1
|
Morales ME, Campo Verde Arbocco F, Muñoz-San Martín C, Abba AM, Ríos TA, Cassini GH, Cattan PE, Jahn GA, Superina M. High Trypanosoma cruzi prevalence in armadillo (Zaedyus pichiy; Xenarthra: Chlamyphoridae) populations from Mendoza, Argentina. Parasitol Res 2023:10.1007/s00436-023-07861-z. [PMID: 37184599 DOI: 10.1007/s00436-023-07861-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 04/27/2023] [Indexed: 05/16/2023]
Abstract
Armadillos are considered important reservoir hosts for Trypanosoma cruzi, the causative agent of Chagas disease. The first report of T. cruzi infection in pichis (Zaedyus pichiy), a small armadillo species endemic to central Argentina and Chile, dates back to 1935. However, more recent reports on T. cruzi in this species are scarce. The objective of this study was to assess T. cruzi infection and parasite load in Z. pichiy from Mendoza Province, an area endemic to human Chagas disease. Blood samples were obtained in 2014-2016 from pichis from Lavalle (low Monte), Malargüe (Patagonian steppe), and San Carlos (ecotone) departments, Mendoza Province, Argentina. The detection and quantification of T. cruzi was performed through qPCR amplification using satellite primers. Of the 265 analyzed samples, 201 (76%) were positive for T. cruzi. Parasite loads varied between < 0.1-55.8 parasite-equivalents/mL (par-eq/mL), with a median of 1.1 par-eq/mL in quantifiable samples. The prevalence was similar in Malargüe and Lavalle (85-94%), but significantly lower in pichis from San Carlos (50%). Animals from Lavalle captured after hibernation had significantly higher parasite loads (median 2.0 par-eq/mL). In Malargüe, T. cruzi infection and parasite loads were significantly lower before than after hibernation in 2016. The high prevalence and low median parasite load suggest a chronic and persistent infection of T. cruzi in pichis. Regional differences and a marked increase in precipitation during 2015-2016 could have influenced annual and seasonal infection rates of this vector-borne disease.
Collapse
Affiliation(s)
- Melisa E Morales
- Laboratorio de Medicina Y Endocrinología de La Fauna Silvestre, IMBECU, UNCuyo - CONICET, Av. Dr. Adrian Ruiz Leal S/N, Parque General San Martín, Mendoza, Argentina
| | - Fiorella Campo Verde Arbocco
- Laboratorio de Reproducción Y Lactancia, IMBECU, UNCuyo - CONICET, Mendoza, Argentina
- Universidad de Mendoza, Mendoza, Argentina
| | - Catalina Muñoz-San Martín
- Facultad de Ciencias Médicas, Escuela de Medicina Veterinaria, Universidad Bernardo O'Higgins, Santiago, Chile
- Núcleo de Investigaciones Aplicadas en Ciencias Veterinarias Y Agronómicas, Universidad de Las Américas, Campus Providencia, Santiago, Chile
| | - Agustín M Abba
- CEPAVE, Universidad Nacional de La Plata - CONICET, La Plata, Argentina
| | - Tatiana A Ríos
- CEPAVE, Universidad Nacional de La Plata - CONICET, La Plata, Argentina
| | - Guillermo H Cassini
- División Mastozoología, Museo Argentino de Ciencias Naturales "Bernardino Rivadavia" (MACN-BR - CONICET), Av. Angel Gallardo 490, C1405DJR, Ciudad Autónoma de Buenos Aires, Argentina
- Departamento de Ciencias Básicas, Universidad Nacional de Luján (UNLu), Ruta 5 Y Av. Constitución, Luján (B), 6700, Buenos Aires, Argentina
| | - Pedro E Cattan
- Departamento de Ciencias Biológicas Animales, Facultad de Ciencias Veterinarias Y Pecuarias, Universidad de Chile, Santiago, Chile
| | - Graciela A Jahn
- Laboratorio de Reproducción Y Lactancia, IMBECU, UNCuyo - CONICET, Mendoza, Argentina
| | - Mariella Superina
- Laboratorio de Medicina Y Endocrinología de La Fauna Silvestre, IMBECU, UNCuyo - CONICET, Av. Dr. Adrian Ruiz Leal S/N, Parque General San Martín, Mendoza, Argentina.
| |
Collapse
|
2
|
Rojas-Cortez M, Pinazo MJ, Gascon J, Gamarra E, Grageda RM, Fernandez R, Rueda E, Pinto J, Anzoleaga HM, Caballero YE, Urioste GS, Sanchez J, Saravia R, Castellon M, Garcia W, Daza LO, Mur IG, Lozano D, Carvalho-Costa FA, Monteiro FA, Torrico F. Community-based entomological surveillance in three Chagas disease-endemic regions in sub-Andean Bolivia. Trans R Soc Trop Med Hyg 2021; 115:1251-1259. [PMID: 34580735 DOI: 10.1093/trstmh/trab150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 08/29/2021] [Accepted: 09/15/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Chagas disease is endemic throughout most of Bolivia, with prevalence rates of 25% observed in some geographic areas located mainly in the sub-Andean region. METHODS Community-based entomological surveillance was carried out in the sub-Andean departments of Cochabamba (municipalities of Cochabamba, Punata and Sacaba), Tarija (municipality of Tarija) and Chuquisaca (municipality of Sucre). The surveillance parameters evaluated were: (i) the proportion of cards with the presence of triatomines; (ii) the distribution of positive cards by area; and (iii) the proportion of cards with the presence of infected triatomines. RESULTS Of the cards returned, in 852 (3.1%) there was a mention of the presence of triatomines. The species Triatoma infestans, Triatoma sordida and Triatoma guasayana were identified in 812 (95.3%), 39 (4.6%) and 1 (0.1%), respectively. The median monthly positivity rate of the cards during 2011-2018 was higher in Punata (9.1%; IQR=3.2-15.4%). The median monthly rate was highest in 2012 (2.7%; IQR=0-5.6%). Fifty positive cards (5.8%) presented insects that were positive for trypanosomatids, mainly in Cochabamba and Punata. CONCLUSIONS The report of triatomines foci by inhabitants represents an effective surveillance system coordinated by a network of specialized and multidisciplinary health centers. These strategies, which should be included in the health policies of endemic countries, enable extending and deepening the dialogue among technicians, communities and their local authorities.
Collapse
Affiliation(s)
| | | | - Joaquim Gascon
- ISGlobal, Barcelona, Hospital Clinic - Universitat de Barcelona, Spain
| | - Enzo Gamarra
- Ministerio de Salud, Programa Nacional de Chagas, Bolivia
| | | | | | | | - Jimy Pinto
- Fundación CEADES, Cochabamba, Bolivia.,Centro Plataforma Chagas Cercado, Cochabamba
| | | | | | - Gloria Sandy Urioste
- Fundación CEADES, Cochabamba, Bolivia.,Centro Plataforma Chagas Sacaba, Cochabamba
| | - Jareth Sanchez
- Fundación CEADES, Cochabamba, Bolivia.,Centro Plataforma Chagas Punata, Cochabamba
| | | | | | - Wilson Garcia
- Fundación CEADES, Cochabamba, Bolivia.,Centro Plataforma Chagas Sucre, Chuquisaca
| | - Lourdes Ortiz Daza
- Centro Plataforma Chagas Tarija.,Universidad Juan Misael Saracho, Tarija
| | | | | | - Filipe Anibal Carvalho-Costa
- Labóratory of Molecular Epidemiology and Systemátics, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - Fernando Araújo Monteiro
- Labóratory of Molecular Epidemiology and Systemátics, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | | |
Collapse
|
3
|
Insights into the evolution and dispersion of pyrethroid resistance among sylvatic Andean Triatoma infestans from Bolivia. INFECTION GENETICS AND EVOLUTION 2021; 90:104759. [PMID: 33556557 DOI: 10.1016/j.meegid.2021.104759] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/29/2021] [Accepted: 02/03/2021] [Indexed: 11/22/2022]
Abstract
Sylvatic populations of Triatoma infestans represent a challenge to Chagas disease control as they are not targeted by vector control activities and may play a key role in post-spraying house re-infestation. Understanding sylvatic foci distribution and gene flow between sylvatic and domestic populations is crucial to optimize vector control interventions and elucidate the development and spread of insecticide resistance. Herein, the genetic profiles of five Andean T. infestans populations from Bolivia with distinct insecticide susceptibility profiles were compared. Multilocus genotypes based on eight microsatellites and the DNA sequence of a fragment of the cytochrome B (cytB) gene were obtained for 92 individuals. CytB haplotypes were analyzed with previously reported Bolivian T. infestans haplotypes to evaluate putative historical gene flow among populations. Each specimen was also screened for two nucleotide mutations in the sodium channel gene (kdr), related to pyrethroid resistance (L1014 and L9251). Significant genetic differentiation was observed among all populations, although individuals of admixed origin were detected in four of them. Notably, the genetic profiles of adjacent domestic and sylvatic populations of Mataral, characterized by higher levels of insecticide resistance, support their common ancestry. Only one sylvatic individual from Mataral carried the kdr mutation L1014, suggesting that this mechanism is unlikely to cause the altered insecticide susceptibility observed in these populations. However, as the resistance mutation is present in the area, it has the potential to be selected under insecticidal pressure. Genetic comparisons of these populations suggest that insecticide resistance is likely conferred by ancient trait(s) in T. infestans sylvatic populations, which are capable of invading domiciles. These results emphasize the need for stronger entomological surveillance in the region, including early detection of house invasion, particularly post-spraying, monitoring for resistance to pyrethroids and the design of integrative control actions that consider sylvatic foci around domestic settings and their dispersion dynamics.
Collapse
|
4
|
Gumiel M, de Mattos DP, Vieira CS, Moraes CS, Moreira CJDC, Gonzalez MS, Teixeira-Ferreira A, Waghabi M, Azambuja P, Carels N. Proteome of the Triatomine Digestive Tract: From Catalytic to Immune Pathways; Focusing on Annexin Expression. Front Mol Biosci 2020; 7:589435. [PMID: 33363206 PMCID: PMC7755933 DOI: 10.3389/fmolb.2020.589435] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/21/2020] [Indexed: 12/15/2022] Open
Abstract
Rhodnius prolixus, Panstrongylus megistus, Triatoma infestans, and Dipetalogaster maxima are all triatomines and potential vectors of the protozoan Trypanosoma cruzi responsible for human Chagas' disease. Considering that the T. cruzi's cycle occurs inside the triatomine digestive tract (TDT), the analysis of the TDT protein profile is an essential step to understand TDT physiology during T. cruzi infection. To characterize the protein profile of TDT of D. maxima, P. megistus, R. prolixus, and T. infestans, a shotgun liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach was applied in this report. Most proteins were found to be closely related to metabolic pathways such as gluconeogenesis/glycolysis, citrate cycle, fatty acid metabolism, oxidative phosphorylation, but also to the immune system. We annotated this new proteome contribution gathering it with those previously published in accordance with Gene Ontology and KEGG. Enzymes were classified in terms of class, acceptor, and function, while the proteins from the immune system were annotated by reference to the pathways of humoral response, cell cycle regulation, Toll, IMD, JNK, Jak-STAT, and MAPK, as available from the Insect Innate Immunity Database (IIID). These pathways were further subclassified in recognition, signaling, response, coagulation, melanization and none. Finally, phylogenetic affinities and gene expression of annexins were investigated for understanding their role in the protection and homeostasis of intestinal epithelial cells against the inflammation.
