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Kai I, Kobayashi D, Itokawa K, Sanjoba C, Itoyama K, Isawa H. Evaluation of long-term preservation methods for viral RNA in mosquitoes at room temperature. J Virol Methods 2024; 325:114887. [PMID: 38237867 DOI: 10.1016/j.jviromet.2024.114887] [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: 11/17/2023] [Revised: 01/05/2024] [Accepted: 01/14/2024] [Indexed: 01/26/2024]
Abstract
Mosquitoes are important vectors of various pathogenic viruses. Almost all viruses transmitted by mosquitoes are RNA viruses. Therefore, to detect viral genes, mosquito samples must be kept at low temperatures to prevent RNA degradation. However, prolonged transport from the field to laboratory can pose challenges for temperature control. The aim of this study was to evaluate methods for preserving viral RNA in mosquito bodies at room temperature. Virus-infected mosquito samples were immersed in ethanol, propylene glycol, and a commercially available nucleic acid preservation reagent at room temperature, and viral RNA stability was compared. As a result, for the two RNA viruses (San Gabriel mononegavirus and dengue virus 1) subjected to this experiment, no significant decrease in the viral RNA was observed for at least eight weeks after immersion in the reagents, and the amount of RNA remaining was equivalent to that of samples stored at - 80 °C. These results indicate that immersion storage in these reagents used in this study is effective in preserving viral RNA in mosquitoes under room temperature conditions and is expected to be implemented in epidemiologic surveillance that is not limited by the cold chain from the field to the laboratory.
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Affiliation(s)
- Izumi Kai
- Graduate school of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki-shi, Kanagawa, Japan; Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan
| | - Daisuke Kobayashi
- Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan; Management Department of Biosafety, Laboratory Animal, and Pathogen Bank, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan.
| | - Kentaro Itokawa
- Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan
| | - Chizu Sanjoba
- Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Kyo Itoyama
- Graduate school of Agriculture, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki-shi, Kanagawa, Japan
| | - Haruhiko Isawa
- Department of Medical Entomology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan
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Kim D, DeBriere TJ, Eastmond BH, Alomar AA, Yaren O, McCarter J, Bradley KM, Benner SA, Alto BW, Burkett-Cadena ND. Rapid detection of West Nile and Dengue viruses from mosquito saliva by loop-mediated isothermal amplification and displaced probes. PLoS One 2024; 19:e0298805. [PMID: 38394282 PMCID: PMC10889885 DOI: 10.1371/journal.pone.0298805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 01/30/2024] [Indexed: 02/25/2024] Open
Abstract
Arthropod-borne viruses are major causes of human and animal disease, especially in endemic low- and middle-income countries. Mosquito-borne pathogen surveillance is essential for risk assessment and vector control responses. Sentinel chicken serosurveillance (antibody testing) and mosquito pool screening (by RT-qPCR or virus isolation) are currently used to monitor arbovirus transmission, however substantial time lags of seroconversion and/or laborious mosquito identification and RNA extraction steps sacrifice their early warning value. As a consequence, timely vector control responses are compromised. Here, we report on development of a rapid arbovirus detection system whereby adding sucrose to reagents of loop-mediated isothermal amplification with displaced probes (DP-LAMP) elicits infectious mosquitoes to feed directly upon the reagent mix and expectorate viruses into the reagents during feeding. We demonstrate that RNA from pathogenic arboviruses (West Nile and Dengue viruses) transmitted in the infectious mosquito saliva was detectable rapidly (within 45 minutes) without RNA extraction. Sucrose stabilized viral RNA at field temperatures for at least 48 hours, important for transition of this system to practical use. After thermal treatment, the DP-LAMP could be reliably visualized by a simple optical image sensor to distinguish between positive and negative samples based on fluorescence intensity. Field application of this technology could fundamentally change conventional arbovirus surveillance methods by eliminating laborious RNA extraction steps, permitting arbovirus monitoring from additional sites, and substantially reducing time needed to detect circulating pathogens.
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Affiliation(s)
- Dongmin Kim
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, United States of America
| | | | - Bradley H. Eastmond
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, United States of America
| | - Abdullah A. Alomar
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, United States of America
| | - Ozlem Yaren
- Firebird Biomolecular Sciences LLC, Alachua, Florida, United States of America
- Foundation for Applied Molecular Evolution, Alachua, Florida, United States of America
| | - Jacquelyn McCarter
- Firebird Biomolecular Sciences LLC, Alachua, Florida, United States of America
- Foundation for Applied Molecular Evolution, Alachua, Florida, United States of America
| | - Kevin M. Bradley
- Foundation for Applied Molecular Evolution, Alachua, Florida, United States of America
| | - Steven A. Benner
- Firebird Biomolecular Sciences LLC, Alachua, Florida, United States of America
- Foundation for Applied Molecular Evolution, Alachua, Florida, United States of America
| | - Barry W. Alto
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, United States of America
| | - Nathan D. Burkett-Cadena
- Florida Medical Entomology Laboratory, University of Florida, Vero Beach, Florida, United States of America
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