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Gürtler RE, Gaspe MS, Macchiaverna NP, Enriquez GF, Rodríguez-Planes LI, Fernández MDP, Provecho YM, Cardinal MV. The Pampa del Indio project: District-wide quasi-elimination of Triatoma infestans after a 9-year intervention program in the Argentine Chaco. PLoS Negl Trop Dis 2023; 17:e0011252. [PMID: 37093886 PMCID: PMC10159358 DOI: 10.1371/journal.pntd.0011252] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 05/04/2023] [Accepted: 03/19/2023] [Indexed: 04/25/2023] Open
Abstract
BACKGROUND The elimination of Triatoma infestans, the main domestic vector of Trypanosoma cruzi, is lagging behind expectations in the Gran Chaco region. We implemented an insecticide-based intervention program and assessed its long-term effects on house infestation and bug abundance in a resource-constrained municipality (Pampa del Indio, northeastern Argentina) inhabited by creole and the Qom indigenous people (2007-2016). Key questions were whether district-wide data integration revealed patterns concealed at lower spatial levels; to what extent preintervention infestation and pyrethroid resistance challenged the effectiveness of insecticide-based control efforts, and how much control effort was needed to meet defined targets. METHODS Supervised vector control teams i) georeferenced every housing unit at baseline (1,546); ii) evaluated house infestation using timed-manual searches with a dislodging aerosol across four rural areas designated for district-wide scaling up; iii) sprayed with pyrethroid insecticide 92.7% of all houses; iv) periodically monitored infestation and promoted householder-based surveillance, and v) selectively sprayed the infested houses, totaling 1,823 insecticide treatments throughout the program. RESULTS Baseline house infestation (mean, 26.8%; range, 14.4-41.4%) and bug abundance plummeted over the first year postintervention (YPI). Timed searches at baseline detected 61.4-88.0% of apparent infestations revealed by any of the methods used. Housing dynamics varied widely among areas and between Qom and creole households. Preintervention triatomine abundance and the cumulative frequency of insecticide treatments were spatially aggregated in three large clusters overlapping with pyrethroid resistance, which ranged from susceptible to high. Persistent foci were suppressed with malathion. Aggregation occurred mainly at house compound or village levels. Preintervention domestic infestation and abundance were much greater in Qom than in creole households, whereas the reverse was recorded in peridomestic habitats. House infestation, rare (1.9-3.7%) over 2-6 YPI, averaged 0.66% (95% confidence interval, 0.28-1.29%) at endpoint. CONCLUSIONS Upscale integration revealed multiple coupled heterogeneities (spatial, sociodemographic and biological) that reflect large inequalities, hamper control efforts, and provide opportunities for targeted, sustainable disease control. High-coverage, professional insecticide spraying combined with systematic surveillance-and-response were essential ingredients to achieve the quasi-elimination of T. infestans within 5 YPI and concomitant transmission blockage despite various structural threats and constraints.
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Affiliation(s)
- Ricardo Esteban Gürtler
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - María Sol Gaspe
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Natalia Paula Macchiaverna
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Gustavo Fabián Enriquez
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
| | - Lucía Inés Rodríguez-Planes
- Instituto de Ciencias Polares, Ambiente y Recursos Naturales, Universidad Nacional de Tierra del Fuego, Ushuaia, Argentina
| | - María Del Pilar Fernández
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, Washington, United States of America
| | - Yael Mariana Provecho
- Ministerio de Salud de la Nación, Dirección de Control de Enfermedades Transmitidas por Vectores, Buenos Aires, Argentina
| | - Marta Victoria Cardinal
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales, Laboratorio de Eco-Epidemiología, Buenos Aires, Argentina
- CONICET-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Buenos Aires, Argentina
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Medina M, Zuluaga S, Martínez MF, Bermúdez JC, Hernández C, Beltrán V, Velásquez-Ortiz N, Muñoz M, Ramírez JD, Triana O, Cantillo-Barraza O. Interrogating the transmission dynamics of Trypanosoma cruzi (Trypanosomatida, Trypanosomatidae) by Triatoma venosa (Hemiptera: Reduviidae) after the elimination of vector transmission by Rhodnius prolixus in Boyacá eastern Colombia. Front Cell Infect Microbiol 2022; 12:998202. [PMID: 36275020 PMCID: PMC9582133 DOI: 10.3389/fcimb.2022.998202] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 09/13/2022] [Indexed: 11/13/2022] Open
Abstract
Chagas disease (CD) is a parasitic zoonosis (Trypanosoma cruzi) that is endemic in Colombia. Vector control of Rhodnius prolixus, the main domestic T. cruzi vector, has been achieved in a large part of the area with historically vector transmission of CD. It is necessary to understand the ecological behavior characteristics of local native vectors to ensure sustainability of the vector control programs. To evaluate the long-term success of a recent vector control campaign in the Boyacá department (Colombia), we used a combined strategy of entomological surveillance with co-existing canine surveillance from ten rural villages within six municipalities of the Tenza valley region (Boyacá, Colombia): Chinavita, Garagoa, Guateque, Somondoco, Sutatenza and Tenza, with historical reports of R. prolixus and secondary vectors. Collected triatomines and canine whole blood were analyzed for T. cruzi infection and genotyping. Triatomine bugs specimens were evaluated for blood meal source. Canine serology was performed using two distinct antibody assays. In total, 101 Triatoma venosa were collected by active search in domestic and peridomestic habitats. A natural infection prevalence of 13.9% (14/101) and four feeding sources were identified: human, dog, rat, and hen. A frequency infection of 46.5% (40/87) was observed from two independent serological tests and T. cruzi DNA was detected in 14 dogs (16.4%). Only TcIsylvatic DTU was detected. The results suggest that T. venosa present eco-epidemiological characteristics to maintain the transmission of T. cruzi in Tenza valley. This species has reinfested the intervened households and it has an active role in domestic and peridomestic transmission of T. cruzi due to their infection rates and feeding behavior. Therefore, this species should be considered as epidemiologically relevant for vector control strategies. Moreover, there is a need for human serological studies to have a close up of risk they are exposed to.