Collapse
Affiliation(s)
- Marcia Gumiel
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, Brazil
- Research Department, Universidad Privada Franz Tamayo (UNIFRANZ), La Paz, Bolivia
| | - Debora Passos de Mattos
- Laboratório de Biologia de Insetos, Departamento de Biologia Geral, Universidade Federal Fluminense, Niterói, Brazil
- Programa de Pós-Graduação em Ciências e Biotecnologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
| | - Cecília Stahl Vieira
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, Brazil
- Departamento de Entomologia Molecular, Instituto Nacional de Entomologia Molecular (INCT-EM), Rio de Janeiro, Brazil
| | - Caroline Silva Moraes
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, Brazil
| | | | - Marcelo Salabert Gonzalez
- Laboratório de Biologia de Insetos, Departamento de Biologia Geral, Universidade Federal Fluminense, Niterói, Brazil
- Programa de Pós-Graduação em Ciências e Biotecnologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
- Departamento de Entomologia Molecular, Instituto Nacional de Entomologia Molecular (INCT-EM), Rio de Janeiro, Brazil
| | | | - Mariana Waghabi
- Laboratório de Genômica Funcional e Bioinformática, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Patricia Azambuja
- Laboratório de Bioquímica e Fisiologia de Insetos, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz (IOC/FIOCRUZ), Rio de Janeiro, Brazil
- Laboratório de Biologia de Insetos, Departamento de Biologia Geral, Universidade Federal Fluminense, Niterói, Brazil
- Programa de Pós-Graduação em Ciências e Biotecnologia, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil
- Departamento de Entomologia Molecular, Instituto Nacional de Entomologia Molecular (INCT-EM), Rio de Janeiro, Brazil
| | - Nicolas Carels
- Laboratório de Modelagem de Sistemas Biológicos, National Institute for Science and Technology on Innovation in Neglected Diseases (INCT-IDN), Centro de Desenvolvimento Tecnológico em Saúde (CDTS), Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Brazil
| |
Collapse
|
5
|
Fast recovery of house infestation with Triatoma brasiliensis after residual insecticide spraying in a semiarid region of Northeastern Brazil. PLoS Negl Trop Dis 2020; 14:e0008404. [PMID: 32687497 PMCID: PMC7371158 DOI: 10.1371/journal.pntd.0008404] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 05/20/2020] [Indexed: 11/24/2022] Open
Abstract
The northeastern semiarid region stands out in the Brazilian context regarding the eco-epidemiology of Chagas disease, in which Triatoma brasiliensis is the main vector of Trypanosoma cruzi. Persistent house invasion threatens the relative levels of progress achieved over previous decades. We conducted an intervention trial with a five-year follow-up to assess the impacts of residual spraying with pyrethroid insecticides on house infestation with T. brasiliensis in 18 rural villages (242 houses) located in the Tauá, Ceará. House infestations were assessed by systematic manual searches for triatomines in every domestic and peridomestic habitat on five occasions. Triatomines were collected in peridomestic (57.5%), sylvatic (35.8%), and intradomiciliary (6.7%) habitats. The most important ecotopes of T. brasiliensis were containing roofing tiles, bricks or rocks (23.4% ± 9.1). Residual insecticide spraying substantially reduced baseline house infestation rates from 27.9% to 5.9% by 6 months post first spraying (MPS). The decline was substantially greater in intradomiciles (11.2% to 0.8%) than in peridomiciles (16.7% to 5%). The mean relative density of triatomines recovered its preintervention values at 14 MPS in intradomiciles, and in the main peridomestic ecotopes. The house infestation levels recorded at 14 MPS persisted thereafter despite all reinfested houses were selectively sprayed on every occasion. Overall average bug infection rates with T. cruzi in the five occasions were in intradomiciles (11.1%), peridomiciles (4.7%) and wild habitats (3.3%). In peridomicile T. cruzi infection rates decreased significantly at all stages after chemical intervention. In intradomicile, the only significant difference occurred at 20 MPS (7.7% to 30.8%). The vectorial capacity of T. brasiliensis, combined with its invasive potential from sylvatic sources and the limited effectiveness of chemical control in the harsh caatinga landscape, pose serious obstacles to the definite elimination of domestic transmission risks. Systematic vector surveillance supported by community participation and locally adapted environmental management measures are needed to reduce the risks of establishment of domestic transmission with T. cruzi in this region. The results demonstrate the ecological potential of Triatoma brasiliensis in the northeastern caatinga and how this species uses the resources available in nature or in the modified environment by man. Triatomines were collected in peridomestic, sylvatic, and intradomicile habitats. House infestations were evaluated on five occasions, with spraying of infested houses. T. brasiliensis was responsible for the high rates of dispersal, infestation, colonization and Trypanosoma cruzi infection in all catches and environments studied here. Spraying strongly reduced the infestation, but the number of triatomines rapidly returned to previous levels. Peridomicile represents a complex set of overlapping infested sites forming a network of shelters that favor the establishment and proliferation of triatomine colonies. Molecular characterization of T. cruzi isolated from triatomines and identification of their food sources emphasize the overlap of habitats and interaction among triatomines, synanthropic reservoirs and humans, increasing the risk of parasite transmission. Therefore, it is clear the need for maintenance of vector control fully and systematically with the use of appropriate strategies where interventions should consider regional ecoepidemiologic differences and the influence of environmental, socioeconomic and cultural factors in T. cruzy transmission process into domicile environment.
Collapse
|
6
|
Monteiro FA, Weirauch C, Felix M, Lazoski C, Abad-Franch F. Evolution, Systematics, and Biogeography of the Triatominae, Vectors of Chagas Disease. ADVANCES IN PARASITOLOGY 2019. [PMID: 29530308 DOI: 10.1016/bs.apar.2017.12.002] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In this chapter, we review and update current knowledge about the evolution, systematics, and biogeography of the Triatominae (Hemiptera: Reduviidae)-true bugs that feed primarily on vertebrate blood. In the Americas, triatomines are the vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. Despite declining incidence and prevalence, Chagas disease is still a major public health concern in Latin America. Triatomines occur also in the Old World, where vector-borne T. cruzi transmission has not been recorded. Triatomines evolved from predatory reduviid bugs, most likely in the New World, and diversified extensively across the Americas (including the Caribbean) and in parts of Asia and Oceania. Here, we first discuss our current understanding of how, how many times, and when the blood-feeding habit might have evolved among the Reduviidae. Then we present a summary of recent advances in the systematics of this diverse group of insects, with an emphasis on the contribution of molecular tools to the clarification of taxonomic controversies. Finally, and in the light of both up-to-date phylogenetic hypotheses and a thorough review of distribution records, we propose a global synthesis of the biogeography of the Triatominae. Over 130 triatomine species contribute to maintaining T. cruzi transmission among mammals (sometimes including humans) in almost every terrestrial ecoregion of the Americas. This means that Chagas disease will never be eradicated and underscores the fact that effective disease prevention will perforce require stronger, long-term vector control-surveillance systems.
Collapse
Affiliation(s)
- Fernando Araujo Monteiro
- Laboratório de Epidemiologia e Sistemática Molecular, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil.
| | | | - Márcio Felix
- Laboratório de Biodiversidade Entomológica, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil
| | - Cristiano Lazoski
- Instituto de Biologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | |
Collapse
|
7
|
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.
Collapse
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.
| |
Collapse
|
8
|
Lobbia PA, Rodríguez C, Mougabure-Cueto G. Effect of nutritional state and dispersal on the reproductive efficiency in Triatoma infestans (Klug, 1834) (Hemiptera: Reduviidae: Triatominae) susceptible and resistant to deltamethrin. Acta Trop 2019; 191:228-238. [PMID: 30653943 DOI: 10.1016/j.actatropica.2019.01.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/10/2019] [Accepted: 01/12/2019] [Indexed: 11/15/2022]
Abstract
The dispersal of insects is determinant in the colonization of new areas and the propagation of insecticide resistance. Nutritional status and reproductive characteristics determine the colonization capacity after the dispersal event. Studies about of the effects of dispersal on reproduction in triatomines are few and none in resistant insects. The aim was to determine the effects of nutritional state and dispersal on the subsequent reproductive potential in Triatoma infestans (Klug, 1834) susceptible and resistant to deltamethrin. Three nutritional states were obtained with the number of feeds (NF) offered (0, 1 or 2). The resistant females were evaluated only with NF1. The experimental arena was 10 m long and contained two shelters. Groups of 30 virgin females of each NF were released in one of the shelters and were able to move during 3 days/nights. Females without possibility of dispersal were the controls. The reproductive parameters were determined on the couples between the experimental females and males from the breeding. The results showed that most of the females dispersed by walking. The dispersal had effects on the reproduction of the deltamethrin-susceptible females and this depended on the number of feeds. Fecundity, fertility and the proportion of females that oviposited were higher in females dispersed with two feeds but was lower in females dispersed with less feeds. In addition, the effect of the dispersal on the reproduction and the life time also depended of the toxicological phenotype. The resistant insect oviposited in higher proportion and showed greater fecundity and more weeks of life when they dispersed that when they did not do it, and was opposite to that observed in susceptible ones. Finally, the resistance to insecticide had an effect on the reproduction and the life span and this effect depended on whether the insects dispersed or not.
Collapse
Affiliation(s)
- P A Lobbia
- Laboratorio de Investigación en Triatominos (LIT), Centro de Referencia de Vectores (CeReVe)-Programa Nacional de Chagas-Ministerio de Salud de la Nación, Santa María de Punilla, Córdoba, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
| | - C Rodríguez
- Cátedra de Introducción a la Biología-Instituto de Investigaciones Biológicas y Tecnológicas-Facultad de Ciencias Exactas, Físicas y Naturales-Universidad Nacional de Córdoba, Córdoba, Argentina
| | - G Mougabure-Cueto
- Laboratorio de Investigación en Triatominos (LIT), Centro de Referencia de Vectores (CeReVe)-Programa Nacional de Chagas-Ministerio de Salud de la Nación, Santa María de Punilla, Córdoba, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
| |
Collapse
|
9
|
Brenière SF, Buitrago R, Waleckx E, Depickère S, Sosa V, Barnabé C, Gorla D. Wild populations of Triatoma infestans: Compilation of positive sites and comparison of their ecological niche with domestic population niche. Acta Trop 2017; 176:228-235. [PMID: 28818626 DOI: 10.1016/j.actatropica.2017.08.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 07/26/2017] [Accepted: 08/10/2017] [Indexed: 11/15/2022]
Abstract
BACKGROUND For several years, the wild populations of Triatoma infestans, main vector of Trypanosoma cruzi causing Chagas disease, have been considered or suspected of being a source of reinfestation of villages. The number of sites reported for the presence of wild T. infestans, often close to human habitats, has greatly increased, but these data are scattered in several publications, and others obtained by our team in Bolivia have not been published yet. METHODOLOGY/PRINCIPAL FINDINGS Herein is compiled the largest number of wild sites explored for the presence of T. infestans collected with two methods The standardized methods aimed to determine the relationship between wild T. infestans and the ecoregion, and the directed method help to confirm the presence/absence of triatomines in the ecoregions. Entomological indices were compared between ecoregions and an environmental niche modelling approach, based on bioclimatic variables, was applied. The active search for wild T. infestans in Bolivia suggests a discontinuous distribution from the Andean valleys to the lowlands (Chaco), while the models used suggest a continuous distribution between the two regions and very large areas where wild populations remain to be discovered. The results compile the description of different habitats where these populations were found, and we demonstrate that the environmental niches of wild and domestic populations, defined by climatic variables, are similar but not equivalent, showing that during domestication, T. infestans has conquered new spaces with wider ranges of temperature and precipitation. CONCLUSIONS/SIGNIFICANCE The great diversity of wild T. infestans habitats and the comparison of their ecological niches with that of domestic populations confirm the behavioural plasticity of the species that increase the possibility of contact with humans. The result of the geographical distribution model of the wild populations calls for more entomological vigilance in the corresponding areas in the Southern Cone countries and in Bolivia. The current presentation is the most comprehensive inventory of wild T. infestans-positive sites that can be used as a reference for further entomological vigilance in inhabited areas.
