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Pereira LC, Pereira NDS, Barbosa da Silva AN, Bezerra CDF, Sousa KMD, Fagundes Neto JC, Sampaio GHF, Brito CRDN, Souza RDCM, Galvão LMDC, Câmara ACJD, Nascimento MSL, Guedes PMM. Insecticidal activity of fluralaner (Exzolt ®) administered to Gallus gallus domesticus against triatomines (Hemiptera, Reduviidae, Triatominae). Parasit Vectors 2024; 17:208. [PMID: 38720313 PMCID: PMC11080163 DOI: 10.1186/s13071-024-06276-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 04/09/2024] [Indexed: 05/12/2024] Open
Abstract
BACKGROUND Triatoma infestans, Triatoma brasiliensis, Triatoma pseudomaculata and Rhodnius prolixus are vectors of Trypanosoma cruzi, the etiological agent of Chagas disease. Chickens serve as an important blood food source for triatomines. This study aimed to assess the insecticidal activity of fluralaner (Exzolt®) administered to chickens against triatomines (R. prolixus, T. infestans, T. brasiliensis and T. pseudomaculata). METHODS Twelve non-breed chickens (Gallus gallus domesticus) were randomized based on weight into three groups: negative control (n = 4); a single dose of 0.5 mg/kg fluralaner (Exzolt®) (n = 4); two doses of 0.5 mg/kg fluralaner (Exzolt®) (n = 4). Nymphs of 3rd, 4th and 5th instars of R. prolixus, T. infestans, T. brasiliensis and T. pseudomaculata (all n = 10) were allowed to feed on chickens before treatment, and at intervals of 1, 7, 14, 21, 28, 35 and 56 days after treatment, with insect mortality determined. RESULTS Treatment with two doses of fluralaner showed higher insecticidal efficacy against R. prolixus, T. infestans and T. brasiliensis compared to the single-dose treatment. Similar insecticidal efficacy was observed for T. pseudomaculata for one and two doses of fluralaner. Insecticidal activity of fluralaner (Exzolt®) against triatomine bugs was noted up to 21 and 28 days after treatment with one and two doses of fluralaner, respectively. CONCLUSIONS The results demonstrate that treatment of chickens with fluralaner (Exzolt®) induces insecticidal activity against triatomines for up to 28 days post-treatment, suggesting its potential use as a control strategy for Chagas disease in endemic areas.
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Affiliation(s)
| | - Nathalie de Sena Pereira
- Graduate Program in Biological and Health Sciences, Federal University of Vale do São Francisco, Petrolina, Brazil
| | | | | | - Kivia Millana de Sousa
- Department of Microbiology and Parasitology, Federal University of Rio Grande do Norte, Natal, Brazil
| | | | | | | | | | - Lúcia Maria da Cunha Galvão
- Graduate Program in Health Sciences, Federal University of Rio Grande do Norte, Natal, Brazil
- Department of Clinical and Toxicological Analyses, Federal University of Rio Grande do Norte, Natal, Brazil
| | | | | | - Paulo Marcos Matta Guedes
- Department of Microbiology and Parasitology, Federal University of Rio Grande do Norte, Natal, Brazil.
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Fiatsonu E, Deka A, Ndeffo-Mbah ML. Effectiveness of Systemic Insecticide Dog Treatment for the Control of Chagas Disease in the Tropics. BIOLOGY 2023; 12:1235. [PMID: 37759635 PMCID: PMC10525078 DOI: 10.3390/biology12091235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/05/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023]
Abstract
Chagas disease, caused by Trypanosoma cruzi and transmitted by triatomines, can lead to severe cardiac issues and mortality in many mammals. Recent studies have shown that systemic insecticide treatment of dogs is highly effective in killing triatomines. Here, we assessed the impact of dog treatment on T. cruzi transmission. We developed a mathematical model of T. cruzi transmission among triatomines, dogs, humans, and rodents. We used the model to evaluate the impact of dog treatment regimens on T. cruzi transmission dynamics to determine their effectiveness in reducing T. cruzi infection among hosts. We show that a 3-month treatment regimen may reduce T. cruzi incidence among humans by 59-80% in a high transmission setting, and 26-82% in a low transmission setting. An annual treatment may reduce incidence among humans by 49-74% in a high transmission setting, and by 11-76% in a low transmission setting. However, dog treatment may substantially increase T. cruzi prevalence among dogs if dog consumption of dead triatomines increases. Our model indicates that dog treatment may reduce T. cruzi infections among humans, but it may increase infections in dogs. Therefore, a holistic approach targeting different hosts is necessary for Chagas elimination.
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Affiliation(s)
- Edem Fiatsonu
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77845, USA; (A.D.); (M.L.N.-M.)
| | - Aniruddha Deka
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77845, USA; (A.D.); (M.L.N.-M.)
| | - Martial L. Ndeffo-Mbah
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77845, USA; (A.D.); (M.L.N.-M.)
- Department of Epidemiology and Biostatistics, School of Public Health, Texas A&M University, College Station, TX 77845, USA
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Valentinuzzi/ VS, Abrahan LB. An increased number of individuals of a potential host facilitates non-photic synchronisation in the haematophagous insect Triatoma infestans. Mem Inst Oswaldo Cruz 2023; 118:e220289. [PMID: 37531507 PMCID: PMC10392893 DOI: 10.1590/0074-02760220289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 06/19/2023] [Indexed: 08/04/2023] Open
Abstract
BACKGROUND Triatoma infestans (Kissing bug) is the main vector of the parasite causative of Chagas disease in Latin-America. This species shows clear activity rhythms easily synchronised to day-night cycles (photic cycle). The haematophagous nature of these insects lead us to think that they may temporally adapt to the particular activity rhythms of potential hosts (non-photic cycle). Our previous data showed that kissing bugs were weakly affected by the activity-inactivity rhythm of a single host. OBJETIVE To determine if by increasing the number of individuals of a potential host, T. infestans could increase the likelihood of synchronisation. METHODS Individual activity rhythms of experimental insects, maintained in constant darkness in light-tight cabinets, localised in a room with 24 rodents, were continuously monitored. Another insect group that served as control was maintained in the same conditions but in a room without rodents. FINDINGS Most of the experimental insects synchronised, expressing a 24 h period coincident with the activity-inactivity rhythms of the rodents, while the controls free ran with a period significantly longer than 24 h. CONCLUSION Analogous to what happens with high vs low light intensity in photic synchronisers, a high number of rodents, in contrast to the previous one-rodent experiment, increased the potency of this non-photic zeitgeber.
