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Real-Jaramillo S, Bustillos JJ, Moncayo AL, Neira M, Fárez L, Beltrán E, Ocaña-Mayorga S. Phenotypic resistance not associated with knockdown mutations (kdr) in Anopheles albimanus exposed to deltamethrin in southern coastal Ecuador. Malar J 2024; 23:17. [PMID: 38217047 PMCID: PMC10787486 DOI: 10.1186/s12936-023-04818-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 12/08/2023] [Indexed: 01/14/2024] Open
Abstract
BACKGROUND Decrease in malaria rates (e.g. incidence and cases) in Latin America maintains this region on track to achieve the goal of elimination. During the last 5 years, three countries have been certified as malaria free. However, the region fails to achieve the goal of 40% reduction on malaria rates and an increase of cases has been reported in some countries, including Ecuador. This scenario has been associated with multiple causes, such as decrease of funding to continue anti-malarial programmes and the development of insecticide resistance of the main malaria vectors. In Ecuador, official reports indicated phenotypic resistance in Aedes aegypti and Anopheles albimanus to deltamethrin and malathion, particularly in the coastal areas of Ecuador, however, information about the mechanisms of resistance have not been yet elucidated. This study aims to evaluate phenotypic response to deltamethrin and its relationship with kdr mutations in An. albimanus from two localities with different agricultural activities in southern coastal Ecuador. METHODS The CDC bottle assay was carried out to evaluate the phenotypic status of the mosquito's population. Sequencing the voltage gated sodium channel gene (VGSC) sought knockdown mutations (kdr) in codons 1010, 1013 and 1014 associated with resistance. RESULTS Phenotypic resistance was found in Santa Rosa (63.3%) and suspected resistance in Huaquillas (82.1%); with females presenting a higher median of knockdown rate (83.7%) than males (45.6%). No statistical differences were found between the distributions of knockdown rate for the two localities (p = 0.6048) which indicates no influence of agricultural activity. Although phenotypic resistance was confirmed, genetic analysis demonstrate that this resistance was not related with the kdr mechanism of the VGSC gene because no mutations were found in codons 1010 and 1013, while in codon 1014, 90.6% showed the susceptible sequence (TTG) and 7.3% ambiguous nucleotides (TKK and TYG). CONCLUSIONS These results highlighted the importance of continuous monitoring of resistance in malaria vectors in Ecuador, particularly in areas that have reported outbreaks during the last years. It is also important to elucidate the mechanism involved in the development of the resistance to PYs to propose alternative insecticides or strategies for vector control in areas where resistance is present.
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Affiliation(s)
- Sebasthian Real-Jaramillo
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Calle Pambacienda y San Pedro del Valle, Campus Nayón, 170530, Nayón, Ecuador
| | - Juan J Bustillos
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Calle Pambacienda y San Pedro del Valle, Campus Nayón, 170530, Nayón, Ecuador
| | - Ana L Moncayo
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Calle Pambacienda y San Pedro del Valle, Campus Nayón, 170530, Nayón, Ecuador
| | - Marco Neira
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Calle Pambacienda y San Pedro del Valle, Campus Nayón, 170530, Nayón, Ecuador
- The Cyprus Institute, Climate and Atmosphere Research Center (CARE-C), Nicosia, Cyprus
| | - Leonardo Fárez
- Laboratorio de Referencia Intermedio de Entomología CZ707D02, Ministerio de Salud Pública de Ecuador, Machala, Ecuador
| | - Efraín Beltrán
- Unidad Académica de Ciencias Químicas y de La Salud, Universidad Técnica de Machala, Machala, Ecuador
| | - Sofía Ocaña-Mayorga
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Calle Pambacienda y San Pedro del Valle, Campus Nayón, 170530, Nayón, Ecuador.
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Coba-Males MA, Medrano-Vizcaíno P, Enríquez S, Brito-Zapata D, Martin-Solano S, Ocaña-Mayorga S, Carrillo-Bilbao GA, Narváez W, Salas JA, Arrivillaga-Henríquez J, González-Suárez M, Poveda A. From roads to biobanks: Roadkill animals as a valuable source of genetic data. PLoS One 2023; 18:e0290836. [PMID: 38060478 PMCID: PMC10703236 DOI: 10.1371/journal.pone.0290836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 08/15/2023] [Indexed: 12/18/2023] Open
Abstract
To protect biodiversity we must understand its structure and composition including the bacteria and microparasites associated with wildlife, which may pose risks to human health. However, acquiring this knowledge often presents challenges, particularly in areas of high biodiversity where there are many undescribed and poorly studied species and funding resources can be limited. A solution to fill this knowledge gap is sampling roadkill (animals that die on roads as a result of collisions with circulating vehicles). These specimens can help characterize local wildlife and their associated parasites with fewer ethical and logistical challenges compared to traditional specimen collection. Here we test this approach by analyzing 817 tissue samples obtained from 590 roadkill vertebrate specimens (Amphibia, Reptilia, Aves and Mammalia) collected in roads within the Tropical Andes of Ecuador. First, we tested if the quantity and quality of recovered DNA varied across roadkill specimens collected at different times since death, exploring if decomposition affected the potential to identify vertebrate species and associated microorganisms. Second, we compared DNA stability across taxa and tissues to identify potential limitations and offer recommendations for future work. Finally, we illustrate how these samples can aid in taxonomic identification and parasite detection. Our study shows that sampling roadkill can help study biodiversity. DNA was recovered and amplified (allowing species identification and parasite detection) from roadkill even 120 hours after death, although risk of degradation increased overtime. DNA was extracted from all vertebrate classes but in smaller quantities and with lower quality from amphibians. We recommend sampling liver if possible as it produced the highest amounts of DNA (muscle produced the lowest). Additional testing of this approach in areas with different environmental and traffic conditions is needed, but our results show that sampling roadkill specimens can help detect and potentially monitor biodiversity and could be a valuable approach to create biobanks and preserve genetic data.