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Affiliation(s)
- Manuel Medina
- Programa de Control de Vectores, Secretaría de Salud Departamental, Tunja, Colombia
| | - Sara Zuluaga
- Grupo Biología y Control de Enfermedades Infecciosas (BCEI), Universidad de Antioquia, Medellín, Colombia
| | | | - Juan Carlos Bermúdez
- Programa de Control de Vectores, Secretaría de Salud Departamental, Tunja, Colombia
| | - Carolina Hernández
- Centro de Investigaciones en Microbiología y Biotecnología – UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Virgilio Beltrán
- Programa de Control de Vectores, Secretaría de Salud Departamental, Tunja, Colombia
| | - Natalia Velásquez-Ortiz
- Centro de Investigaciones en Microbiología y Biotecnología – UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, Bogotá, Colombia
| | - Marina Muñoz
- Centro de Investigaciones en Microbiología y Biotecnología – UR (CIMBIUR), Facultad de Ciencias Naturales, Universidad del Rosario, 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, United States
| | - Omar Triana
- Grupo Biología y Control de Enfermedades Infecciosas (BCEI), Universidad de Antioquia, Medellín, Colombia
| | - Omar Cantillo-Barraza
- Grupo Biología y Control de Enfermedades Infecciosas (BCEI), Universidad de Antioquia, Medellín, Colombia
- *Correspondence: Omar Cantillo-Barraza,
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de Arias AR, Monroy C, Guhl F, Sosa-Estani S, Santos WS, Abad-Franch F. Chagas disease control-surveillance in the Americas: the multinational initiatives and the practical impossibility of interrupting vector-borne Trypanosoma cruzi transmission. Mem Inst Oswaldo Cruz 2022; 117:e210130. [PMID: 35830010 PMCID: PMC9261920 DOI: 10.1590/0074-02760210130] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 11/21/2022] Open
Abstract
Chagas disease (CD) still imposes a heavy burden on most Latin American countries. Vector-borne and mother-to-child transmission cause several thousand new infections per year, and at least 5 million people carry Trypanosoma cruzi. Access to diagnosis and medical care, however, is far from universal. Starting in the 1990s, CD-endemic countries and the Pan American Health Organization-World Health Organization (PAHO-WHO) launched a series of multinational initiatives for CD control-surveillance. An overview of the initiatives’ aims, achievements, and challenges reveals some key common themes that we discuss here in the context of the WHO 2030 goals for CD. Transmission of T. cruzi via blood transfusion and organ transplantation is effectively under control. T. cruzi, however, is a zoonotic pathogen with 100+ vector species widely spread across the Americas; interrupting vector-borne transmission seems therefore unfeasible. Stronger surveillance systems are, and will continue to be, needed to monitor and control CD. Prevention of vertical transmission demands boosting current efforts to screen pregnant and childbearing-aged women. Finally, integral patient care is a critical unmet need in most countries. The decades-long experience of the initiatives, in sum, hints at the practical impossibility of interrupting vector-borne T. cruzi transmission in the Americas. The concept of disease control seems to provide a more realistic description of what can in effect be achieved by 2030.
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Affiliation(s)
| | - Carlota Monroy
- Universidad de San Carlos, Laboratorio de Entomología y Parasitología Aplicadas, Ciudad de Guatemala, Guatemala
| | - Felipe Guhl
- Universidad de los Andes, Facultad de Ciencias, Centro de Investigaciones en Microbiología y Parasitología Tropical, Bogotá, Colombia
| | - Sergio Sosa-Estani
- Drugs for Neglected Diseases initiative Latin America, Rio de Janeiro, RJ, Brasil.,Centro de Investigaciones en Epidemiología y Salud Pública, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Walter Souza Santos
- Ministério da Saúde, Secretaria de Vigilância em Saúde, Instituto Evandro Chagas, Laboratório de Epidemiologia das Leishmanioses, Ananindeua, PA, Brasil
| | - Fernando Abad-Franch
- Universidade de Brasília, Faculdade de Medicina, Núcleo de Medicina Tropical, Brasília, DF, Brasil
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Alonso-Vega C, Urbina JA, Sanz S, Pinazo MJ, Pinto JJ, Gonzalez VR, Rojas G, Ortiz L, Garcia W, Lozano D, Soy D, Maldonado RA, Nagarkatti R, Debrabant A, Schijman A, Thomas MC, López MC, Michael K, Ribeiro I, Gascon J, Torrico F, Almeida IC. New chemotherapy regimens and biomarkers for Chagas disease: the rationale and design of the TESEO study, an open-label, randomised, prospective, phase-2 clinical trial in the Plurinational State of Bolivia. BMJ Open 2021; 11:e052897. [PMID: 34972765 PMCID: PMC8720984 DOI: 10.1136/bmjopen-2021-052897] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
INTRODUCTION Chagas disease (CD) affects ~7 million people worldwide. Benznidazole (BZN) and nifurtimox (NFX) are the only approved drugs for CD chemotherapy. Although both drugs are highly effective in acute and paediatric infections, their efficacy in adults with chronic CD (CCD) is lower and variable. Moreover, the high incidence of adverse events (AEs) with both drugs has hampered their widespread use. Trials in CCD adults showed that quantitative PCR (qPCR) assays remain negative for 12 months after standard-of-care (SoC) BZN treatment in ~80% patients. BZN pharmacokinetic data and the nonsynchronous nature of the proliferative mammal-dwelling parasite stage suggested that a lower BZN/NFX dosing frequency, combined with standard or extended treatment duration, might have the same or better efficacy than either drug SoC, with fewer AEs. METHODS AND ANALYSIS New ThErapies and Biomarkers for ChagaS infEctiOn (TESEO) is an open-label, randomised, prospective, phase-2 clinical trial, with six treatment arms (75 patients/arm, 450 patients). Primary objectives are to compare the safety and efficacy of two new proposed chemotherapy regimens of BZN and NFX in adults with CCD with the current SoC for BZN and NFX, evaluated by qPCR and biomarkers for 36 months posttreatment and correlated with CD conventional serology. Recruitment of patients was initiated on 18 December 2019 and on 20 May 2021, 450 patients (study goal) were randomised among the six treatment arms. The treatment phase was finalised on 18 August 2021. Secondary objectives include evaluation of population pharmacokinetics of both drugs in all treatment arms, the incidence of AEs, and parasite genotyping. ETHICS AND DISSEMINATION The TESEO study was approved by the National Institutes of Health (NIH), U.S. Food and Drug Administration (FDA), federal regulatory agency of the Plurinational State of Bolivia and the Ethics Committees of the participating institutions. The results will be disseminated via publications in peer-reviewed journals, conferences and reports to the NIH, FDA and participating institutions. TRIAL REGISTRATION NUMBER NCT03981523.
