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Rice LM, Robb LL, Hartman DA, Anderson JR, Kading RC. Application of the Droplet Digital Polymerase Chain Reaction (ddPCR) Platform for Detection and Quantification of Vertebrate Host DNA in Engorged Mosquitoes. J Med Entomol 2019; 56:1150-1153. [PMID: 30856248 DOI: 10.1093/jme/tjz016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 01/25/2019] [Accepted: 01/31/2019] [Indexed: 06/09/2023]
Abstract
Hematophagous arthropod bloodmeal identification has remained a challenge in the field of vector biology, but these studies are important to understand blood feeding patterns of arthropods, spatial, and temporal patterns in arbovirus transmission cycles, and risk of human and veterinary disease. We investigated the use of an existing vertebrate primer set for use on the droplet digital polymerase chain reaction (ddPCR) platform, to explore the use of this technology in the identification and quantification of vertebrate DNA in mosquito blood meals. Host DNA was detectable 48-h post-engorgement in some mosquitoes by ddPCR, compared with 24-h post-engorgement using traditional PCR. The capability of ddPCR for absolute quantification of template DNA offers unique potential applications of this new technology to field studies on the ecology of vector-borne diseases, but currently with limited scope.
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Affiliation(s)
- L M Rice
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO
| | - L L Robb
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO
| | - D A Hartman
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO
| | - J R Anderson
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO
| | - R C Kading
- Department of Microbiology, Immunology, and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO
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Hartman DA, Rice LM, DeMaria J, Borland EM, Bergren NA, Fagre AC, Robb LL, Webb CT, Kading RC. Entomological risk factors for potential transmission of Rift Valley fever virus around concentrations of livestock in Colorado. Transbound Emerg Dis 2019; 66:1709-1717. [PMID: 31002468 DOI: 10.1111/tbed.13206] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 04/11/2019] [Accepted: 04/12/2019] [Indexed: 01/07/2023]
Abstract
Rift Valley fever virus (RVFV) poses a major threat of introduction to several continents, including North America. Such an introduction could cause significant losses to the livestock industry, in addition to substantial human morbidity and mortality. Because of the opportunistic blood host selection of Culex tarsalis mosquitoes, we hypothesized that this species could be an important bridge vector of RVFV near feedlots in the event of an introduction. We investigated the mosquito community composition at livestock feedlots and surrounding natural and residential areas to determine differences in mosquito relative abundance and blood feeding patterns attributed to cattle feeding operations. DNA extracted from abdomens of blood-fed mosquitoes were sequenced to determine host identity. Multivariate regression analyses revealed differences between mosquito community assemblages at feedlots and non-feedlot sites (p < 0.05), with this effect driven largely by differential abundances of Aedes vexans (padj < 0.05). Mosquito diversity was lower on feedlots than surrounding areas for three out of four feedlots. Culex tarsalis was abundant at both feedlots and nearby sites. Diverse vertebrate blood meals were detected in Cx. tarsalis at non-feedlot sites, with a shift towards feeding on cattle at feedlots. These data support a potential for Cx. tarsalis to serve as a bridge vector of RVFV between livestock and humans in Colorado.
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Affiliation(s)
- Daniel A Hartman
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Lauren M Rice
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Justin DeMaria
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Erin M Borland
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Nicholas A Bergren
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Anna C Fagre
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - Lucy L Robb
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado
| | - Colleen T Webb
- Department of Biology, Colorado State University, Fort Collins, Colorado
| | - Rebekah C Kading
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
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Robb LL, Hartman DA, Rice L, deMaria J, Bergren NA, Borland EM, Kading RC. Continued Evidence of Decline in the Enzootic Activity of Western Equine Encephalitis Virus in Colorado. J Med Entomol 2019; 56:584-588. [PMID: 30535264 DOI: 10.1093/jme/tjy214] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Indexed: 06/09/2023]
Abstract
Western equine encephalitis (WEE) was once prevalent and routinely isolated from mosquitoes in Colorado; however, isolations of Western equine encephalitis virus (WEEV) have not been reported from mosquito pools since the early 1990s. The objective of the present study was to test pools of Culex tarsalis (Coquillett) mosquitoes sampled from Weld County, CO, in 2016 for evidence of WEEV infection. Over 7,000 mosquitoes were tested, but none were positive for WEEV RNA. These data indicate that WEEV either was not circulating enzootically in Northern Colorado, was very rare, and would require much more extensive mosquito sampling to detect, or was heterogeneously distributed spatially and temporally and happened to not be present in the area sampled during 2016. Even though the reported incidence of WEE remains null, screening for WEEV viral RNA in mosquito vectors offers forewarning toward the detection and prevention of future outbreaks.
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Affiliation(s)
- Lucy L Robb
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Daniel A Hartman
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Lauren Rice
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Justin deMaria
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Nicholas A Bergren
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Erin M Borland
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
| | - Rebekah C Kading
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO, USA
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