Collapse
Affiliation(s)
- Simone Frédérique Brenière
- INTERTRYP, CIRAD, IRD, TA A-17/G, International Campus in Baillarguet, Montpellier, France; Centro de Investigación para la Salud en América Latina (CISeAL), Pontificia Universidad Católica del Ecuador (PUCE), Av. 12 de Octubre 1076 y Roca, Campus Nayón, Quito, Ecuador.
| | - Rosio Buitrago
- INTERTRYP, CIRAD, IRD, TA A-17/G, International Campus in Baillarguet, Montpellier, France; Instituto Nacional de Laboratorios de Salud (INLASA), Laboratorio de Entomología Médica, Rafael Zubieta #1889, Miraflores, Casilla M-10019, La Paz, Bolivia
| | - Etienne Waleckx
- Laboratorio de Parasitología, Centro de Investigaciones Regionales "Hideyo Noguchi", Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - Stéphanie Depickère
- INTERTRYP, CIRAD, IRD, TA A-17/G, International Campus in Baillarguet, Montpellier, France; Instituto Nacional de Laboratorios de Salud (INLASA), Laboratorio de Entomología Médica, Rafael Zubieta #1889, Miraflores, Casilla M-10019, La Paz, Bolivia; Grupo de Sistemas Complejos, Instituto de Investigaciones Físicas, Universidad Mayor de San Andrés, La Paz, Bolivia
| | - Victor Sosa
- INTERTRYP, CIRAD, IRD, TA A-17/G, International Campus in Baillarguet, Montpellier, France; Dirección de Recursos Naturales, Secretaria de Desarrollo Sostenible y Medio Ambiente, Gobierno Autónomo Departamental de Santa Cruz, Av. Fransisco Mora 3er Anillo interno, Zona Polanco, Mexico
| | - Christian Barnabé
- INTERTRYP, CIRAD, IRD, TA A-17/G, International Campus in Baillarguet, Montpellier, France
| | - David Gorla
- Instituto Altos Estudios Espaciales Mario Gulich, Universidad Nacional Córdoba-CONAE, Ruta C45 Km 8, Falda del Cañete, 5187 Córdoba, Argentina
| |
Collapse
|
10
|
de Arias AR, Carbajal de la Fuente AL, Gómez A, Cecere MC, Rolón M, Gómez MCV, Villalba C. Morphometric Wings Similarity among Sylvatic and Domestic Populations of Triatoma infestans (Hemiptera: Reduviidae) from the Gran Chaco Region of Paraguay. Am J Trop Med Hyg 2017; 97:481-488. [PMID: 28829725 PMCID: PMC5544089 DOI: 10.4269/ajtmh.16-1013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/14/2017] [Indexed: 12/03/2022] Open
Abstract
Despite sustained efforts for eliminating Triatoma infestans, reinfestation still persists in large part of the endemic area of Chagas disease from the Gran Chaco region. Sylvatic T. infestans populations seem to threat success of control programs of domestic T. infestans. In this study, we analyze whether T. infestans collected after a community-wide spraying were survivors or were immigrants from elsewhere using geometric morphometric tools. We used 101 right wings of female T. infestans captured before and after intervention program carried out in 12 de Junio and Casuarina, villages from Paraguayan Chaco, and in Puerto Casado during presprayed collection. There were no significant differences in wing size of domestic T. infestans between pre- and postspraying populations, and between domestic and sylvatic ones. When shape variables originating from postintervention individuals from 12 de Junio were introduced one by one into a discriminant analysis, the greatest weight (53%) was allocated to the sylvatic group. Furthermore, from the prespraying population, 25% were reallocated as postintervention individuals. Only 11% of the insects were reassigned to other groups Puerto Casado and Casuarina. These results suggest that postspraying individuals appear to have different origins. Half of the postspraying individuals from 12 de Junio were similar to the sylvatic ones and 25% of these were similar to those captured in the prespraying period. This remarkable morphometric wings similarity between sylvatic and domestic populations is new evidence suggesting that they could be highly related to each other in the Paraguayan Chaco; human-fed bugs from sylvatic area also support this.
Collapse
Affiliation(s)
- Antonieta Rojas de Arias
- Centro para el Desarrollo de la Investigación Científica (CEDIC), Diaz Gill Medicina Laboratorial/Fundación Moisés Bertoni, Asunción, Paraguay
| | - Ana Laura Carbajal de la Fuente
- Laboratorio de Eco-Epidemiología, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Ana Gómez
- Centro para el Desarrollo de la Investigación Científica (CEDIC), Diaz Gill Medicina Laboratorial/Fundación Moisés Bertoni, Asunción, Paraguay
| | - María Carla Cecere
- Laboratorio de Eco-Epidemiología, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales (FCEyN), Universidad de Buenos Aires (UBA), Buenos Aires, Argentina
| | - Miriam Rolón
- Centro para el Desarrollo de la Investigación Científica (CEDIC), Diaz Gill Medicina Laboratorial/Fundación Moisés Bertoni, Asunción, Paraguay
| | - María Celeste Vega Gómez
- Centro para el Desarrollo de la Investigación Científica (CEDIC), Diaz Gill Medicina Laboratorial/Fundación Moisés Bertoni, Asunción, Paraguay
| | - Cesia Villalba
- Programa Nacional de Control de la Enfermedad de Chagas, SENEPA, Asunción, Paraguay
| |
Collapse
|
11
|
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).
Collapse
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
| |
Collapse
|
12
|
Justi SA, Galvão C. The Evolutionary Origin of Diversity in Chagas Disease Vectors. Trends Parasitol 2016; 33:42-52. [PMID: 27986547 DOI: 10.1016/j.pt.2016.11.002] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/01/2016] [Accepted: 11/04/2016] [Indexed: 11/16/2022]
Abstract
Chagas disease is amongst the ten most important neglected tropical diseases but knowledge on the diversification of its vectors, Triatominae (Hemiptera: Reduviidae), is very scarce. Most Triatominae species occur in the Americas, and are all considered potential vectors. Despite its amazing ecological vignette, there are remarkably few evolutionary studies of the whole subfamily, and only one genome sequence has been published. The young age of the subfamily, coupled with the high number of independent lineages, are intriguing, yet the lack of genome-wide data makes it a challenge to infer the phylogenetic relationships within Triatominae. Here we synthesize what is known, and suggest the next steps towards a better understanding of how this important group of disease vectors came to be.
Collapse
Affiliation(s)
- Silvia A Justi
- Department of Biology, College of Arts and Sciences, University of Vermont, Burlington, VT, USA
| | - Cleber Galvão
- Laboratório Nacional e Internacional de Referência em Taxonomia de Triatomíneos, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, Brazil.
| |
Collapse
|
13
|
Buitrago R, Bosseno MF, Depickère S, Waleckx E, Salas R, Aliaga C, Barnabé C, Brenière SF. Blood meal sources of wild and domestic Triatoma infestans (Hemiptera: Reduviidae) in Bolivia: connectivity between cycles of transmission of Trypanosoma cruzi. Parasit Vectors 2016; 9:214. [PMID: 27090297 PMCID: PMC4835887 DOI: 10.1186/s13071-016-1499-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 04/06/2016] [Indexed: 12/05/2022] Open
Abstract
Background Chagas disease is a major public health problem in Latin America. Its etiologic agent, Trypanosoma cruzi, is mainly transmitted through the contaminated faeces of blood-sucking insects called triatomines. Triatoma infestans is the main vector in various countries in South America and recently, several foci of wild populations of this species have been described in Bolivia and other countries. These wild populations are suspected of affecting the success of insecticide control campaigns being carried out in South America. To assess the risk that these T. infestans populations pose to human health, it is helpful to determine blood meal sources. Methods In the present work, blood meals were identified in various Bolivian wild T. infestans populations and in three specific areas, in both wild and intra-peridomestic populations to assess the links between wild and domestic cycles of T. cruzi transmission. PCR-HDA and sequencing of Cytb gene were used to identify these blood meal sources. Results and discussion Fourteen vertebrate species were identified as wild blood meal sources. Of those, the most prevalent species were two Andean endemic rodents, Octodontomys gliroides (36 %) and Galea musteloides (30 %), while humans were the third most prevalent source (18.7 %). Of 163 blood meals from peridomestic areas, more than half were chickens, and the others were generally domestic animals or humans. Interestingly, blood from wild animals was identified in triatomines captured in the peridomestic and domestic environment, and blood from domestic animals was found in triatomines captured in the wild, revealing links between wild and domestic cycles of T. cruzi transmission. Conclusion The current study suggests that wild T. infestans attack humans in the wild, but is also able to bite humans in domestic settings before going back to its natural environment. These results support the risk to human health posed by wild populations of T. infestans.
Collapse
Affiliation(s)
- Rosio Buitrago
- IRD, Institut de Recherche pour le Développement, UMR INTERTRYP, (IRD-CIRAD), Interactions hôtes-vecteurs-parasites-environnement dans les maladies tropicales négligées dues aux trypanosomatidés, 911 Av. Agropolis, Montpellier, cédex 5, 34394, France.
| | - Marie-France Bosseno
- IRD, Institut de Recherche pour le Développement, UMR INTERTRYP, (IRD-CIRAD), Interactions hôtes-vecteurs-parasites-environnement dans les maladies tropicales négligées dues aux trypanosomatidés, 911 Av. Agropolis, Montpellier, cédex 5, 34394, France
| | - Stéphanie Depickère
- Instituto Nacional de Laboratorios de Salud (INLASA), Laboratorio de Entomología Médica, Rafael Zubieta #1889, Miraflores, Casilla M-10019, La Paz, Bolivia
| | - Etienne Waleckx
- IRD, Institut de Recherche pour le Développement, UMR INTERTRYP, (IRD-CIRAD), Interactions hôtes-vecteurs-parasites-environnement dans les maladies tropicales négligées dues aux trypanosomatidés, 911 Av. Agropolis, Montpellier, cédex 5, 34394, France
| | - Renata Salas
- Instituto Nacional de Laboratorios de Salud (INLASA), Laboratorio de Entomología Médica, Rafael Zubieta #1889, Miraflores, Casilla M-10019, La Paz, Bolivia
| | - Claudia Aliaga
- Instituto Nacional de Laboratorios de Salud (INLASA), Laboratorio de Entomología Médica, Rafael Zubieta #1889, Miraflores, Casilla M-10019, La Paz, Bolivia
| | - Christian Barnabé
- IRD, Institut de Recherche pour le Développement, UMR INTERTRYP, (IRD-CIRAD), Interactions hôtes-vecteurs-parasites-environnement dans les maladies tropicales négligées dues aux trypanosomatidés, 911 Av. Agropolis, Montpellier, cédex 5, 34394, France
| | - Simone Frédérique Brenière
- IRD, Institut de Recherche pour le Développement, UMR INTERTRYP, (IRD-CIRAD), Interactions hôtes-vecteurs-parasites-environnement dans les maladies tropicales négligées dues aux trypanosomatidés, 911 Av. Agropolis, Montpellier, cédex 5, 34394, France
| |
Collapse
|
14
|
Wong YY, Sornosa Macias KJ, Guale Martínez D, Solorzano LF, Ramirez-Sierra MJ, Herrera C, Dumonteil E. Molecular epidemiology of Trypanosoma cruzi and Triatoma dimidiata in costal Ecuador. INFECTION GENETICS AND EVOLUTION 2016; 41:207-212. [PMID: 27079265 DOI: 10.1016/j.meegid.2016.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/01/2016] [Accepted: 04/03/2016] [Indexed: 11/17/2022]
Abstract
Chagas disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi. In Ecuador, Triatoma dimidiata and Rhodnius ecuadoriensis are the main vector species, responsible for over half of the cases of T. cruzi infection in the country. T. dimidiata is believed to have been introduced in Ecuador during colonial times, and its elimination from the country is thus believed to be feasible. We investigated here the molecular ecology of T. dimidiata and T. cruzi in costal Ecuador to further guide control efforts. Analysis of the Internal Transcribed Spacer 2 (ITS-2) of 23 specimens from Progreso, Guayas, unambiguously supported the likely importation of T. dimidiata from Central America to Ecuador. The observation of a very high parasite infection rate (54%) and frequent feeding on humans (3/5) confirmed a continued risk of transmission to humans. All genotyped parasites corresponded to TcI DTU and Trypanosoma rangeli was not detected in T. dimidiata. TcI subgroups corresponded to TcIa (25%), and mixed infections with TcIa and TcId (75%). Further studies should help clarify T. cruzi genetic structure in the country, and the possible impact of the introduction of T. dimidiata on the circulating parasite strains. The elevated risk posed by this species warrants continuing efforts for its control, but its apparent mobility between peridomestic and domestic habitats may favor reinfestation following insecticide spraying.