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Affiliation(s)
| | - Julio A Urbina
- Center for Biochemistry and Biophysics, Venezuelan Institute for Scientific Research (IVIC), Caracas, Distrito Capital, Venezuela, Bolivarian Republic of
| | - Sergi Sanz
- Biostatistics and Data Management Unit, Barcelona Institute for Global Health, Barcelona, Spain
- Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
- Department of Basic Clinical Practice, Universitat de Barcelona, Barcelona, Spain
| | - María-Jesús Pinazo
- Barcelona Institute for Global Health (ISGLOBAL), Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Jimy José Pinto
- Fundación Ciencia y Estudios Aplicados para el Desarrollo en Salud y Medio Ambiente (CEADES), Cochabamba, Bolivia, Plurinational State of
| | - Virginia R Gonzalez
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, Texas, USA
| | - Gimena Rojas
- Fundación Ciencia y Estudios Aplicados para el Desarrollo en Salud y Medio Ambiente (CEADES), Cochabamba, Bolivia, Plurinational State of
| | - Lourdes Ortiz
- Fundación Ciencia y Estudios Aplicados para el Desarrollo en Salud y Medio Ambiente (CEADES), Tarija, Bolivia, Plurinational State of
- Universidad Autónoma Juan Misael Saracho, Tarija, Bolivia, Plurinational State of
| | - Wilson Garcia
- Centro Plataforma Chagas Sucre, Fundación Ciencia y Estudios Aplicados para el Desarrollo en Salud y Medio Ambiente (CEADES), Sucre, Bolivia, Plurinational State of
- Programa Departamental de Chagas Chuquisaca, Servicio Departamental de Salud de Chuquisaca, Chuquisaca, Bolivia, Plurinational State of
| | - Daniel Lozano
- Fundación Ciencia y Estudios Aplicados para el Desarrollo en Salud y Medio Ambiente (CEADES), Cochabamba, Bolivia, Plurinational State of
| | - Dolors Soy
- Pharmacy Service, Division of Medicines, Hospital Clinic de Barcelona, Barcelona, Spain
- Institut de Investigació Biomèdica Agustí Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
| | - Rosa A Maldonado
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, Texas, USA
| | - Rana Nagarkatti
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration (FDA), Silver Spring, Maryland, USA
| | - Alain Debrabant
- Division of Emerging and Transfusion Transmitted Diseases, Center for Biologics Evaluation and Research, U.S. Food and Drug Administration (FDA), Silver Spring, Maryland, USA
| | - Alejandro Schijman
- Laboratorio de Biología Molecular de la Enfermedad de Chagas, Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Buenos Aires, Argentina
- National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - M Carmen Thomas
- Consejo Superior de Investigaciones Científicas, Instituto de Parasitología y Biomedicina López-Neyra, Granada, Spain
| | - Manuel Carlos López
- Consejo Superior de Investigaciones Científicas, Instituto de Parasitología y Biomedicina López-Neyra, Granada, Spain
| | - Katja Michael
- Department of Chemistry and Biochemistry, The University of Texas at El Paso, El Paso, Texas, USA
| | - Isabela Ribeiro
- Dynamic Portfolio Unit, Drugs for Neglected Diseases initiative, Geneva, Switzerland
| | - Joaquim Gascon
- Barcelona Institute for Global Health (ISGLOBAL), Barcelona, Spain
- CIBER de Enfermedades Infecciosas (CIBERINFEC), Madrid, Spain
| | - Faustino Torrico
- Fundación Ciencia y Estudios Aplicados para el Desarrollo en Salud y Medio Ambiente (CEADES), Cochabamba, Bolivia, Plurinational State of
| | - Igor C Almeida
- Department of Biological Sciences, The University of Texas at El Paso, El Paso, Texas, USA
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Roca C, Málaga-Machaca ES, Verastegui MR, Scola B, Valencia-Ayala E, Menduiña MDC, Noazin S, Bowman NM, Tinajeros F, Gilman RH. IgG Subclasses and Congenital Transmission of Chagas Disease. Am J Trop Med Hyg 2021; 105:1187-1192. [PMID: 34491223 PMCID: PMC8592205 DOI: 10.4269/ajtmh.20-1524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 06/25/2021] [Indexed: 11/07/2022] Open
Abstract
The mechanism of vertical transmission of Trypanosoma cruzi is poorly understood. In this study, we evaluated the role of IgG subclasses in the congenital transmission of Chagas disease. We conducted a case-control study in a public maternity hospital in Santa Cruz, Bolivia, enrolling women at delivery. Thirty women who transmitted T. cruzi to their newborns (cases), and 51 women who did not (controls) were randomly selected from 676 total seropositive women. Trypanosoma cruzi-specific IgG1, IgG2, and IgG3 levels were measured by in-house ELISA. The IgG4 levels were unmeasurable as a result of low levels in all participants. Quantitative polymerase chain reaction results and demographic factors were also analyzed. One-unit increases in normalized absorbance ratio of IgG1 or IgG2 levels increased the odds of congenital T. cruzi transmission in Chagas-seropositive women by 2.0 (95% CI: 1.1-3.6) and 2.27 (95% CI: 0.9-5.7), adjusted for age and previous blood transfusion. Odds of congenital transmission were 7.0 times higher in parasitemic mothers (95% CI: 2.3-21.3, P < 0.01) compared with nonparasitemic mothers. We observed that all mothers with IgG1 ≥ 4 were transmitters (sensitivity = 20%, specificity = 100%). Additionally, no mothers with IgG2 < 1.13 were transmitters (sensitivity = 100%, specificity = 21.6%). We demonstrated that IgG subclasses and parasite presence in blood are associated with vertical transmission of T. cruzi and could identify women at increased risk for congenital transmission by measuring IgG subclasses. These measures have potential as objective screening tests to predict the congenital transmission of Chagas.
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Affiliation(s)
- Cristian Roca
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Laboratorio de Investigación de Enfermedades Infecciosas, Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Edith S. Málaga-Machaca
- Laboratorio de Investigación de Enfermedades Infecciosas, Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Manuela R. Verastegui
- Laboratorio de Investigación de Enfermedades Infecciosas, Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Billy Scola
- Miller School of Medicine, University of Miami, Miami, Florida
| | - Edward Valencia-Ayala
- Laboratorio de Investigación de Enfermedades Infecciosas, Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Sassan Noazin
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Natalie M. Bowman
- Department of Medicine, Division of Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | | | - Robert H. Gilman
- Laboratorio de Investigación de Enfermedades Infecciosas, Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
- Asociación Benéfica PRISMA, Lima, Perú
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Castaldo M, Cavani A, Segneri MC, Costanzo G, Mirisola C, Marrone R. Anthropological study on Chagas Disease: Sociocultural construction of illness and embodiment of health barriers in Bolivian migrants in Rome, Italy. PLoS One 2020; 15:e0240831. [PMID: 33064748 PMCID: PMC7567347 DOI: 10.1371/journal.pone.0240831] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 10/02/2020] [Indexed: 01/10/2023] Open
Abstract
INTRODUCTION Chagas Disease (CD) is endemic in many Latin-American countries, Bolivia in particular. It is now spreading in Italy as a host country for transcontinental migrants and becoming an emerging health problem. This anthropological action-research, as part of a wider medical project on Neglected Tropical Diseases, has the purpose of analyzing the sociocultural construction of CD and its representation in Bolivian people living in Rome as well as barriers, such as the stigma about the illness, to access the National Health Service for those potentially affected. METHODS The ethnographic study was carried out from 2016 to 2018 by a medical anthropologist at the National Institute for Health, Migration and Poverty (INMP) on 72 Bolivian migrants (47 women and 25 men) living in Rome. The study was carried out through: a territorial mapping of Bolivian networks and communities aimed at recruiting people, participant observation, and application of semi-structured and unstructured interviews. The interviews were hold in Spanish and proposed to all participants before or during medical examination, or during events organized by the Bolivian community in Rome. The interview consisted of 16 items and covered four macro areas: personal and migration history, health status, access to the Italian National Health Service and knowledge about CD; plus 5 items for those who received a diagnosis of Chagas Disease in Italy. RESULTS The sociocultural construction and the deep stigma about the illness built by participants and their families could hinder both diagnosis and treatment. Institutional barriers also contributed to reduce adherence to screening tests: often, opening hours of the outpatient clinic were incompatible with participants' precarious employments. To guarantee participant's access to public health services and their adherence to the diagnostic protocol, we implemented a profound revision of our cultural and institutional approach to them. CONCLUSIONS The analysis evidenced the limitations of the conventional approach applied by the Italian National Health Service to this migrant community, such as the absence of socio-cultural and linguistics competences that can help understanding patients' perception and representation of the illness. The multidisciplinary approach instead-with clinicians using the ethnographic results to adjust their work to the participants' needs-was a successful attempt to ensure therapeutic alliance.
