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Tufts DM, Goethert HK, Diuk-Wasser MA. Host-pathogen associations inferred from bloodmeal analyses of Ixodes scapularis ticks in a low biodiversity setting. Appl Environ Microbiol 2024; 90:e0066724. [PMID: 39207157 PMCID: PMC11409645 DOI: 10.1128/aem.00667-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Accepted: 08/14/2024] [Indexed: 09/04/2024] Open
Abstract
Tick-borne pathogen emergence is dependent on the abundance and distribution of competent hosts in the environment. Ixodes scapularis ticks are generalist feeders, and their pathogen infection prevalence depends on their relative feeding on local competent and non-competent hosts. The ability to determine what host a larval life stage tick fed on can help predict infection prevalence, emergence, and spread of certain tick-borne pathogens and the risks posed to public health. Here, we use a newly developed genomic target-based technique to detect the source of larval bloodmeals by sampling questing nymphs from Block Island, RI, a small island with a depauperate mammalian community. We used previously designed specific assays to target all known hosts on this island and analyzed ticks for four human pathogenic tick-borne pathogens. We determined the highest proportion of larvae fed on avian species (42.34%), white-footed mice (36.94%), and white-tailed deer (20.72%) and occasionally fed on feral cats, rats, and voles, which are in low abundance on Block Island. Additionally, larvae that had fed on white-footed mice were significantly more likely to be infected with Borrelia burgdorferi and Babesia microti, while larvae that had fed on white-footed mice or white-tailed deer were significantly more likely to be infected with, respectively, mouse- and deer-associated genotypes of Anaplasma phagocytophilum. The ability to detect a nymph's larval host allows for a better understanding of tick feeding behavior, host distribution, pathogen prevalence, and zoonotic risks to humans, which can contribute to better tick management strategies. IMPORTANCE Tick-borne diseases, such as Lyme disease, babesiosis, and anaplasmosis, pose significant public health burdens. Tick bloodmeal analysis provides a noninvasive sampling method to evaluate tick-host associations and combined with a zoonotic pathogen assay, can generate crucial insights into the epidemiology and transmission of tick-borne diseases by identifying potential key maintenance hosts. We investigated the bloodmeals of questing Ixodes scapularis nymphs. We found that avian hosts, white-footed mice, and white-tailed deer fed the majority of larval ticks and differentially contributed to the prevalence of multiple tick-borne pathogens and pathogen genotypes in a low biodiversity island setting. Unraveling the intricate network of host-vector-pathogen interactions will contribute to improving wildlife management and conservation efforts, to developing targeted surveillance, and vector and host control efforts, ultimately reducing the incidence of tick-borne diseases and improving public health.
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Affiliation(s)
- Danielle M. Tufts
- Infectious Diseases and Microbiology Department, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Veterinary Tropical Diseases, University of Pretoria, Pretoria, South Africa
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, New York, USA
| | - Heidi K. Goethert
- Cummings School of Veterinary Medicine, Tufts University, Grafton, Massachusetts, USA
| | - Maria A. Diuk-Wasser
- Department of Ecology, Evolution, and Environmental Biology, Columbia University, New York, New York, USA
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2
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Pascoe EL, Vaughn CE, Jones MI, Barrett RH, Foley JE, Lane RS. Recovery of western black-legged tick and vertebrate populations after a destructive wildfire in an intensively-studied woodland in northern California. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2023; 48:19-36. [PMID: 37255356 DOI: 10.52707/1081-1710-48.1.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 12/13/2022] [Indexed: 06/01/2023]
Abstract