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Affiliation(s)
- Manuel Alejandro Coba-Males
- Grupo de Investigación en Biodiversidad, Zoonosis y Salud Pública (GIBCIZ), Instituto de Investigación en Zoonosis (CIZ), Facultad de Ciencias Químicas (FCQ), Universidad Central del Ecuador, Quito, Ecuador
| | - Pablo Medrano-Vizcaíno
- Ecology and Evolutionary Biology, School of Biological Sciences, University of Reading, Reading, United Kingdom
- Universidad Regional Amazónica IKIAM, Grupo de Investigación Población y Ambiente, Tena, Ecuador
- Red Ecuatoriana para el Monitoreo de Fauna Atropellada-REMFA, Quito, Ecuador
| | - Sandra Enríquez
- Grupo de Investigación en Biodiversidad, Zoonosis y Salud Pública (GIBCIZ), Instituto de Investigación en Zoonosis (CIZ), Facultad de Ciencias Químicas (FCQ), Universidad Central del Ecuador, Quito, Ecuador
| | - David Brito-Zapata
- Red Ecuatoriana para el Monitoreo de Fauna Atropellada-REMFA, Quito, Ecuador
- Instituto iBIOTROP, Museo de Zoología & Laboratorio de Zoología Terrestre, Universidad San Francisco de Quito USFQ, Quito, Ecuador
| | - Sarah Martin-Solano
- Grupo de Investigación en Sanidad Animal y Humana (GISAH), Carrera Ingeniería en Biotecnología, Departamento de Ciencias de la Vida y la Agricultura, Universidad de las Fuerzas Armadas—ESPE, Sangolquí, Ecuador
| | - Sofía Ocaña-Mayorga
- Centro de Investigación para la Salud en América Latina, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Gabriel Alberto Carrillo-Bilbao
- Grupo de Investigación en Biodiversidad, Zoonosis y Salud Pública (GIBCIZ), Instituto de Investigación en Zoonosis (CIZ), Facultad de Ciencias Químicas (FCQ), Universidad Central del Ecuador, Quito, Ecuador
| | - Wilmer Narváez
- Grupo de Investigación en Biodiversidad, Zoonosis y Salud Pública (GIBCIZ), Instituto de Investigación en Zoonosis (CIZ), Facultad de Ciencias Químicas (FCQ), Universidad Central del Ecuador, Quito, Ecuador
| | - Jaime Antonio Salas
- Facultad de Ciencias Naturales, Carrera de Biología, Universidad de Guayaquil, Guayaquil, Ecuador
| | - Jazzmín Arrivillaga-Henríquez
- Grupo de Investigación en Biodiversidad, Zoonosis y Salud Pública (GIBCIZ), Instituto de Investigación en Zoonosis (CIZ), Facultad de Ciencias Químicas (FCQ), Universidad Central del Ecuador, Quito, Ecuador
| | - Manuela González-Suárez
- Ecology and Evolutionary Biology, School of Biological Sciences, University of Reading, Reading, United Kingdom
| | - Ana Poveda
- Grupo de Investigación en Biodiversidad, Zoonosis y Salud Pública (GIBCIZ), Instituto de Investigación en Zoonosis (CIZ), Facultad de Ciencias Químicas (FCQ), Universidad Central del Ecuador, Quito, Ecuador
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Hernandez-Castro LE, Villacís AG, Jacobs A, Cheaib B, Day CC, Ocaña-Mayorga S, Yumiseva CA, Bacigalupo A, Andersson B, Matthews L, Landguth EL, Costales JA, Llewellyn MS, Grijalva MJ. Population genomics and geographic dispersal in Chagas disease vectors: Landscape drivers and evidence of possible adaptation to the domestic setting. PLoS Genet 2022; 18:e1010019. [PMID: 35120121 PMCID: PMC8849464 DOI: 10.1371/journal.pgen.1010019] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 02/16/2022] [Accepted: 01/06/2022] [Indexed: 12/19/2022] Open
Abstract
Accurate prediction of vectors dispersal, as well as identification of adaptations that allow blood-feeding vectors to thrive in built environments, are a basis for effective disease control. Here we adopted a landscape genomics approach to assay gene flow, possible local adaptation, and drivers of population structure in Rhodnius ecuadoriensis, an important vector of Chagas disease. We used a reduced-representation sequencing technique (2b-RADseq) to obtain 2,552 SNP markers across 272 R. ecuadoriensis samples from 25 collection sites in southern Ecuador. Evidence of high and directional gene flow between seven wild and domestic population pairs across our study site indicates insecticide-based control will be hindered by repeated re-infestation of houses from the forest. Preliminary genome scans across multiple population pairs revealed shared outlier loci potentially consistent with local adaptation to the domestic setting, which we mapped to genes involved with embryogenesis and saliva production. Landscape genomic models showed elevation is a key barrier to R. ecuadoriensis dispersal. Together our results shed early light on the genomic adaptation in triatomine vectors and facilitate vector control by predicting that spatially-targeted, proactive interventions would be more efficacious than current, reactive approaches. Re-infestation of recently insecticide-treated houses by wild/secondary triatomine, their potential adaptation to this new environment and capabilities to geographically disperse across multiple human communities jeopardise sustainable Chagas disease control. This is the first study in Chagas disease vectors that identifies genomic regions possibly linked to adaptations to the built environment and describes landscape drivers for accurate prediction of geographic dispersal. We sampled multiple domestic and wild Rhodnius ecuadoriensis population pairs across a mountainous terrain in southern Ecuador. We evidenced that triatomine movement from forest to built enviroments does occur at a high rate. In these highly connected population pairs we detected loci possibly linked to local adaptation among the genomic makers we evaluated and in doing so we pave the way for future triatomine genomic research. We highlighted that current haphazardous vector control in the zone will be hindered by reinfestation of triatomines from the forest. Instead, we recommend frequent and spatially-targeted vector control and provided a landacape genomic model that identifies highly connected and isolated triatomine populations to facilitate efficient vector control.
