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Hodoameda P, Ebel GD, Mukhopadhyay S, Clem RJ. Extreme infectious titer variability in individual Aedes aegypti mosquitoes infected with Sindbis virus is associated with both differences in virus population structure and dramatic disparities in specific infectivity. PLoS Pathog 2024; 20:e1012047. [PMID: 38412195 PMCID: PMC10923411 DOI: 10.1371/journal.ppat.1012047] [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: 07/15/2023] [Revised: 03/08/2024] [Accepted: 02/13/2024] [Indexed: 02/29/2024] Open
Abstract
Variability in how individuals respond to pathogens is a hallmark of infectious disease, yet the basis for individual variation in host response is often poorly understood. The titer of infectious virus among individual mosquitoes infected with arboviruses is frequently observed to vary by several orders of magnitude in a single experiment, even when the mosquitoes are highly inbred. To better understand the basis for this titer variation, we sequenced populations of Sindbis virus (SINV) obtained from individual infected Aedes aegypti mosquitoes that, despite being from a highly inbred laboratory colony, differed in their titers of infectious virus by approximately 10,000-fold. We observed genetic differences between these virus populations that indicated the virus present in the midguts of low titer mosquitoes was less fit than that of high titer mosquitoes, possibly due to founder effects that occurred during midgut infection. Furthermore, we found dramatic differences in the specific infectivity or SI (the ratio of infectious units/viral genome equivalents) between these virus populations, with the SI of low titer mosquitoes being up to 10,000-fold lower than that of high titer mosquitoes. Despite having similar amounts of viral genomes, low titer mosquitoes appeared to contain less viral particles, suggesting that viral genomes were packaged into virions less efficiently than in high titer mosquitoes. Finally, antibiotic treatment, which has been shown to suppress mosquito antiviral immunity, caused an increase in SI. Our results indicate that the extreme variation that is observed in SINV infectious titer between individual Ae. aegypti mosquitoes is due to both genetic differences between virus populations and to differences in the proportion of genomes that are packaged into infectious particles.
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Affiliation(s)
- Peter Hodoameda
- Division of Biology, Kansas State University, Manhattan, Kansas United States of America
| | - Gregory D. Ebel
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado United States of America
| | - Suchetana Mukhopadhyay
- Department of Biology, Indiana University, Bloomington, Indiana United States of America
| | - Rollie J. Clem
- Division of Biology, Kansas State University, Manhattan, Kansas United States of America
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Ledermann JP, Burns PL, Perinet LC, Powers AM, Byers NM. Improved Mosquito Housing and Saliva Collection Method Enhances Safety While Facilitating Longitudinal Assessment of Individual Mosquito Vector Competence for Arboviruses. Vector Borne Zoonotic Dis 2024; 24:55-63. [PMID: 37844065 DOI: 10.1089/vbz.2022.0093] [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] [Indexed: 10/18/2023] Open
Abstract
Background: Assessing the potential for mosquitoes to transmit medically important arboviruses is essential for understanding their threat to human populations. Currently, vector competence studies are typically performed by collecting saliva using a glass capillary tube system which involves sacrificing the mosquito at the time of saliva collection allowing only a single data point. These techniques also require handling infected mosquitoes and glass capillaries, constituting a safety risk. Materials and Methods: To improve the efficiency and safety of assessing vector competence, a novel containment and saliva collection approach for individually housed mosquitoes was developed. The improved housing, allowing longitudinal tracking of individual mosquitoes, consists of a 12-well Corning polystyrene plate sealed with a three-dimensional printed lid that holds organdy netting firmly against the rims of the wells. Results: This method provides excellent mosquito survival for five species of mosquitoes, with at least 79% of each species tested surviving for more than 2 weeks, comparable to the carton survival rates of ≥76%. When the plate housing system was used to assess vector infection, replication of West Nile virus (WNV) in mosquito tissues was similar to traditional containment mosquito housing. Mosquito saliva was collected using either blotting paper pads or traditional glass capillaries to assay viral transmission. The blotting paper collection showed similar or better sensitivity than the capillary method; in addition, longitudinal saliva samples could be collected from individual mosquitoes housed in the 12-well plates. Conclusions: The improved housing and saliva collection technique described herein provides a safer and more informative method for determining vector competence in mosquitoes.