Despite increasing severity and frequency of wildfires, knowledge about how fire impacts the ecology of tick-borne pathogens is limited. In 2018, the River Fire burned a forest in the far-western U.S.A. where the ecology of tick-borne pathogens had been studied for decades. Forest structure, avifauna, large and small mammals, lizards, ticks, and tick-borne pathogens (Anaplasma phagocytophilum, Borrelia burgdorferi, Borrelia miyamotoi) were assessed after the wildfire in 2019 and 2020. Burning reduced canopy cover and eliminated the layer of thick leaf litter that hosted free-living ticks, which over time was replaced by forbs and grasses. Tick abundance and the vertebrate host community changed dramatically. Avian species adapted to cavity nesting became most prevalent, while the number of foliage-foraging species increased by 83% as vegetation regenerated. Nine mammalian species were observed on camera traps, including sentinel (black-tailed jackrabbits) and reservoir hosts (western gray squirrels) of B. burgdorferi. One Peromyscus sp. mouse was captured in 2019 but by 2020, numbers were rebounding (n=37), although tick infestations on rodents remained sparse (0.2/rodent). However, western fence lizards (n=19) hosted 8.6 ticks on average in 2020. Assays for pathogens found no B. miyamotoi in either questing or host-feeding ticks, A. phagocytophilum DNA in 4% (1/23) in 2019, and 17% (29/173) in 2020 for questing and host-feeding ticks combined, and B. burgdorferi DNA in just 1% of all ticks collected in 2020 (2/173). We conclude that a moderately severe wildfire can have dramatic impacts on the ecology of tick-borne pathogens, with changes posited to continue for multiple years.
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Affiliation(s)
- Emily L Pascoe
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, U.S.A.,
| | - Charles E Vaughn
- University of California Hopland Research and Extension Center, Hopland, CA 95449, U.S.A
| | - Michael I Jones
- University of California Cooperative Extension-Mendocino County, Ukiah, CA 95482, U.S.A
| | - Reginald H Barrett
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, U.S.A
| | - Janet E Foley
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, U.S.A
| | - Robert S Lane
- Department of Environmental Science, Policy and Management, University of California, Berkeley, CA 94720, U.S.A
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3
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O’Connor C, Prusinski MA, Jiang S, Russell A, White J, Falco R, Kokas J, Vinci V, Gall W, Tober K, Haight J, Oliver J, Meehan L, Sporn LA, Brisson D, Backenson PB. A Comparative Spatial and Climate Analysis of Human Granulocytic Anaplasmosis and Human Babesiosis in New York State (2013-2018). JOURNAL OF MEDICAL ENTOMOLOGY 2021; 58:2453-2466. [PMID: 34289040 PMCID: PMC8824452 DOI: 10.1093/jme/tjab107] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Indexed: 05/25/2023]
Abstract
Human granulocytic anaplasmosis (HGA) and human babesiosis are tick-borne diseases spread by the blacklegged tick (Ixodes scapularis Say, Acari: Ixodidae) and are the result of infection with Anaplasma phagocytophilum and Babesia microti, respectively. In New York State (NYS), incidence rates of these diseases increased concordantly until around 2013, when rates of HGA began to increase more rapidly than human babesiosis, and the spatial extent of the diseases diverged. Surveillance data of tick-borne pathogens (2007 to 2018) and reported human cases of HGA (n = 4,297) and human babesiosis (n = 2,986) (2013-2018) from the New York State Department of Health (NYSDOH) showed a positive association between the presence/temporal emergence of each pathogen and rates of disease in surrounding areas. Incidence rates of HGA were higher than human babesiosis among White and non-Hispanic/non-Latino individuals, as well as all age and sex groups. Human babesiosis exhibited higher rates among non-White individuals. Climate, weather, and landscape data were used to build a spatially weighted zero-inflated negative binomial (ZINB) model to examine and compare associations between the environment and rates of HGA and human babesiosis. HGA and human babesiosis ZINB models indicated similar associations with forest cover, forest land cover change, and winter minimum temperature; and differing associations with elevation, urban land cover change, and winter precipitation. These results indicate that tick-borne disease ecology varies between pathogens spread by I. scapularis.