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Affiliation(s)
- Luis E. Hernandez-Castro
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- The Epidemiology, Economics and Risk Assessment Group, The Roslin Institute, Easter Bush Campus, The University of Edinburgh, Midlothian, United Kingdom
- * E-mail: (LEH-C); (MSL)
| | - Anita G. Villacís
- Centro de Investigación para la Salud en América Latina, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Arne Jacobs
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- Department of Natural Resources and the Environment, Cornell University, Ithaca, New York, United States of America
| | - Bachar Cheaib
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Casey C. Day
- Computational Ecology Lab, School of Public and Community Health Sciences, University of Montana, Missoula, Montana, United States of America
| | - Sofía Ocaña-Mayorga
- Centro de Investigación para la Salud en América Latina, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Cesar A. Yumiseva
- Centro de Investigación para la Salud en América Latina, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Antonella Bacigalupo
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Björn Andersson
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Louise Matthews
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Erin L. Landguth
- Computational Ecology Lab, School of Public and Community Health Sciences, University of Montana, Missoula, Montana, United States of America
- Center for Population Health Research, School of Public and Community Health Sciences, University of Montana, Missoula, Montana, United States of America
| | - Jaime A. Costales
- Centro de Investigación para la Salud en América Latina, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Martin S. Llewellyn
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- * E-mail: (LEH-C); (MSL)
| | - Mario J. Grijalva
- Centro de Investigación para la Salud en América Latina, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
- Infectious and Tropical Disease Institute, Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
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Talavera-López C, Messenger LA, Lewis MD, Yeo M, Reis-Cunha JL, Matos GM, Bartholomeu DC, Calzada JE, Saldaña A, Ramírez JD, Guhl F, Ocaña-Mayorga S, Costales JA, Gorchakov R, Jones K, Nolan MS, Teixeira SMR, Carrasco HJ, Bottazzi ME, Hotez PJ, Murray KO, Grijalva MJ, Burleigh B, Grisard EC, Miles MA, Andersson B. Repeat-Driven Generation of Antigenic Diversity in a Major Human Pathogen, Trypanosoma cruzi. Front Cell Infect Microbiol 2021; 11:614665. [PMID: 33747978 PMCID: PMC7966520 DOI: 10.3389/fcimb.2021.614665] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 01/22/2021] [Indexed: 12/18/2022] Open
Abstract
Trypanosoma cruzi, a zoonotic kinetoplastid protozoan parasite, is the causative agent of American trypanosomiasis (Chagas disease). Having a very plastic, repetitive and complex genome, the parasite displays a highly diverse repertoire of surface molecules, with pivotal roles in cell invasion, immune evasion and pathogenesis. Before 2016, the complexity of the genomic regions containing these genes impaired the assembly of a genome at chromosomal level, making it impossible to study the structure and function of the several thousand repetitive genes encoding the surface molecules of the parasite. We here describe the genome assembly of the Sylvio X10/1 genome sequence, which since 2016 has been used as a reference genome sequence for T. cruzi clade I (TcI), produced using high coverage PacBio single-molecule sequencing. It was used to analyze deep Illumina sequence data from 34 T. cruzi TcI isolates and clones from different geographic locations, sample sources and clinical outcomes. Resolution of the surface molecule gene distribution showed the unusual duality in the organization of the parasite genome, a synteny of the core genomic region with related protozoa flanked by unique and highly plastic multigene family clusters encoding surface antigens. The presence of abundant interspersed retrotransposons in these multigene family clusters suggests that these elements are involved in a recombination mechanism for the generation of antigenic variation and evasion of the host immune response on these TcI strains. The comparative genomic analysis of the cohort of TcI strains revealed multiple cases of such recombination events involving surface molecule genes and has provided new insights into T. cruzi population structure.