Collapse
Affiliation(s)
- Yim Yan Wong
- Centro de Referencia Nacional de Parasitología, Instituto Nacional de Investigación en Salud Pública Leopoldo Izquieta Perez (INSPI), Guayaquil, Ecuador
| | - Karen Jeniffer Sornosa Macias
- Centro de Referencia Nacional de Parasitología, Instituto Nacional de Investigación en Salud Pública Leopoldo Izquieta Perez (INSPI), Guayaquil, Ecuador
| | - Doris Guale Martínez
- Centro de Referencia Nacional de Parasitología, Instituto Nacional de Investigación en Salud Pública Leopoldo Izquieta Perez (INSPI), Guayaquil, Ecuador
| | - Luis F Solorzano
- Centro de Referencia Nacional de Parasitología, Instituto Nacional de Investigación en Salud Pública Leopoldo Izquieta Perez (INSPI), Guayaquil, Ecuador
| | - Maria Jesus Ramirez-Sierra
- Laboratorio de Parasitología, Centro de Investigaciones Regionales "Hideyo Noguchi", Universidad Autónoma de Yucatán, Merida, Yucatan, Mexico
| | - Claudia Herrera
- Department of Tropical Medicine, Vector-Borne Infection Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
| | - Eric Dumonteil
- Centro de Referencia Nacional de Parasitología, Instituto Nacional de Investigación en Salud Pública Leopoldo Izquieta Perez (INSPI), Guayaquil, Ecuador; Laboratorio de Parasitología, Centro de Investigaciones Regionales "Hideyo Noguchi", Universidad Autónoma de Yucatán, Merida, Yucatan, Mexico; Department of Tropical Medicine, Vector-Borne Infection Disease Research Center, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA.
| |
Collapse
|
15
|
Bustamante Gomez M, Gonçalves Diotaiuti L, Gorla DE. Distribution of Pyrethroid Resistant Populations of Triatoma infestans in the Southern Cone of South America. PLoS Negl Trop Dis 2016; 10:e0004561. [PMID: 27007658 PMCID: PMC4805280 DOI: 10.1371/journal.pntd.0004561] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 02/29/2016] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND A number of studies published during the last 15 years showed the occurrence of insecticide resistance in Triatoma infestans populations. The different toxicological profiles and mechanisms of resistance to insecticides is due to a genetic base and environmental factors, being the insecticide selective pressure the best studied among the last factors. The studies on insecticide resistance on T. infestans did not consider the effect of environmental factors that may influence the distribution of resistance to pyrethroid insecticides. To fill this knowledge gap, the present study aims at studying the association between the spatial distribution of pyrethroid resistant populations of T. infestans and environmental variables. METHODOLOGY/PRINCIPAL FINDINGS A total of 24 articles reporting on studies that evaluated the susceptibility to pyrethroids of 222 field-collected T. infestans populations were compiled. The relationship between resistance occurrence (according to different criteria) with environmental variables was studied using a generalized linear model. The lethal dose that kills 50% of the evaluated population (LD50) showed a strong linear relationship with the corresponding resistance ratio (RR50). The statistical descriptive analysis of showed that the frequency distribution of the Log (LD50) is bimodal, suggesting the existence of two statistical groups. A significant model including 5 environmental variables shows the geographic distribution of high and low LD50 groups with a particular concentration of the highest LD50 populations over the region identified as the putative center of dispersion of T. infestans. CONCLUSIONS/SIGNIFICANCE The occurrence of these two groups concentrated over a particular region that coincides with the area where populations of the intermediate cytogenetic group were found might reflect the spatial heterogeneity of the genetic variability of T. infestans, that seems to be the cause of the insecticide resistance in the area, even on sylvatic populations of T. infestans, never before exposed to pyrethroid insecticides, representing natural and wild toxicological phenotypes. The strong linear relationship found between LD50 and RR50 suggest RR50 might not be the best indicator of insecticide resistance in triatomines.
Collapse
Affiliation(s)
- Marinely Bustamante Gomez
- Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou—FIOCRUZ Minas, Belo Horizonte, Brazil
| | - Liléia Gonçalves Diotaiuti
- Laboratório de Referência em Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou—FIOCRUZ Minas, Belo Horizonte, Brazil
| | - David E. Gorla
- Instituto Multidisciplinario de Biología Vegetal (IMBIV), CONICET-Universidad Nacional de Córdoba, Córdoba, Argentina
| |
Collapse
|
16
|
Galvão C, Justi SA. An overview on the ecology of Triatominae (Hemiptera:Reduviidae). Acta Trop 2015; 151:116-25. [PMID: 26086951 DOI: 10.1016/j.actatropica.2015.06.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 06/04/2015] [Accepted: 06/10/2015] [Indexed: 11/16/2022]
Abstract
Chagas disease, the American trypanosomiasis, is an important neglected tropical illness caused by the flagellate protozoan Trypanosoma cruzi (Kinetoplastida, Trypanosomatidae) and transmitted by insects of the subfamily Triatominae (Hemiptera: Reduviidae). Here we provide an overview on the current knowledge about Triatominae ecology, its association with human, T. cruzi infection and the immediate consequences of habitat fragmentation. We also discuss the geographic distribution of the species and the importance of predicting their distributions to control programs.
Collapse
Affiliation(s)
- Cleber Galvão
- Laboratório Nacional e Internacional de Referência em Taxonomia de Triatomíneos, Instituto Oswaldo Cruz, Fiocruz, Av. Brasil 4365, Rio de Janeiro - RJ, Brazil.
| | - Silvia A Justi
- Laboratório Nacional e Internacional de Referência em Taxonomia de Triatomíneos, Instituto Oswaldo Cruz, Fiocruz, Av. Brasil 4365, Rio de Janeiro - RJ, Brazil; Laboratório de Biologia Evolutiva Teórica e Aplicada, Departamento de Genética, Universidade Federal do Rio de Janeiro, Brazil
| |
Collapse
|
17
|
Medone P, Balsalobre A, Rabinovich JE, Marti GA, Menu F. Life History Traits and Demographic Parameters of Triatoma infestans (Hemiptera: Reduviidae) Fed on Human Blood. JOURNAL OF MEDICAL ENTOMOLOGY 2015; 52:1282-1290. [PMID: 26373893 DOI: 10.1093/jme/tjv138] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 08/25/2015] [Indexed: 06/05/2023]
Abstract
Triatoma infestans (Klug, 1834) (Hemiptera: Reduviidae), the main vector of Chagas disease in South America, feeds primarily on humans, but ethical reasons preclude carrying out demographical studies using people. Thus, most laboratory studies of T. infestans are conducted using bird or mammal live hosts that may result in different demographic parameters from those obtained on human blood. Therefore, it is of interest to determine whether the use of an artificial feeder with human blood would be operational to rear triatomines and estimate population growth rates. We estimated life history traits and demographic parameters using an artificial feeder with human blood and compared them with those obtained on live hens. Both groups of T. infestans were kept under constant conditions [28 ± 1°C, 40 ± 5% relative humidity, a photoperiod of 12:12 (L:D) h] and fed weekly. On the basis of age-specific survival and age-specific fecundity, we calculated the intrinsic rate of natural increase (r), the finite rate of population growth (λ), the net reproductive rate (Ro), and the mean generation time (Tg). Our results show differences in life history traits between blood sources, resulting in smaller population growth rates on human blood than on live hens. Although demographic growth rate was smaller on human blood than on hens, it still remains positive, so the benefit/cost ratio of this feeding method seems relatively attractive. We discuss possibility of using the artificial feeder with human blood for both ecological and behavioral studies.
Collapse
Affiliation(s)
- Paula Medone
- Centro de Parasitológicos y de Vectores (CEPAVE-CCT-La Plata-CONICET-UNLP), Boulevard 120 S/N e/61 y 62 (B1902CHX), La Plata, Argentina.
| | - Agustin Balsalobre
- Centro de Parasitológicos y de Vectores (CEPAVE-CCT-La Plata-CONICET-UNLP), Boulevard 120 S/N e/61 y 62 (B1902CHX), La Plata, Argentina
| | - Jorge E Rabinovich
- Centro de Parasitológicos y de Vectores (CEPAVE-CCT-La Plata-CONICET-UNLP), Boulevard 120 S/N e/61 y 62 (B1902CHX), La Plata, Argentina
| | - Gerardo A Marti
- Centro de Parasitológicos y de Vectores (CEPAVE-CCT-La Plata-CONICET-UNLP), Boulevard 120 S/N e/61 y 62 (B1902CHX), La Plata, Argentina
| | - Frédéric Menu
- Laboratory of Biometry and Evolutionary Biology, CNRS, UMR 5558, Lyon University, F-69000 Lyon, France. Claude Bernard University, Lyon 1 F-69622, Villeurbanne, France
| |
Collapse
|
18
|
de Souza RDCM, Campolina-Silva GH, Bezerra CM, Diotaiuti L, Gorla DE. Does Triatoma brasiliensis occupy the same environmental niche space as Triatoma melanica? Parasit Vectors 2015; 8:361. [PMID: 26156398 PMCID: PMC4496957 DOI: 10.1186/s13071-015-0973-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 06/30/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Triatomines (Hemiptera, Reduviidae) are vectors of Trypanosoma cruzi, the causative agent of Chagas disease, one of the most important vector-borne diseases in Latin America. This study compares the environmental niche spaces of Triatoma brasiliensis and Triatoma melanica using ecological niche modelling and reports findings on DNA barcoding and wing geometric morphometrics as tools for the identification of these species. METHODS We compared the geographic distribution of the species using generalized linear models fitted to elevation and current data on land surface temperature, vegetation cover and rainfall recorded by earth observation satellites for northeastern Brazil. Additionally, we evaluated nucleotide sequence data from the barcode region of the mitochondrial cytochrome c oxidase subunit I (CO1) and wing geometric morphometrics as taxonomic identification tools for T. brasiliensis and T. melanica. RESULTS The ecological niche models show that the environmental spaces currently occupied by T. brasiliensis and T. melanica are similar although not equivalent, and associated with the caatinga ecosystem. The CO1 sequence analyses based on pair wise genetic distance matrix calculated using Kimura 2-Parameter (K2P) evolutionary model, clearly separate the two species, supporting the barcoding gap. Wing size and shape analyses based on seven landmarks of 72 field specimens confirmed consistent differences between T. brasiliensis and T. melanica. CONCLUSION Our results suggest that the separation of the two species should be attributed to a factor that does not include the current environmental conditions. However, as the caatinga is a biome that has existed in the area for at least the last 18,000 years, past conditions might have had an influence in the speciation process. The DNA Barcoding approach may be extended to these members of the subfamily Triatominae.
Collapse
Affiliation(s)
- Rita de Cássia Moreira de Souza
- Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, CEP 30.190-002, Belo Horizonte, Minas Gerais, Brazil.
| | - Gabriel H Campolina-Silva
- Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, CEP 30.190-002, Belo Horizonte, Minas Gerais, Brazil.
| | | | - Liléia Diotaiuti
- Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou, Fundação Oswaldo Cruz, CEP 30.190-002, Belo Horizonte, Minas Gerais, Brazil.
| | - David E Gorla
- IMBIV-CONICET, Casilla de Correo 495, 5000, Córdoba, Argentina.
| |
Collapse
|
19
|
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.
Collapse
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
| |
Collapse
|
20
|
Santo-Orihuela PL, Carvajal G, Picollo MI, Vassena CV. Analysing deltamethrin susceptibility and pyrethroid esterase activity variations in sylvatic and domestic Triatoma infestans at the embryonic stage. Mem Inst Oswaldo Cruz 2015; 108:1031-6. [PMID: 24402155 PMCID: PMC4005558 DOI: 10.1590/0074-0276130184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Accepted: 09/26/2013] [Indexed: 11/22/2022] Open
Abstract
The aim of the present work was to study the deltamethrin susceptibility of eggs from Triatoma infestans populations and the contribution of pyrethroid esterases to deltamethrin degradation. Insects were collected from sylvatic areas, including Veinte de Octubre and Kirus-Mayu (Bolivia) and from domiciliary areas, including El Palmar (Bolivia) and La Pista (Argentina). Deltamethrin susceptibility was determined by dose-response bioassays. Serial dilutions of deltamethrin (0.0005-1 mg/mL) were topically applied to 12-day-old eggs. Samples from El Palmar had the highest lethal dose ratio (LDR) value (44.90) compared to the susceptible reference strain (NFS), whereas the Veinte de Octubre samples had the lowest value (0.50). Pyrethroid esterases were evaluated using 7-coumaryl permethrate (7-CP) on individually homogenised eggs from each population and from NFS. The El Palmar and La Pista samples contained 40.11 and 36.64 pmol/min/mg protein, respectively, and these values were statistically similar to NFS (34.92 pmol/min/mg protein) and different from Kirus-Mayu and Veinte de Octubre (27.49 and 22.69 pmol/min/mg protein, respectively). The toxicological data indicate that the domestic populations were resistant to deltamethrin, but no statistical contribution of 7-CP esterases was observed. The sylvatic populations had similar LDR values to NFS, but lower 7-CP esterase activities. Moreover, this is the first study of the pyrethroid esterases on T. infestans eggs employing a specific substrate (7-CP).