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Affiliation(s)
- Veronica Sandra Valentinuzzi/
- Centro Regional de Investigaciones Científicas y de Transferencia Tecnológica de La Rioja, Universidad Nacional de La Rioja, Servicio Geológico Minero Argentino, Universidad Nacional de Catamarca, Consejo Nacional de Investigaciones Científicas y Técnicas, Entre Ríos y Mendoza, La Rioja, Argentina
| | - Luciana Beatriz Abrahan
- Centro Regional de Investigaciones Científicas y de Transferencia Tecnológica de La Rioja, Universidad Nacional de La Rioja, Servicio Geológico Minero Argentino, Universidad Nacional de Catamarca, Consejo Nacional de Investigaciones Científicas y Técnicas, Entre Ríos y Mendoza, La Rioja, Argentina
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Durden C, Tian Y, Knape K, Klemashevich C, Norman KN, Carey JB, Hamer SA, Hamer GL. Fluralaner systemic treatment of chickens results in mortality in Triatoma gerstaeckeri, vector of the agent of Chagas disease. Parasit Vectors 2023; 16:178. [PMID: 37268980 DOI: 10.1186/s13071-023-05805-1] [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: 02/09/2023] [Accepted: 05/10/2023] [Indexed: 06/04/2023] Open
Abstract
BACKGROUND Chagas disease remains a persistent vector-borne neglected tropical disease throughout the Americas and threatens both human and animal health. Diverse control methods have been used to target triatomine vector populations, with household insecticides being the most common. As an alternative to environmental sprays, host-targeted systemic insecticides (or endectocides) allow for application of chemicals to vertebrate hosts, resulting in toxic blood meals for arthropods (xenointoxication). In this study, we evaluated three systemic insecticide products for their ability to kill triatomines. METHODS Chickens were fed the insecticides orally, following which triatomines were allowed to feed on the treated chickens. The insecticide products tested included: Safe-Guard® Aquasol (fenbendazole), Ivomec® Pour-On (ivermectin) and Bravecto® (fluralaner). Triatoma gerstaeckeri nymphs were allowed to feed on insecticide-live birds at 0, 3, 7, 14, 28 and 56 days post-treatment. The survival and feeding status of the T. gerstaeckeri insects were recorded and analyzed using Kaplan-Meier curves and logistic regression. RESULTS Feeding on fluralaner-treated chickens resulted 50-100% mortality in T. gerstaeckeri over the first 14 days post-treatment but not later; in contrast, all insects that fed on fenbendazole- and ivermectin-treated chickens survived. Liquid chromatography tandem mass spectrometry (LC-QQQ) analysis, used to detect the concentration of fluralaner and fenbendazole in chicken plasma, revealed the presence of fluralaner in plasma at 3, 7, and 14 days post-treatment but not later, with the highest concentrations found at 3 and 7 days post-treatment. However, fenbendazole concentration was below the limit of detection at all time points. CONCLUSIONS Xenointoxication using fluralaner in poultry is a potential new tool for integrated vector control to reduce risk of Chagas disease.
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Affiliation(s)
- Cassandra Durden
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, USA
- Schubot Center for Avian Health, Department of Veterinary Pathobiology, Texas A&M University, College Station, USA
| | - Yuexun Tian
- Department of Entomology, Texas A&M University, College Station, USA
| | - Koyle Knape
- Department of Poultry Science, Texas A&M University, College Station, USA
| | - Cory Klemashevich
- Integrated Metabolomics Analysis Core, Texas A&M University, College Station, USA
| | - Keri N Norman
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, USA
| | - John B Carey
- Department of Poultry Science, Texas A&M University, College Station, USA
| | - Sarah A Hamer
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, USA
- Schubot Center for Avian Health, Department of Veterinary Pathobiology, Texas A&M University, College Station, USA
| | - Gabriel L Hamer
- Department of Entomology, Texas A&M University, College Station, USA.
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Alejandra A, Sol GM, Fabián EG, Paula MN, Esteban GR, Victoria CM. Marginal risk of domestic vector-borne Trypanosoma cruzi transmission after improved vector control of Triatoma infestans across a rural-to-urban gradient in the Argentine Chaco. Acta Trop 2023; 243:106933. [PMID: 37119837 DOI: 10.1016/j.actatropica.2023.106933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/24/2023] [Accepted: 04/26/2023] [Indexed: 05/01/2023]
Abstract
The interruption of domestic vector-borne transmission of Trypanosoma cruzi in the Americas remains one of the main goals of the World Health Organization 2021-2030 road map for neglected tropical diseases. We implemented a longitudinal intervention program over 2015-2022 to suppress (peri)domestic Triatoma infestans in the municipality of Avia Terai, Chaco Province, Argentina and found that house infestation (3851 houses inspected) and triatomine abundance decreased over the first 2 years post-intervention (YPI), and remained stable thereafter associated to moderate pyrethroid resistant foci. Here we assessed selected components of transmission risk after interventions across the rural-to-urban gradient. We used multistage random sampling to select a municipality-wide sample of T. infestans. We examined 356 insects collected in 87 houses for T. cruzi infection using kDNA-PCR and identified their bloodmeal sources using an indirect ELISA. The overall prevalence of T. cruzi infection post-intervention was 1.7% (95% CI 0.7-3.6). Few houses (5.7%) (95% CI 2.5-12.8) harbored infected triatomines across the gradient. Infected triatomines were found in 5 peri-urban or rural dwellings over 1-4 years post-intervention. No infected insect was found in the urban area. The human blood index decreased from 66.2 at baseline to 42.8 at 1YPI and then increased to 92.9 at 4-5 YPI in the few infested domiciles detected. The percentage of houses with human-fed bugs displayed a similar temporal trend. Our results indicate marginal risks of domestic vector-borne transmission across the district after implementation of the intervention program. Ensuring sustainable vector surveillance coupled with human etiological diagnosis and treatment in hiperendemic areas like the Gran Chaco region, is urgently needed. 252 words.