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Affiliation(s)
- Miriam Castaldo
- Department of Mental Health - Medical Anthropological Unit, National Institute for Health, Migration and Poverty (INMP), Rome, Italy
| | - Andrea Cavani
- Scientific Coordination Unit, National Institute for Health, Migration and Poverty (NIHMP), Rome, Italy
| | - Maria Concetta Segneri
- Department of Mental Health - Medical Anthropological Unit, National Institute for Health, Migration and Poverty (INMP), Rome, Italy
| | - Gianfranco Costanzo
- Medical Directorate, National Institute for Health, Migration and Poverty (INMP), Rome, Italy
| | - Concetta Mirisola
- INMP Directorate, National Institute for Health, Migration and Poverty (INMP), Rome, Italy
| | - Rosalia Marrone
- Multispecialty and Medical Professions Department, National Institute for Health, Migration and Poverty (INMP), Rome, Italy
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Cucunubá ZM, Nouvellet P, Peterson JK, Bartsch SM, Lee BY, Dobson AP, Basáñez MG. Complementary Paths to Chagas Disease Elimination: The Impact of Combining Vector Control With Etiological Treatment. Clin Infect Dis 2019; 66:S293-S300. [PMID: 29860294 PMCID: PMC5982731 DOI: 10.1093/cid/ciy006] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Background The World Health Organization’s 2020 goals for Chagas disease are (1) interrupting vector-borne intradomiciliary transmission and (2) having all infected people under care in endemic countries. Insecticide spraying has proved efficacious for reaching the first goal, but active transmission remains in several regions. For the second, treatment has mostly been restricted to recently infected patients, who comprise only a small proportion of all infected individuals. Methods We extended our previous dynamic transmission model to simulate a domestic Chagas disease transmission cycle and examined the effects of both vector control and etiological treatment on achieving the operational criterion proposed by the Pan American Health Organization for intradomiciliary, vectorial transmission interruption (ie, <2% seroprevalence in children <5 years of age). Results Depending on endemicity, an antivectorial intervention that decreases vector density by 90% annually would achieve the transmission interruption criterion in 2–3 years (low endemicity) to >30 years (high endemicity). When this strategy is combined with annual etiological treatment in 10% of the infected human population, the seroprevalence criterion would be achieved, respectively, in 1 and 11 years. Conclusions Combining highly effective vector control with etiological (trypanocidal) treatment in humans would substantially reduce time to transmission interruption as well as infection incidence and prevalence. However, the success of vector control may depend on prevailing vector species. It will be crucial to improve the coverage of screening programs, the performance of diagnostic tests, the proportion of people treated, and the efficacy of trypanocidal drugs. While screening and access can be incremented as part of strengthening the health systems response, improving diagnostics performance and drug efficacy will require further research.
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Affiliation(s)
- Zulma M Cucunubá
- London Centre for Neglected Tropical Disease Research, United Kingdom.,Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
| | - Pierre Nouvellet
- London Centre for Neglected Tropical Disease Research, United Kingdom.,Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, United Kingdom
| | - Jennifer K Peterson
- Zoonotic Disease Research Center, Arequipa, Peru.,Department of Biostatistics, Epidemiology and Bioinformatics, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Sarah M Bartsch
- Public Health Computational and Operations Research, John Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Bruce Y Lee
- Public Health Computational and Operations Research, John Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Andrew P Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, New Jersey
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8
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Salm A, Gertsch J. Cultural perception of triatomine bugs and Chagas disease in Bolivia: a cross-sectional field study. Parasit Vectors 2019; 12:291. [PMID: 31182163 PMCID: PMC6558697 DOI: 10.1186/s13071-019-3546-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 05/30/2019] [Indexed: 01/09/2023] Open
Abstract
Background Chagas disease remains a major public health risk in Bolivia, particularly among rural indigenous communities. Here we studied the cultural perception of the triatomine vectors and Chagas disease among selected rural and urban ethnic groups from different socio-economic and geographical milieus. We focused on the indigenous communities in the Bolivian Chaco where the disease is hyperendemic. Methods A cross-sectional study using field observations and structured interviews was carried out among 480 informants in five different regions of Bolivia. Additional semi-structured interviews were conducted. Statistical analyses were performed to determine the correlation of socio-economic variables and indigenous Chagas disease knowledge systems. A total of 170 domestic Triatoma infestans vectors were collected and infection with Trypanosoma cruzi was analyzed by real-time PCR. Results Triatomine bugs were associated with Chagas disease in 70.2% (n = 480) of the responses (48.0% Ayoreo, 87.5% Chiquitano, 83.9% Guaraní, 72.2% Quechua, 46.1% La Paz citizens and 67.7% Santa Cruz citizens). Generally, indigenous informants have been educated on the association between triatomine bugs and Chagas disease by institutional anti-Chagas disease campaigns. While communities were largely aware of the vectors as a principal mode of disease transmission, rather unexpectedly, health campaigns had little influence on their prevention practices, apparently due to cultural constraints. Overall, 71.9% of the collected domestic vectors in the Chaco region were infected with T. cruzi, matching the high infection rates in the indigenous communities. Conclusions Among the Guaraní, Ayoreo and Quechua communities, the groups living in traditional houses have not integrated the scientific knowledge about Chagas disease transmission into their daily hygiene and continue to cohabit with T. infestans vectors hyperinfected with T. cruzi. An effective translation of Western disease concepts into traditional preventive measures is missing because asymptomatic infections are not generally perceived as threat by the communities. New participatory approaches involving existing ethnomedical knowledge systems could be a successful strategy in the control of T. cruzi infection.
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Affiliation(s)
- Andrea Salm
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland
| | - Jürg Gertsch
- Institute of Biochemistry and Molecular Medicine, University of Bern, 3012, Bern, Switzerland.
