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Holcomb KM, Nguyen C, Komar N, Foy BD, Panella NA, Baskett ML, Barker CM. Predicted reduction in transmission from deployment of ivermectin-treated birdfeeders for local control of West Nile virus. Epidemics 2023; 44:100697. [PMID: 37348378 PMCID: PMC10529638 DOI: 10.1016/j.epidem.2023.100697] [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: 05/04/2022] [Revised: 05/01/2023] [Accepted: 06/12/2023] [Indexed: 06/24/2023] Open
Abstract
Ivermectin (IVM)-treated birds provide the potential for targeted control of Culex mosquitoes to reduce West Nile virus (WNV) transmission. Ingestion of IVM increases mosquito mortality, which could reduce WNV transmission from birds to humans and in enzootic maintenance cycles affecting predominantly bird-feeding mosquitoes and from birds to humans. This strategy might also provide an alternative method for WNV control that is less hampered by insecticide resistance and the logistics of large-scale pesticide applications. Through a combination of field studies and modeling, we assessed the feasibility and impact of deploying IVM-treated birdfeed in residential neighborhoods to reduce WNV transmission. We first tracked 105 birds using radio telemetry and radio frequency identification to monitor their feeder usage and locations of nocturnal roosts in relation to five feeder sites in a neighborhood in Fort Collins, Colorado. Using these results, we then modified a compartmental model of WNV transmission to account for the impact of IVM on mosquito mortality and spatial movement of birds and mosquitoes on the neighborhood level. We found that, while the number of treated lots in a neighborhood strongly influenced the total transmission potential, the arrangement of treated lots in a neighborhood had little effect. Increasing the proportion of treated birds, regardless of the WNV competency status, resulted in a larger reduction in infection dynamics than only treating competent birds. Taken together, model results indicate that deployment of IVM-treated feeders could reduce local transmission throughout the WNV season, including reducing the enzootic transmission prior to the onset of human infections, with high spatial coverage and rates of IVM-induced mortality in mosquitoes. To improve predictions, more work is needed to refine estimates of daily mosquito movement in urban areas and rates of IVM-induced mortality. Our results can guide future field trials of this control strategy.
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Affiliation(s)
- Karen M Holcomb
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA, United States.
| | - Chilinh Nguyen
- Center for Vector-Borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States; Arboviral Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States
| | - Nicholas Komar
- Arboviral Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States
| | - Brian D Foy
- Center for Vector-Borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Nicholas A Panella
- Arboviral Diseases Branch, Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, CO, United States
| | - Marissa L Baskett
- Department of Environmental Science and Policy, University of California, Davis, CA, United States
| | - Christopher M Barker
- Davis Arbovirus Research and Training Laboratory, Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA, United States.
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Durden C, Tian Y, Knape K, Klemashevich C, Norman KN, Carey JB, Hamer SA, Hamer GL. Fluralaner systemic treatment of chickens results in mortality in Triatoma gerstaeckeri, vector of the agent of Chagas disease. Parasit Vectors 2023; 16:178. [PMID: 37268980 DOI: 10.1186/s13071-023-05805-1] [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] [Received: 02/09/2023] [Accepted: 05/10/2023] [Indexed: 06/04/2023] Open
Abstract
BACKGROUND Chagas disease remains a persistent vector-borne neglected tropical disease throughout the Americas and threatens both human and animal health. Diverse control methods have been used to target triatomine vector populations, with household insecticides being the most common. As an alternative to environmental sprays, host-targeted systemic insecticides (or endectocides) allow for application of chemicals to vertebrate hosts, resulting in toxic blood meals for arthropods (xenointoxication). In this study, we evaluated three systemic insecticide products for their ability to kill triatomines. METHODS Chickens were fed the insecticides orally, following which triatomines were allowed to feed on the treated chickens. The insecticide products tested included: Safe-Guard® Aquasol (fenbendazole), Ivomec® Pour-On (ivermectin) and Bravecto® (fluralaner). Triatoma gerstaeckeri nymphs were allowed to feed on insecticide-live birds at 0, 3, 7, 14, 28 and 56 days post-treatment. The survival and feeding status of the T. gerstaeckeri insects were recorded and analyzed using Kaplan-Meier curves and logistic regression. RESULTS Feeding on fluralaner-treated chickens resulted 50-100% mortality in T. gerstaeckeri over the first 14 days post-treatment but not later; in contrast, all insects that fed on fenbendazole- and ivermectin-treated chickens survived. Liquid chromatography tandem mass spectrometry (LC-QQQ) analysis, used to detect the concentration of fluralaner and fenbendazole in chicken plasma, revealed the presence of fluralaner in plasma at 3, 7, and 14 days post-treatment but not later, with the highest concentrations found at 3 and 7 days post-treatment. However, fenbendazole concentration was below the limit of detection at all time points. CONCLUSIONS Xenointoxication using fluralaner in poultry is a potential new tool for integrated vector control to reduce risk of Chagas disease.
