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Eads DA, Matchett MR, Poje JE, Biggins DE. Comparison of Flea Sampling Methods and Yersinia pestis Detection on Prairie Dog Colonies. Vector Borne Zoonotic Dis 2021; 21:753-761. [PMID: 34388354 DOI: 10.1089/vbz.2021.0025] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Scientists collect fleas (Siphonaptera) to survey for Yersinia pestis, the bacterial agent of plague. When studying fleas parasitizing prairie dogs (Cynomys spp.), two primary methods are used: (1) combing fleas from live-trapped prairie dogs and (2) swabbing fleas from burrows with cloth swabs attached to metal cables. Ideally, burrow swabbing, the cheaper and easier method, would explain flea burdens on prairie dogs and provide reliable information on plague prevalence. In a linear regression analysis of data from 1-month intervals (June-August 2010-2011) on 13 colonies of black-tailed prairie dogs (Cynomys ludovicianus, BTPDs) in New Mexico, flea abundance on swabs explained 0-26% of variation in BTPD flea burdens. In an analysis of data (May-August 2016) from six colonies of BTPDs in Montana, flea abundance on swabs explained 2% of variation in BTPD flea burdens. In an analysis of data from a short-term interval (July 23-27, 2019) on four colonies of BTPDs in Montana, flea abundance on swabs explained 0.1% of variation in BTPD flea burdens. In an analysis of data from 1-week intervals (August-October 2000) on four colonies of white-tailed prairie dogs (Cynomys leucurus, WTPD) in Utah, swabbing data explained 0.1% of variation in WTPD flea burdens. Pools of fleas from two WTPD colonies were tested for Y. pestis by mouse inoculation and isolation; 65% from WTPDs tested positive, whereas 4% from burrows tested positive. Data herein also show that results from burrow swabbing can misrepresent flea species composition and phenology on prairie dogs. Burrow swabbing is useful for some purposes, but limitations should be acknowledged, and accumulated data should be interpreted with caution.
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Affiliation(s)
- David A Eads
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, USA
| | - Marc R Matchett
- U.S. Fish and Wildlife Service, Charles M. Russell National Wildlife Refuge, Lewistown, Montana, USA
| | - Julia E Poje
- Department of Epidemiology, University of Iowa, Iowa City, Iowa, USA
| | - Dean E Biggins
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado, USA
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2
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Colman RE, Brinkerhoff RJ, Busch JD, Ray C, Doyle A, Sahl JW, Keim P, Collinge SK, Wagner DM. No evidence for enzootic plague within black-tailed prairie dog (Cynomys ludovicianus) populations. Integr Zool 2021; 16:834-851. [PMID: 33882192 PMCID: PMC9292313 DOI: 10.1111/1749-4877.12546] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Yersinia pestis, causative agent of plague, occurs throughout the western United States in rodent populations and periodically causes epizootics in susceptible species, including black‐tailed prairie dogs (Cynomys ludovicianus). How Y. pestis persists long‐term in the environment between these epizootics is poorly understood but multiple mechanisms have been proposed, including, among others, a separate enzootic transmission cycle that maintains Y. pestis without involvement of epizootic hosts and persistence of Y. pestis within epizootic host populations without causing high mortality within those populations. We live‐trapped and collected fleas from black‐tailed prairie dogs and other mammal species from sites with and without black‐tailed prairie dogs in 2004 and 2005 and tested all fleas for presence of Y. pestis. Y. pestis was not detected in 2126 fleas collected in 2004 but was detected in 294 fleas collected from multiple sites in 2005, before and during a widespread epizootic that drastically reduced black‐tailed prairie dog populations in the affected colonies. Temporal and spatial patterns of Y. pestis occurrence in fleas and genotyping of Y. pestis present in some infected fleas suggest Y. pestis was introduced multiple times from sources outside the study area and once introduced, was dispersed between several sites. We conclude Y. pestis likely was not present in these black‐tailed prairie dog colonies prior to epizootic activity in these colonies. Although we did not identify likely enzootic hosts, we found evidence that deer mice (Peromyscus maniculatus) may serve as bridging hosts for Y. pestis between unknown enzootic hosts and black‐tailed prairie dogs.