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Affiliation(s)
- Carlos Talavera-López
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
- European Bioinformatics Institute, Wellcome Sanger Institute, Hinxton, United Kingdom
| | - Louisa A. Messenger
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Michael D. Lewis
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Matthew Yeo
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - João Luís Reis-Cunha
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Gabriel Machado Matos
- Departamento de Biologia Celular, Embriologia e Genética, Universidade Federal Santa Catarina, Florianópolis, Brazil
| | | | - José E. Calzada
- Departamento de Parasitología, Instituto Conmemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, Panama
| | - Azael Saldaña
- Departamento de Parasitología, Instituto Conmemorativo Gorgas de Estudios de la Salud, Ciudad de Panamá, Panama
| | - Juan David Ramírez
- Grupo de Investigaciones Microbiológicas-UR (GIMUR), Departamento de Biología, Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Felipe Guhl
- Grupo de Investigaciones en Microbiología y Parasitología Tropical (CIMPAT), Tropical Parasitology Research Center, Universidad de Los Andes, Bogotá, Colombia
| | - Sofía Ocaña-Mayorga
- Centro de Investigación para la Salud en América Latina (CISeAL), Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Jaime A. Costales
- Centro de Investigación para la Salud en América Latina (CISeAL), Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Rodion Gorchakov
- Sabin Vaccine Institute and Texas Children’s Hospital Center for Vaccine Development, National School of Tropical Medicine, Department of Pediatrics - Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Kathryn Jones
- Sabin Vaccine Institute and Texas Children’s Hospital Center for Vaccine Development, National School of Tropical Medicine, Department of Pediatrics - Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Melissa S. Nolan
- Sabin Vaccine Institute and Texas Children’s Hospital Center for Vaccine Development, National School of Tropical Medicine, Department of Pediatrics - Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Santuza M. R. Teixeira
- Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Hernán José Carrasco
- Laboratorio de Biología Molecular de Protozoarios, Instituto de Medicina Tropical, Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela
| | - Maria Elena Bottazzi
- Sabin Vaccine Institute and Texas Children’s Hospital Center for Vaccine Development, National School of Tropical Medicine, Department of Pediatrics - Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Peter J. Hotez
- Sabin Vaccine Institute and Texas Children’s Hospital Center for Vaccine Development, National School of Tropical Medicine, Department of Pediatrics - Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Kristy O. Murray
- Sabin Vaccine Institute and Texas Children’s Hospital Center for Vaccine Development, National School of Tropical Medicine, Department of Pediatrics - Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Mario J. Grijalva
- Centro de Investigación para la Salud en América Latina (CISeAL), Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Infectious and Tropical Disease Institute, Ohio University, Athens, OH, United States
| | - Barbara Burleigh
- Department of Immunology and Infectious Diseases, T.H. Chan School of Public Health, Harvard University, Boston, MA, United States
| | - Edmundo C. Grisard
- Departamento de Microbiologia, Imunologia e Parasitologia, Universidade Federal Santa Catarina, Florianópolis, Brazil
| | - Michael A. Miles
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Björn Andersson
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
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Schwabl P, Maiguashca Sánchez J, Costales JA, Ocaña-Mayorga S, Segovia M, Carrasco HJ, Hernández C, Ramírez JD, Lewis MD, Grijalva MJ, Llewellyn MS. Culture-free genome-wide locus sequence typing (GLST) provides new perspectives on Trypanosoma cruzi dispersal and infection complexity. PLoS Genet 2020; 16:e1009170. [PMID: 33326438 PMCID: PMC7743988 DOI: 10.1371/journal.pgen.1009170] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 10/02/2020] [Indexed: 12/30/2022] Open
Abstract
Analysis of genetic polymorphism is a powerful tool for epidemiological surveillance and research. Powerful inference from pathogen genetic variation, however, is often restrained by limited access to representative target DNA, especially in the study of obligate parasitic species for which ex vivo culture is resource-intensive or bias-prone. Modern sequence capture methods enable pathogen genetic variation to be analyzed directly from host/vector material but are often too complex and expensive for resource-poor settings where infectious diseases prevail. This study proposes a simple, cost-effective 'genome-wide locus sequence typing' (GLST) tool based on massive parallel amplification of information hotspots throughout the target pathogen genome. The multiplexed polymerase chain reaction amplifies hundreds of different, user-defined genetic targets in a single reaction tube, and subsequent agarose gel-based clean-up and barcoding completes library preparation at under 4 USD per sample. Our study generates a flexible GLST primer panel design workflow for Trypanosoma cruzi, the parasitic agent of Chagas disease. We successfully apply our 203-target GLST panel to direct, culture-free metagenomic extracts from triatomine vectors containing a minimum of 3.69 pg/μl T. cruzi DNA and further elaborate on method performance by sequencing GLST libraries from T. cruzi reference clones representing discrete typing units (DTUs) TcI, TcIII, TcIV, TcV and TcVI. The 780 SNP sites we identify in the sample set repeatably distinguish parasites infecting sympatric vectors and detect correlations between genetic and geographic distances at regional (< 150 km) as well as continental scales. The markers also clearly separate TcI, TcIII, TcIV and TcV + TcVI and appear to distinguish multiclonal infections within TcI. We discuss the advantages, limitations and prospects of our method across a spectrum of epidemiological research.