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Affiliation(s)
- Collin O’Connor
- New York State Department of Health, Bureau of Communicable Disease Control, Albany, NY, USA
| | - Melissa A Prusinski
- New York State Department of Health, Bureau of Communicable Disease Control, Albany, NY, USA
| | - Shiguo Jiang
- State University of New York, University at Albany, Department of Geography and Planning, Albany, NY, USA
| | - Alexis Russell
- New York State Department of Health, Bureau of Communicable Disease Control, Albany, NY, USA
- Wadsworth Center, Division of Infectious Disease, Albany, NY, USA
| | - Jennifer White
- New York State Department of Health, Bureau of Communicable Disease Control, Albany, NY, USA
| | - Richard Falco
- New York State Department of Health, Bureau of Communicable Disease Control, Armonk, NY, USA
| | - John Kokas
- New York State Department of Health, Bureau of Communicable Disease Control, Armonk, NY, USA
- Retired
| | - Vanessa Vinci
- New York State Department of Health, Bureau of Communicable Disease Control, Armonk, NY, USA
| | - Wayne Gall
- New York State Deparment of Health, Bureau of Communicable Disease Control, Buffalo, NY, USA
- United States Department of Agriculture, Animal and Plant Health Inspection Service, Buffalo, NY, USA
| | - Keith Tober
- New York State Deparment of Health, Bureau of Communicable Disease Control, Buffalo, NY, USA
- Retired
| | - Jamie Haight
- New York State Department of Health, Bureau of Communicable Disease Control, Falconer, NY, USA
| | - JoAnne Oliver
- New York State Department of Health, Bureau of Communicable Disease Control, Syracuse, NY, USA
| | - Lisa Meehan
- New York State Department of Health, Bureau of Communicable Disease Control, Albany, NY, USA
- Wadsworth Center, Division of Environmental Health Sciences, Albany, NY, USA
| | - Lee Ann Sporn
- Paul Smith’s College, Department of Natural Science, Paul Smiths, NY, USA
| | - Dustin Brisson
- University of Pennsylvania, Department of Biology, Philadelphia, PA, USA
| | - P Bryon Backenson
- New York State Department of Health, Bureau of Communicable Disease Control, Albany, NY, USA
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4
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Pascoe EL, Plourde BT, Lopéz-Perez AM, Foley JE. Response of small mammal and tick communities to a catastrophic wildfire and implications for tick-borne pathogens. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2020; 45:269-284. [PMID: 33207067 DOI: 10.1111/jvec.12398] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 07/25/2020] [Indexed: 06/11/2023]
Abstract
Through their potentially devastating impacts on the environment, wildfires may impact pathogen, vector, and host interactions, leading to changing risks of vector-borne disease in humans and other animals. Despite established risks for tick-borne disease and increasing frequency and severity of wildfires in the United States, impacts of wildfire on ticks and tick-borne pathogens are understudied. In 2015, the large Wragg fire extensively burned a long-term field site at Stebbins Cold Canyon University of California Reserve (CC). We characterized the tick, reservoir host and pathogen community over a two-year period after the burn, comparing our findings to pre-fire data and to data from Quail Ridge Reserve (QR), a nearby unburned site. After the fire, there were 5.5 times more rodent, primarily Peromyscus spp., captures at CC than QR (compared to 3.5 times more pre-fire). There were significantly fewer dusky-footed woodrats (Neotoma fuscipes) at both sites post-fire, likely due to drought but not fire. Pre-fire tick infestation prevalence on rodents was comparable across sites (12.5% at CC and 9.9% at QR) and remained low at CC post-fire (13.7%) but was significantly higher at QR (48.0%), suggesting that ticks or their habitat were destroyed during the burn. Normalized difference vegetation indices documented a 16-fold loss of vegetation post- compared to pre-fire at CC; loss of vegetation and direct impacts on fauna are likely the main drivers of the post-fire differences in ticks we saw at CC. These data contribute to our understanding of tick-associated disease risks in our increasingly disturbed landscapes.