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Affiliation(s)
- Rebecca E Colman
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - R Jory Brinkerhoff
- Environmental Studies Program, University of Colorado at Boulder, Boulder, Colorado, USA
| | - Joseph D Busch
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Chris Ray
- Environmental Studies Program, University of Colorado at Boulder, Boulder, Colorado, USA
| | - Adina Doyle
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Jason W Sahl
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Paul Keim
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
| | - Sharon K Collinge
- Environmental Studies Program, University of Colorado at Boulder, Boulder, Colorado, USA
| | - David M Wagner
- Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, Arizona, USA
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3
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Bron GM, Malavé CM, Boulerice JT, Osorio JE, Rocke TE. Plague-Positive Mouse Fleas on Mice Before Plague Induced Die-Offs in Black-Tailed and White-Tailed Prairie Dogs. Vector Borne Zoonotic Dis 2019; 19:486-493. [PMID: 30994405 DOI: 10.1089/vbz.2018.2322] [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] [Indexed: 11/12/2022] Open
Abstract
Plague is a lethal zoonotic disease associated with rodents worldwide. In the western United States, plague outbreaks can decimate prairie dog (Cynomys spp.) colonies. However, it is unclear where the causative agent, Yersinia pestis, of this flea-borne disease is maintained between outbreaks, and what triggers plague-induced prairie dog die-offs. Less susceptible rodent hosts, such as mice, could serve to maintain the bacterium, transport infectious fleas across a colony, or introduce the pathogen to other colonies, possibly facilitating an outbreak. Here, we assess the potential role of two short-lived rodent species, North American deer mice (Peromyscus maniculatus) and Northern grasshopper mice (Onychomys leucogaster) in plague dynamics on prairie dog colonies. We live-trapped short-lived rodents and collected their fleas on black-tailed (Cynomys ludovicianus, Montana and South Dakota), white-tailed (Cynomys leucurus, Utah and Wyoming), and Utah prairie dog colonies (Cynomys parvidens, Utah) annually, from 2013 to 2016. Plague outbreaks occurred on colonies of all three species. In all study areas, deer mouse abundance was high the year before plague-induced prairie dog die-offs, but mouse abundance per colony was not predictive of plague die-offs in prairie dogs. We did not detect Y. pestis DNA in mouse fleas during prairie dog die-offs, but in three cases we found it beforehand. On one white-tailed prairie dog colony, we detected Y. pestis positive fleas on one grasshopper mouse and several prairie dogs live-trapped 10 days later, months before visible declines and plague-confirmed mortality of prairie dogs. On one black-tailed prairie dog colony, we detected Y. pestis positive fleas on two deer mice 3 months before evidence of plague was detected in prairie dogs or their fleas and also well before a plague-induced die-off. These observations of plague positive fleas on mice could represent early spillover events of Y. pestis from prairie dogs or an unknown reservoir, or possible movement of infectious fleas by mice.
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Affiliation(s)
- Gebbiena M Bron
- 1 U.S. Geological Survey National Wildlife Health Center, Madison, Wisconsin.,2 Department of Pathobiological Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, Wisconsin
| | - Carly M Malavé
- 1 U.S. Geological Survey National Wildlife Health Center, Madison, Wisconsin
| | | | - Jorge E Osorio
- 2 Department of Pathobiological Sciences, University of Wisconsin-Madison, School of Veterinary Medicine, Madison, Wisconsin
| | - Tonie E Rocke
- 1 U.S. Geological Survey National Wildlife Health Center, Madison, Wisconsin
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Abbott RC, Russell RE, Richgels KLD, Tripp DW, Matchett MR, Biggins DE, Rocke TE. Factors Influencing Uptake of Sylvatic Plague Vaccine Baits by Prairie Dogs. ECOHEALTH 2018; 15:12-22. [PMID: 29159477 DOI: 10.1007/s10393-017-1294-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 08/29/2017] [Accepted: 10/03/2017] [Indexed: 06/07/2023]
Abstract
Sylvatic plague vaccine (SPV) is a virally vectored bait-delivered vaccine expressing Yersinia pestis antigens that can protect prairie dogs (Cynomys spp.) from plague and has potential utility as a management tool. In a large-scale 3-year field trial, SPV-laden baits containing the biomarker rhodamine B (used to determine bait consumption) were distributed annually at a rate of approximately 100-125 baits/hectare along transects at 58 plots encompassing the geographic ranges of four species of prairie dogs. We assessed site- and individual-level factors related to bait uptake in prairie dogs to determine which were associated with bait uptake rates. Overall bait uptake for 7820 prairie dogs sampled was 70% (95% C.I. 69.9-72.0). Factors influencing bait uptake rates by prairie dogs varied by species, however, in general, heavier animals had greater bait uptake rates. Vegetation quality and day of baiting influenced this relationship for black-tailed, Gunnison's, and Utah prairie dogs. For these species, baiting later in the season, when normalized difference vegetation indices (a measure of green vegetation density) are lower, improves bait uptake by smaller animals. Consideration of these factors can aid in the development of species-specific SPV baiting strategies that maximize bait uptake and subsequent immunization of prairie dogs against plague.