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9
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Modelling the association between deltamethrin resistance in Triatoma infestans populations of the Argentinian Gran Chaco region with environmental factors. Acta Trop 2019; 194:53-61. [PMID: 30898614 DOI: 10.1016/j.actatropica.2019.03.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/26/2019] [Accepted: 03/16/2019] [Indexed: 11/21/2022]
Abstract
In Latin America, Triatoma infestans is the main vector of the protozoan Trypanosoma cruzi, causal agent of Chagas disease. This blood-sucking triatomine is widely distributed in the Gran Chaco ecoregion, where chemical control has failed because of the evolution of resistance to pyrethroid insecticides. Recently, we described a deltamethrin high resistant focus in Güemes Department (Chaco province) characterized by susceptible populations, populations with low resistance (without field control failures) and some of the populations with the highest resistance level detected. This toxicological heterogeneity could be a result of non-homogenous insecticide pressure and be influenced by environmental factors. The present study evaluated the association of deltamethrin resistance ratios (RR50s) of T. infestans populations with explanatory variables extracted from the WorldClim dataset and constructed from information of National Chagas Program actions during 2005-2015. Control actions were distributed throughout the analyzed period, representing a homogeneous selective pressure. The average percentage of total positive houses was 33.66%. Models that included temperature and precipitation indicators presented 65% explanation. When village size variables where added, the explanatory power reached 70%. This observational result suggests that the climate may favor directly or indirectly the development/selection for resistance, representing a valuable tool to understand the occurrence of resistance that could increase the Chagas disease in the Gran Chaco.
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10
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Fournet F, Jourdain F, Bonnet E, Degroote S, Ridde V. Effective surveillance systems for vector-borne diseases in urban settings and translation of the data into action: a scoping review. Infect Dis Poverty 2018; 7:99. [PMID: 30217142 PMCID: PMC6137924 DOI: 10.1186/s40249-018-0473-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 08/01/2018] [Indexed: 11/25/2022] Open
Abstract
Background Vector-borne diseases (VBDs) continue to represent a global threat, with “old” diseases like malaria, and “emergent” or “re-emergent” ones like Zika, because of an increase in international trade, demographic growth, and rapid urbanization. In this era of globalization, surveillance is a key element in controlling VBDs in urban settings, but surveillance alone cannot solve the problem. A review of experiences is of interest to examine other solution elements. The objectives were to assess the different means of VBD surveillance in urban environments, to evaluate their potential for supporting public health actions, and to describe the tools used for public health actions, the constraints they face, and the research and health action gaps to be filled. Main body For this scoping review we searched peer-reviewed articles and grey literature published between 2000 and 2016. Various tools were used for data coding and extraction. A quality assessment was done for each study reviewed, and descriptive characteristics and data on implementation process and transferability were analyzed in all studies. After screening 414 full-text articles, we retained a total of 79 articles for review. The main targets of the articles were arboviral diseases (65.8%) and malaria (16.5%). The positive aspects of many studies fit within the framework of integrated vector management. Public awareness is considered a key to successful vector control programs. Advocacy and legislation can reinforce both empowerment and capacity building. These can be achieved by collaboration within the health sector and with other sectors. Research is needed to develop well designed studies and new tools for surveillance and control. Conclusions The need for surveillance systems in urban settings in both developing and developed countries was highlighted. Countries face the same challenges relating to human, financial, and structural resources. These findings also constitute a wake-up call for governments, academia, funders, and World Health Organization to strengthen control programs and enhance VBD research in urban environments. Electronic supplementary material The online version of this article (10.1186/s40249-018-0473-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Florence Fournet
- Infectious Diseases and Vectors Ecology, Genetics, Evolution and Control (MIVEGEC), French National Research Institute for Sustainable Development, 911 Avenue Agropolis, BP 64501, 34394, Montpellier Cedex 5, France.
| | - Frédéric Jourdain
- Infectious Diseases and Vectors Ecology, Genetics, Evolution and Control (MIVEGEC), French National Research Institute for Sustainable Development, 911 Avenue Agropolis, BP 64501, 34394, Montpellier Cedex 5, France
| | - Emmanuel Bonnet
- Résiliences, French National Research Institute for Sustainable Development, 32 Avenue Henri Varagnat, 93140, Bondy, France
| | - Stéphanie Degroote
- University of Montreal, Public Health Research Institute, 7101 avenue du Parc, Montréal, Québec, Canada
| | - Valéry Ridde
- University of Montreal, Public Health Research Institute, 7101 avenue du Parc, Montréal, Québec, Canada.,Population and Development Center (CEPED), French National Research Institute for Sustainable Development, Université Paris Sorbonne, 45, rue des Saints Pères, 75006, Paris, France
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11
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Cavallo MJ, Amelotti I, Abrahan L, Cueto G, Gorla DE. Rural houses infestation by Triatoma infestans in northwestern Argentina: Vector control in a high spatial heterogeneous infestation area. PLoS One 2018; 13:e0201391. [PMID: 30071071 PMCID: PMC6072006 DOI: 10.1371/journal.pone.0201391] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 07/13/2018] [Indexed: 11/18/2022] Open
Abstract
Triatoma infestans (Hemiptera: Reduviidae) is a vector of the Trypanosoma cruzi parasite, causative agent of Chagas disease. During the last decade, vector control activities have been systematically carried out in northwestern Argentina, an endemic region for this disease. The general aim of this study to evaluate was spatio-temporal variation of infestation by T. infestans in rural communities of Los Llanos in La Rioja province. We estimated house infestation using two sampling methods: passive and active. Passive collection was conducted with community participation collecting triatomines. Six passive collections were carried out in 397 houses during the warm season between 2014 and 2017. Active collection of T. infestans was thoroughly performed by trained staff for 60 minutes and was carried out once in March 2016. The estimate of intradomestic infestation did not show significant differences between both collection methods (p = 0.39). However, passive collection method had lower sensitivity than active collection method for the estimation of peridomestic infestation and intradomestic colonization (PDI: p< 0.01; ID colonization: p< 0.01). The results obtained with passive collection methods showed that the infestation in the study area was spatially heterogeneous and temporally variable. Intradomiciliary infestation decreased over time (14.4% to 7.9%, p<0.05) although the effect of the chemical treatment application was not associated with the infestation level of T. infestans (p = 0.15) and the Departments had a different response each year (p<0.01). A high infestation cluster was located in the south of our study area during 2016–2017. The vector presence in the houses confirms the importance of to improve entomological surveillance programs. The search for triatomines carried out by the inhabitants might be a useful method to complement the activities of vector control programs in isolated and rural areas.