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Affiliation(s)
- Jeremy P Ledermann
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA
| | - Paul L Burns
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA
| | - Lara C Perinet
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA
| | - Ann M Powers
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA
| | - Nathaniel M Byers
- Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado, USA
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Vector Competence of Mosquitoes from Germany for Sindbis Virus. Viruses 2022; 14:v14122644. [PMID: 36560650 PMCID: PMC9785343 DOI: 10.3390/v14122644] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
Transmission of arthropod-borne viruses (arboviruses) are an emerging global health threat in the last few decades. One important arbovirus family is the Togaviridae, including the species Sindbis virus within the genus Alphavirus. Sindbis virus (SINV) is transmitted by mosquitoes, but available data about the role of different mosquito species as potent vectors for SINV are scarce. Therefore, we investigated seven mosquito species, collected from the field in Germany (Ae. koreicus, Ae. geniculatus, Ae. sticticus, Cx. torrentium, Cx. pipiens biotype pipiens) as well as lab strains (Ae. albopictus, Cx. pipiens biotype molestus, Cx. quinquefasciatus), for their vector competence for SINV. Analysis was performed via salivation assay and saliva was titrated to calculate the amount of infectious virus particles per saliva sample. All Culex and Aedes species were able to transmit SINV. Transmission could be detected at all four investigated temperature profiles (of 18 ± 5 °C, 21 ± 5 °C, 24 ± 5 °C or 27 ± 5 °C), and no temperature dependency could be observed. The concentration of infectious virus particles per saliva sample was in the same range for all species, which may suggest that all investigated mosquito species are able to transmit SINV in Germany.
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Gysin G, Urbano P, Brandner-Garrod L, Begum S, Kristan M, Walker T, Hernández C, Ramírez JD, Messenger LA. Towards environmental detection of Chagas disease vectors and pathogen. Sci Rep 2022; 12:9849. [PMID: 35701602 PMCID: PMC9194887 DOI: 10.1038/s41598-022-14051-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 05/31/2022] [Indexed: 12/02/2022] Open
Abstract
Chagas disease vector control relies on prompt, accurate identification of houses infested with triatomine bugs for targeted insecticide spraying. However, most current detection methods are laborious, lack standardization, have substantial operational costs and limited sensitivity, especially when triatomine bug densities are low or highly focal. We evaluated the use of FTA cards or cotton-tipped swabs to develop a low-technology, non-invasive method of detecting environmental DNA (eDNA) from both triatomine bugs and Trypanosoma cruzi for use in household surveillance in eastern Colombia, an endemic region for Chagas disease. Study findings demonstrated that Rhodnius prolixus eDNA, collected on FTA cards, can be detected at temperatures between 21 and 32 °C, when deposited by individual, recently blood-fed nymphs. Additionally, cotton-tipped swabs are a feasible tool for field sampling of both T. cruzi and R. prolixus eDNA in infested households and may be preferable due to their lower cost. eDNA detection should not yet replace current surveillance tools, but instead be evaluated in parallel as a more sensitive, higher-throughput, lower cost alternative. eDNA collection requires virtually no skills or resources in situ and therefore has the potential to be implemented in endemic communities as part of citizen science initiatives to control Chagas disease transmission.
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Affiliation(s)
- Grace Gysin
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Plutarco Urbano
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia.,Grupo de Investigaciones Biológicas de la Orinoquia, Universidad Internacional del Trópico Americano (Unitrópico), Yopal, Colombia
| | - Luke Brandner-Garrod
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Shahida Begum
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Mojca Kristan
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Thomas Walker
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK
| | - Carolina Hernández
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia.,Centro de Tecnología en Salud (CETESA), Innovaseq SAS, Bogotá, Colombia
| | - Juan David Ramírez
- Centro de Investigaciones en Microbiología y Biotecnología-UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia.,Molecular Microbiology Laboratory, Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Louisa A Messenger
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
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