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Affiliation(s)
- Alvedro Alejandra
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Gaspe María Sol
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Enriquez Gustavo Fabián
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Macchiaverna Natalia Paula
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Gürtler Ricardo Esteban
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - Cardinal Marta Victoria
- Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Laboratorio de Eco-Epidemiología. Intendente Güiraldes 2160, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina.
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Martínez-Ibarra JA, Nogueda-Torres B, Montañez-Valdez OD, Michel-Parra JG. Influence of blood meal source on the biological parameters of Triatoma pallidipennis (Heteroptera: Reduviidae) from Mexico. MEDICAL AND VETERINARY ENTOMOLOGY 2023; 37:124-131. [PMID: 36315043 DOI: 10.1111/mve.12617] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 09/19/2022] [Indexed: 06/16/2023]
Abstract
Chagas disease is one of the most important vector-borne diseases in Latin America, including Mexico. Triatoma pallidipennis (Stål) (Hemiptera: Reduviidae) is a Mexican triatomine vector commonly associated with different hosts. The influence of six blood meals (rabbits, rats, mice, dogs, cats and chickens) on six biological parameters of the biology of T. pallidipennis was evaluated. A significant difference was found in the period of egg-to-adult development between the five mammalian feeds (mean 195 days) and the chicken feed (221 days). The probability of survival was significantly lower in the chicken cohort (0.285). The total number of blood meals to moult from the first instar to the adult stage was the highest in the chicken cohort (10-15). This cohort had the significantly highest rate of females at the end cycle. The mean number of eggs laid per female and the egg eclosion rate were similar among the six food sources. Most results seemed to be influenced by the higher nutritional quality of the mammalian blood compared to the bird's blood and the increased energy expenditure required for the digestion of bird blood. These results clearly show that T. pallidipennis, unlike other triatomine species, has a high reproductive capacity when feeding on different hosts.
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Affiliation(s)
- José Alejandro Martínez-Ibarra
- Departmento de Ciencas Naturales, Laboratorio de Entomología Médica, Ciudad Guzmán, Mexico
- Cuerpo Académico de Cuencas, Humedales y Sustentabilidad, Departamento de Ciencias de la Naturaleza, Centro Universitario del Sur, Universidad de Guadalajara, Ciudad Guzmán, Mexico
| | - Benjamín Nogueda-Torres
- Becario de COFAA, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Oziel Dante Montañez-Valdez
- Departmento de Ciencas Naturales, Laboratorio de Entomología Médica, Ciudad Guzmán, Mexico
- Cuerpo Académico de Cuencas, Humedales y Sustentabilidad, Departamento de Ciencias de la Naturaleza, Centro Universitario del Sur, Universidad de Guadalajara, Ciudad Guzmán, Mexico
| | - J Guadalupe Michel-Parra
- Cuerpo Académico de Cuencas, Humedales y Sustentabilidad, Departamento de Ciencias de la Naturaleza, Centro Universitario del Sur, Universidad de Guadalajara, Ciudad Guzmán, Mexico
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Freitas NEM, Habib FL, Santos EF, Silva ÂAO, Fontes ND, Leony LM, Sampaio DD, de Almeida MC, Dantas-Torres F, Santos FLN. Technological advances in the serological diagnosis of Chagas disease in dogs and cats: a systematic review. Parasit Vectors 2022; 15:343. [PMID: 36167575 PMCID: PMC9516836 DOI: 10.1186/s13071-022-05476-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/10/2022] [Indexed: 11/12/2022] Open
Abstract
Background Chagas disease (CD) is caused by Trypanosoma cruzi, which is transmitted mainly through the feces/urine of infected triatomine bugs. The acute phase lasts 2–3 months and is characterized by high parasitemia and nonspecific symptoms, whereas the lifelong chronic phase features symptoms affecting the heart and/or digestive tract occurring in 30–40% of infected individuals. As in humans, cardiac abnormalities are observed in T. cruzi-infected dogs and cats. We reviewed the technological advances in the serological diagnosis of CD in dogs and cats. Methods A review of the published literature during the last 54 years (1968–2022) on the epidemiology, clinical features, diagnosis, treatment and prevention of CD in dogs and cats was conducted. Results Using predefined eligibility criteria for a search of the published literature, we retrieved and screened 436 publications. Of these, 84 original studies were considered for inclusion in this review. Dogs and cats are considered as sentinels, potentially indicating an active T. cruzi transmission and thus the risk for human infection. Although dogs and cats are reputed to be important for maintaining the T. cruzi domestic transmission cycle, there are no commercial tests to detect past or active infections in these animals. Most published research on CD in dogs and cats have used in-house serological tests prepared with native and/or full-length recombinant antigens, resulting in variable diagnostic performance. In recent years, chimeric antigens have been used to improve the diagnosis of chronic CD in humans with encouraging results. Some of them have high performance values (> 95%) and extremely low cross-reactivity rates for Leishmania spp., especially the antigens IBMP-8.1 to IBMP-8.4. The diagnostic performance of IBMP antigens was also investigated in dogs, showing high diagnostic performance with negligible cross-reactivity with anti-Leishmania infantum antibodies. Conclusions The development of a commercial immunodiagnostic tool to identify past or active T. cruzi infections in dogs and cats is urgently needed. The use of chimeric recombinant T. cruzi antigens may help to fill this gap and is discussed in this review. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05476-4.