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Affiliation(s)
- Rachel C Abbott
- U.S. Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI, 53711, USA
| | - Robin E Russell
- U.S. Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI, 53711, USA
| | - Katherine L D Richgels
- U.S. Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI, 53711, USA
| | - Daniel W Tripp
- Colorado Parks and Wildlife, Wildlife Health Program, 4330 Laporte Avenue, Fort Collins, CO, USA
| | - Marc R Matchett
- U.S. Fish and Wildlife Service, Charles M. Russell National Wildlife Refuge, Lewistown, MT, USA
| | - Dean E Biggins
- Fort Collins Science Center, U.S. Geological Survey, Fort Collins, CO, USA
| | - Tonie E Rocke
- U.S. Geological Survey, National Wildlife Health Center, 6006 Schroeder Rd., Madison, WI, 53711, USA.
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Eads DA, Hoogland JL. Precipitation, Climate Change, and Parasitism of Prairie Dogs by Fleas that Transmit Plague. J Parasitol 2017; 103:309-319. [PMID: 28359175 DOI: 10.1645/16-195] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Fleas (Insecta: Siphonaptera) are hematophagous ectoparasites that can reduce the fitness of vertebrate hosts. Laboratory populations of fleas decline under dry conditions, implying that populations of fleas will also decline when precipitation is scarce under natural conditions. If precipitation and hence vegetative production are reduced, however, then herbivorous hosts might suffer declines in body condition and have weakened defenses against fleas, so that fleas will increase in abundance. We tested these competing hypotheses using information from 23 yr of research on 3 species of colonial prairie dogs in the western United States: Gunnison's prairie dog (Cynomys gunnisoni, 1989-1994), Utah prairie dog (Cynomys parvidens, 1996-2005), and white-tailed prairie dog (Cynomys leucurus, 2006-2012). For all 3 species, flea-counts per individual varied inversely with the number of days in the prior growing season with >10 mm of precipitation, an index of the number of precipitation events that might have caused a substantial, prolonged increase in soil moisture and vegetative production. Flea-counts per Utah prairie dog also varied inversely with cumulative precipitation of the prior growing season. Furthermore, flea-counts per Gunnison's and white-tailed prairie dog varied inversely with cumulative precipitation of the just-completed January and February. These results complement research on black-tailed prairie dog (Cynomys ludovicianus) and might have important ramifications for plague, a bacterial disease transmitted by fleas that devastates populations of prairie dogs. In particular, our results might help to explain why, at some colonies, epizootics of plague, which can kill >95% of prairie dogs, are more likely to occur during or shortly after periods of reduced precipitation. Climate change is projected to increase the frequency of droughts in the grasslands of western North America. If so, then climate change might affect the occurrence of plague epizootics among prairie dogs and other mammalian species that associate with them.