Collapse
|
21
|
Gomez MB, D'Avila GCP, Orellana ALG, Cortez MR, Rosa ACL, Noireau F, Diotaiuti LG. Susceptibility to deltamethrin of wild and domestic populations of Triatoma infestans of the Gran Chaco and the Inter-Andean Valleys of Bolivia. Parasit Vectors 2014; 7:497. [PMID: 25394392 PMCID: PMC4240893 DOI: 10.1186/s13071-014-0497-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Accepted: 10/21/2014] [Indexed: 11/26/2022] Open
Abstract
Background The persistence of Triatoma infestans and the continuous transmission of Trypanosoma cruzi in the Inter-Andean Valleys and in the Gran Chaco of Bolivia are of great significance. Coincidentally, it is in these regions the reach of the vector control strategies is limited, and reports of T. infestans resistance to insecticides, including in wild populations, have been issued. This study aims to characterize the susceptibility to deltamethrin of wild and domestic populations of T. infestans from Bolivia, in order to better understand the extent of this relevant problem. Methods Susceptibility to deltamethrin was assessed in nine, wild and domestic, populations of T. infestans from the Gran Chaco and the Inter-Andean Valleys of Bolivia. Serial dilutions of deltamethrin in acetone (0.2 μL) were topically applied in first instar nymphs (F1, five days old, fasting, weight 1.2 ± 0.2 mg). Dose response results were analyzed with PROBIT version 2, determining the lethal doses, slope and resistance ratios (RR). Qualitative tests were also performed. Results Three wild T. infestans dark morph samples of Chaco from the Santa Cruz Department were susceptible to deltamethrin with RR50 of <2, and 100% mortality to the diagnostic dose (DD); however, two domestic populations from the same region were less susceptible than the susceptibility reference lineage (RR50 of 4.21 and 5.04 respectively and 93% DD). The domestic population of Villa Montes from the Chaco of the Tarija Department presented high levels of resistance (RR50 of 129.12 and 0% DD). Moreover, the domestic populations from the Valleys of the Cochabamba Department presented resistance (RR50 of 8.49 and 62% DD), the wild populations were less susceptible than SRL and T. infestans dark morph populations (RR50 < 5). Conclusion The elimination of T. infestans with pyrethroid insecticides in Brazil, Uruguay, Chile, and its drastic reduction in large parts of Paraguay and Argentina, clearly indicates that pyrethroid resistance was very uncommon in non-Andean regions. The pyrethroid susceptibility of non-Andean T. infestans dark morph population, and the resistance towards it, of Andean T. infestans wild and domestic populations, indicates that the Andean populations from Bolivia are less susceptible.
Collapse
Affiliation(s)
- Marinely Bustamante Gomez
- Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou - FIOCRUZ Minas, Belo Horizonte, Brazil.
| | - Grasielle Caldas Pessoa D'Avila
- Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou - FIOCRUZ Minas, Belo Horizonte, Brazil.
| | - Ana Lineth Garcia Orellana
- Instituto de Investigaciones Biomédicas - Facultad de Medicina, Universidad Mayor de San Simón, Cochabamba, Bolivia.
| | | | - Aline Cristine Luiz Rosa
- Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou - FIOCRUZ Minas, Belo Horizonte, Brazil.
| | - François Noireau
- Institute de Recherche pour le Developemente (IRD), La Paz, Bolivia.
| | - Liléia Gonçalves Diotaiuti
- Laboratório de Triatomíneos e Epidemiologia da Doença de Chagas, Centro de Pesquisas René Rachou - FIOCRUZ Minas, Belo Horizonte, Brazil.
| |
Collapse
|
22
|
Dias FBS, Jaramillo-O N, Diotaiuti L. Description and characterization of the melanic morphotype of Rhodnius nasutus Stål, 1859 (Hemiptera: Reduviidae: Triatominae). Rev Soc Bras Med Trop 2014; 47:637-41. [DOI: 10.1590/0037-8682-0007-2014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 04/09/2014] [Indexed: 11/22/2022] Open
|
23
|
Brémond P, Salas R, Waleckx E, Buitrago R, Aliaga C, Barnabé C, Depickère S, Dangles O, Brenière SF. Variations in time and space of an Andean wild population of T. infestans at a microgeographic scale. Parasit Vectors 2014; 7:164. [PMID: 24708673 PMCID: PMC3992151 DOI: 10.1186/1756-3305-7-164] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 03/21/2014] [Indexed: 11/13/2022] Open
Abstract
Background Wild populations of Triatoma infestans are now believed to be the source of reinfestation of dwellings in some Andean areas and could impede the full achievement of vector control campaigns in this region. Given the poor knowledge of these populations in natural conditions, their basic biology traits, such as monthly demographic variations and movements of individuals, were explored. Methods A previously identified wild population of T. infestans in a field adjacent to a group of isolated houses in an Andean valley (department of La Paz, Bolivia) was explored using regular capture assays over 13 months in 50 sites selected at the beginning of the study. The capture-mark-recapture method was applied monthly using mouse-baited adhesive traps for captures and fingernail polish of different colors for the marking. Results The monthly capture assays did not show significant differences between rainy and dry seasons, showing evidence for a certain stability of the wild T. infestans population with only the nymph population tending to decline during the middle of the rainy season when rain is more intensive. Throughout the study, the monthly average number of bugs was 51.1 ± 25.3 per assay, 91.1% were nymphs, and they were found at 30 of the 50 sites (60%). The number of times a site was positive varied from one to 13. Site infestation was associated with the underground position of the traps, and rocks around and in the surroundings of the traps. The recaptures after marking were successful (138 recaptures over the study). The marking made it possible to detect for 14.5% of the recaptures significant movements of adults (up to 168 m) and nymphs (up to 34 m). Some bugs (nymphs and females) were recaptured after 5 months. For adults, recaptures (46 in total) mostly occurred between September and March. Females were recaptured twice as frequently as males. Conclusion The Andean wild populations of T. infestans showed a strong spatial and temporal stability during the year-long study. Dispersal may occur mainly during the rainy season. The capture-mark-recapture method was successful and the longevity of the bugs and the distances covered by nymphs and adults were recorded.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Simone Frédérique Brenière
- IRD, Institut de Recherche pour le Développement, UMR INTERTRYP (IRD-CIRAD), Interactions hôtes-vecteurs-parasites dans les infections par trypanosomatidae), 911 Av, Agropolis, 34394 Montpellier, cédex 5, France.
| |
Collapse
|
24
|
Espinoza N, Borrás R, Abad-Franch F. Chagas disease vector control in a hyperendemic setting: the first 11 years of intervention in Cochabamba, Bolivia. PLoS Negl Trop Dis 2014; 8:e2782. [PMID: 24699407 PMCID: PMC3974664 DOI: 10.1371/journal.pntd.0002782] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 02/24/2014] [Indexed: 11/25/2022] Open
Abstract
Background Chagas disease has historically been hyperendemic in the Bolivian Department of Cochabamba. In the early 2000s, an extensive vector control program was implemented; 1.34 million dwelling inspections were conducted to ascertain infestation (2000–2001/2003–2011), with blanket insecticide spraying in 2003–2005 and subsequent survey-spraying cycles targeting residual infestation foci. Here, we assess the effects of this program on dwelling infestation rates (DIRs). Methodology/Principal Findings Program records were used to calculate annual, municipality-level aggregate DIRs (39 municipalities); very high values in 2000–2001 (median: 0.77–0.69) dropped to ∼0.03 from 2004 on. A linear mixed model (with municipality as a random factor) suggested that infestation odds decreased, on average, by ∼28% (95% confidence interval [CI95] 6–44%) with each 10-fold increase in control effort. A second, better-fitting mixed model including year as an ordinal predictor disclosed large DIR reductions in 2001–2003 (odds ratio [OR] 0.11, CI95 0.06–0.19) and 2003–2004 (OR 0.22, CI95 0.14–0.34). Except for a moderate decrease in 2005–2006, no significant changes were detected afterwards. In both models, municipality-level DIRs correlated positively with previous-year DIRs and with the extent of municipal territory originally covered by montane dry forests. Conclusions/Significance Insecticide-spraying campaigns had very strong, long-lasting effects on DIRs in Cochabamba. However, post-intervention surveys consistently detected infestation in ∼3% of dwellings, underscoring the need for continuous surveillance; higher DIRs were recorded in the capital city and, more generally, in municipalities dominated by montane dry forest – an eco-region where wild Triatoma infestans are widespread. Traditional strategies combining insecticide spraying and longitudinal surveillance are thus confirmed as very effective means for area-wide Chagas disease vector control; they will be particularly beneficial in highly-endemic settings, but should also be implemented or maintained in other parts of Latin America where domestic infestation by triatomines is still commonplace. Chagas disease is among the most serious public health problems in Latin America; the highest prevalence of infection by its causative agent, the parasite Trypanosoma cruzi, has historically been recorded in some parts of Bolivia. In the early 2000s, a massive insecticide-spraying program was set up to control dwelling infestation by the blood-sucking bugs that transmit the disease. Here we provide a detailed assessment of the effects of this program in the Department of Cochabamba, one of the most highly-endemic settings worldwide. Our analyses show that municipality-level dwelling infestation rates plummeted from over 70–80% in 2001–2003 to about 2–3% in 2004–2011. This residual infestation was higher in the capital city and, more generally, in municipalities where montane dry forests dominate – probably because wild populations of the main vector, Triatoma infestans, are common in that eco-region. Despite the impressive early achievements of the program, with about 0.5 million people protected from contagion, sustained disease control will require fully operational long-term surveillance systems.
Collapse
Affiliation(s)
- Natalisisy Espinoza
- Departamento de Microbiología y Ecología, Facultad de Medicina y Odontología, Universitat de València, Valencia, Spain
| | - Rafael Borrás
- Departamento de Microbiología y Ecología, Facultad de Medicina y Odontología, Universitat de València, Valencia, Spain
| | | |
Collapse
|
25
|
Risk of transmission of Trypanosoma cruzi by wild Triatoma infestans (Hemiptera: Reduviidae) in Bolivia supported by the detection of human blood meals. INFECTION GENETICS AND EVOLUTION 2013; 19:141-4. [PMID: 23856437 DOI: 10.1016/j.meegid.2013.07.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 06/29/2013] [Accepted: 07/02/2013] [Indexed: 11/22/2022]
Abstract
We analyzed the food sources of Bolivian wild Triatoma infestans (the main vector of Chagas disease in this country), to assess the role of these populations in the epidemiological context of Chagas disease. Ninety-eight blood meals were identified by heteroduplex assay and sequencing. Most of them were from wild mammals but surprisingly 27 were from humans. This brings to light the occurrence of human-vector contacts at risk of Trypanosoma cruzi transmission in the wild environment by highly infected insects.