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Affiliation(s)
- Natália Erdens Maron Freitas
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Fernanda Lopes Habib
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Emily Ferreira Santos
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Ângelo Antônio Oliveira Silva
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Natália Dantas Fontes
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Leonardo Maia Leony
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil
| | - Daniel Dias Sampaio
- Brazil's Family Health Strategy, Municipal Health Department, Tremedal City Hall, Bahia, Tremedal, Brazil
| | - Marcio Cerqueira de Almeida
- Pathology and Molecular Biology Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Salvador, Bahia, Brazil
| | - Filipe Dantas-Torres
- Laboratory of Immunoparasitology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
| | - Fred Luciano Neves Santos
- Advanced Health Public Laboratory, Gonçalo Moniz Institute, Oswaldo Cruz Foundation, Waldemar Falcão Street, 121, Candeal, Bahia, Salvador, 40296-710, Brazil. .,Integrated Translational Program in Chagas Disease From Fiocruz (Fio-Chagas), Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
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Chen L, Chen S, Kong P, Zhou L. Host competence, interspecific competition and vector preference interact to determine the vector-borne infection ecology. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.993844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Understanding how ecological interactions affect vector-borne disease dynamics is crucial in the context of rapid biodiversity loss and increased emerging vector-borne diseases. Although there have been many studies on the impact of interspecific competition and host competence on disease dynamics, few of them have addressed the case of a vector-borne disease. Using a simple compartment model with two competing host species and one vector, we investigated the combined effects of vector preference, host competence, and interspecific competition on disease risk in a vector-borne system. Our research demonstrated that disease transmission dynamics in multi-host communities are more complex than anticipated. Vector preference and differences in host competence shifted the direction of the effect of competition on community disease risk, yet interspecific competition quantitatively but not qualitatively changed the effect of vector preference on disease risk. Our work also identified the conditions of the dilution effect and amplification effect in frequency-dependent transmission mode, and we discovered that adding vector preference and interspecific competition into a simple two-host-one-vector model altered the outcomes of how increasing species richness affects disease risk. Our work explains some of the variation in outcomes in previous empirical and theoretical studies on the dilution effect.
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Gürtler RE, Laiño MA, Alvedro A, Enriquez GF, Macchiaverna NP, Gaspe MS, Cardinal MV. Treatment of dogs with fluralaner reduced pyrethroid-resistant Triatoma infestans abundance, Trypanosoma cruzi infection and human-triatomine contact in the Argentine Chaco. Parasit Vectors 2022; 15:257. [PMID: 35831874 PMCID: PMC9277862 DOI: 10.1186/s13071-022-05343-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 05/23/2022] [Indexed: 11/16/2022] Open
Abstract
Background Triatomine elimination efforts and the interruption of domestic transmission of Trypanosoma cruzi are hampered by pyrethroid resistance. Fluralaner, a long-lasting ectoparasiticide administered to dogs, substantially reduced site infestation and abundance of pyrethroid-resistant Triatoma infestans Klug (Heteroptera: Reduviidae) in an ongoing 10-month trial in Castelli (Chaco Province, Argentina). We assessed the effects of fluralaner on vector infection with T. cruzi and blood meal sources stratified by ecotope and quantified its medium-term effects on site infestation and triatomine abundance. Methods We conducted a placebo-controlled, before-and-after efficacy trial of fluralaner in 28 infested sites over a 22-month period. All dogs received either an oral dose of fluralaner (treated group) or placebo (control group) at 0 month post-treatment [MPT]. Placebo-treated dogs were rescue-treated with fluralaner at 1 MPT, as were all eligible dogs at 7 MPT. Site-level infestation and abundance were periodically assessed by timed manual searches with a dislodging aerosol. Vector infection was mainly determined by kDNA-PCR and blood meal sources were determined by enzyme-linked immunosorbent assay. Results In fluralaner-treated households, site infestation dropped from 100% at 0 MPT to 18–19% over the period 6–22 MPT while mean abundance plummeted from 5.5 to 0.6 triatomines per unit effort. In control households, infestation dropped similarly post-treatment. The overall prevalence of T. cruzi infection steadily decreased from 13.8% at 0–1 MPT (baseline) to 6.4% and subsequently 2.3% thereafter, while in domiciles, kitchens and storerooms it dropped from 17.4% to 4.7% and subsequently 3.3% thereafter. Most infected triatomines occurred in domiciles and had fed on humans. Infected-bug abundance plummeted after fluralaner treatment and remained marginal or nil thereafter. The human blood index of triatomines collected in domiciles, kitchens and storerooms highly significantly fell from 42.9% at baseline to 5.3–9.1% over the period 6–10 MPT, increasing to 36.8% at 22 MPT. Dog blood meals occurred before fluralaner administration only. The cat blood index increased from 9.9% at baseline to 57.9–72.7% over the period 6–10 MPT and dropped to 5.3% at 22 MPT, whereas chicken blood meals rose from 39.6% to 63.2–88.6%. Conclusion Fluralaner severely impacted infestation- and transmission-related indices over nearly 2 years, causing evident effects at 1 MPT, and deserves larger efficacy trials. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05343-2.
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Affiliation(s)
- Ricardo Esteban Gürtler
- Laboratory of Eco-Epidemiology, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina. .,Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina.
| | - Mariano Alberto Laiño
- Laboratory of Eco-Epidemiology, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina.,Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
| | - Alejandra Alvedro
- Laboratory of Eco-Epidemiology, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina.,Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
| | - Gustavo Fabián Enriquez
- Laboratory of Eco-Epidemiology, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina.,Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
| | - Natalia Paula Macchiaverna
- Laboratory of Eco-Epidemiology, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina.,Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
| | - María Sol Gaspe
- Laboratory of Eco-Epidemiology, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina.,Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
| | - Marta Victoria Cardinal
- Laboratory of Eco-Epidemiology, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina. .,Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina.
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10
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Chen L, Wu X, Xu Y, Rong L. Modelling the dynamics of Trypanosoma rangeli and triatomine bug with logistic growth of vector and systemic transmission. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2022; 19:8452-8478. [PMID: 35801473 DOI: 10.3934/mbe.2022393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In this paper, an insect-parasite-host model with logistic growth of triatomine bugs is formulated to study the transmission between hosts and vectors of the Chagas disease by using dynamical system approach. We derive the basic reproduction numbers for triatomine bugs and Trypanosoma rangeli as two thresholds. The local and global stability of the vector-free equilibrium, parasite-free equilibrium and parasite-positive equilibrium is investigated through the derived two thresholds. Forward bifurcation, saddle-node bifurcation and Hopf bifurcation are proved analytically and illustrated numerically. We show that the model can lose the stability of the vector-free equilibrium and exhibit a supercritical Hopf bifurcation, indicating the occurrence of a stable limit cycle. We also find it unlikely to have backward bifurcation and Bogdanov-Takens bifurcation of the parasite-positive equilibrium. However, the sustained oscillations of infected vector population suggest that Trypanosoma rangeli will persist in all the populations, posing a significant challenge for the prevention and control of Chagas disease.