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Affiliation(s)
- Philipp Schwabl
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Jalil Maiguashca Sánchez
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Jaime A. Costales
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Sofía Ocaña-Mayorga
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Maikell Segovia
- Laboratorio de Biología Molecular de Protozoarios, Instituto de Medicina Tropical, Universidad Central de Venezuela, Caracas, Venezuela
| | - Hernán J. Carrasco
- Laboratorio de Biología Molecular de Protozoarios, Instituto de Medicina Tropical, Universidad Central de Venezuela, Caracas, Venezuela
| | - Carolina Hernández
- Grupo de Investigaciones Microbiológicas-UR (GIMUR), Departamento de Biología, Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Juan David Ramírez
- Grupo de Investigaciones Microbiológicas-UR (GIMUR), Departamento de Biología, Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Michael D. Lewis
- London School of Hygiene & Tropical Medicine, Keppel Street, London, United Kingdom
| | - Mario J. Grijalva
- Centro de Investigación para la Salud en América Latina, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
- Infectious and Tropical Disease Institute, Biomedical Sciences Department, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH, United States of America
| | - Martin S. Llewellyn
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
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Martin JA, Hendershot AL, Saá Portilla IA, English DJ, Woodruff M, Vera-Arias CA, Salazar-Costa BE, Bustillos JJ, Saénz FE, Ocaña-Mayorga S, Koepfli C, Lobo NF. Anopheline and human drivers of malaria risk in northern coastal, Ecuador: a pilot study. Malar J 2020; 19:354. [PMID: 33008438 PMCID: PMC7532652 DOI: 10.1186/s12936-020-03426-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/23/2020] [Indexed: 11/28/2022] Open
Abstract
Background Understanding local anopheline vector species and their bionomic traits, as well as related human factors, can help combat gaps in protection. Methods In San José de Chamanga, Esmeraldas, at the Ecuadorian Pacific coast, anopheline mosquitoes were sampled by both human landing collections (HLCs) and indoor-resting aspirations (IAs) and identified using both morphological and molecular methods. Human behaviour observations (HBOs) (including temporal location and bed net use) were documented during HLCs as well as through community surveys to determine exposure to mosquito bites. A cross-sectional evaluation of Plasmodium falciparum and Plasmodium vivax infections was conducted alongside a malaria questionnaire. Results Among 222 anopheline specimens captured, based on molecular analysis, 218 were Nyssorhynchus albimanus, 3 Anopheles calderoni (n = 3), and one remains unidentified. Anopheline mean human-biting rate (HBR) outdoors was (13.69), and indoors (3.38) (p = 0.006). No anophelines were documented resting on walls during IAs. HBO-adjusted human landing rates suggested that the highest risk of being bitten was outdoors between 18.00 and 20.00 h. Human behaviour-adjusted biting rates suggest that overall, long-lasting insecticidal bed nets (LLINs) only protected against 13.2% of exposure to bites, with 86.8% of exposure during the night spent outside of bed net protection. The malaria survey found 2/398 individuals positive for asymptomatic P. falciparum infections. The questionnaire reported high (73.4%) bed net use, with low knowledge of malaria. Conclusion The exophagic feeding of anopheline vectors in San Jose de Chamanga, when analysed in conjunction with human behaviour, indicates a clear gap in protection even with high LLIN coverage. The lack of indoor-resting anophelines suggests that indoor residual spraying (IRS) may have limited effect. The presence of asymptomatic infections implies the presence of a human reservoir that may maintain transmission.
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Affiliation(s)
- James A Martin
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Allison L Hendershot
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Iván Alejandro Saá Portilla
- Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador
| | - Daniel J English
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Madeline Woodruff
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Claudia A Vera-Arias
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA.,Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador
| | - Bibiana E Salazar-Costa
- Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador
| | - Juan José Bustillos
- Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador
| | - Fabián E Saénz
- Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador
| | - Sofía Ocaña-Mayorga
- Centro de Investigación Para La Salud en América Latina, Facultad de Ciencias Exactas Y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro Y Pambahacienda, 170530, Nayón, Ecuador.
| | - Cristian Koepfli
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Neil F Lobo
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, IN, 46556, USA
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Ocaña-Mayorga S, Lobos SE, Crespo-Pérez V, Villacís AG, Pinto CM, Grijalva MJ. Influence of ecological factors on the presence of a triatomine species associated with the arboreal habitat of a host of Trypanosoma cruzi. Parasit Vectors 2018; 11:567. [PMID: 30373640 PMCID: PMC6206927 DOI: 10.1186/s13071-018-3138-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 10/08/2018] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The white-naped squirrel, Simosciurus nebouxii (previously known as Sciurus stramineus), has recently been identified as an important natural host for Trypanosoma cruzi in Ecuador. The nests of this species have been reported as having high infestation rates with the triatomine vector Rhodnius ecuadoriensis. The present study aims to determine the levels of nest infestation with R. ecuadoriensis, the ecological variables that are influencing the nest site selection, and the relationship between R. ecuadoriensis infestation and trypanosome infection. RESULTS The study was carried out in transects in forest patches near two rural communities in southern Ecuador. We recorded ecological information of the trees that harbored squirrel nests and the trees within a 10 m radius. Manual examinations of each nest determined infestation with triatomines. We recorded 498 trees (n = 52 with nests and n = 446 without nests). Rhodnius ecuadoriensis was present in 59.5% of the nests and 60% presented infestation with nymphs (colonization). Moreover, we detected T. cruzi in 46% of the triatomines analyzed. CONCLUSIONS We observed that tree height influences nest site selection, which is consistent with previous observations of squirrel species. Factors such as the diameter at breast height and the interaction between tree height and tree species were not sufficient to explain squirrel nest presence or absence. However, the nest occupancy and tree richness around the nest were significant predictors of the abundance of triatomines. Nevertheless, the variables of colonization and infection were not significant, and the data observed could be expected because of chance alone (under the null hypothesis). This study ratifies the hypothesis that the ecological features of the forest patches around rural communities in southern Ecuador favor the presence of nesting areas for S. nebouxii and an increase of the chances of having triatomines that maintain T. cruzi populations circulating in areas near human dwellings. Additionally, these results highlight the importance of including ecological studies to understand the dynamics of T. cruzi transmission due to the existence of similar ecological and land use features along the distribution of the dry forest of southern Ecuador and northern Peru, which implies similar challenges for Chagas disease control.