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Affiliation(s)
- María José Cavallo
- Entomología Médica, Centro Regional de Investigaciones Científicas y Transferencia La Rioja, UNLAR, SEGEMAR, UNCa, CONICET, Anillaco, La Rioja, Argentina
- * E-mail:
| | - Ivana Amelotti
- Entomología Médica, Centro Regional de Investigaciones Científicas y Transferencia La Rioja, UNLAR, SEGEMAR, UNCa, CONICET, Anillaco, La Rioja, Argentina
- Universidad Nacional de La Rioja, La Rioja, Argentina
| | - Luciana Abrahan
- Entomología Médica, Centro Regional de Investigaciones Científicas y Transferencia La Rioja, UNLAR, SEGEMAR, UNCa, CONICET, Anillaco, La Rioja, Argentina
| | - Gerardo Cueto
- Instituto de Ecología, Genética y Evolución, Buenos Aires, Argentina
| | - David E. Gorla
- Instituto de Altos Estudios Espaciales Mario Gulich, CONAE-Universidad Nacional de Córdoba, Córdoba, Argentina
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12
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Espinoza Echeverria J, Rodriguez AN, Cortez MR, Diotaiuti LG, Gorla DE. Spatial and temporal distribution of house infestation by Triatoma infestans in the Toro Toro municipality, Potosi, Bolivia. Parasit Vectors 2017; 10:58. [PMID: 28148283 PMCID: PMC5288887 DOI: 10.1186/s13071-017-1984-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Accepted: 01/12/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Triatoma infestans is the main vector of Trypanosoma cruzi in Bolivia. The species is present both in domestic and peridomestic structures of rural areas, and in wild ecotopes of the Andean valleys and the Great Chaco. The identification of areas persistently showing low and high house infestation by the vector is important for the management of vector control programs. This study aimed at analyzing the temporal and spatial distribution of house infestation by T. infestans in the Toro Toro municipality (Potosi, Bolivia) between 2009 and 2014, and its association with environmental variables. METHODS House infestation and T. infestans density were calculated from entomological surveys of houses in the study area, using a fixed-time effort sampling technique. The spatial heterogeneity of house infestation was evaluated using the SatScan statistic. Association between house infestation with Bioclim variables (Worldclim database) and altitude was analyzed using a generalized linear model (GLM) with a logit link. Model selection was based on the Akaike information criteria after eliminating collinearity between variables using the variable inflation factor. The final model was used to create a probability map of house infestation for the Toro Toro municipality. RESULTS A total of 73 communities and 16,489 house evaluation events were analyzed. Presence of T. infestans was recorded on 480 house evaluation events, giving an overall annual infestation of 2.9% during the studied period (range 1.5-5.4% in 2009 and 2012). Vector density remained at about 1.25 insects/ house. Infestation was highly aggregated in five clusters, including 11 communities. Relative risk of infestation within these clusters was 1.7-3.9 times the value for the regional average. Four environmental variables were identified as good descriptors of house infestation, explaining 57% of house infestation variability. The model allowed the estimation of a house infestation surface for the Toro Toro municipality. CONCLUSION This study shows that residual and persistent populations of T. infestans maintain low house infestation, representing a potential risk for the transmission of T. cruzi in these communities, and it is possible to stratify house infestation using EV, and produce a risk map to guide the activities of vector control interventions in the municipality of Toro Toro (Potosi, Bolivia).
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Affiliation(s)
- Jorge Espinoza Echeverria
- Laboratório de Referência Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, FIOCRUZ- MG, Belo Horizonte, Brazil
| | | | | | - Liléia Gonçalves Diotaiuti
- Laboratório de Referência Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, FIOCRUZ- MG, Belo Horizonte, Brazil
| | - David E. Gorla
- Instituto Multidisciplinario de Biología Vegetal (IMBIV-CONICET), Córdoba, Argentina
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13
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Barbu CM, Buttenheim AM, Pumahuanca MLH, Calderón JEQ, Salazar R, Carrión M, Rospigliossi AC, Chavez FSM, Alvarez KO, Cornejo del Carpio J, Náquira C, Levy MZ. Residual infestation and recolonization during urban Triatoma infestans Bug Control Campaign, Peru. Emerg Infect Dis 2016; 20:2055-63. [PMID: 25423045 PMCID: PMC4257819 DOI: 10.3201/eid2012.131820] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Chagas disease vector control campaigns are being conducted in Latin America, but little is known about medium-term or long-term effectiveness of these efforts, especially in urban areas. After analyzing entomologic data for 56,491 households during the treatment phase of a Triatoma infestans bug control campaign in Arequipa, Peru, during 2003-2011, we estimated that 97.1% of residual infestations are attributable to untreated households. Multivariate models for the surveillance phase of the campaign obtained during 2009-2012 confirm that nonparticipation in the initial treatment phase is a major risk factor (odds ratio [OR] 21.5, 95% CI 3.35-138). Infestation during surveillance also increased over time (OR 1.55, 95% CI 1.15-2.09 per year). In addition, we observed a negative interaction between nonparticipation and time (OR 0.73, 95% CI 0.53-0.99), suggesting that recolonization by vectors progressively dilutes risk associated with nonparticipation. Although the treatment phase was effective, recolonization in untreated households threatens the long-term success of vector control.
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14
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Quinde-Calderón L, Rios-Quituizaca P, Solorzano L, Dumonteil E. Ten years (2004-2014) of Chagas disease surveillance and vector control in Ecuador: successes and challenges. Trop Med Int Health 2015; 21:84-92. [PMID: 26458237 DOI: 10.1111/tmi.12620] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
OBJECTIVE To describe the current situation of Chagas disease in Ecuador and to evaluate the impact of vector control for the period 2004-2014. METHODS Since 2004, the Ministry of Public Health has formalized activities for the surveillance and control of Chagas disease and we analyzed here available records. RESULTS More than 200 000 houses were surveyed, and 2.6% were found to be infested (95% CI: 2.6-2.7), and more than 51 000 houses were sprayed with residual insecticide, with important yearly variations. A total of 915 cases of T. cruzi infection were registered. The Amazon region is emerging as a high priority area, where nearly half of T. cruzi infection cases originate. The costal region and the southern highland valleys remain important high-risk area. Vector control efforts over the past 10 years have been effective in the coastal region, where T. dimidiata predominates, and resulted in important reductions in house infestation indices in many areas, even reaching negligible levels in some parishes. CONCLUSION Vector efforts need to be sustained and expanded for the elimination of T. dimidiata to be feasible. Novel vector control interventions need to be designed to reduce intrusion by several triatomine species present in the Amazon region and southern Ecuador. Strong political commitment is needed to sustain current achievements and improve the national coverage of these programmes.
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Affiliation(s)
- Leonardo Quinde-Calderón
- Programa Nacional de Chagas, Leishmaniasis y Oncocercosis, Ministerio de Salud Pública, Guayaquil, Ecuador
| | | | - Luis Solorzano
- Subproceso de Parasitologia, Instituto Nacional de Investigación en Salud Pública, Guayaquil, Ecuador
| | - Eric Dumonteil
- Subproceso de Parasitologia, Instituto Nacional de Investigación en Salud Pública, Guayaquil, Ecuador.,Laboratorio de Parasitología, Centro de Investigaciones Regionales "Hideyo Noguchi", Universidad Autónoma de Yucatán, Mérida, Yucatán, México
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15
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Peterson JK, Bartsch SM, Lee BY, Dobson AP. Broad patterns in domestic vector-borne Trypanosoma cruzi transmission dynamics: synanthropic animals and vector control. Parasit Vectors 2015; 8:537. [PMID: 26489493 PMCID: PMC4618875 DOI: 10.1186/s13071-015-1146-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/05/2015] [Indexed: 12/22/2022] Open
Abstract
Background Chagas disease (caused by Trypanosoma cruzi) is the most important neglected tropical disease (NTD) in Latin America, infecting an estimated 5.7 million people in the 21 countries where it is endemic. It is one of the NTDs targeted for control and elimination by the 2020 London Declaration goals, with the first goal being to interrupt intra-domiciliary vector-borne T. cruzi transmission. A key question in domestic T. cruzi transmission is the role that synanthropic animals play in T. cruzi transmission to humans. Here, we ask, (1) do synanthropic animals need to be targeted in Chagas disease prevention policies?, and (2) how does the presence of animals affect the efficacy of vector control? Methods We developed a simple mathematical model to simulate domestic vector-borne T.cruzi transmission and to specifically examine the interaction between the presence of synanthropic animals and effects of vector control. We used the model to explore how the interactions between triatomine bugs, humans and animals impact the number and proportion of T. cruzi-infected bugs and humans. We then examined how T. cruzi dynamics change when control measures targeting vector abundance are introduced into the system. Results We found that the presence of synanthropic animals slows the speed of T. cruzi transmission to humans, and increases the sensitivity of T. cruzi transmission dynamics to vector control measures at comparable triatomine carrying capacities. However, T. cruzi transmission is amplified when triatomine carrying capacity increases with the abundance of syntathoropic hosts. Conclusions Our results suggest that in domestic T. cruzi transmission scenarios where no vector control measures are in place, a reduction in synanthropic animals may slow T. cruzi transmission to humans, but it would not completely eliminate transmission. To reach the 2020 goal of interrupting intra-domiciliary T. cruzi transmission, it is critical to target vector populations. Additionally, where vector control measures are in place, synanthropic animals may be beneficial.