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Affiliation(s)
- David A Eads
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523. Correspondence should be sent to David A. Eads at:
| | - John L Hoogland
- Department of Biology, Colorado State University, Fort Collins, Colorado 80523. Correspondence should be sent to David A. Eads at:
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SEASON OF DELTAMETHRIN APPLICATION AFFECTS FLEA AND PLAGUE CONTROL IN WHITE-TAILED PRAIRIE DOG (CYNOMYS LEUCURUS) COLONIES, COLORADO, USA. J Wildl Dis 2016; 52:553-61. [DOI: 10.7589/2015-10-290] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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7
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Mize EL, Britten HB. Detections of Yersinia pestis East of the Known Distribution of Active Plague in the United States. Vector Borne Zoonotic Dis 2016; 16:88-95. [PMID: 26771845 DOI: 10.1089/vbz.2015.1825] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We examined fleas collected from black-tailed prairie dog (Cynomys ludovicianus) burrows from 2009 through 2011 in five national park units east of the known distribution of active plague across the northern Great Plains for the presence of Yersinia pestis. Across all national park units, Oropsylla tuberculata and Oropsylla hirsuta were the most common fleas collected from prairie dog burrows, 42.4% and 56.9%, respectively, of the 3964 fleas collected from burrow swabbing. Using a nested PCR assay, we detected 200 Y. pestis-positive fleas from 3117 assays. In total, 6.4% of assayed fleas were Y. pestis positive and 13.9% of prairie dog burrows swabbed contained Y. pestis-positive fleas. Evidence of the presence of Y. pestis was observed at all national park units except Devils Tower National Monument in Wyoming. We detected the presence of Y. pestis without large die-offs, i.e., enzootic sylvatic plague, east of the known distribution of active plague and near the eastern edge of the present distribution of black-tailed prairie dogs. This study, in combination with previous work suggests that sylvatic plague likely occurs across the range of black-tailed prairie dogs and should now be treated as endemic across this range.
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Affiliation(s)
- Erica L Mize
- Department of Biology, University of South Dakota , Vermillion, South Dakota
| | - Hugh B Britten
- Department of Biology, University of South Dakota , Vermillion, South Dakota
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8
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St Romain K, Tripp DW, Salkeld DJ, Antolin MF. Duration of plague (Yersinia pestis) outbreaks in black-tailed prairie dog (Cynomys ludovicianus) colonies of northern Colorado. ECOHEALTH 2013; 10:241-5. [PMID: 24057801 DOI: 10.1007/s10393-013-0860-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 06/21/2013] [Accepted: 06/21/2013] [Indexed: 05/24/2023]
Abstract
Plague, caused by the bacterium Yersinia pestis, triggers die-offs in colonies of black-tailed prairie dogs (Cynomys ludovicianus), but the time-frame of plague activity is not well understood. We document plague activity in fleas from prairie dogs and their burrows on three prairie dog colonies that suffered die-offs. We demonstrate that Y. pestis transmission occurs over periods from several months to over a year in prairie dog populations before observed die-offs.
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Affiliation(s)
- Krista St Romain
- Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA
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9
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Jachowski DS, Skipper S, Gompper ME. Field evaluation of imidacloprid as a systemic approach to flea control in black-tailed prairie dogs, Cynomys ludovicianus. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2011; 36:100-107. [PMID: 21635647 DOI: 10.1111/j.1948-7134.2011.00146.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Epizootic outbreaks of sylvatic plague have dramatically influenced prairie dog (Cynomys sp.) populations across North America. While a great deal of debate surrounds the cause and persistence of plague, flea control can stop the spread of plague epizootic outbreaks and even increase prairie dog survival under non-epizootic conditions. We investigated a newly-developed imidacloprid-treated grain bait that could potentially reduce flea infestations and mitigate the effects of plague on black-tailed prairie dogs (C. ludovicianus). We used a study design involving randomly assigned experimental and control study plots to assess the effectiveness of the systemic flea control product. We observed a significant difference in flea prevalence and abundance between experimental and control sites on three of the four sites treated with a single application of imidacloprid-treated grain bait for up to 90 days post-treatment. We observed an even greater reduction in flea infestations following the double application of treatment bait on two of three additional experimental sites. While we were unable to reduce flea infestations to the extent reported for more commonly used topical insecticides containing deltamethrin, imidacloprid might still be effective at reducing the risk of plague and halting epizootics. In addition, this systemic product can be more rapidly applied than topical insecticides, providing managers with a tool to quickly reduce flea infestations. Future research is needed to evaluate the effectiveness of different application timing and rates, the utility of the product in limiting plague, and the potential effects on non-target species that might also consume the treated bait.