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Affiliation(s)
- Sofía Ocaña-Mayorga
- Centro de Investigación para la Salud en América Latina (CISeAL), Escuela de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro y Pamba Hacienda, 170530 Nayón, Ecuador
| | - Simón E. Lobos
- Centro de Investigación para la Salud en América Latina (CISeAL), Escuela de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro y Pamba Hacienda, 170530 Nayón, Ecuador
- Museo de Zoología, Escuela de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Av. 12 de octubre 1076 y Roca, 170525 Quito, Ecuador
| | - Verónica Crespo-Pérez
- Laboratorio de Entomología, Escuela de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Av. 12 de octubre 1076 y Roca, 170525 Quito, Ecuador
| | - Anita G. Villacís
- Centro de Investigación para la Salud en América Latina (CISeAL), Escuela de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro y Pamba Hacienda, 170530 Nayón, Ecuador
| | - C. Miguel Pinto
- Centro de Investigación para la Salud en América Latina (CISeAL), Escuela de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro y Pamba Hacienda, 170530 Nayón, Ecuador
- Instituto de Ciencias Biológicas, Escuela Politécnica Nacional, Ladrón de Guevara E11-254, 170517 Quito, Ecuador
| | - Mario J. Grijalva
- Centro de Investigación para la Salud en América Latina (CISeAL), Escuela de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Pontificia Universidad Católica del Ecuador, Calle San Pedro y Pamba Hacienda, 170530 Nayón, Ecuador
- Infectious and Tropical Disease Institute, Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, OH 45701 USA
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Hernandez-Castro LE, Paterno M, Villacís AG, Andersson B, Costales JA, De Noia M, Ocaña-Mayorga S, Yumiseva CA, Grijalva MJ, Llewellyn MS. 2b-RAD genotyping for population genomic studies of Chagas disease vectors: Rhodnius ecuadoriensis in Ecuador. PLoS Negl Trop Dis 2017; 11:e0005710. [PMID: 28723901 PMCID: PMC5536387 DOI: 10.1371/journal.pntd.0005710] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 07/31/2017] [Accepted: 06/13/2017] [Indexed: 11/26/2022] Open
Abstract
Background Rhodnius ecuadoriensis is the main triatomine vector of Chagas disease, American trypanosomiasis, in Southern Ecuador and Northern Peru. Genomic approaches and next generation sequencing technologies have become powerful tools for investigating population diversity and structure which is a key consideration for vector control. Here we assess the effectiveness of three different 2b restriction site-associated DNA (2b-RAD) genotyping strategies in R. ecuadoriensis to provide sufficient genomic resolution to tease apart microevolutionary processes and undertake some pilot population genomic analyses. Methodology/Principal findings The 2b-RAD protocol was carried out in-house at a non-specialized laboratory using 20 R. ecuadoriensis adults collected from the central coast and southern Andean region of Ecuador, from June 2006 to July 2013. 2b-RAD sequencing data was performed on an Illumina MiSeq instrument and analyzed with the STACKS de novo pipeline for loci assembly and Single Nucleotide Polymorphism (SNP) discovery. Preliminary population genomic analyses (global AMOVA and Bayesian clustering) were implemented. Our results showed that the 2b-RAD genotyping protocol is effective for R. ecuadoriensis and likely for other triatomine species. However, only BcgI and CspCI restriction enzymes provided a number of markers suitable for population genomic analysis at the read depth we generated. Our preliminary genomic analyses detected a signal of genetic structuring across the study area. Conclusions/Significance Our findings suggest that 2b-RAD genotyping is both a cost effective and methodologically simple approach for generating high resolution genomic data for Chagas disease vectors with the power to distinguish between different vector populations at epidemiologically relevant scales. As such, 2b-RAD represents a powerful tool in the hands of medical entomologists with limited access to specialized molecular biological equipment. Understanding Chagas disease vector (triatomine) population dispersal is key for the design of control measures tailored for the epidemiological situation of a particular region. In Ecuador, Rhodnius ecuadoriensis is a cause of concern for Chagas disease transmission, since it is widely distributed from the central coast to southern Ecuador. Here, a genome-wide sequencing (2b-RAD) approach was performed in 20 specimens from four communities from Manabí (central coast) and Loja (southern) provinces of Ecuador, and the effectiveness of three type IIB restriction enzymes was assessed. The findings of this study show that this genotyping methodology is cost effective in R. ecuadoriensis and likely in other triatomine species. In addition, preliminary population genomic analysis results detected a signal of population structure among geographically distinct communities and genetic variability within communities. As such, 2b-RAD shows significant promise as a relatively low-tech solution for determination of vector population genomics, dynamics, and spread.
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Affiliation(s)
- Luis E. Hernandez-Castro
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- * E-mail: (LEHC); (MSL)
| | - Marta Paterno
- Department of Biology, University of Padua, Padua, Italy
- Consorzio Nazionale Interuniversitario per le Scienze del Mare (CoNISMa), Rome, Italy
| | - Anita G. Villacís
- Center for Research on Health in Latin America, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador
| | - Björn Andersson
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Jaime A. Costales
- Center for Research on Health in Latin America, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador
| | - Michele De Noia
- Department of Animal Behaviour, Bielefeld University, Bielefeld, Germany
| | - Sofía Ocaña-Mayorga
- Center for Research on Health in Latin America, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador
| | - Cesar A. Yumiseva
- Center for Research on Health in Latin America, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador
| | - Mario J. Grijalva
- Center for Research on Health in Latin America, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador
- Infectious and Tropical Disease Institute, Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Ohio, United States of America
| | - Martin S. Llewellyn
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
- * E-mail: (LEHC); (MSL)
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Pinto CM, Ocaña-Mayorga S, Tapia EE, Lobos SE, Zurita AP, Aguirre-Villacís F, MacDonald A, Villacís AG, Lima L, Teixeira MMG, Grijalva MJ, Perkins SL. Bats, Trypanosomes, and Triatomines in Ecuador: New Insights into the Diversity, Transmission, and Origins of Trypanosoma cruzi and Chagas Disease. PLoS One 2015; 10:e0139999. [PMID: 26465748 PMCID: PMC4605636 DOI: 10.1371/journal.pone.0139999] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 09/21/2015] [Indexed: 12/30/2022] Open
Abstract
The generalist parasite Trypanosoma cruzi has two phylogenetic lineages associated almost exclusively with bats—Trypanosoma cruzi Tcbat and the subspecies T. c. marinkellei. We present new information on the genetic variation, geographic distribution, host associations, and potential vectors of these lineages. We conducted field surveys of bats and triatomines in southern Ecuador, a country endemic for Chagas disease, and screened for trypanosomes by microscopy and PCR. We identified parasites at species and genotype levels through phylogenetic approaches based on 18S ribosomal RNA (18S rRNA) and cytochrome b (cytb) genes and conducted a comparison of nucleotide diversity of the cytb gene. We document for the first time T. cruzi Tcbat and T. c. marinkellei in Ecuador, expanding their distribution in South America to the western side of the Andes. In addition, we found the triatomines Cavernicola pilosa and Triatoma dispar sharing shelters with bats. The comparisons of nucleotide diversity revealed a higher diversity for T. c. marinkellei than any of the T. c. cruzi genotypes associated with Chagas disease. Findings from this study increased both the number of host species and known geographical ranges of both parasites and suggest potential vectors for these two trypanosomes associated with bats in rural areas of southern Ecuador. The higher nucleotide diversity of T. c. marinkellei supports a long evolutionary relationship between T. cruzi and bats, implying that bats are the original hosts of this important parasite.