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Affiliation(s)
- Cassandra Durden
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, USA
- Schubot Center for Avian Health, Department of Veterinary Pathobiology, Texas A&M University, College Station, USA
| | - Yuexun Tian
- Department of Entomology, Texas A&M University, College Station, USA
| | - Koyle Knape
- Department of Poultry Science, Texas A&M University, College Station, USA
| | - Cory Klemashevich
- Integrated Metabolomics Analysis Core, Texas A&M University, College Station, USA
| | - Keri N Norman
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, USA
| | - John B Carey
- Department of Poultry Science, Texas A&M University, College Station, USA
| | - Sarah A Hamer
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, USA
- Schubot Center for Avian Health, Department of Veterinary Pathobiology, Texas A&M University, College Station, USA
| | - Gabriel L Hamer
- Department of Entomology, Texas A&M University, College Station, USA.
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Johan SA, Abu Bakar U, Mohd Taib FS, Khairat JE. House crows ( Corvus splendens): the carrier of pathogenic viruses or the misunderstood bird? JOURNAL OF APPLIED ANIMAL RESEARCH 2022. [DOI: 10.1080/09712119.2022.2133902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Siti Aishah Johan
- Microbiology & Molecular Genetics Programme, Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Umarqayum Abu Bakar
- Microbiology & Molecular Genetics Programme, Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Farah Shafawati Mohd Taib
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Malaysia
| | - Jasmine Elanie Khairat
- Microbiology & Molecular Genetics Programme, Institute of Biological Sciences (ISB), Faculty of Science, Universiti Malaya, Kuala Lumpur, Malaysia
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González-Morales MA, Thomson AE, Petritz OA, Crespo R, Haija A, Santangelo RG, Schal C. Systemic veterinary drugs for control of the common bed bug, Cimex lectularius, in poultry farms. Parasit Vectors 2022; 15:431. [PMID: 36397113 PMCID: PMC9670615 DOI: 10.1186/s13071-022-05555-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 10/24/2022] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The common bed bug, Cimex lectularius L., is a hematophagous ectoparasite that was a common pest in poultry farms through the 1960s. Dichlorodiphenyltrichloroethane (DDT) and organophosphates eradicated most infestations, but concurrent with their global resurgence as human ectoparasites, infestations of bed bugs have been reappearing in poultry farms. Although the impact of bed bugs on chicken health has not been quantified, frequent biting and blood-feeding are expected to cause stress, infections and even anemia in birds. Bed bug control options are limited due to the sensitive nature of the poultry environment, limited products labeled for bed bug control and resistance of bed bug populations to a broad spectrum of active ingredients. Veterinary drugs are commonly used to control endo- and ectoparasites in animals. In this study, we evaluated the effects of two common veterinary drugs on bed bugs by treating the host with systemic antiparasitic drugs. METHODS We conducted dose-response studies of ivermectin and fluralaner against several bed bug strains using a membrane feeding system. Also, different doses of these drugs were given to chickens and two delivery methods (topical treatment and ingestion) were used to evaluate the efficacy of ivermectin and fluralaner on bed bug mortality. RESULTS Using an artificial feeding system, both ivermectin and fluralaner caused high mortality in insecticide-susceptible bed bugs, and fluralaner was found to be effective on pyrethroid- and fipronil-resistant bed bugs. Ivermectin was ineffective in chickens either by the topical treatment or ingestion, whereas bed bugs that fed on chickens which had ingested fluralaner suffered high mortality when feeding on these chickens for up to 28 days post treatment. CONCLUSIONS These findings suggest that systemic ectoparasitic drugs have great potential for practical use to control bed bug infestations in poultry farms. These findings also demonstrate the efficacy of fluralaner (and potentially other isoxazolines) as a potent new active ingredient for bed bug control.