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Affiliation(s)
- David S Jachowski
- U.S. Fish and Wildlife Service, South Dakota Ecological Services Field Office, Pierre, SD 57501, USA
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10
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JONES PHILIPH, BRITTEN HUGHB. The absence of concordant population genetic structure in the black-tailed prairie dog and the flea, Oropsylla hirsuta, with implications for the spread of Yersinia pestis. Mol Ecol 2010; 19:2038-49. [DOI: 10.1111/j.1365-294x.2010.04634.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Biggins DE, Godbey JL, Gage KL, Carter LG, Montenieri JA. Vector Control Improves Survival of Three Species of Prairie Dogs (Cynomys) in Areas Considered Enzootic for Plague. Vector Borne Zoonotic Dis 2010; 10:17-26. [DOI: 10.1089/vbz.2009.0049] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Dean E. Biggins
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado
| | - Jerry L. Godbey
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, Colorado
| | - Kenneth L. Gage
- Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado
| | - Leon G. Carter
- Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado
| | - John A. Montenieri
- Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado
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12
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JONES PHILIPH, WALLACE LISA, BITTEN HUGHB. Isolation and characterization of 11 microsatellite loci fromOropsylla hirsuta, a vector of sylvatic plague. Mol Ecol Resour 2009; 9:1041-4. [DOI: 10.1111/j.1755-0998.2009.02558.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Wilder AP, Eisen RJ, Bearden SW, Montenieri JA, Gage KL, Antolin MF. Oropsylla hirsuta (Siphonaptera: Ceratophyllidae) can support plague epizootics in black-tailed prairie dogs (Cynomys ludovicianus) by early-phase transmission of Yersinia pestis. Vector Borne Zoonotic Dis 2008; 8:359-67. [PMID: 18454591 DOI: 10.1089/vbz.2007.0181] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Plague, caused by the bacterium Yersinia pestis, often leads to rapid decimation of black-tailed prairie dog colonies. Flea-borne transmission of Y. pestis has been thought to occur primarily via blocked fleas, and therefore studies of vector efficiency have focused on the period when blockage is expected to occur (> or =5 days post-infection [p.i.]). Oropsylla hirsuta, a prairie dog flea, rarely blocks and transmission is inefficient > or =5 days p.i.; thus, this flea has been considered incapable of explaining rapid dissemination of Y. pestis among prairie dogs. By infecting wild-caught fleas with Y. pestis and exposing naïve mice to groups of fleas at 24, 48, 72, and 96 h p.i., we examined the early-phase (1-4 days p.i.) efficiency of O. hirsuta to transmit Y. pestis to hosts and showed that O. hirsuta is a considerably more efficient vector at this largely overlooked stage (5.19% of fleas transmit Y. pestis at 24 h p.i.) than at later stages. Using a model of vectorial capacity, we suggest that this level of transmission can support plague at an enzootic level in a population when flea loads are within the average observed for black-tailed prairie dogs in nature. Shared burrows and sociality of prairie dogs could lead to accumulation of fleas when host population is reduced as a result of the disease, enabling epizootic spread of plague among prairie dogs.
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Affiliation(s)
- Aryn P Wilder
- Bacterial Diseases Branch, Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80522, USA.
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Salkeld DJ, Stapp P. Prevalence and abundance of fleas in black-tailed prairie dog burrows: implications for the transmission of plague (Yersinia pestis). J Parasitol 2008; 94:616-21. [PMID: 18605787 DOI: 10.1645/ge-1368.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 10/10/2007] [Indexed: 11/10/2022] Open
Abstract
Plague, the disease caused by the bacterium Yersinia pestis, can have devastating impacts on North American wildlife. Epizootics, or die-offs, in prairie dogs (Cynomys ludovicianus) occur sporadically and fleas (Siphonaptera) are probably important in the disease's transmission and possibly as maintenance hosts of Y. pestis between epizootics. We monitored changes in flea abundance in prairie dog burrows in response to precipitation, temperature, and plague activity in shortgrass steppe in northern Colorado. Oropsylla hirsuta was the most commonly found flea, and it increased in abundance with temperature. In contrast, Oropsylla tuberculata cynomuris declined with rising temperature. During plague epizootics, flea abundance in burrows increased and then subsequently declined after the extirpation of their prairie dog hosts.
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Affiliation(s)
- Dan J Salkeld
- IUCN--The World Conservation Union, NW, Washington, DC 20009, USA.