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Affiliation(s)
- Lin Chen
- Department of Mathematics, Hangzhou Normal University, Hangzhou 311121, China
| | - Xiaotian Wu
- College of Arts and Sciences, Shanghai Maritime University, Shanghai 201306, China
| | - Yancong Xu
- Department of Mathematics, Hangzhou Normal University, Hangzhou 311121, China
| | - Libin Rong
- Department of Mathematics, University of Florida, Gainesville 32611, USA
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11
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Laiño MA, Cardinal MV, Gaspe MS, Enriquez GF, Alvedro A, Macchiaverna NP, Gürtler RE. Control of pyrethroid-resistant populations of Triatoma infestans, the main vector of Trypanosoma cruzi, by treating dogs with fluralaner in the Argentine Chaco. MEDICAL AND VETERINARY ENTOMOLOGY 2022; 36:149-158. [PMID: 34866216 DOI: 10.1111/mve.12561] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 11/12/2021] [Accepted: 11/24/2021] [Indexed: 06/13/2023]
Abstract
We assessed whether fluralaner administered to outbred healthy dogs reduced or supressed site infestation and abundance of pyrethroid-resistant populations of Triatoma infestans Klug (Heteroptera: Reduviidae). We conducted a placebo-controlled before-and-after efficacy trial in 28 infested sites in Castelli (Argentine Chaco) over 10 months. All 72 dogs initially present received either an oral dose of fluralaner (treated group) or placebo (control group) at month 0 posttreatment (MPT). Preliminary results justified treating all 38 control-house dogs with fluralaner 1 month later, and 71 of 78 existing dogs at 7 MPT. Site-level infestation and triatomine abundance were evaluated using timed manual searches with a dislodging aerosol. In the fluralaner-treated group, infestation dropped significantly from 100% at baseline to 19% over 6-10 MPT whereas mean abundance fell highly significantly from 5.5 to 0.8-0.9 triatomines per unit effort. In the placebo group, site infestation and mean abundance remained stable between 0 and 1 MPT, and strongly declined after fluralaner administration from 13.0-14.7 - triatomines at 0-1 MPT to 4.0-4.2 over 6-10 MPT. Only one of 81 noninfested sites before fluralaner treatment became infested subsequently. Fluralaner significantly reduced the site-level infestation and abundance of pyrethroid-resistant T. infestans and should be tested more widely in Phase III efficacy trials.
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Affiliation(s)
- Mariano Alberto Laiño
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
| | - Marta Victoria Cardinal
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
| | - María Sol Gaspe
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
| | - Gustavo Fabián Enriquez
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
| | - Alejandra Alvedro
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
| | - Natalia Paula Macchiaverna
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
| | - Ricardo E Gürtler
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Ciudad Universitaria, Buenos Aires, Argentina
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12
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Queiroga TBD, Gomez LCP, de Sena ER, Dos Santos WV, Ferreira HRP, de Araújo-Neto VT, Barbosa-Silva AN, Brito CRDN, Lima RKDR, Fagundes-Neto JC, Galvão LMDC, de Medeiros HR, da Câmara ACJ, Nascimento MSL, Gama RA, Guedes PMM. Insecticidal efficacy of fluralaner (Bravecto ®) against Triatoma brasiliensis, a major vector of Trypanosoma cruzi in Brazil. Parasit Vectors 2021; 14:456. [PMID: 34488865 PMCID: PMC8422713 DOI: 10.1186/s13071-021-04978-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 08/24/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Triatomines are responsible for the vector transmission of the protozoan parasite Trypanosoma cruzi, which causes Chagas disease. Triatoma brasiliensis is the main vector of the parasite in Brazil, and dogs are an important reservoir of the parasite. The aim of this study was to evaluate the insecticidal effect of fluralaner (Bravecto®) on T. brasiliensis after a blood meal in treated dogs. METHODS Healthy mongrel dogs (n = 8) were recruited from the Zoonoses Control Center (ZCC) in the city of Natal, Rio Grande do Norte, Brazil, and randomized into two groups, a fluralaner (Bravecto®)-treated group (n = 4) and a control group (n = 4). Colony-reared third-, fourth- and fifth-instar nymphs of T. brasiliensis nymphs (n = 10) were allowed to feed on dogs from both groups for 30-40 min, once monthly, for up to 12 months. Bug mortality was observed up to 5 days after each blood meal. RESULTS Mortality in triatomines which had a blood meal on fluralaner (Bravecto®)-treated dogs was 100% for up to 7 months after treatment, with mortality decreasing to 66.4% after 8 months, 57% after 9 months, 35% after 10 months, 10% after 11 months and 0% after 12 months. The mortality of triatomines that fed on non-treated control dogs was always ≤ 2.5%. CONCLUSIONS Our results suggest that fluralaner (Bravecto®) treatment of dogs induces long-term mortality of T. brasiliensis after the blood meal. This is a potential approach to be used to control vector transmission of T. cruzi, the etiological agent of Chagas disease, especially in endemic areas.
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Affiliation(s)
| | | | - Eduardo Rodrigues de Sena
- Graduate Program in Parasitary Biology, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Wilo Victor Dos Santos
- Graduate Program in Parasitary Biology, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | | | - Vicente Toscano de Araújo-Neto
- Graduate Program in Pharmaceutical Sciences, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Andressa Noronha Barbosa-Silva
- Graduate Program in Pharmaceutical Sciences, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Carlos Ramon do Nascimento Brito
- Department of Clinical and Toxicological Analyses, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | | | | | - Lúcia Maria da Cunha Galvão
- Department of Clinical and Toxicological Analyses, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Henrique Rocha de Medeiros
- Agricultural School of Jundiaí, Federal University of Rio Grande Do Norte, Macaíba, Rio Grande Do Norte, Brazil
| | - Antônia Cláudia Jácome da Câmara
- Department of Clinical and Toxicological Analyses, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Manuela Sales Lima Nascimento
- Department of Microbiology and Parasitology, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Renata Antonaci Gama
- Department of Microbiology and Parasitology, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil
| | - Paulo Marcos Matta Guedes
- Department of Microbiology and Parasitology, Federal University of Rio Grande Do Norte, Natal, Rio Grande Do Norte, Brazil.