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Affiliation(s)
- Emily L Pascoe
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616, U.S.A
| | - Benjamin T Plourde
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616, U.S.A
| | - Andrés M Lopéz-Perez
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616, U.S.A
| | - Janet E Foley
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, 95616, U.S.A
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5
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Dumler JS, Lichay M, Chen WH, Rennoll-Bankert KE, Park JH. Anaplasma phagocytophilum Activates NF-κB Signaling via Redundant Pathways. Front Public Health 2020; 8:558283. [PMID: 33194960 PMCID: PMC7661751 DOI: 10.3389/fpubh.2020.558283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 09/22/2020] [Indexed: 11/28/2022] Open
Abstract
Anaplasma phagocytophilum subverts neutrophil function permitting intracellular survival, propagation and transmission. Sustained pro-inflammatory response, recruitment of new host cells for population expansion, and delayed apoptosis are associated with prolonged nuclear presence of NF-κB. We investigated NF-κB signaling and transcriptional activity with A. phagocytophilum infection using inhibitors of NF-κB signaling pathways, and through silencing of signaling pathway genes. How inhibitors or silencing affected A. phagocytophilum growth, inflammatory response (transcription of the κB-enhanced genes CXCL8 and MMP9), and NF-κB signaling pathway gene expression were tested. Among A. phagocytophilum-infected HL-60 cells, nuclear NF-κB p50, p65, and p52 were detected by immunoblots or iTRAQ proteomics. A. phagocytophilum growth was affected most by the IKKαβ inhibitor wedelolactone (reductions of 96 to 99%) as compared with SC-514 that selectively inhibits IKKβ, illustrating a role for the non-canonical pathway. Wedelolactone inhibited transcription of both CXCL8 (p = 0.001) and MMP9 (p = 0.002) in infected cells. Compared to uninfected THP-1 cells, A. phagocytophilum infection led to >2-fold down regulation of 64 of 92 NF-κB signaling pathway genes, and >2-fold increased expression in only 4. Wedelolactone and SC-514 reversed downregulation in all 64 and 45, respectively, of the genes down-regulated by infection, but decreased expression in 1 gene with SC-514 only. Silencing of 20 NF-κB signal pathway genes increased bacterial growth in 12 (IRAK1, MAP3K1, NFKB1B, MAP3K7, TICAM2, TLR3, TRADD, TRAF3, CHUK, IRAK2, LTBR, and MALT1). Most findings support canonical pathway activation; however, the presence of NFKB2 in infected cell nuclei, selective non-canonical pathway inhibitors that dampen CXCL8 and MMP9 transcription with infection, upregulation of non-canonical pathway target genes CCL13 and CCL19, enhanced bacterial growth with TRAF3 and LTBR silencing provide evidence for non-canonical pathway signaling. Whether this impacts distinct inflammatory processes that underlie disease, and whether and how A. phagocytophilum subverts NF-κB signaling via these pathways, need to be investigated.