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15
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Wilder AP, Eisen RJ, Bearden SW, Montenieri JA, Tripp DW, Brinkerhoff RJ, Gage KL, Antolin MF. Transmission efficiency of two flea species (Oropsylla tuberculata cynomuris and Oropsylla hirsuta) involved in plague epizootics among prairie dogs. ECOHEALTH 2008; 5:205-212. [PMID: 18787922 DOI: 10.1007/s10393-008-0165-1] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 01/11/2008] [Accepted: 01/28/2008] [Indexed: 05/26/2023]
Abstract
Plague, caused by Yersinia pestis, is an exotic disease in North America circulating predominantly in wild populations of rodents and their fleas. Black-tailed prairie dogs (Cynomys ludovicianus) are highly susceptible to infection, often experiencing mortality of nearly all individuals in a town as a result of plague. The fleas of black-tailed prairie dogs are Oropsylla tuberculata cynomuris and Oropsylla hirsuta. We tested the efficiency of O. tuberculata cynomuris to transmit Y. pestis daily from 24 to 96 h postinfection and compared it to previously collected data for O. hirsuta. We found that O. tuberculata cynomuris has over threefold greater transmission efficiency (0.18 infected fleas transmit Y. pestis at 24 h postinfection) than O. hirsuta (0.05 fleas transmit). Using a simple model of flea-borne transmission, we combine these laboratory measurements with field data on monthly flea loads to compare the seasonal vectorial capacity of these two flea species. Coinciding with seasonal patterns of flea abundance, we find a peak in potential for flea-borne transmission in March, during high O. tuberculata cynomuris abundance, and in September-October when O. hirsuta is common. Our findings may be useful in determining the timing of insecticidal dusting to slow plague transmission in black-tailed prairie dogs.
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Affiliation(s)
- Aryn P Wilder
- Bacterial Diseases Branch, Division of Vector-Borne Infectious Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80522, USA.
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16
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Biogeography of diseases: a framework for analysis. Naturwissenschaften 2008; 95:483-91. [PMID: 18320161 PMCID: PMC7079904 DOI: 10.1007/s00114-008-0352-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2007] [Revised: 01/08/2008] [Accepted: 01/24/2008] [Indexed: 10/26/2022]
Abstract
A growing body of literature offers a framework for understanding geographic and ecological distributions of species; a few applications of this framework have treated disease transmission systems and their geography. The general framework focuses on interactions among abiotic requirements, biotic constraints, and dispersal abilities of species as determinants of distributional areas. Disease transmission systems have key differences from other sorts of biological phenomena: Interactions among species are particularly important, interactions may be stable or unstable, abiotic conditions may be relatively less important in shaping disease distributions, and dispersal abilities may be quite variable. The ways in which these differences may influence disease transmission geography are complex; I illustrate their effects by means of worked examples regarding West Nile Virus, plague, filoviruses, and yellow fever.
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17
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Salkeld DJ, Stapp P. Prevalence and Abundance of Fleas in black-tailed Prairie Dog Burrows: Implications for the Transmission of Plague (Yersinia pestis). J Parasitol 2008. [DOI: 10.1645/ge-1368r.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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High prevalence of Yersinia pestis in black-tailed prairie dog colonies during an apparent enzootic phase of sylvatic plague. CONSERV GENET 2006. [DOI: 10.1007/s10592-006-9226-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Hoogland JL, Davis S, Benson-Amram S, Labruna D, Goossens B, Hoogland MA. PYRAPERM KILLS FLEAS AND HALTS PLAGUE AMONG UTAH PRAIRIE DOGS. SOUTHWEST NAT 2004. [DOI: 10.1894/0038-4909(2004)049<0376:pkfahp>2.0.co;2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Biggins DE, Godbey JL. Challenges to reestablishment of free-ranging populations of black-footed ferrets. C R Biol 2003; 326 Suppl 1:S104-11. [PMID: 14558458 DOI: 10.1016/s1631-0691(03)00046-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The black-footed ferret (Mustela nigripes) of North America is critically endangered due in part to its extreme specialization on formerly stable and abundant prairie dogs (Cynomys). Its close relative, the Siberian polecat (M. eversmannii) seems to have been subjected to a varying environment that was not conductive to specialization. One source of environmental variation in Asian steppes was plague (caused by Yersina pestis), which was absent from North America. Introduction of plague to North America presents serious challenges to ferret recovery. Partial solutions to other biological and political problems have been found, resulting in improved production in captivity, increased survival post-release, and thriving populations in plague-free South Dakota.
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Affiliation(s)
- Dean E Biggins
- United States Geological Survey, Midcontinent Ecological Science Center, 4512 McMurry Avenue, Fort Collins, CO 80525, USA.
