton rats and quail were inoculated with R. parkeri and nymphal A. maculatum ticks were allowed to feed on animals. Animals were euthanized on 14, 20, 28, 31, and 38 dpi and blood and tissues were collected for serology and PCR assays. Fed ticks were tested for R. parkeri by PCR and Vero cell culture. Results Rickettsia parkeri was isolated in cell culture and detected by PCR in skin, blood, and spleen tissues of cotton rats in the initial trial 2, 4, and 7 dpi, but not in quail tissues. In the second trial, no ticks tested positive for R. parkeri by PCR or cell culture. Conclusions These studies demonstrate that viable R. parkeri rickettsiae can persist in the tissues of cotton rats for at least 7 days following subcutaneous inoculation of these bacteria; however, quail are apparently resistant to infection. Rickettsia parkeri was not detected in nymphal ticks that fed on R. parkeri-inoculated cotton rats or quail, suggesting an alternate route of transmission to naïve ticks.
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Affiliation(s)
- Gail Miriam Moraru
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Wise Center, Spring Street, Mississippi State, MS 39762, USA
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Hamer SA, Goldberg TL, Kitron UD, Brawn JD, Anderson TK, Loss SR, Walker ED, Hamer GL. Wild birds and urban ecology of ticks and tick-borne pathogens, Chicago, Illinois, USA, 2005-2010. Emerg Infect Dis 2013; 18:1589-95. [PMID: 23017244 PMCID: PMC3471635 DOI: 10.3201/eid1810.120511] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
No longer do you have to visit rural areas to find ticks; birds are flying them directly to you. When researchers sampled several thousand birds in Chicago, they found that some carried ticks and that some of these ticks carried the organism that spreads Lyme disease. Although the number of infected ticks on these birds was low, risk for their invading an area and spreading infection to humans cannot be ignored. If conditions are favorable, a few infected ticks can quickly multiply. Migratory birds also carried tick species only known to be established in Central and South America. Limited introduction and successful establishment of ticks and disease-carrying organisms pose a major health risk for humans, wildlife, and domestic animals in urban environments worldwide. Bird-facilitated introduction of ticks and associated pathogens is postulated to promote invasion of tick-borne zoonotic diseases into urban areas. Results of a longitudinal study conducted in suburban Chicago, Illinois, USA, during 2005–2010 show that 1.6% of 6,180 wild birds captured in mist nets harbored ticks. Tick species in order of abundance were Haemaphysalis leporispalustris, Ixodes dentatus, and I. scapularis, but 2 neotropical tick species of the genus Amblyomma were sampled during the spring migration. I. scapularis ticks were absent at the beginning of the study but constituted the majority of ticks by study end and were found predominantly on birds captured in areas designated as urban green spaces. Of 120 ticks, 5 were infected with Borrelia burgdorferi, spanning 3 ribotypes, but none were infected with Anaplasma phagocytophilum. Results allow inferences about propagule pressure for introduction of tick-borne diseases and emphasize the large sample sizes required to estimate this pressure.
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Affiliation(s)
- Sarah A Hamer
- Michigan State University, East Lansing, Michigan, USA.
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Ferrari FAG, Goddard J, Paddock CD, Varela-Stokes AS. Rickettsia parkeri and Candidatus Rickettsia andeanae in Gulf Coast ticks, Mississippi, USA. Emerg Infect Dis 2013; 18:1705-7. [PMID: 23018026 PMCID: PMC3471625 DOI: 10.3201/eid1810.120250] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
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Leydet BF, Liang FT. Detection of human bacterial pathogens in ticks collected from Louisiana black bears (Ursus americanus luteolus). Ticks Tick Borne Dis 2013; 4:191-6. [PMID: 23415850 DOI: 10.1016/j.ttbdis.2012.12.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 11/30/2012] [Accepted: 12/07/2012] [Indexed: 11/30/2022]
Abstract
There are 4 major human-biting tick species in the northeastern United States, which include: Amblyomma americanum, Amblyomma maculatum, Dermacentor variabilis, and Ixodes scapularis. The black bear is a large mammal that has been shown to be parasitized by all the aforementioned ticks. We investigated the bacterial infections in ticks collected from Louisiana black bears (Ursus americanus subspecies luteolus). Eighty-six ticks were collected from 17 black bears in Louisiana from June 2010 to March 2011. All 4 common human-biting tick species were represented. Each tick was subjected to polymerase chain reaction (PCR) targeting select bacterial pathogens and symbionts. Bacterial DNA was detected in 62% of ticks (n=53). Rickettsia parkeri, the causative agent of an emerging spotted fever group rickettsiosis, was identified in 66% of A. maculatum, 28% of D. variabilis, and 11% of I. scapularis. The Lyme disease bacterium, Borrelia burgdorferi, was detected in 2 I. scapularis, while one A. americanum was positive for Borrelia bissettii, a putative human pathogen. The rickettsial endosymbionts Candidatus Rickettsia andeanae, rickettsial endosymbiont of I. scapularis, and Rickettsia amblyommii were detected in their common tick hosts at 21%, 39%, and 60%, respectively. All ticks were PCR-negative for Anaplasma phagocytophilum, Ehrlichia spp., and Babesia microti. This is the first reported detection of R. parkeri in vector ticks in Louisiana; we also report the novel association of R. parkeri with I. scapularis. Detection of both R. parkeri and B. burgdorferi in their respective vectors in Louisiana demands further investigation to determine potential for human exposure to these pathogens.
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Affiliation(s)
- Brian F Leydet
- Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA.
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Fornadel CM, Smith JD, Zawada SE, Arias JR, Norris DE. Detection of Rickettsia massiliae in Rhipicephalus sanguineus from the eastern United States. Vector Borne Zoonotic Dis 2012. [PMID: 23199270 DOI: 10.1089/vbz.2012.1058] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
We report the first evidence of Rickettsia massiliae in the brown dog tick, Rhipicephalus sanguineus, from the East Coast of the United States. As part of routine pathogen surveillance, DNA samples from ixodid ticks were tested for spotted fever group rickettsiae by nested PCR. A R. massiliae-positive tick was collected off a beagle mix recently rescued from North Carolina. Infection was confirmed by partial sequence analysis of the htrA, gltA, ompB, ompA, and sca4 genes, which had 100% identity to a R. massiliae isolate from Arizona.
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Affiliation(s)
- Christen M Fornadel
- The W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205-2179, USA.
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Stromdahl EY, Hickling GJ. Beyond Lyme: Aetiology of Tick-borne Human Diseases with Emphasis on the South-Eastern United States. Zoonoses Public Health 2012; 59 Suppl 2:48-64. [DOI: 10.1111/j.1863-2378.2012.01475.x] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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