Collapse
|
26
|
Lardeux F. Niche invasion, competition and coexistence amongst wild and domestic Bolivian populations of Chagas vector Triatoma infestans (Hemiptera, Reduviidae, Triatominae). C R Biol 2013; 336:183-93. [DOI: 10.1016/j.crvi.2013.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Revised: 05/17/2013] [Accepted: 05/17/2013] [Indexed: 11/30/2022]
|
27
|
Post-control surveillance of Triatoma infestans and Triatoma sordida with chemically-baited sticky traps. PLoS Negl Trop Dis 2012; 6:e1822. [PMID: 23029583 PMCID: PMC3441417 DOI: 10.1371/journal.pntd.0001822] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 08/05/2012] [Indexed: 11/20/2022] Open
Abstract
Background Chagas disease prevention critically depends on keeping houses free of triatomine vectors. Insecticide spraying is very effective, but re-infestation of treated dwellings is commonplace. Early detection-elimination of re-infestation foci is key to long-term control; however, all available vector-detection methods have low sensitivity. Chemically-baited traps are widely used in vector and pest control-surveillance systems; here, we test this approach for Triatoma spp. detection under field conditions in the Gran Chaco. Methodology/Principal Findings Using a repeated-sampling approach and logistic models that explicitly take detection failures into account, we simultaneously estimate vector occurrence and detection probabilities. We then model detection probabilities (conditioned on vector occurrence) as a function of trapping system to measure the effect of chemical baits. We find a positive effect of baits after three (odds ratio [OR] 5.10; 95% confidence interval [CI95] 2.59–10.04) and six months (OR 2.20, CI95 1.04–4.65). Detection probabilities are estimated at p≈0.40–0.50 for baited and at just p≈0.15 for control traps. Bait effect is very strong on T. infestans (three-month assessment: OR 12.30, CI95 4.44–34.10; p≈0.64), whereas T. sordida is captured with similar frequency in baited and unbaited traps. Conclusions/Significance Chemically-baited traps hold promise for T. infestans surveillance; the sensitivity of the system at detecting small re-infestation foci rises from 12.5% to 63.6% when traps are baited with semiochemicals. Accounting for imperfect detection, infestation is estimated at 26% (CI95 16–40) after three and 20% (CI95 11–34) after six months. In the same assessments, traps detected infestation in 14% and 8.5% of dwellings, whereas timed manual searches (the standard approach) did so in just 1.4% of dwellings only in the first survey. Since infestation rates are the main indicator used for decision-making in control programs, the approach we present may help improve T. infestans surveillance and control program management. Triatoma infestans is the main vector of Chagas disease in southern South America. Dwelling-infesting populations are controlled through insecticide-spraying campaigns; however, dwellings are often re-infested when insecticide effects wane, and this leads to the re-establishment of disease transmission. Detecting and eliminating re-infestation foci is therefore crucial to prevent new cases. Unfortunately, available vector detection methods all have low sensitivity. Here, we show that simple sticky traps baited with widely available chemicals are significantly more sensitive than either unbaited traps or active manual searches by trained staff — the standard method used in control programs. Increased trap sensitivity (about 500% higher), together with an analytical approach that takes detection failures into account, allows us to estimate dwelling infestation rates at about 20–26%; in contrast, just 0–1.4% of dwellings were identified as infested by manual searches. This large difference highlights the importance of enhancing surveillance systems, and reveals how crude infestation indices may mislead decision-makers. We conclude that chemically baited sticky traps can help improve T. infestans surveillance systems and thus strengthen vector control program management.
Collapse
|
28
|
Bacigalupo A, Segovia V, García A, Botto-Mahan C, Ortiz S, Solari A, Acuna-Retamar M, Torres-Pérez F, Cattan PE. Differential pattern of infection of sylvatic nymphs and domiciliary adults of Triatoma infestans with Trypanosoma cruzi genotypes in Chile. Am J Trop Med Hyg 2012; 87:473-80. [PMID: 22802439 PMCID: PMC3435350 DOI: 10.4269/ajtmh.2012.11-0237] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Accepted: 05/03/2012] [Indexed: 11/07/2022] Open
Abstract
In Chile, the main vector of Chagas disease, Triatoma infestans, is under control after insecticide spraying. However, it has been found colonizing wild habitats. This study evaluated Trypanosoma cruzi infection of sylvatic and domiciliary T. infestans and identified their parasite genotypes. The sample studied was composed mainly of T. infestans sylvatic nymphs and domiciliary adults from a semi-urban area with human dwellings under vector control surveillance. Results showed prevalences of 57.7% in nymphs and 68.6% in adults. Hybridization tests showed a major T. cruzi lineage (TcI) circulating in sylvatic (93.3%) and domiciliary (100%) T. infestans. TcII, TcV, and TcVI were also detected, mainly in nymphs, suggesting differential adaptation of T. cruzi lineages among instars. We also discuss the origin of domiciliary individuals of T. infestans and the risk of human infection by triatomines of sylvatic foci that invade houses despite vector control programs.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Pedro E. Cattan
- Departamento de Ciencias Biológicas Animales, Facultad de Ciencias Veterinarias y Pecuarias, Unidad de Parasitología, Facultad de Medicina Occidente, Departamento de Ciencias Ecológicas, Facultad de Ciencias, Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina Norte, Departamento de Patología Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile; Instituto de Biología, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| |
Collapse
|
29
|
Genetic characterization of Trypanosoma cruzi DTUs in wild Triatoma infestans from Bolivia: predominance of TcI. PLoS Negl Trop Dis 2012; 6:e1650. [PMID: 22685616 PMCID: PMC3368956 DOI: 10.1371/journal.pntd.0001650] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 04/07/2012] [Indexed: 11/20/2022] Open
Abstract
Background The current persistence of Triatoma infestans (one of the main vectors of Chagas disease) in some domestic areas could be related to re-colonization by wild populations which are increasingly reported. However, the infection rate and the genetic characterization of the Trypanosoma cruzi strains infecting these populations are very limited. Methodology/Principal Findings Of 333 wild Triatoma infestans specimens collected from north to south of a Chagas disease endemic area in Bolivia, we characterized 234 stocks of Trypanosoma cruzi using mini-exon multiplex PCR (MMPCR) and sequencing the glucose phosphate isomerase (Gpi) gene. Of the six genetic lineages (“discrete typing units”; DTU) (TcI-VI) presently recognized in T. cruzi, TcI (99.1%) was overdominant on TcIII (0.9%) in wild Andean T. infestans, which presented a 71.7% infection rate as evaluated by microscopy. In the lowlands (Bolivian Chaco), 17 “dark morph” T. infestans were analyzed. None of them were positive for parasites after microscopic examination, although one TcI stock and one TcII stock were identified using MMPCR and sequencing. Conclusions/Significance By exploring large-scale DTUs that infect the wild populations of T. infestans, this study opens the discussion on the origin of TcI and TcV DTUs that are predominant in domestic Bolivian cycles. Chagas disease is a neglected parasitic disease transmitted by bugs (vectors) and represents a serious health problem in the Americas. Although the transmission generally occurs in the houses where the bugs are living, wild populations of vectors are now considered a problem because these populations might enter the houses and recolonize them after eliminating of house populations by insecticide spraying. This is the case of the Southern countries where Triatoma infestans, the principal vector, transmits Trypanosoma cruzi the agent of the disease. This parasite presents a large genetic variability and it is important to know which T. cruzi genotypes are carried by the vectors. The authors found that in the wild T. infestans from the Bolivian Andean region, a principal group of genotype was circulating. In the lowlands (Bolivian Chaco), another additional genotype group was detected. Together with exploring at large scale which genotypes are infecting T. infestans wild populations, this study opens the discussion on the origin T. cruzi genotype groups. Also this study completes our basic knowledge on T. cruzi subspecific genetic variability, and therefore brings new tools for molecular epidemiology of Chagas disease.
Collapse
|
30
|
Waleckx E, Depickère S, Salas R, Aliaga C, Monje M, Calle H, Buitrago R, Noireau F, Brenière SF. New discoveries of sylvatic Triatoma infestans (Hemiptera: Reduviidae) throughout the Bolivian Chaco. Am J Trop Med Hyg 2012; 86:455-8. [PMID: 22403316 DOI: 10.4269/ajtmh.2012.11-0205] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Sylvatic populations of Triatoma infestans might be involved in the recolonization of human dwellings. We report here the discoveries of new T. infestans sylvatic foci in the Bolivian Chaco. Eighty-one triatomines were caught, 38 of which were identified as T. infestans. Triatoma sordida and Panstrongylus geniculatus were the other species collected. One T. infestans and one T. sordida were infected with Trypanosoma cruzi TcI; one T. infestans was infected with TcII. These discoveries add to the debate on the geographic distribution of sylvatic T. infestans populations, the geographic origin of the species, and the epidemiological role of these populations.
Collapse
Affiliation(s)
- Etienne Waleckx
- Maladies Infectieuses et Vecteurs: Ecologie, Génétique, Evolution et Contrôle, Université Montpellier - CNRS - IRD, Institut de Recherche pour le Développement, La Paz, Bolivia.
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Ceballos LA, Piccinali RV, Marcet PL, Vazquez-Prokopec GM, Cardinal MV, Schachter-Broide J, Dujardin JP, Dotson EM, Kitron U, Gürtler RE. Hidden sylvatic foci of the main vector of Chagas disease Triatoma infestans: threats to the vector elimination campaign? PLoS Negl Trop Dis 2011; 5:e1365. [PMID: 22039559 PMCID: PMC3201917 DOI: 10.1371/journal.pntd.0001365] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 09/05/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Establishing the sources of reinfestation after residual insecticide spraying is crucial for vector elimination programs. Triatoma infestans, traditionally considered to be limited to domestic or peridomestic (abbreviated as D/PD) habitats throughout most of its range, is the target of an elimination program that has achieved limited success in the Gran Chaco region in South America. METHODOLOGY/PRINCIPAL FINDINGS During a two-year period we conducted semi-annual searches for triatomine bugs in every D/PD site and surrounding sylvatic habitats after full-coverage spraying of pyrethroid insecticides of all houses in a well-defined rural area in northwestern Argentina. We found six low-density sylvatic foci with 24 T. infestans in fallen or standing trees located 110-2,300 m from the nearest house or infested D/PD site detected after insecticide spraying, when house infestations were rare. Analysis of two mitochondrial gene fragments of 20 sylvatic specimens confirmed their species identity as T. infestans and showed that their composite haplotypes were the same as or closely related to D/PD haplotypes. Population studies with 10 polymorphic microsatellite loci and wing geometric morphometry consistently indicated the occurrence of unrestricted gene flow between local D/PD and sylvatic populations. Mitochondrial DNA and microsatellite sibship analyses in the most abundant sylvatic colony revealed descendents from five different females. Spatial analysis showed a significant association between two sylvatic foci and the nearest D/PD bug population found before insecticide spraying. CONCLUSIONS Our study shows that, despite of its high degree of domesticity, T. infestans has sylvatic colonies with normal chromatic characters (not melanic morphs) highly connected to D/PD conspecifics in the Argentinean Chaco. Sylvatic habitats may provide a transient or permanent refuge after control interventions, and function as sources for D/PD reinfestation. The occurrence of sylvatic foci of T. infestans in the Gran Chaco may pose additional threats to ongoing vector elimination efforts.
Collapse
Affiliation(s)
- Leonardo A. Ceballos
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Romina V. Piccinali
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Paula L. Marcet
- Centers for Disease Control and Prevention, Division of Parasitic Diseases and Malaria, Atlanta, Georgia, United States of America
| | - Gonzalo M. Vazquez-Prokopec
- Department of Environmental Studies, Emory University, Atlanta, Georgia, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - M. Victoria Cardinal
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Judith Schachter-Broide
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Jean-Pierre Dujardin
- Unité Mixte de Recherche, Institut de Recherches pour le Développment-Centre National de Recherche Scientifique, Montpellier, France
| | - Ellen M. Dotson
- Centers for Disease Control and Prevention, Division of Parasitic Diseases and Malaria, Atlanta, Georgia, United States of America
| | - Uriel Kitron
- Department of Environmental Studies, Emory University, Atlanta, Georgia, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ricardo E. Gürtler
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires, Buenos Aires, Argentina
| |
Collapse
|
32
|
Piccinali RV, Marcet PL, Ceballos LA, Kitron U, Gürtler RE, Dotson EM. Genetic variability, phylogenetic relationships and gene flow in Triatoma infestans dark morphs from the Argentinean Chaco. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2011; 11:895-903. [PMID: 21352954 PMCID: PMC3104122 DOI: 10.1016/j.meegid.2011.02.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2010] [Revised: 02/10/2011] [Accepted: 02/15/2011] [Indexed: 11/18/2022]
Abstract
The recent discovery of sylvatic populations of Triatoma infestans outside the Andean Valleys of Bolivia prompted an evolutionary question about the putative ancestral area of origin and dispersal of the species, and an epidemiological question regarding the possible role of these sylvatic populations in the recolonization process of insecticide-treated houses. The finding of a population of sylvatic melanic T. infestans (dark morphs) in the Argentinean dry Chaco at 7 km from a peridomestic bug population of typical coloration gave us the opportunity to test both questions simultaneously by employing phylogenetic and population genetic approaches. For this purpose we analyzed sylvatic and peridomestic bugs using sequence-based mitochondrial and nuclear markers (mtCOI and ITS-1) and microsatellites. Sylvatic bugs were confirmed to be T. infestans and not hybrids, and showed high levels of genetic variability and departures from neutral expectations for mtCOI variation. New ITS-1 and mtCOI haplotypes were recorded, as well as haplotypes shared with peridomestic and/or domestic bugs from previous records. The peridomestic population was invariant for ITS-1 and mtCOI, but showed variability for microsatellites and signatures of a population bottleneck, probably due to a limited number of founders. Phylogenetic analyses were consistent with the presence of ancestral haplotypes in sylvatic bugs. According to F-statistics and assignment methods there was a significant differentiation between sylvatic and peridomestic bugs and gene flow was low and asymmetric, with more bugs moving from the peridomicile to the sylvatic environment. These results support the hypothesis of the Chaco region as the area of origin of T. infestans, and a limited role of sylvatic melanic T. infestans in peridomestic infestation in the Argentinean Chaco.