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Affiliation(s)
- C. Miguel Pinto
- Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, United States of America
- Department of Mammalogy, American Museum of Natural History, New York, New York, United States of America
- The Graduate Center, The City University of New York, New York, New York, United States of America
- Division of Mammals, National Museum of Natural History, Smithsonian Institution, Washington, District of Columbia, United States of America
- * E-mail:
| | - Sofía Ocaña-Mayorga
- Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
- Tropical Disease Institute, Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
| | | | - Simón E. Lobos
- Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Alejandra P. Zurita
- Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Fernanda Aguirre-Villacís
- Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Amber MacDonald
- Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Anita G. Villacís
- Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
| | - Luciana Lima
- Departamento de Parasitologia, Instituto de Ciencias Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Marta M. G. Teixeira
- Departamento de Parasitologia, Instituto de Ciencias Biomédicas, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Mario J. Grijalva
- Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
- Tropical Disease Institute, Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America
| | - Susan L. Perkins
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, United States of America
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Villacís AG, Ocaña-Mayorga S, Lascano MS, Yumiseva CA, Baus EG, Grijalva MJ. Abundance, natural infection with trypanosomes, and food source of an endemic species of triatomine, Panstrongylus howardi (Neiva 1911), on the Ecuadorian Central Coast. Am J Trop Med Hyg 2014; 92:187-92. [PMID: 25385867 DOI: 10.4269/ajtmh.14-0250] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The elimination of domestic triatomines is the foundation of Chagas disease control. Regional initiatives are eliminating introduced triatomine species. In this scenario, endemic triatomines can occupy the ecological niches left open and become a threat to long-term Chagas disease control efforts. This study determined the abundance, colonization, and Trypanosoma cruzi infection rate of the endemic Panstrongylus howardi in 10 rural communities located in Ecuador's Manabí Province. In total, 518 individuals of P. howardi were collected. Infestation indices of 1.4% and 6.6% were found in the domestic and peridomestic environments, respectively. We determined a T. cruzi infection rate of 53.2% (N = 47) in this species. P. howardi has a high capacity to adapt to different habitats, especially in the peridomicile. This implies a considerable risk of transmission because of the frequency of intradomicile invasion. Therefore, this species needs to be taken into account in Chagas control and surveillance efforts in the region.
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Affiliation(s)
- Anita G Villacís
- Center for Infectious Disease Research, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador; Tropical Disease Institute, Biomedical Sciences Department, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | - Sofía Ocaña-Mayorga
- Center for Infectious Disease Research, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador; Tropical Disease Institute, Biomedical Sciences Department, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | - Mauricio S Lascano
- Center for Infectious Disease Research, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador; Tropical Disease Institute, Biomedical Sciences Department, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | - César A Yumiseva
- Center for Infectious Disease Research, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador; Tropical Disease Institute, Biomedical Sciences Department, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | - Esteban G Baus
- Center for Infectious Disease Research, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador; Tropical Disease Institute, Biomedical Sciences Department, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | - Mario J Grijalva
- Center for Infectious Disease Research, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador; Tropical Disease Institute, Biomedical Sciences Department, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
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Grijalva MJ, Villacís AG, Ocaña-Mayorga S, Yumiseva CA, Baus EG. Limitations of selective deltamethrin application for triatomine control in central coastal Ecuador. Parasit Vectors 2011; 4:20. [PMID: 21332985 PMCID: PMC3050847 DOI: 10.1186/1756-3305-4-20] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Accepted: 02/18/2011] [Indexed: 11/21/2022] Open
Abstract
Background This year-long study evaluated the effectiveness of a strategy involving selective deltamethrin spraying and community education for control of Chagas disease vectors in domestic units located in rural communities of coastal Ecuador. Results Surveys for triatomines revealed peridomestic infestation with Rhodnius ecuadoriensis and Panstrongylus howardi, with infestation indices remaining high during the study (13%, 17%, and 10%, at initial, 6-month, and 12-month visits, respectively), which indicates a limitation of this strategy for triatomine population control. Infestation was found 6 and 12 months after spraying with deltamethrin. In addition, a large number of previously vector-free domestic units also were found infested at the 6- and 12-month surveys, which indicates new infestations by sylvatic triatomines. The predominance of young nymphs and adults suggests new infestation events, likely from sylvatic foci. In addition, infection with Trypanosoma cruzi was found in 65%, 21% and 29% at initial, 6-month and 12-month visits, respectively. All parasites isolated (n = 20) were identified as TcI. Conclusion New vector control strategies need to be devised and evaluated for reduction of T. cruzi transmission in this region.