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Affiliation(s)
- Jennifer K Peterson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.
| | - Sarah M Bartsch
- Public Health Computational and Operations Research (PHICOR), John Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Bruce Y Lee
- Public Health Computational and Operations Research (PHICOR), John Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
| | - Andrew P Dobson
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ, USA.
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16
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Messenger LA, Garcia L, Vanhove M, Huaranca C, Bustamante M, Torrico M, Torrico F, Miles MA, Llewellyn MS. Ecological host fitting of Trypanosoma cruzi TcI in Bolivia: mosaic population structure, hybridization and a role for humans in Andean parasite dispersal. Mol Ecol 2015; 24:2406-22. [PMID: 25847086 PMCID: PMC4737126 DOI: 10.1111/mec.13186] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 03/02/2015] [Accepted: 03/13/2015] [Indexed: 01/04/2023]
Abstract
An improved understanding of how a parasite species exploits its genetic repertoire to colonize novel hosts and environmental niches is crucial to establish the epidemiological risk associated with emergent pathogenic genotypes. Trypanosoma cruzi, a genetically heterogeneous, multi-host zoonosis, provides an ideal system to examine the sylvatic diversification of parasitic protozoa. In Bolivia, T. cruzi I, the oldest and most widespread genetic lineage, is pervasive across a range of ecological clines. High-resolution nuclear (26 loci) and mitochondrial (10 loci) genotyping of 199 contemporaneous sylvatic TcI clones was undertaken to provide insights into the biogeographical basis of T. cruzi evolution. Three distinct sylvatic parasite transmission cycles were identified: one highland population among terrestrial rodent and triatomine species, composed of genetically homogenous strains (Ar = 2.95; PA/L = 0.61; DAS = 0.151), and two highly diverse, parasite assemblages circulating among predominantly arboreal mammals and vectors in the lowlands (Ar = 3.40 and 3.93; PA/L = 1.12 and 0.60; DAS = 0.425 and 0.311, respectively). Very limited gene flow between neighbouring terrestrial highland and arboreal lowland areas (distance ~220 km; FST = 0.42 and 0.35) but strong connectivity between ecologically similar but geographically disparate terrestrial highland ecotopes (distance >465 km; FST = 0.016-0.084) strongly supports ecological host fitting as the predominant mechanism of parasite diversification. Dissimilar heterozygosity estimates (excess in highlands, deficit in lowlands) and mitochondrial introgression among lowland strains may indicate fundamental differences in mating strategies between populations. Finally, accelerated parasite dissemination between densely populated, highland areas, compared to uninhabited lowland foci, likely reflects passive, long-range anthroponotic dispersal. The impact of humans on the risk of epizootic Chagas disease transmission in Bolivia is discussed.
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Affiliation(s)
- Louisa A. Messenger
- Department of Pathogen Molecular BiologyFaculty of Infectious and Tropical DiseasesLondon School of Hygiene and Tropical MedicineLondonUK
| | - Lineth Garcia
- Institute of Biomedical ResearchUniversidad Mayor de San SimónCochabambaBolivia
| | - Mathieu Vanhove
- Department of Infectious Disease EpidemiologyImperial College LondonLondonUK
| | - Carlos Huaranca
- Institute of Biomedical ResearchUniversidad Mayor de San SimónCochabambaBolivia
| | - Marinely Bustamante
- Institute of Biomedical ResearchUniversidad Mayor de San SimónCochabambaBolivia
| | - Marycruz Torrico
- Institute of Biomedical ResearchUniversidad Mayor de San SimónCochabambaBolivia
| | - Faustino Torrico
- Institute of Biomedical ResearchUniversidad Mayor de San SimónCochabambaBolivia
| | - Michael A. Miles
- Department of Pathogen Molecular BiologyFaculty of Infectious and Tropical DiseasesLondon School of Hygiene and Tropical MedicineLondonUK
| | - Martin S. Llewellyn
- Department of Pathogen Molecular BiologyFaculty of Infectious and Tropical DiseasesLondon School of Hygiene and Tropical MedicineLondonUK
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Llewellyn MS, Messenger LA, Luquetti AO, Garcia L, Torrico F, Tavares SBN, Cheaib B, Derome N, Delepine M, Baulard C, Deleuze JF, Sauer S, Miles MA. Deep sequencing of the Trypanosoma cruzi GP63 surface proteases reveals diversity and diversifying selection among chronic and congenital Chagas disease patients. PLoS Negl Trop Dis 2015; 9:e0003458. [PMID: 25849488 PMCID: PMC4388557 DOI: 10.1371/journal.pntd.0003458] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 12/05/2014] [Indexed: 01/07/2023] Open
Abstract
Background Chagas disease results from infection with the diploid protozoan parasite Trypanosoma cruzi. T. cruzi is highly genetically diverse, and multiclonal infections in individual hosts are common, but little studied. In this study, we explore T. cruzi infection multiclonality in the context of age, sex and clinical profile among a cohort of chronic patients, as well as paired congenital cases from Cochabamba, Bolivia and Goias, Brazil using amplicon deep sequencing technology. Methodology/ Principal Findings A 450bp fragment of the trypomastigote TcGP63I surface protease gene was amplified and sequenced across 70 chronic and 22 congenital cases on the Illumina MiSeq platform. In addition, a second, mitochondrial target—ND5—was sequenced across the same cohort of cases. Several million reads were generated, and sequencing read depths were normalized within patient cohorts (Goias chronic, n = 43, Goias congenital n = 2, Bolivia chronic, n = 27; Bolivia congenital, n = 20), Among chronic cases, analyses of variance indicated no clear correlation between intra-host sequence diversity and age, sex or symptoms, while principal coordinate analyses showed no clustering by symptoms between patients. Between congenital pairs, we found evidence for the transmission of multiple sequence types from mother to infant, as well as widespread instances of novel genotypes in infants. Finally, non-synonymous to synonymous (dn:ds) nucleotide substitution ratios among sequences of TcGP63Ia and TcGP63Ib subfamilies within each cohort provided powerful evidence of strong diversifying selection at this locus. Conclusions/Significance Our results shed light on the diversity of parasite DTUs within each patient, as well as the extent to which parasite strains pass between mother and foetus in congenital cases. Although we were unable to find any evidence that parasite diversity accumulates with age in our study cohorts, putative diversifying selection within members of the TcGP63I gene family suggests a link between genetic diversity within this gene family and survival in the mammalian host. Trypanosoma cruzi, the causal agent of Chagas disease in Latin America, infects several million people in some of the most economically deprived regions of Latin America. T. cruzi infection is lifelong and has a variable prognosis: some patients never exhibit symptoms while others experience debilitating and fatal complications. Available data suggest that parasite genetic diversity within and among disease foci can be exceedingly high. However, little is know about the frequency of multiple genotype infections in humans, as well as their distribution among different age classes and possible impact on disease outcome. In this study we develop a next generation amplicon deep sequencing approach to profile parasite diversity within chronic Chagas Disease patients from Bolivia and Brazil. We were also able to compare parasite genetic diversity present in eleven congenitally infants with parasite genetic diversity present in their mothers. We did not detect any specific association between the number and diversity of parasite genotypes in each patient with their age, sex or disease status. We were, however, able to detect the transmission of multiple parasite genotypes between mother and foetus. Furthermore, we also detected powerful evidence for natural selection at the antigenic locus we targeted, suggesting a possible interaction with the host immune system.