Collapse
Affiliation(s)
- R V Piccinali
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina.
| | | | | | | | | | | |
Collapse
|
33
|
Rolón M, Vega MC, Román F, Gómez A, Rojas de Arias A. First report of colonies of sylvatic Triatoma infestans (Hemiptera: Reduviidae) in the Paraguayan Chaco, using a trained dog. PLoS Negl Trop Dis 2011; 5:e1026. [PMID: 21572522 PMCID: PMC3086807 DOI: 10.1371/journal.pntd.0001026] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 02/16/2011] [Indexed: 11/17/2022] Open
Abstract
In the Gran Chaco region, control of Triatoma infestans has been limited by persistent domestic infestations despite the efforts of the Vector Control Services. In Paraguay, this region is the highest endemic area in the country, showing high levels of indoor and outdoor infestation. Although sylvatic T. infestans have been found in the Bolivian and Argentine Chaco, similar searches for sylvatic populations of this species in Paraguay had been unsuccessful over the last 20 years. Here we present a new approach to detecting sylvatic Triatominae, using a trained dog, which has successfully confirmed sylvatic populations of T. infestans and other triatomine species in Paraguay. A total of 22 specimens corresponding to dark morph forms of T. infestans were collected, and 14 were confirmed as T. infestans by the mitochondrial cytochrome B gene analysis. Through this analysis, one of which were previously reported and a second that was a new haplotype. Triatomines were captured from amongst vegetation such as dry branches and hollows trees of different species such Aspidosperma quebracho-blanco, Bulnesia sarmientoi and Stetsonia coryne. The colonies found have been small and without apparent infection with Trypanosoma cruzi. During the study, Triatoma sordida and Triatoma guasayana have also been found in ecotopes close to those of T. infestans.
Collapse
Affiliation(s)
- Miriam Rolón
- Centro para el Desarrollo de la Investigación Científica (CEDIC/Díaz Gill Medicina Laboratorial/Fundación Moisés Bertoni), Asunción, Paraguay
| | - María Celeste Vega
- Centro para el Desarrollo de la Investigación Científica (CEDIC/Díaz Gill Medicina Laboratorial/Fundación Moisés Bertoni), Asunción, Paraguay
| | - Fabiola Román
- Centro para el Desarrollo de la Investigación Científica (CEDIC/Díaz Gill Medicina Laboratorial/Fundación Moisés Bertoni), Asunción, Paraguay
| | - Ana Gómez
- Centro para el Desarrollo de la Investigación Científica (CEDIC/Díaz Gill Medicina Laboratorial/Fundación Moisés Bertoni), Asunción, Paraguay
| | - Antonieta Rojas de Arias
- Centro para el Desarrollo de la Investigación Científica (CEDIC/Díaz Gill Medicina Laboratorial/Fundación Moisés Bertoni), Asunción, Paraguay
| |
Collapse
|
34
|
Waleckx E, Salas R, Huamán N, Buitrago R, Bosseno MF, Aliaga C, Barnabé C, Rodriguez R, Zoveda F, Monje M, Baune M, Quisberth S, Villena E, Kengne P, Noireau F, Brenière SF. New insights on the Chagas disease main vector Triatoma infestans (Reduviidae, Triatominae) brought by the genetic analysis of Bolivian sylvatic populations. INFECTION GENETICS AND EVOLUTION 2011; 11:1045-57. [PMID: 21463708 DOI: 10.1016/j.meegid.2011.03.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 03/10/2011] [Accepted: 03/26/2011] [Indexed: 11/28/2022]
Abstract
Triatoma infestans is the main and most widespread vector of Chagas disease in South America. For the first time, a large sample of sylvatic populations of T. infestans was analyzed by ITS-2 and mtCytB sequencing. ITS-2 showed a low level of polymorphism but revealed a dichotomy between the Andean and non-Andean sylvatic populations. On the contrary, mtCytB sequences showed a high polymorphism (19 haplotypes determined by 35 variable sites) revealing a strong structuring between most of the sylvatic populations and possible ancient isolation and bottleneck in the Northern Andes. The dichotomy Andean vs. non-Andean populations was not observed with this marker. Moreover, mtCytB haplotype genealogies showed that the non-Andean haplotypes would have derived from the Andean ones, supporting somewhat an Andean origin of the species. Nevertheless, a non-Andean origin could not be discarded because a remarkable genetic diversity was found in the non-Andean sample. The comparison of the sylvatic haplotypes with the domestic ones from GenBank suggested multiple events of T. infestans domestication in Andean and non-Andean areas, instead of a major and unique domestication event in the Bolivian Andes, as previously proposed.
Collapse
Affiliation(s)
- Etienne Waleckx
- MIVEGEC (Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle, IRD 224 - CNRS 5290 - Université Montpellier 1 - Université Montpellier 2, Institut de Recherche pour le Développement, 911 Avenue Agropolis, BP 64501, 34394 Montpellier, France.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Ryelandt J, Noireau F, Lazzari CR. A multimodal bait for trapping blood-sucking arthropods. Acta Trop 2011; 117:131-6. [PMID: 21114956 DOI: 10.1016/j.actatropica.2010.11.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Revised: 11/07/2010] [Accepted: 11/10/2010] [Indexed: 11/26/2022]
Abstract
Artificial baits constitute important tools for the detection and sampling of blood-sucking arthropods, in particular those that are vectors of parasites affecting human health. At present, many different devices have been proposed to attract blood-sucking arthropods, mostly based on the attractiveness of particular chemicals or blends. However, most of them revealed themselves as unpractical (e.g. they require an electrical supply), expensive (e.g. gas bottles) or not efficient enough. On the other hand, the use of living baits is as effective but it has practical constraints and/or raises ethical questions. We present here a multimodal lure to attract blood-sucking arthropods designed taking into account both practical constraints and costs. The main characteristics of our bait are: (1) artificiality (no living-host); (2) multimodality (it associates heat, carbon dioxide and chemical attractants); (3) independency from any energy source; (4) no need for gas bottles; (5) easy to prepare and use in the field; (6) low cost. We tested the ability of the bait to attract blood-sucking arthropods in the laboratory and in the field, using capture sticky-traps. Our bait evinced to be almost as efficient as live hosts (mice) for the capture of Chagas disease and Borrelia vectors in Bolivia. The multimodal lure here presented is a generalist bait, i.e. effective for attracting different haematophagous species.
Collapse
|
36
|
Sarquis O, Carvalho-Costa FA, Oliveira LS, Duarte R, D Andrea PS, de Oliveira TG, Lima MM. Ecology of Triatoma brasiliensis in northeastern Brazil: seasonal distribution, feeding resources, and Trypanosoma cruzi infection in a sylvatic population. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2010; 35:385-394. [PMID: 21175946 DOI: 10.1111/j.1948-7134.2010.00097.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We assessed some ecological parameters of Triatoma brasiliensis in rock piles in the state of Ceará during the rainy and dry seasons. The greatest density was in April (median = 12.5 triatomines/site). The greatest abundance was in December, when the insects were more dispersed and the density per site was lower (6 triatomines/site). The nutritional status of females and 5th instar nymphs was increased in July. The rate of T. cruzi infection reached its highest peak in July (10.9%). ELISA revealed that the principal food sources were birds (33.1%), followed by armadillos (18.8%). Food sources were more frequently identified during the rainy season. T. brasiliensis specimens collected in the drought tended to: i) present lower rates of T. cruzi infection and gut content reactivity to tested antisera, ii) have a poorer nutritional status, iii) exhibit lower fecundity, iv) be more dispersed among the studied collection sites, and v) be more abundant and easily collected in the surface of the rocks, possibly reflecting an increased searching for blood meals. Such findings underscore epidemiological concerns and allow inferences about the season when triatomines can more frequently invade the peridomestic environment in search of food and recolonize artificial structures.
Collapse
Affiliation(s)
- Otilia Sarquis
- Laboratório de Eco-Epidemiologia da Doença de Chagas, Instituto Oswaldo Cruz (IOC/Fiocruz), Rio de Janeiro, RJ, Brazil
| | | | | | | | | | | | | |
Collapse
|
37
|
Bacigalupo A, Torres-Pérez F, Segovia V, García A, Correa JP, Moreno L, Arroyo P, Cattan PE. Sylvatic foci of the Chagas disease vector Triatoma infestans in Chile: description of a new focus and challenges for control programs. Mem Inst Oswaldo Cruz 2010; 105:633-41. [DOI: 10.1590/s0074-02762010000500006] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2009] [Accepted: 04/27/2010] [Indexed: 11/21/2022] Open
|
38
|
Buitrago R, Waleckx E, Bosseno MF, Zoveda F, Vidaurre P, Salas R, Mamani E, Noireau F, Brenière SF. First report of widespread wild populations of Triatoma infestans (Reduviidae, Triatominae) in the valleys of La Paz, Bolivia. Am J Trop Med Hyg 2010; 82:574-9. [PMID: 20348501 DOI: 10.4269/ajtmh.2010.09-0325] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Wild populations of Triatoma infestans, the main vector of Chagas disease in the Southern Cone countries, may be involved in reinfestation of human dwellings, limiting the success of vector-control campaigns in Bolivia. Knowledge of the distribution of these populations remains incomplete. We report here the detection of T. infestans wild populations in large areas in the department of La Paz, Bolivia. Among 18 sylvatic areas investigated, 17 were positive with T. infestans specimens. The infection rate of captured T. infestans with Trypanosoma cruzi was 85.7% in adult specimens. These results expand the geographical distribution of wild populations of T. infestans; it may be distributed throughout the Inter-Andean Dry Forest eco-region of Bolivia. The current information allows us to propose the hypothesis that a sylvatic origin of the reinfestation is located in the valleys of La Paz.
Collapse
Affiliation(s)
- Rosio Buitrago
- Département Société et Santé, Institut de Recherche pour le Développement (IRD), Montpellier, France
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Camargo EP. Perspectives of vaccination in Chagas disease revisited. Mem Inst Oswaldo Cruz 2010; 104 Suppl 1:275-80. [PMID: 19753485 DOI: 10.1590/s0074-02762009000900036] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Accepted: 06/16/2009] [Indexed: 05/25/2023] Open
Abstract
The perspectives for a Chagas Disease vaccine 30 years ago and today are compared. Antigens and adjuvants have improved, but logistic problems remain the same. Sterilizing vaccines have not been produced and animal models for chronic Chagas have not been developed. Vector control has been successful and Chagas incidence has come to a halt. We do not have a population candidate to vaccination now in Brazil. And if we had, we would not know how to evaluate the success of vaccination in a short time period. A vaccine may not seem important at the moment. However, scientific reasons and incertitudes about the future recommend that a search for a vaccine be continued.
Collapse
Affiliation(s)
- Erney Plessmann Camargo
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil.
| |
Collapse
|
40
|
New insights on the spread of Triatoma infestans from Bolivia--implications for Chagas disease emergence in the southern cone. INFECTION GENETICS AND EVOLUTION 2010; 10:350-3. [PMID: 20060504 DOI: 10.1016/j.meegid.2009.12.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Accepted: 12/18/2009] [Indexed: 11/20/2022]
Abstract
Triatoma infestans, now eliminated from most of South America by control campaigns, has been and still is the main Chagas disease vector due to its ability to colonize rural dwellings. The traditional hypothesis put forth to explain T. infestans adaptation to the synanthropic environment rests on the domestication of wild guinea pigs, one of its natural hosts, by Andean tribes about 5000 BC. Here we present two new hypotheses, based on organized human social activities. The first involves maize production, storage and distribution during the Inca period. Maize granaries could host wild rodent populations that would attract sylvatic T. infestans that were later dispersed during maize distribution. The second hypothesis is associated with the contemporary Urkupiña Virgin festival, near Cochabamba, where thousands of pilgrims gather for rituals in an area that is part of a sylvatic T. infestans focus, thus favoring the contact with the insects and leading to their passive dispersal.