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Osorio JE, Powell TD, Frank RS, Moss K, Haanes EJ, Smith SR, Rocke TE, Stinchcomb DT. Recombinant raccoon pox vaccine protects mice against lethal plague. Vaccine 2003; 21:1232-8. [PMID: 12559803 DOI: 10.1016/s0264-410x(02)00557-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Using a raccoon poxvirus (RCN) expression system, we have developed new recombinant vaccines that can protect mice against lethal plague infection. We tested the effects of a translation enhancer (EMCV-IRES) in combination with a secretory (tPA) signal or secretory (tPA) and membrane anchoring (CHV-gG) signals on in vitro antigen expression of F1 antigen in tissue culture and the induction of antibody responses and protection against Yersinia pestis challenge in mice. The RCN vector successfully expressed the F1 protein of Y. pestis in vitro. In addition, the level of expression was increased by the insertion of the EMCV-IRES and combinations of this and the secretory signal or secretory and anchoring signals. These recombinant viruses generated protective immune responses that resulted in survival of 80% of vaccinated mice upon challenge with Y. pestis. Of the RCN-based vaccines we tested, the RCN-IRES-tPA-YpF1 recombinant construct was the most efficacious. Mice vaccinated with this construct withstood challenge with as many as 1.5 million colony forming units of Y. pestis (7.7 x 10(4)LD(50)). Interestingly, vaccination with F1 fused to the anchoring signal (RCN-IRES-tPA-YpF1-gG) elicited significant anti-F1 antibody titers, but failed to protect mice from plague challenge. Our studies demonstrate, in vitro and in vivo, the potential importance of the EMCV-IRES and secretory signals in vaccine design. These molecular tools provide a new approach for improving the efficacy of vaccines. In addition, these novel recombinant vaccines could have human, veterinary, and wildlife applications in the prevention of plague.
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Affiliation(s)
- Jorge E Osorio
- Heska Corporation, 1613 Prospect Parkway, Ft Collins, CO 80525, USA.
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Engelthaler DM, Gage KL. Quantities of Yersinia pestis in fleas (Siphonaptera: Pulicidae, Ceratophyllidae, and Hystrichopsyllidae) collected from areas of known or suspected plague activity. JOURNAL OF MEDICAL ENTOMOLOGY 2000; 37:422-426. [PMID: 15535587 DOI: 10.1093/jmedent/37.3.422] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We used a quantitative competitive polymerase chain reaction (PCR) (QC-PCR) to determine bacterial loads in 669 fleas collected in areas of confirmed and suspected plague epizootics. Fleas were collected out of rodent burrows (67.9%) and off of captured animals (24.1%) and rodent carcasses (8.1%). An initial PCR screening assay indicated that 12.1% (81/669) of all fleas were positive for Yersinia pestis. Fleas collected from burrows had significantly lower (chi2 = 264.9, P < 0.0001) infection rates (6.8%) but significantly higher (Student t-test, P < 0.0001) bacterial loads (mean = 10(5.6) Y. pestis per flea) than fleas collected off of rodent carcasses (infection rate = 92.6%; mean bacterial load = 10(4.8) Y. pestis per flea). None of the fleas collected off of captured animals were positive for Y. pestis by PCR, although seven of the 176 captured animals were serologically positive for Y. pestis.
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Affiliation(s)
- D M Engelthaler
- Division of Vector-Borne Infectious Diseases, Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services, P.O. Box 2087, Fort Collins, CO 80522, USA
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Grenfell BT, Gulland FM. Introduction: ecological impact of parasitism on wildlife host populations. Parasitology 1995; 111 Suppl:S3-14. [PMID: 8632922 DOI: 10.1017/s0031182000075788] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The study of parasite population dynamics has been one of the major developments in ecology over the last 15 years (Kennedy, 1975). The seminal articles of Crofton (1971) and Anderson & May (1978, 1979; May & Anderson, 1978, 1979) began this process by illustrating the potential role of parasites in regulating or destabilizing the dynamics of wildlife host populations. Since then, a variety of empirical and theoretical studies (reviewed by Grenfell & Dobson, 1995) have explored the role of parasites in natural populations. In parallel with these population dynamical developments, a growing interest in the evolutionary ecology of parasites has also led to a large literature, examining the evolutionary impact of parasites and the importance of host-parasite coevolution (Hamilton, 1982; May & Anderson, 1990; Lively & Apanius, 1995; Read et al. 1995; Herre, this volume).
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