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Eads DA, Castle KT, Wild MA, Borchert JN, Livieri TM, Matchett MR, Dobesh P, Hughes JP, Childers E. EVALUATING BAITS WITH LUFENURON AND NITENPYRAM FOR FLEA CONTROL ON PRAIRIE DOGS (CYNOMYS SPP.) TO MITIGATE PLAGUE. J Wildl Dis 2023; 59:662-672. [PMID: 37486875 DOI: 10.7589/jwd-d-22-00168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 03/24/2023] [Indexed: 07/26/2023]
Abstract
Plague, caused by Yersinia pestis, is a widespread threat to endangered black-footed ferrets (Mustela nigripes) and their primary prey, prairie dogs (Cynomys spp.). Wildlife biologists most commonly manage plague using insecticides to control fleas, the primary vectors of Y. pestis. We tested edible baits containing the insecticides lufenuron and/or nitenpyram in prairie dogs. During a laboratory study, we treated 26 white-tailed prairie dogs (Cynomys leucurus) with lufenuron at 300 mg/kg body mass. All animals remained clinically healthy over the 9 wk monitoring period. Although serum lufenuron concentrations were >130 ppb in two treatment groups at week 1, concentrations declined to ≤60 ppb after 3 wk in non-torpid prairie dogs and after 7 wk in torpid prairie dogs. In a field experiment, we tested baits containing a combination of 75 mg lufenuron and 6 mg nitenpyram, respectively, in black-tailed prairie dogs (Cynomys ludovicianus). We uniformly distributed baits at 125 baits/ha on two plots (treated once) and 250 baits/ha on two plots (each treated twice 4.4 wk apart). Following treatments, flea abundance increased on prairie dogs and remained stable in burrows. Our findings indicate that baits containing lufenuron and nitenpyram, at the reported treatment rates, are ineffective tools for flea control on prairie dogs. Future experiments might evaluate efficacy of higher doses of lufenuron and nitenpyram, and repetitive treatments at differing intervals over time to evaluate potentially therapeutic treatments.
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Affiliation(s)
- David A Eads
- U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Avenue, Building C, Fort Collins, Colorado 80526, USA
| | - Kevin T Castle
- Wildlife Veterinary Consulting LLC, 840 Sundance Drive, Livermore, Colorado 80536, USA
| | - Margaret A Wild
- Department of Veterinary Microbiology and Pathology, Washington State University, P.O. Box 647040, Pullman, Washington 99164, USA
| | - Jeff N Borchert
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, Colorado 80521, USA
| | - Travis M Livieri
- Prairie Wildlife Research, 1574 Timber Shores Drive, Stevens Point, Wisconsin 54481, USA
| | - Marc R Matchett
- U.S. Fish and Wildlife Service, Charles M. Russell National Wildlife Refuge, P.O. Box 110, 333 Airport Road Lewistown, Montana 59457, USA
| | - Phillip Dobesh
- U.S. Forest Service, Wall Ranger District, 710 Main Street, Wall, South Dakota 57790, USA
| | - John P Hughes
- U.S. Fish and Wildlife Service, National Black-footed Ferret Conservation Center, P.O. Box 190, Carr, Colorado 80549, USA
| | - Eddie Childers
- National Park Service, Badlands National Park, 25216 Ben Reifel Road, Interior, South Dakota 57750, USA
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Eads DA, Livieri TM, Dobesh P, Hughes JP, Fly J, Redmond H, Childers E, Schwarz MS, Biggins DE. Plague mitigation for prairie dog and black-footed ferret conservation: Degree and duration of flea control with 0.005% fipronil grain bait. CURRENT RESEARCH IN PARASITOLOGY & VECTOR-BORNE DISEASES 2023; 3:100124. [PMID: 37305434 PMCID: PMC10250916 DOI: 10.1016/j.crpvbd.2023.100124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/11/2023] [Accepted: 05/15/2023] [Indexed: 06/13/2023]
Abstract
Sylvatic plague, a primarily flea-borne zoonosis, is a significant threat to prairie dogs (Cynomys spp., PDs) and their specialized predators, endangered black-footed ferrets (Mustela nigripes, BFFs). Host-fed fipronil baits have proven effective in controlling fleas on PDs for the purposes of plague mitigation and BFF conservation. Currently, annual treatments are the norm. We tested the long-term efficacy of fipronil bait treatments with black-tailed PDs (C. ludovicianus, BTPDs) and BFFs in South Dakota, USA. During 2018-2020, we provided BTPDs on 21 sites with grain bait formula, laced with 0.005% fipronil (50 mg/kg); 18 non-treated sites functioned as baselines. In 2020-2022, we live-trapped, anesthetized, and combed BTPDs for fleas. Flea control was significant for at least 639-885 days. Flea abundance on the treated sites was < 0.5 fleas/BTPD for ∼750 days. During 2020-2022, we sampled BFFs for fleas on 4 BTPD colonies treated with fipronil grain bait and 8 non-treated colonies. Flea control was significant with BFFs, but flea abundance began to rebound within ∼240 days post-treatment. When feasible, the combination of insecticide treatments, such as fipronil baits, and BFF vaccination against plague provide a "two-pronged" protection approach for these endangered carnivores. If fipronil bait treatments are less effective with predatory BFFs than PDs, as found herein, the "two-pronged" approach might be used to protect BFFs and biennial fipronil bait treatments might be used to protect PDs. If BFF vaccination is not possible, or few BFFs can be vaccinated, annual fipronil bait treatments might be used as a precaution to protect BFFs. Flea densities might be surveyed to determine when/where more frequent treatments seem useful.