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13
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Marliére NP, Lorenzo MG, Guarneri AA. Trypanosoma cruzi-infected Rhodnius prolixus endure increased predation facilitating parasite transmission to mammal hosts. PLoS Negl Trop Dis 2021; 15:e0009570. [PMID: 34197458 PMCID: PMC8279422 DOI: 10.1371/journal.pntd.0009570] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 07/14/2021] [Accepted: 06/16/2021] [Indexed: 11/19/2022] Open
Abstract
Triatomine bugs aggregate with conspecifics inside shelters during daylight hours. At dusk, they leave their refuges searching for hosts on which to blood feed. After finding a host, triatomines face the threat of being killed, because hosts often prey on them. As it is known that many parasites induce the predation of intermediate hosts to promote transmission, and that ingestion of Trypanosoma cruzi-infected bugs represents a very effective means for mammal infection, we hypothesized that trypanosomes induce infected bugs to take increased risk, and, as a consequence, be predated when approaching a host. Therefore, we evaluated whether the predation risk and predation rates endured by Rhodnius prolixus increase when infected with T. cruzi. Assays were performed in square glass arenas offering one central refuge to infected and uninfected 5th instar nymphs. A caged mouse was introduced in each arena after a three-day acclimation interval to activate sheltered insects and induce them to approach it. As hypothesized, a significantly higher proportion of infected insects was predated when compared with uninfected ones (36% and 19%, respectively). Indeed, T. cruzi-infected bugs took higher risk (Approximation Index = 0.642) when compared with healthy ones (Approximation Index = 0.302) and remained outside the shelters when the host was removed from the arena. Our results show that infection by T. cruzi induces bugs to assume higher risk and endure higher predation rates. We reveal a hitherto unknown trypanosome-vector interaction process that increases infected bug predation, promoting increased rates of robust oral transmission. The significant consequences of the mechanism revealed here make it a fundamental component for the resilient maintenance of sylvatic, peridomestic and domestic cycles.
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Affiliation(s)
- Newmar Pinto Marliére
- Vector Behavior and Pathogen Interaction Group, Instituto René Rachou, Fundação Oswaldo Cruz-FIOCRUZ, Belo Horizonte, Brazil
| | - Marcelo Gustavo Lorenzo
- Vector Behavior and Pathogen Interaction Group, Instituto René Rachou, Fundação Oswaldo Cruz-FIOCRUZ, Belo Horizonte, Brazil
| | - Alessandra Aparecida Guarneri
- Vector Behavior and Pathogen Interaction Group, Instituto René Rachou, Fundação Oswaldo Cruz-FIOCRUZ, Belo Horizonte, Brazil
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14
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Orientation of Belminus triatomines to cockroaches and cockroaches’ fecal volatiles: an ethological approach. Acta Ethol 2021. [DOI: 10.1007/s10211-021-00361-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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Alvedro A, Gaspe MS, Milbourn H, Macchiaverna NP, Laiño MA, Enriquez GF, Gürtler RE, Cardinal MV. Trypanosoma cruzi infection in Triatoma infestans and high levels of human-vector contact across a rural-to-urban gradient in the Argentine Chaco. Parasit Vectors 2021; 14:35. [PMID: 33422133 PMCID: PMC7796388 DOI: 10.1186/s13071-020-04534-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 12/10/2020] [Indexed: 11/24/2022] Open
Abstract
Background Peri-urban and urban settings have recently gained more prominence in studies on vector-borne transmission of Trypanosoma cruzi due to sustained rural-to-urban migrations and reports of urban infestations with triatomines. Prompted by the finding of Triatoma infestans across the rural-to-urban gradient in Avia Terai, an endemic municipality of the Argentine Chaco, we assessed selected components of domestic transmission risk in order to determine its variation across the gradient. Methods A baseline vector survey was conducted between October 2015 and March 2016, following which we used multistage random sampling to select a representative sample of T. infestans at the municipal level. We assessed T. cruzi infection and blood-feeding sources of 561 insects collected from 109 houses using kinetoplast DNA-PCR assays and direct enzyme-linked immunosorbent assays, respectively. We stratified triatomines according to their collection site (domestic or peridomestic), and we further categorized peridomestic sites in ecotopes of low- or high-risk for T. cruzi infection. Results The overall adjusted prevalence of T. cruzi-infected T. infestans was 1.8% (95% confidence interval [CI] 1.3–2.3) and did not differ between peri-urban (1.7%) and rural (2.2%) environments. No infection was detected in bugs captured in the urban setting; rather, infected triatomines were mainly collected in rural and peri-urban domiciles, occurring in 8% of T. infestans-infested houses. The main blood-feeding sources of domestic and peridomestic triatomines across the gradient were humans and chickens, respectively. The proportion of triatomines that had fed on humans did not differ between peri-urban (62.5%) and rural (65.7%) domiciles, peaking in the few domestic triatomines collected in urban houses and decreasing significantly with an increasing proportion of chicken- and dog- or cat-fed bugs. The relative odds ratio (OR) of having a T. cruzi infection was nearly threefold higher in bugs having a blood meal on humans (OR 3.15), dogs (OR 2.80) or cats (OR: 4.02) in a Firth-penalized multiple logistic model. Conclusions Trypanosoma cruzi transmission was likely occurring both in peri-urban and rural houses of Avia Terai. Widespread infestation in a third of urban blocks combined with high levels of human–triatomine contact in the few infested domiciles implies a threat to urban inhabitants. Vector control strategies and surveillance originally conceived for rural areas should be tailored to peri-urban and urban settings in order to achieve sustainable interruption of domestic transmission in the Chaco region.![]()
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Affiliation(s)
- Alejandra Alvedro
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Sol Gaspe
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Natalia Paula Macchiaverna
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Mariano Alberto Laiño
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gustavo Fabián Enriquez
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ricardo Esteban Gürtler
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Marta Victoria Cardinal
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina. .,Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Buenos Aires, Argentina.