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Affiliation(s)
- J Stephen Dumler
- Department of Pathology, F. Edward Hébert School of Medicine, Uniformed Services University for the Health Sciences, Bethesda, MD, United States.,Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Marguerite Lichay
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Wan-Hsin Chen
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Kristen E Rennoll-Bankert
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jin-Ho Park
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
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6
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Gettings JR, Self SCW, McMahan CS, Brown DA, Nordone SK, Yabsley MJ. Regional and Local Temporal Trends of Borrelia burgdorferi and Anaplasma spp. Seroprevalence in Domestic Dogs: Contiguous United States 2013-2019. Front Vet Sci 2020; 7:561592. [PMID: 33195537 PMCID: PMC7653440 DOI: 10.3389/fvets.2020.561592] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 09/17/2020] [Indexed: 11/19/2022] Open
Abstract
In 2019, in the United States, over 220,000 and 350,000 dogs tested positive for exposure to Anaplasma spp. and Borrelia burgdorferi, respectively. To evaluate regional and local temporal trends of pathogen exposure we used a Bayesian spatio-temporal binomial regression model, analyzing serologic test results for these pathogens from January 2013 to December 2019. Regional trends were not static over time, but rather increased within and beyond the borders of historically endemic regions. Increased seroprevalence was observed as far as North Carolina and North Dakota for both pathogens. Local trends were estimated to evaluate the heterogeneity of underlying changes. A large cluster of counties with increased B. burgdorferi seroprevalence centered around West Virginia, while a similar cluster of counties with increased Anaplasma spp. seroprevalence centered around Pennsylvania and extended well into Maine. In the Midwest, only a small number of counties experienced an increase in seroprevalence; instead, most counties had a decrease in seroprevalence for both pathogens. These trends will help guide veterinarians and pet owners in adopting the appropriate preventative care practices for their area. Additionally, B. burgdorferi and A. phagocytophilum cause disease in humans. Dogs are valuable sentinels for some vector-borne pathogens, and these trends may help public health providers better understand the risk of exposure for humans.
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Affiliation(s)
- Jenna R Gettings
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA, United States
| | - Stella C W Self
- Arnold School of Public of Health, University of South Carolina, Columbia, SC, United States
| | - Christopher S McMahan
- School of Mathematical and Statistical Sciences, Clemson University, Clemson, SC, United States
| | - D Andrew Brown
- School of Mathematical and Statistical Sciences, Clemson University, Clemson, SC, United States
| | - Shila K Nordone
- Department of Molecular Biomedical Sciences, Comparative Medicine Institute, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, United States
| | - Michael J Yabsley
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA, United States.,Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, United States
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7
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Sholty K, Pascoe EL, Foley J, Stephenson N, Hacker G, Straub M, Roy A, Brown R. Borrelia burgdorferi and Anaplasma phagocytophilum Genospecies in Northern California. Vector Borne Zoonotic Dis 2020; 20:325-333. [PMID: 32155394 DOI: 10.1089/vbz.2019.2483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The sensu lato (s.l.) complexes of Borrelia burgdorferi and Anaplasma phagocytophilum include pathogenic genospecies each with distinct ecologies in northern California, yet, most work conflates the genospecies of each pathogen into one sensu lato species. Detailed understanding of the differences in geographic distributions and ecology among genospecies is lacking. We aimed to evaluate whether two B. burgdorferi and two A. phagocytophilum genospecies in high-risk locations in coastal northern California were spatially clustered and if presence of a particular genospecies was associated with geographical site, host species, or other demographic or ecological variables. DNA sequencing was performed to differentiate genospecies of Borreliae and Anaplasma from PCR-positive dusky-footed woodrats (Neotoma fuscipes) and sciurids (chipmunks, Tamias spp., and Douglas squirrels, Tamiasciurus douglasii) at four sites in northwestern California. Logistic regression was performed to assess associations of genospecies with the predictor variables host species, host sex, site, season, and year. Spatial clustering was assessed using a Poisson spatial scan statistic in SaTScan. Host species was a significant predictor for Borrelia bissettiae, B. burgdorferi sensu stricto (s.s.), A. phagocytophilum s.s., and the DU1 Anaplasma genospecies. Woodrats were significantly more likely to be PCR-positive for B. bissettiae and A. phagocytophilum DU1 genospecies, while A. phagocytophilum s.s. and B. burgdorferi s.s. were significantly associated with sciurids. We report a single Borrelia lanei in an Allen's chipmunk (Tamias senex) from the Hoopa Valley Tribal Reservation. A significant spatial cluster of A. phagocytophilum s.s. was detected at Hendy Woods State Park in Mendocino County. These results highlight the need to better understand genospecies partitioning according to host species to further assess human risks, aid in future surveillance, and inform targeted research.