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Affiliation(s)
| | - Andrea E. Thomson
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC USA
| | - Olivia A. Petritz
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC USA
| | - Rocio Crespo
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC USA
| | - Ahmed Haija
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC USA
| | - Richard G. Santangelo
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC USA
| | - Coby Schal
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC USA
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Wald ME, Claus C, Konrath A, Nieper H, Muluneh A, Schmidt V, Vahlenkamp TW, Sieg M. Ivermectin Inhibits the Replication of Usutu Virus In Vitro. Viruses 2022; 14:v14081641. [PMID: 36016263 PMCID: PMC9413757 DOI: 10.3390/v14081641] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/18/2022] [Accepted: 07/26/2022] [Indexed: 02/01/2023] Open
Abstract
Usutu virus (USUV) is an emerging mosquito-borne arbovirus within the genus Flavivirus, family Flaviviridae. Similar to the closely related West Nile virus (WNV), USUV infections are capable of causing mass mortality in wild and captive birds, especially blackbirds. In the last few years, a massive spread of USUV was present in the avian population of Germany and other European countries. To date, no specific antiviral therapies are available. Nine different approved drugs were tested for their antiviral effects on the replication of USUV in vitro in a screening assay. Ivermectin was identified as a potent inhibitor of USUV replication in three cell types from different species, such as simian Vero CCL-81, human A549 and avian TME R. A 2- to 7-log10 reduction of the viral titer in the supernatant was detected at a non-cytotoxic concentration of 5 µM ivermectin dependent on the applied cell line. IC50 values of ivermectin against USUV lineage Africa 3 was found to be 0.55 µM in Vero CCL-81, 1.94 µM in A549 and 1.38 µM in TME-R cells. The antiviral efficacy was comparable between the USUV lineages Africa 2, Africa 3 and Europe 3. These findings show that ivermectin may be a candidate for further experimental and clinical studies addressing the treatment of USUV disease, especially in captive birds.
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Affiliation(s)
- Maria Elisabeth Wald
- Institute of Virology, Faculty of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany; (M.E.W.); (T.W.V.)
| | - Claudia Claus
- Institute of Virology, Faculty of Medicine, Leipzig University, 04103 Leipzig, Germany;
| | - Andrea Konrath
- Saxon State Laboratory of Health and Veterinary Affairs, 01099 Dresden, Germany; (A.K.); (H.N.); (A.M.)
| | - Hermann Nieper
- Saxon State Laboratory of Health and Veterinary Affairs, 01099 Dresden, Germany; (A.K.); (H.N.); (A.M.)
| | - Aemero Muluneh
- Saxon State Laboratory of Health and Veterinary Affairs, 01099 Dresden, Germany; (A.K.); (H.N.); (A.M.)
| | - Volker Schmidt
- Clinic for Birds and Reptiles, Faculty of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany;
| | - Thomas Wilhelm Vahlenkamp
- Institute of Virology, Faculty of Veterinary Medicine, Leipzig University, 04103 Leipzig, Germany; (M.E.W.); (T.W.V.)
| | - Michael Sieg
- Institute of Virology, Faculty of Medicine, Leipzig University, 04103 Leipzig, Germany;
- Correspondence:
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