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16
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Triatomine Feeding Profiles and Trypanosoma cruzi Infection, Implications in Domestic and Sylvatic Transmission Cycles in Ecuador. Pathogens 2021; 10:pathogens10010042. [PMID: 33430264 PMCID: PMC7825724 DOI: 10.3390/pathogens10010042] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/22/2020] [Accepted: 01/05/2021] [Indexed: 11/17/2022] Open
Abstract
Understanding the blood meal patterns of insects that are vectors of diseases is fundamental in unveiling transmission dynamics and developing strategies to impede or decrease human–vector contact. Chagas disease has a complex transmission cycle that implies interactions between vectors, parasites and vertebrate hosts. In Ecuador, limited data on human infection are available; however, the presence of active transmission in endemic areas has been demonstrated. The aim of this study was to determine the diversity of hosts that serve as sources of blood for triatomines in domestic, peridomestic and sylvatic transmission cycles, in two endemic areas of Ecuador (central coastal and southern highland regions). Using conserved primers and DNA extracted from 507 intestinal content samples from five species of triatomines (60 Panstrongylus chinai, 17 Panstrongylus howardi, 1 Panstrongylus rufotuberculatus, 427 Rhodnius ecuadoriensis and 2 Triatoma carrioni) collected from 2006 to 2013, we amplified fragments of the cytb mitochondrial gene. After sequencing, blood meal sources were identified in 416 individuals (146 from central coastal and 270 from southern highland regions), achieving ≥ 95% identity with GenBank sequences (NCBI-BLAST tool). The results showed that humans are the main source of food for triatomines, indicating that human–vector contact is more frequent than previously thought. Although other groups of mammals, such as rodents, are also an available source of blood, birds (particularly chickens) might have a predominant role in the maintenance of triatomines in these areas. However, the diversity of sources of blood found might indicate a preference driven by triatomine species. Moreover, the presence of more than one source of blood in triatomines collected in the same place indicated that dispersal of vectors occurs regardless the availability of food. Dispersal capacity of triatomines needs to be evaluated to propose an effective strategy that limits human–vector contact and, in consequence, to decrease the risk of T. cruzi transmission.
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17
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Ordóñez-Krasnowski PC, Lanati LA, Gaspe MS, Cardinal MV, Ceballos LA, Gürtler RE. Domestic host availability modifies human-triatomine contact and host shifts of the Chagas disease vector Triatoma infestans in the humid Argentine Chaco. MEDICAL AND VETERINARY ENTOMOLOGY 2020; 34:459-469. [PMID: 32700806 DOI: 10.1111/mve.12463] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/18/2020] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
Domestic animals may affect human-vector contact and parasite transmission rates. We investigated the relationships between host-feeding choices, site-specific host availability, bug nutritional status, stage and abundance of Triatoma infestans Klug (Heteroptera: Reduviidae) in rural houses of Pampa del Indio during spring. We identified the bloodmeal sources of 865 triatomines collected in 70 sites from four main ecotopes. The main sources in domiciles were human (65.9%), chicken (23.4%) and dog (22.4%); dog (64.4%, 35.3%) and chicken (33.1%, 75.4%) in kitchens and storerooms, respectively; and chicken (94.7%) in chicken coops. Using random-intercept logistic regression clustered by domicile, the fraction of human-fed triatomines strongly decreased with increasing proportions of chicken- and dog-fed bugs, dropping from 96.4% when no chicken or dog slept indoors at night to 59.4% when both did. The fraction of dog-fed bugs significantly decreased with increasing human and chicken blood indices, and marginally increased with an indoor-resting dog. Mixed blood meals occurred 3.62 times more often when a chicken or a dog slept indoors. Host blood source did not affect mean body weight adjusted for body length and bug stage. Indoor-resting chickens and dogs greatly modified human-bug contact rates, and may be targeted with long-lasting systemic insecticides to suppress infestation.
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Affiliation(s)
- P C Ordóñez-Krasnowski
- Laboratorio de Eco-Epidemiología, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Buenos Aires, Argentina
| | - L A Lanati
- Instituto Nacional de Diagnóstico e Investigación en la Enfermedad de Chagas Dr Mario Fatala Chaben, Buenos Aires, Argentina
| | - M S Gaspe
- Laboratorio de Eco-Epidemiología, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, Buenos Aires, Argentina
| | - M V Cardinal
- Laboratorio de Eco-Epidemiología, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, Buenos Aires, Argentina
| | - L A Ceballos
- Laboratorio de Eco-Epidemiología, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Buenos Aires, Argentina
- Experimental Zooprophylactic Institute of Piedmont, Liguria and Aosta Valley, Turin, Italy
| | - R E Gürtler
- Laboratorio de Eco-Epidemiología, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires. Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, Buenos Aires, Argentina
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18
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Elucidating the Mechanism of Trypanosoma cruzi Acquisition by Triatomine Insects: Evidence from a Large Field Survey of Triatoma infestans. Trop Med Infect Dis 2020; 5:tropicalmed5020087. [PMID: 32492771 PMCID: PMC7344819 DOI: 10.3390/tropicalmed5020087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/21/2020] [Accepted: 05/26/2020] [Indexed: 12/01/2022] Open
Abstract
Blood-sucking triatomine bugs transmit the protozoan parasite Trypanosoma cruzi, the etiologic agent of Chagas disease. We measured the prevalence of T. cruzi infection in 58,519 Triatoma infestans captured in residences in and near Arequipa, Peru. Among bugs from infected colonies, T. cruzi prevalence increased with stage from 12% in second instars to 36% in adults. Regression models demonstrated that the probability of parasite acquisition was roughly the same for each developmental stage. Prevalence increased by 5.9% with each additional stage. We postulate that the probability of acquiring the parasite may be related to the number of feeding events. Transmission of the parasite does not appear to be correlated with the amount of blood ingested during feeding. Similarly, other hypothesized transmission routes such as coprophagy fail to explain the observed pattern of prevalence. Our results could have implications for the feasibility of late-acting control strategies that preferentially kill older insects.