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Affiliation(s)
- Kathleen Sholty
- Department of Wildlife, Humboldt State University, Arcata, California, USA
| | - Emily L Pascoe
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Janet Foley
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Nicole Stephenson
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Greg Hacker
- Department of Wildlife, Humboldt State University, Arcata, California, USA
| | - Mary Straub
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Austin Roy
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, Davis, California, USA
| | - Richard Brown
- Department of Wildlife, Humboldt State University, Arcata, California, USA
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8
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Pascoe EL, Stephenson N, Abigana A, Clifford D, Gabriel M, Wengert G, Brown R, Higley M, Bloch EM, Foley JE. Human Seroprevalence of Tick-Borne Anaplasma phagocytophilum, Borrelia burgdorferi, and Rickettsia Species in Northern California. Vector Borne Zoonotic Dis 2019; 19:871-878. [PMID: 31295054 DOI: 10.1089/vbz.2019.2489] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
There is a paucity of data on human exposure to tick-borne pathogens in the western United States. This study reports prevalence of antibodies against three clinically important tick-borne pathogens (Borrelia burgdorferi, Anaplasma phagocytophilum, and Rickettsia spp.) among 249 people in five counties in northern California. Individuals from Humboldt County were recruited and answered a questionnaire to assess risk of exposure to tick-borne pathogens. Samples from other counties were obtained from a blood bank and were anonymized. Seventeen (6.8%) samples were seropositive for antibodies against at least one pathogen: five for A. phagocytophilum, eight for B. burgdorferi, and four for Rickettsia spp. Women and people aged 26-35 had higher seroprevalence compared to other demographic groups. Santa Cruz County had no seropositive individuals, northern Central Valley counties had three seropositive individuals (all against A. phagocytophilum), and Humboldt County had 14 (all three pathogens), a significant, four-fold elevated risk of exposure. The Humboldt County questionnaire revealed that a bird feeder in the yard was statistically associated with exposure to ticks, and lifetime number of tick bites was associated with increasing age, time watching wildlife, and time hiking. Three-quarters of respondents were concerned about tick-associated disease, 81.0% reported experiencing tick bites, and 39.0% of those bitten reported a tick-borne disease symptom, including skin lesions (76.4%), muscle aches (49.1%), joint pain (25.5%), or fever (23.6%). Despite high levels of concern, many individuals who had been bitten by a tick were not tested for a tick-borne pathogen, including those with consistent symptoms. We highlight the need for further research and dissemination of information to residents and physicians in Northern California regarding tick-associated disease, so that appropriate medical attention can be rapidly sought and administered.
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Affiliation(s)
- Emily L Pascoe
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California
| | - Nicole Stephenson
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California
| | - Ashley Abigana
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California
| | - Deana Clifford
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California.,Wildlife Investigations Laboratory, California Department of Fish and Wildlife, Rancho Cordova, California
| | | | - Greta Wengert
- Integral Ecology Research Center, Blue Lake, California
| | - Richard Brown
- Department of Wildlife, Humboldt State University, Arcata, California
| | - Mark Higley
- Wildlife Department, Hoopa Tribal Forestry, Hoopa, California
| | - Evan M Bloch
- Department of Pathology and Transfusion Medicine, John Hopkins University, Baltimore, Maryland
| | - Janet E Foley
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California
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9
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Pascoe EL, Marcantonio M, Caminade C, Foley JE. Modeling Potential Habitat for Amblyomma Tick Species in California. INSECTS 2019; 10:insects10070201. [PMID: 31288467 PMCID: PMC6681388 DOI: 10.3390/insects10070201] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 06/21/2019] [Accepted: 07/02/2019] [Indexed: 12/22/2022]
Abstract
The Amblyomma genus of ticks comprises species that are aggressive human biters and vectors of pathogens. Numerous species in the genus are undergoing rapid range expansion. Amblyomma ticks have occasionally been introduced into California, but as yet, no established populations have been reported in the state. Because California has high ecological diversity and is a transport hub for potentially parasitized humans and animals, the risk of future Amblyomma establishment may be high. We used ecological niche modeling to predict areas in California suitable for four tick species that pose high risk to humans: Amblyomma americanum, Amblyomma maculatum, Amblyomma cajennense and Amblyomma mixtum. We collected presence data in the Americas for each species from the published literature and online databases. Twenty-three climatic and ecological variables were used in a MaxEnt algorithm to predict the distribution of each species. The minimum temperature of the coldest month was an important predictor for all four species due to high mortality of Amblyomma at low temperatures. Areas in California appear to be ecologically suitable for A. americanum, A. maculatum, and A. cajennense, but not A. mixtum. These findings could inform targeted surveillance prior to an invasion event, to allow mitigation actions to be quickly implemented.