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Affiliation(s)
- Mario J Grijalva
- Tropical Disease Institute, Biomedical Sciences Department, College of Osteopathic Medicine, Ohio University, Athens, Ohio, USA.
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Ocaña-Mayorga S, Llewellyn MS, Costales JA, Miles MA, Grijalva MJ. Sex, subdivision, and domestic dispersal of Trypanosoma cruzi lineage I in southern Ecuador. PLoS Negl Trop Dis 2010; 4:e915. [PMID: 21179502 PMCID: PMC3001902 DOI: 10.1371/journal.pntd.0000915] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 11/15/2010] [Indexed: 11/25/2022] Open
Abstract
Background Molecular epidemiology at the community level has an important guiding role in zoonotic disease control programmes where genetic markers are suitably variable to unravel the dynamics of local transmission. We evaluated the molecular diversity of Trypanosoma cruzi, the etiological agent of Chagas disease, in southern Ecuador (Loja Province). This kinetoplastid parasite has traditionally been a paradigm for clonal population structure in pathogenic organisms. However, the presence of naturally occurring hybrids, mitochondrial introgression, and evidence of genetic exchange in the laboratory question this dogma. Methodology/Principal Findings Eighty-one parasite isolates from domiciliary, peridomiciliary, and sylvatic triatomines and mammals were genotyped across 10 variable microsatellite loci. Two discrete parasite populations were defined: one predominantly composed of isolates from domestic and peridomestic foci, and another predominantly composed of isolates from sylvatic foci. Spatial genetic variation was absent from the former, suggesting rapid parasite dispersal across our study area. Furthermore, linkage equilibrium between loci, Hardy-Weinberg allele frequencies at individual loci, and a lack of repeated genotypes are indicative of frequent genetic exchange among individuals in the domestic/peridomestic population. Conclusions/Significance These data represent novel population-level evidence of an extant capacity for sex among natural cycles of T. cruzi transmission. As such they have dramatic implications for our understanding of the fundamental genetics of this parasite. Our data also elucidate local disease transmission, whereby passive anthropogenic domestic mammal and triatomine dispersal across our study area is likely to account for the rapid domestic/peridomestic spread of the parasite. Finally we discuss how this, and the observed subdivision between sympatric sylvatic and domestic/peridomestic foci, can inform efforts at Chagas disease control in Ecuador. Trypanosoma cruzi is transmitted by blood sucking insects known as triatomines. This protozoan parasite commonly infects wild and domestic mammals in South and Central America. However, triatomines also transmit the parasite to people, and human infection with T. cruzi is known as Chagas disease, a major public health concern in Latin America. Understanding the complex dynamics of parasite spread between wild and domestic environments is essential to design effective control measures to prevent the spread of Chagas disease. Here we describe T. cruzi genetic diversity and population dynamics in southern Ecuador. Our findings indicate that the parasite circulates in two largely independent cycles: one corresponding to the sylvatic environment and one related to the domestic/peridomestic environment. Furthermore, our data indicate that human activity might promote parasite dispersal among communties. This information is the key for the design of control programmes in Southern Ecuador. Finally, we have encountered evidence of a sexual reproductive mode in the domestic T. cruzi population, which constitutes a new and intriguing finding with regards to the biology of this parasite.
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Affiliation(s)
- Sofía Ocaña-Mayorga
- Centro de Investigación en Enfermedades Infecciosas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
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Black CL, Seed JR, Costales JA, Riner DK, Preisser JS, Lascano MS, Ocaña-Mayorga S, Grijalva MJ, Arcos-Terán L. Seroprevalence of Trypanosoma cruzi in Rural Ecuador and Clustering of Seropositivity within Households. Am J Trop Med Hyg 2009; 81:1035-40. [DOI: 10.4269/ajtmh.2009.08-0594] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Pinto CM, Ocaña-Mayorga S, Lascano MS, Grijalva MJ. Infection by trypanosomes in marsupials and rodents associated with human dwellings in Ecuador. J Parasitol 2007; 92:1251-5. [PMID: 17304802 DOI: 10.1645/ge-886r.1] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Small mammals trapped in domestic and peridomestic environments of rural Ecuador were screened for trypanosome infection by direct microscopy and hemoculture. Identification of species of trypanosomes was then performed by morphological characteristics and by polymerase chain reaction (PCR) assays. Of 194 animals collected, 15 were positive for infection (7.73%). Eight (4.12%) were infected with Trypanosoma cruzi (1 of 33 Didelphis marsupialis; 7 of 61 Rattus rattus). Eleven R. rattus (18.03%) harbored T. lewisi, 5 of which presented mixed infections with T. cruzi. Additionally, 1 of 3 Oryzomys xanthaeolus was infected with T. rangeli. No trypanosome infection was detected in Philander opossum (n = 1), Mus musculus (n = 79), Rattus norvegicus (n = 8), Akodon orophilus (n = 4), Sigmodon peruanus (n = 3), or Proechimys decumanus (n = 2). Many of the isolates belong to T. cruzi, the causative agent of Chagas disease, and R. rattus had the highest prevalence. Because of its abundance in the study areas, this species is considered an important reservoir for Chagas disease. This is the first report of T. lewisi and T. rangeli in Ecuador. This study is also the first to describe natural mixed infections of T. cruzi-T. lewisi.
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Affiliation(s)
- C Miguel Pinto
- Laboratorio de Investigación en Enfermedades Infecciosas, Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
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