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Affiliation(s)
- David A. Eads
- U. S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, USA
| | | | - Phillip Dobesh
- U. S. Forest Service, Wall Ranger District, Wall, SD, USA
| | - John P. Hughes
- U. S. Fish and Wildlife Service, National Black-footed Ferret Conservation Center, Carr, CO, USA
| | - Jason Fly
- U. S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, USA
| | - Holly Redmond
- U. S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, USA
| | - Eddie Childers
- National Park Service, Badlands National Park, Interior, SD, USA
| | - Matthew S. Schwarz
- U. S. Fish and Wildlife Service, South Dakota Field Office, Pierre, SD, USA
| | - Dean E. Biggins
- U. S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, USA
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Miarinjara A, Eads DA, Bland DM, Matchett MR, Biggins DE, Hinnebusch BJ. Reevaluation of the Role of Blocked Oropsylla hirsuta Prairie Dog Fleas (Siphonaptera: Ceratophyllidae) in Yersinia pestis (Enterobacterales: Enterobacteriaceae) Transmission. JOURNAL OF MEDICAL ENTOMOLOGY 2022; 59:1053-1059. [PMID: 35380675 PMCID: PMC9113170 DOI: 10.1093/jme/tjac021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Indexed: 05/17/2023]
Abstract
Prairie dogs in the western United States experience periodic epizootics of plague, caused by the flea-borne bacterial pathogen Yersinia pestis. An early study indicated that Oropsylla hirsuta (Baker), often the most abundant prairie dog flea vector of plague, seldom transmits Y. pestis by the classic blocked flea mechanism. More recently, an alternative early-phase mode of transmission has been proposed as the driving force behind prairie dog epizootics. In this study, using the same flea infection protocol used previously to evaluate early-phase transmission, we assessed the vector competence of O. hirsuta for both modes of transmission. Proventricular blockage was evident during the first two weeks after infection and transmission during this time was at least as efficient as early-phase transmission 2 d after infection. Thus, both modes of transmission likely contribute to plague epizootics in prairie dogs.
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Affiliation(s)
- Adélaïde Miarinjara
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, MT, USA
- Department of Environmental Sciences, Emory University, Atlanta, GA, USA
| | - David A Eads
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, USA
| | - David M Bland
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, MT, USA
| | | | - Dean E Biggins
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO, USA
| | - B Joseph Hinnebusch
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, NIH, Hamilton, MT, USA
- Corresponding author, e-mail:
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Eads DA, Biggins DE, Wimsatt J, Eisen RJ, Hinnebusch BJ, Matchett MR, Goldberg AR, Livieri TM, Hacker GM, Novak MG, Buttke DE, Grassel SM, Hughes JP, Atiku LA. Exploring and Mitigating Plague for One Health Purposes. CURRENT TROPICAL MEDICINE REPORTS 2022; 9:169-184. [PMID: 39210935 PMCID: PMC11358858 DOI: 10.1007/s40475-022-00265-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2022] [Indexed: 10/14/2022]
Abstract
Purpose of Review In 2020, the Appropriations Committee for the U.S. House of Representatives directed the CDC to develop a national One Health framework to combat zoonotic diseases, including sylvatic plague, which is caused by the flea-borne bacterium Yersinia pestis. This review builds upon that multisectoral objective. We aim to increase awareness of Y. pestis and to highlight examples of plague mitigation for One Health purposes (i.e., to achieve optimal health outcomes for people, animals, plants, and their shared environment). We draw primarily upon examples from the USA, but also discuss research from Madagascar and Uganda where relevant, as Y. pestis has emerged as a zoonotic threat in those foci. Recent Findings Historically, the bulk of plague research has been directed at the disease in humans. This is not surprising, given that Y. pestis is a scourge of human history. Nevertheless, the ecology of Y. pestis is inextricably linked to other mammals and fleas under natural conditions. Accumulating evidence demonstrates Y. pestis is an unrelenting threat to multiple ecosystems, where the bacterium is capable of significantly reducing native species abundance and diversity while altering competitive and trophic relationships, food web connections, and nutrient cycles. In doing so, Y. pestis transforms ecosystems, causing "shifting baselines syndrome" in humans, where there is a gradual shift in the accepted norms for the condition of the natural environment. Eradication of Y. pestis in nature is difficult to impossible, but effective mitigation is achievable; we discuss flea vector control and One Health implications in this context. Summary There is an acute need to rapidly expand research on Y. pestis, across multiple host and flea species and varied ecosystems of the Western US and abroad, for human and environmental health purposes. The fate of many wildlife species hangs in the balance, and the implications for humans are profound in some regions. Collaborative multisectoral research is needed to define the scope of the problem in each epidemiological context and to identify, refine, and implement appropriate and effective mitigation practices.