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Affiliation(s)
- Emily L Pascoe
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.
| | - Matteo Marcantonio
- Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | - Cyril Caminade
- Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool CH64 7TE, UK
- Health Protection Research Unit in Emerging and Zoonotic Infections, University of Liverpool, Liverpool L69 3GL, UK
| | - Janet E Foley
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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10
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Straub MH, Roy AN, Martin A, Sholty KE, Stephenson N, Foley JE. Distribution and prevalence of vector-borne diseases in California chipmunks (Tamias spp.). PLoS One 2017; 12:e0189352. [PMID: 29232397 PMCID: PMC5726628 DOI: 10.1371/journal.pone.0189352] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 11/24/2017] [Indexed: 11/18/2022] Open
Abstract
California, with 13 chipmunk (Tamias) species, has more than any other state or country, occupying habitats ranging from chaparral to the high peaks of the Sierra Nevada. Chipmunks host zoonotic pathogens including Yersinia pestis, Anaplasma phagocytophilum, relapsing fever (RF) Borrelia spp., Borrelia burgdorferi, and spotted fever group (SFG) Rickettsia species. Chipmunk species are often not differentiated by public health workers, yet different species utilize different ecological niches and may have intrinsically different capacities for maintaining vector-borne pathogens and infecting vectors. We surveyed over 700 individuals from nine species of chipmunks throughout California for exposure to and infection by Y. pestis, A. phagocytophilum, RF Borrelia spp., Borrelia burgdorferi, and SFG Rickettsia species. DNA of all five pathogens was found and all chipmunks except Merriam's chipmunk (T. merriami) were PCR-positive for at least one of the pathogens. Anaplasma phagocytophilum was most common (40.0%, 2/5) in Sonoma chipmunks (T. sonomae) from Marin county and B. burgdorferi most common (37.5%, 27/72) in redwood chipmunks (T. ochrogenys) from Mendocino county. RF Borrelia spp. was detected in 2% (6/297) of redwood chipmunks in Mendocino county and 10% (1/10) of both least (T. minimus) and lodgepole (T. speciosus) chipmunks in the western Sierra. Exposure to SFG Rickettsia spp. was found in the Northern Coastal region (Del Norte, Humboldt and Mendocino counties) and in the northern and western Sierra in several species of chipmunks. Y. pestis infection was found only in the western Sierra-in a yellow-pine (T. amoenus) and a long-eared (T. quadrimaculatus) chipmunk. Though more data are needed to thoroughly understand the roles that different chipmunk species play in disease transmission, our findings suggest that some chipmunk species may be more important to the maintenance of vector-borne diseases than others within each geographic area.
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Affiliation(s)
- Mary H. Straub
- Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Austin N. Roy
- Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Amanda Martin
- Museum of Wildlife and Fish Biology, University of California, Davis, California, United States of America
| | - Kathleen E. Sholty
- Wildlife Investigations Laboratory, California Department of Fish and Wildlife, Rancho Cordova, California, United States of America
| | - Nicole Stephenson
- Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California, United States of America
| | - Janet E. Foley
- Department of Veterinary Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California, United States of America
- * E-mail:
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