Collapse
|
41
|
CEBALLOS LA, PICCINALI RV, BERKUNSKY I, KITRON U, GÜRTLER RE. First finding of melanic sylvatic Triatoma infestans (Hemiptera: Reduviidae) colonies in the Argentine Chaco. JOURNAL OF MEDICAL ENTOMOLOGY 2009; 46:1195-202. [PMID: 19769054 PMCID: PMC2782367 DOI: 10.1603/033.046.0530] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Triatoma infestans (Klug), the most important vector of Chagas disease in southern South America, is a highly domiciliated species with well-known sylvatic foci only in the Bolivian Andean valleys and in the Bolivian Chaco, where melanic insects designated as "dark morphs" were found. After the tentative identification of two melanic bugs collected from parrot nests in a forest reserve in the Argentine Chaco as T. infestans, we conducted an intensive search there using mouse-baited sticky traps in summer 2006 and 2007. Four live T. infestans bugs were collected in trees without parrot nests in 288 trap-nights, whereas no bug was collected from inside trees with active parrot nests in 51 trap-nights. To increase bug captures, hollow tree trunks that recently had had Amazona aestiva (Berlepsch) and Aratinga acuticaudata (Vieillot) parrot nests were treated with insecticide fumigant canisters exhibiting strong knockdown power. Four (22%) of 18 trees were positive for T. infestans with a dark phenotype. A fragment of the mitochondrial gene COI of 8 of the 14 triatomine bugs collected was successfully sequenced and confirmed as T. infestans. Most of the bugs were captured from Aspidosperma quebracho-blanco (Schlechter) hollow tree trunks harboring parrot nests. All of the T. infestans collected from the nearest house located at 10 km from the sylvatic foci displayed normal chromatic characters. The repeated finding of T. infestans in sylvatic habitats, albeit at very low density, shows that this species is capable of maintaining viable sylvatic foci in the absence of human hosts and immigration from domestic populations. These are the first confirmed findings of sylvatic T. infestans colonies in Argentina and of dark morphs in the Argentine Chaco.
Collapse
Affiliation(s)
- L. A. CEBALLOS
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - R. V. PICCINALI
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - I. BERKUNSKY
- Laboratorio de Ecología y Comportamiento Animal, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
| | - U. KITRON
- Department of Environmental Studies, Emory University, 400 Dowman Dr., Math and Science Center, Suite E511, Atlanta, GA 30322
| | - R. E. GÜRTLER
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina
- Corresponding author,
| |
Collapse
|
42
|
Noireau F. Wild Triatoma infestans, a potential threat that needs to be monitored. Mem Inst Oswaldo Cruz 2009; 104 Suppl 1:60-4. [DOI: 10.1590/s0074-02762009000900010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Accepted: 06/04/2009] [Indexed: 11/21/2022] Open
Affiliation(s)
- François Noireau
- Institut de Recherche pour le Développement, France; Universidad Mayor de San Simón, Bolivia
| |
Collapse
|
43
|
Costa J, Lorenzo M. Biology, diversity and strategies for the monitoring and control of triatomines - Chagas disease vectors. Mem Inst Oswaldo Cruz 2009; 104 Suppl 1:46-51. [DOI: 10.1590/s0074-02762009000900008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2009] [Accepted: 06/10/2009] [Indexed: 11/22/2022] Open
|
44
|
Populations, hybrids and the systematic concepts of species and subspecies in Chagas disease triatomine vectors inferred from nuclear ribosomal and mitochondrial DNA. Acta Trop 2009; 110:112-36. [PMID: 19073132 DOI: 10.1016/j.actatropica.2008.10.013] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2008] [Revised: 09/12/2008] [Accepted: 10/15/2008] [Indexed: 10/21/2022]
Abstract
In Chagas disease, triatomine vectors are the main target for control measures because of the absence of effective drugs. The broad usefulness of nuclear rDNA and mtDNA sequences explains why triatomine studies using these markers have increased so pronouncedly in recent years. This indicates the appropriateness of an updated review about these molecular markers, concentrating on aspects useful for research on Chagas disease vectors. A comparative analysis is presented on the efficiency, weight of their different characteristics, limitations and problems of each of the different DNA markers in the light of the results obtained in studies on populations, hybrids, subspecies and species of the subfamily Triatominae. The use of a standardized composite haplotype code nomenclature for both nuclear rDNA and mtDNA markers is strongly encouraged to avoid difficulties in comparative studies. Triatomine aspects related to concerted evolution, microsatellites, minisatellites and insertions/deletions in nuclear rDNA and silent/non-silent mutations, pseudogenes and weaknesses of partial sequences in mtDNA are analysed. Introgression and hybrids, nuclear and mitochondrial DNA strengths, and compared evolutionary rates of nuclear rDNA and mtDNA in triatomines are discussed. Many conclusions are obtained thanks to the availability, for the first time in triatomines, of a complete sequence of a protein-coding mtDNA gene as ND1 from very numerous triatomine species covering from different populations of a species up to members belonging to different tribes. The evolutionary rates of each nuclear rDNA marker and mtDNA marker are analysed by comparison at subspecies level (intrapopulational, interpopulational, between morphs, and between subspecies) and species level (close and distant species of the same genus, species of different genera, and species of different tribes). Weaknesses of mtDNA for systematic-taxonomic purposes detected recently and newly in insects and triatomines, respectively, are discussed in detail. Emphasis is given to taxonomic units and biological entities presenting well-known problematics, both from the systematic-taxonomic and/or epidemiological-control points of view, as well as to molecular situations which can give rise to erroneous conclusions. All these aspects constitute the background on which the key question about the systematic concepts of species and subspecies in triatomines is focused. The global purpose is to facilitate future work on triatomines by highlighting present gaps, how better choice the appropriate markers, and marker aspects which should be taken into account. Key characteristics as alpha, CI and transformation rate matrices ought to be obtained and noted to get appropriate results and allow correct interpretations. The main aim is to offer a baseline for future fundamental research on triatomines and applied research on transmission, epidemiology and control measures related to Chagas disease vectors.
Collapse
|
45
|
Llewellyn MS, Miles MA, Carrasco HJ, Lewis MD, Yeo M, Vargas J, Torrico F, Diosque P, Valente V, Valente SA, Gaunt MW. Genome-scale multilocus microsatellite typing of Trypanosoma cruzi discrete typing unit I reveals phylogeographic structure and specific genotypes linked to human infection. PLoS Pathog 2009; 5:e1000410. [PMID: 19412340 PMCID: PMC2669174 DOI: 10.1371/journal.ppat.1000410] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Accepted: 04/01/2009] [Indexed: 11/28/2022] Open
Abstract
Trypanosoma cruzi is the most important parasitic infection in Latin America and is also genetically highly diverse, with at least six discrete typing units (DTUs) reported: Tc I, IIa, IIb, IIc, IId, and IIe. However, the current six-genotype classification is likely to be a poor reflection of the total genetic diversity present in this undeniably ancient parasite. To determine whether epidemiologically important information is "hidden" at the sub-DTU level, we developed a 48-marker panel of polymorphic microsatellite loci to investigate population structure among 135 samples from across the geographic distribution of TcI. This DTU is the major cause of resurgent human disease in northern South America but also occurs in silvatic triatomine vectors and mammalian reservoir hosts throughout the continent. Based on a total dataset of 12,329 alleles, we demonstrate that silvatic TcI populations are extraordinarily genetically diverse, show spatial structuring on a continental scale, and have undergone recent biogeographic expansion into the southern United States of America. Conversely, the majority of human strains sampled are restricted to two distinct groups characterised by a considerable reduction in genetic diversity with respect to isolates from silvatic sources. In Venezuela, most human isolates showed little identity with known local silvatic strains, despite frequent invasion of the domestic setting by infected adult vectors. Multilocus linkage indices indicate predominantly clonal parasite propagation among all populations. However, excess homozygosity among silvatic strains and raised heterozygosity among domestic populations suggest that some level of genetic recombination cannot be ruled out. The epidemiological significance of these findings is discussed.
Collapse
|
46
|
Noireau F, Diosque P, Jansen AM. Trypanosoma cruzi: adaptation to its vectors and its hosts. Vet Res 2009; 40:26. [PMID: 19250627 PMCID: PMC2695024 DOI: 10.1051/vetres/2009009] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 02/26/2009] [Indexed: 12/19/2022] Open
Abstract
American trypanosomiasis is a parasitic zoonosis that occurs throughout Latin America. The etiological agent, Trypanosoma cruzi, is able to infect almost all tissues of its mammalian hosts and spreads in the environment in multifarious transmission cycles that may or not be connected. This biological plasticity, which is probably the result of the considerable heterogeneity of the taxon, exemplifies a successful adaptation of a parasite resulting in distinct outcomes of infection and a complex epidemiological pattern. In the 1990s, most endemic countries strengthened national control programs to interrupt the transmission of this parasite to humans. However, many obstacles remain to the effective control of the disease. Current knowledge of the different components involved in elaborate system that is American trypanosomiasis (the protozoan parasite T. cruzi, vectors Triatominae and the many reservoirs of infection), as well as the interactions existing within the system, is still incomplete. The Triatominae probably evolve from predatory reduvids in response to the availability of vertebrate food source. However, the basic mechanisms of adaptation of some of them to artificial ecotopes remain poorly understood. Nevertheless, these adaptations seem to be associated with a behavioral plasticity, a reduction in the genetic repertoire and increasing developmental instability.
Collapse
Affiliation(s)
- François Noireau
- UR 016, Institut de Recherche pour le Développement (IRD), Montpellier, France.
| | | | | |
Collapse
|
47
|
Pizarro JC, Stevens L. A new method for forensic DNA analysis of the blood meal in chagas disease vectors demonstrated using Triatoma infestans from Chuquisaca, Bolivia. PLoS One 2008; 3:e3585. [PMID: 18974787 PMCID: PMC2570791 DOI: 10.1371/journal.pone.0003585] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 09/17/2008] [Indexed: 11/18/2022] Open
Abstract
Background Feeding patterns of the vector are important in the epidemiology of Chagas disease, the leading cause of heart disease in Latin America. Chagas disease is caused by the parasite, Trypanasoma cruzi, which is transmitted by blood feeding insects. Historically, feeding behaviours of haematophagous insects have been investigated using serological reactions, which have detection limits in terms of both taxonomic resolution, and quantity and quality of the blood meal. They are labor intensive, require technical expertise, need fresh or frozen samples and antibodies often are either not available commercially or the resources for synthesis and purification are not available. We describe an assay to identify vertebrate blood meal sources, and the parasite T. cruzi using species-specific PCR assays from insect vectors and use the method to provide information regarding three questions: (1) Do domestic and peri-domestic (chicken coop and animal corral) habitats vary in the blood meals detected in the vectors? (2) What is the pattern of multiple blood meals? (3) Does the rate of T. cruzi infection vary among habitats and is it associated with specific blood meal types? Methodology/Principal Findings Assays based on the polymerase chain reaction were evaluated for identification of the blood meal source in the heamatophagous Chagas disease vector Triatoma infestans. We evaluate a technique to identify 11 potential vertebrate food sources from the complex mixture extracted from the vector's abdomen. We tested the assay on 81 T. infestans specimens collected from the Andean highlands in the department of Chuquisaca, located in central Bolivia, one of the regions in South America where sylvatic T. infestans have been reported. This area is suggested to be the geographic origin of T. infestans and has very high human infection rates that may be related to sylvatic vector populations. Conclusion/Significance The results of the assays revealed that a high percentage of insects collected in human dwellings had fed on peri-domestic animals. In contrast, one insect from a chicken coop but no bugs from corrals tested positive for human blood. Forty-eight percent of insects tested positive for more than one vertebrate species. T. cruzi infection was detected in 42% of the specimens. From the epidemiological point of view, the results reveal an overall pattern of movement from peri-domestic structures to human habitations for T. infestans in this region of Bolivia as well as the important role of pigs, dogs, chickens and guinea pigs in the dynamics of T. cruzi infection.
Collapse
Affiliation(s)
- Juan Carlos Pizarro
- Department of Biology, University of Vermont, Burlington, Vermont, United States of America
- Facultad de Bioquímica, Universidad de San Francisco Xavier de Chuquisaca, Sucre, Bolivia
| | - Lori Stevens
- Department of Biology, University of Vermont, Burlington, Vermont, United States of America
- * E-mail:
| |
Collapse
|