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Affiliation(s)
- David A. Eads
- U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Avenue Building C, Fort Collins, CO 80526, USA
| | - Dean E. Biggins
- U.S. Geological Survey, Fort Collins Science Center, 2150 Centre Avenue Building C, Fort Collins, CO 80526, USA
| | - Jeffrey Wimsatt
- Department of Medicine, West Virginia University, Morgantown, WV, USA
| | - Rebecca J. Eisen
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, USA
| | - B. Joseph Hinnebusch
- Laboratory of Bacteriology, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Marc R. Matchett
- U.S. Fish and Wildlife Service, Charles M. Russell National Wildlife Refuge, Lewistown, MT, USA
| | | | | | - Gregory M. Hacker
- Vector-Borne Disease Section, California Department of Public Health, Sacramento, CA, USA
| | - Mark G. Novak
- Vector-Borne Disease Section, California Department of Public Health, Sacramento, CA, USA
| | - Danielle E. Buttke
- National Park Service Biological Resources Division and Office of Public Health, Fort Collins, CO, USA
| | | | - John P. Hughes
- U.S. Fish and Wildlife Service, National Black-Footed Ferret Conservation Center, Carr, CO, USA
| | - Linda A. Atiku
- Plague Unit, Uganda Virus Research Institute, Entebbe, Uganda
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Matchett MR, Stanley TR, Mccollister MF, Eads DA, Boulerice JT, Biggins DE. Oral Sylvatic Plague Vaccine Does Not Adequately Protect Prairie Dogs ( Cynomys spp.) for Endangered Black-Footed Ferret ( Mustela nigripes) Conservation. Vector Borne Zoonotic Dis 2021; 21:921-940. [PMID: 34757815 PMCID: PMC8742283 DOI: 10.1089/vbz.2021.0049] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The plague bacterium Yersinia pestis is lethal to endangered black-footed ferrets (Mustela nigripes, BFF) and the prairie dogs (Cynomys spp., PD) on which they depend for habitat and prey. We assessed the effectiveness of an oral sylvatic plague vaccine delivered in baits to black-tailed PD (Cynomys ludovicianus, BTPD) from 2013 to 2017 on the Charles M. Russell National Wildlife Refuge (CMR) in northcentral Montana. We permanently marked BTPD on four paired vaccine (N = 1,349 individuals) and placebo plots (N = 926; 7,027 total captures). We analyzed capture–recapture data under a Cormack–Jolly–Seber model to estimate annual apparent survival. Overall, survival averaged 0.05 lower on vaccine plots than on paired placebo plots. Immediately before noticeable die-offs and detecting plague on pairs CMR1 and CMR2, 89% of BTPD sampled on vaccine plots had consumed at least one bait and the immune systems of 40% were likely boosted by consuming baits over multiple years. Survival to the following year was 0.16 and 0.05 on the vaccine plots and 0.19 and 0.06 on the placebo plots for pairs CMR1 and CMR2, respectively. These rates were markedly lower than 0.63, the overall average estimate on those same plots during the previous 3 years. PD populations subjected to such large die-offs would not be expected to sustain a BFF population. An overriding limitation to achieving sufficient protection rests with vaccine delivery constraints. Late summer/fall bait distribution results in the highest bait uptake rates. However, the PD birth pulse each spring can double the size of populations in most years, greatly reducing the proportion of vaccinates in populations and diminishing potential herd immunity benefits. In addition to nonvaccinated juveniles and PD that do not consume bait, incomplete vaccine protection and time required for immunity to develop leaves a large majority of PD populations vulnerable to plague for 6–7 months or more each year.
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Affiliation(s)
- Marc R Matchett
- Charles M. Russell National Wildlife Refuge, U.S. Fish and Wildlife Service, Lewistown, Montana, USA
| | - Thomas R Stanley
- Fort Collins Science Center, U.S. Geological Survey, Fort Collins, Colorado, USA
| | - Matthew F Mccollister
- Charles M. Russell National Wildlife Refuge, U.S. Fish and Wildlife Service, Lewistown, Montana, USA
| | - David A Eads
- Fort Collins Science Center, U.S. Geological Survey, Fort Collins, Colorado, USA
| | | | - Dean E Biggins
- Fort Collins Science Center, U.S. Geological Survey, Fort Collins, Colorado, USA
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