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Affiliation(s)
- Martin S. Llewellyn
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, University of Wales, Bangor, Bangor, Gwynedd, United Kingdom
- * E-mail:
| | | | - Alejandro O. Luquetti
- Laboratório de Pesquisa da doença de Chagas, Hospital das Clínicas da Universidade Federal de Goiás, Brazil
| | - Lineth Garcia
- Facultad de Medicine, Universidad Mayor de San Simon, Cochabamba, Bolivia
| | - Faustino Torrico
- Facultad de Medicine, Universidad Mayor de San Simon, Cochabamba, Bolivia
| | - Suelene B. N. Tavares
- Laboratório de Pesquisa da doença de Chagas, Hospital das Clínicas da Universidade Federal de Goiás, Brazil
| | - Bachar Cheaib
- Institut de Biologie Integrative et de Systemes, Universite de Laval, Quebec, Canada
| | - Nicolas Derome
- Institut de Biologie Integrative et de Systemes, Universite de Laval, Quebec, Canada
| | - Marc Delepine
- Centre National de Génotypage, CEA, Evry, Paris, France
| | | | | | - Sascha Sauer
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Michael A. Miles
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
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Abad-Franch F, Valença-Barbosa C, Sarquis O, Lima MM. All that glisters is not gold: sampling-process uncertainty in disease-vector surveys with false-negative and false-positive detections. PLoS Negl Trop Dis 2014; 8:e3187. [PMID: 25233352 PMCID: PMC4169387 DOI: 10.1371/journal.pntd.0003187] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 08/14/2014] [Indexed: 11/06/2022] Open
Abstract
Background Vector-borne diseases are major public health concerns worldwide. For many of them, vector control is still key to primary prevention, with control actions planned and evaluated using vector occurrence records. Yet vectors can be difficult to detect, and vector occurrence indices will be biased whenever spurious detection/non-detection records arise during surveys. Here, we investigate the process of Chagas disease vector detection, assessing the performance of the surveillance method used in most control programs – active triatomine-bug searches by trained health agents. Methodology/Principal Findings Control agents conducted triplicate vector searches in 414 man-made ecotopes of two rural localities. Ecotope-specific ‘detection histories’ (vectors or their traces detected or not in each individual search) were analyzed using ordinary methods that disregard detection failures and multiple detection-state site-occupancy models that accommodate false-negative and false-positive detections. Mean (±SE) vector-search sensitivity was ∼0.283±0.057. Vector-detection odds increased as bug colonies grew denser, and were lower in houses than in most peridomestic structures, particularly woodpiles. False-positive detections (non-vector fecal streaks misidentified as signs of vector presence) occurred with probability ∼0.011±0.008. The model-averaged estimate of infestation (44.5±6.4%) was ∼2.4–3.9 times higher than naïve indices computed assuming perfect detection after single vector searches (11.4–18.8%); about 106–137 infestation foci went undetected during such standard searches. Conclusions/Significance We illustrate a relatively straightforward approach to addressing vector detection uncertainty under realistic field survey conditions. Standard vector searches had low sensitivity except in certain singular circumstances. Our findings suggest that many infestation foci may go undetected during routine surveys, especially when vector density is low. Undetected foci can cause control failures and induce bias in entomological indices; this may confound disease risk assessment and mislead program managers into flawed decision making. By helping correct bias in naïve indices, the approach we illustrate has potential to critically strengthen vector-borne disease control-surveillance systems. Vector-borne disease prevention often relies on health agents inspecting dwellings and eliminating the vector infestation foci they detect. The effectiveness of prevention programs thus depends on vector-detection performance. Unfortunately, detection failures can be common, particularly when infestation is rare and vector foci small. Although this can threaten vector control, the actual performance of vector searches has seldom been investigated in detail. Here, we assess Chagas disease vector detection by trained control-surveillance agents. We used models that explicitly account for detection errors to analyze triplicate vector detection/non-detection records from 414 man-made ‘ecotopes’ (houses, henhouses, woodpiles, etc.) in two rural localities. On average, a single round of vector searches correctly identified about 28% of the infested ecotopes; detection was more challenging in lightly-infested ecotopes and in some ecotope types, particularly houses and brick piles. After correcting detection errors, we estimated that ∼45% of the ecotopes were most likely infested, while observed rates were ∼11–19%; standard, single-round vector searches therefore missed many infestation foci. Our findings underscore the importance of taking detection failures into account when assessing infestation by disease vectors, and illustrate a straightforward approach to tackle the major but still underappreciated problem of imperfect vector detection.
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Affiliation(s)
- Fernando Abad-Franch
- Infectious Disease Ecology Laboratory, Instituto Leônidas e Maria Deane – Fiocruz Amazônia, Manaus, Brazil
- * E-mail: ;
| | - Carolina Valença-Barbosa
- Chagas Disease Eco-epidemiology Laboratory, Instituto Oswaldo Cruz – Fiocruz, Rio de Janeiro, Brazil
| | - Otília Sarquis
- Chagas Disease Eco-epidemiology Laboratory, Instituto Oswaldo Cruz – Fiocruz, Rio de Janeiro, Brazil
| | - Marli M. Lima
- Chagas Disease Eco-epidemiology Laboratory, Instituto Oswaldo Cruz – Fiocruz, Rio de Janeiro, Brazil
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