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A study of the effects of imidacloprid under laboratory and field conditions on nymphs of Triatoma infestans (Hemiptera: Reduviidae). Vet Parasitol 2020; 280:109092. [DOI: 10.1016/j.vetpar.2020.109092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 11/18/2022]
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20
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Botto-Mahan C, Bacigalupo A, Correa JP, Fontúrbel FE, Cattan PE, Solari A. Prevalence, infected density or individual probability of infection? Assessing vector infection risk in the wild transmission of Chagas disease. Proc Biol Sci 2020; 287:20193018. [PMID: 32156212 DOI: 10.1098/rspb.2019.3018] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Vector-borne infectious disease dynamics result mainly from the intertwined effect of the diversity, abundance, and behaviour of hosts and vectors. Most studies, however, have analysed the relationship between host-species diversity and infection risk, focusing on vector population instead of individuals, probably dismissing the level at which the transmission process occurs. In this paper, we examine the importance of the host community in accounting for infection risk, at both population and individual levels, using the wild transmission of the protozoan that causes Chagas disease as a vector-borne disease model. Chagas disease is caused by Trypanosoma cruzi, transmitted by triatomine insects to mammals. We assessed if T. cruzi infection in vectors is explained by small mammal diversity and their densities (total and infected), when infection risk is measured at population level as infection prevalence (under a frequency-dependent transmission approach) and as density of infected vectors (density-dependent transmission approach), and when measured at individual level as vector infection probability. We analysed the infection status of 1974 vectors and co-occurring small mammal hosts in a semiarid-Mediterranean ecosystem. Results revealed that regardless of the level of analysis, only one host rodent species accounted for most variation in vector infection risk, suggesting a key role in the transmission cycle. To determine the factors explaining vector-borne disease dynamics, infection risk should be assessed at different scales, reflecting the factors meaningful from the vector's perspective and considering vector class-specific features.
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Affiliation(s)
- Carezza Botto-Mahan
- Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, P.O. Box 653, Santiago, Chile
| | - Antonella Bacigalupo
- Departamento de Ciencias Biológicas Animales, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile.,Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Juana P Correa
- Departamento de Ciencias Biológicas Animales, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile.,Facultad de Medicina Veterinaria, Universidad San Sebastián, Concepción, Chile
| | - Francisco E Fontúrbel
- Instituto de Biología, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Pedro E Cattan
- Departamento de Ciencias Biológicas Animales, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile, Santiago, Chile
| | - Aldo Solari
- Programa Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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21
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Modelling triatomine bug population and Trypanosoma rangeli transmission dynamics: Co-feeding, pathogenic effect and linkage with chagas disease. Math Biosci 2020; 324:108326. [PMID: 32092467 DOI: 10.1016/j.mbs.2020.108326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 02/18/2020] [Accepted: 02/18/2020] [Indexed: 11/21/2022]
Abstract
Trypanosoma rangeli (T. rangeli), a parasite, is not pathogenic to human but pathogenic to some vector species to induce the behavior changes of infected vectors and subsequently impact the transmission dynamics of other diseases such as Chagas disease which shares the same vector species. Here we develop a mathematical model and conduct qualitative analysis for the transmission dynamics of T. rangeli. We incorporate both systemic and co-feeding transmission routes, and account for the pathogenic effect using infection-induced fecundity and fertility change of the triatomine bugs. We derive two thresholds Rv (the triatomine bug basic reproduction number) and R0 (the T. rangeli basic reproduction number) to delineate the dynamical behaviors of the ecological and epidemiological systems. We show that when Rv>1 and R0>1, a unique parasite positive equilibrium E* appears. We find that E* can be unstable and periodic oscillations can be observed where the pathogenic effect plays a significant role. Implications of the qualitative analysis and numerical simulations suggest the need of an integrative vector-borne disease prevention and control strategy when multiple vector-borne diseases are transmitted by the same set of vector species.
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22
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Fraenkel S, Salvioni OD, de Arias AR, Arze VP, Rolón M, Ramirez N, Vega Gómez C. Identification of bloodmeal sources of triatomines captured in the Paraguayan Chaco region of South America by means of molecular biology analysis. Pathog Glob Health 2020; 114:30-39. [PMID: 31973639 DOI: 10.1080/20477724.2020.1716558] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The Paraguayan Chaco is an isolated environment with its own unique ecosystem. In this region, Chagas disease remains a health problem. Chagas disease is caused by the parasite Trypanosoma cruzi, and it is primarily transmitted by triatomines. In order to identify the blood meal sources of triatomines, specimens of the vector were collected in domestic and peridomestic areas and the PCR-RFLP method was implemented. Cytochrome b was amplified from the samples and later subjected to digestion with two restriction enzymes: Hae III and Xho I.It was possible to generate distinct restriction patterns on the amplified material to identify several blood meal sources for the vectors. We employed the blood from several species as positive controls: human, chicken, canine, feline, and armadillo blood. However, we identified only 3 sources for the blood meals of the insect vectors: human, chicken and canine blood. In total, 76 triatomines were captured. T. cruzi was not found in any of them. In 61% of the captured specimens, the blood meal sources for the vectors could be identified. In 30% of these cases, the presence of DNA from more than one vertebrate was detected in the same triatomine. The most common blood meal source found was chicken blood. The presence of human and chicken blood in triatomines captured in domestic and peridomestic areas strongly suggests that the parasite can freely move amongst both areas regardless of food availability. Free vector movement in these areas constitutes an epidemiological threat for the inhabitants of the community under study.
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Affiliation(s)
- Stefanía Fraenkel
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Oscar Daniel Salvioni
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Antonieta Rojas de Arias
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Verónica Paola Arze
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Miriam Rolón
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Natalia Ramirez
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
| | - Celeste Vega Gómez
- Laboratorio de Biología Molecular, Centro para el Desarrollo de la Investigación Científica, Asunción, Paraguay
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23
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Flores-Ferrer A, Waleckx E, Rascalou G, Dumonteil E, Gourbière S. Trypanosoma cruzi transmission dynamics in a synanthropic and domesticated host community. PLoS Negl Trop Dis 2019; 13:e0007902. [PMID: 31834879 PMCID: PMC6934322 DOI: 10.1371/journal.pntd.0007902] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 12/27/2019] [Accepted: 11/04/2019] [Indexed: 12/26/2022] Open
Abstract
Trypanosoma cruzi is the causative agent of Chagas disease, a Neglected Tropical Disease affecting 8 million people in the Americas. Triatomine hematophagous vectors feed on a high diversity of vertebrate species that can be reservoirs or dead-end hosts, such as avian species refractory to T. cruzi. To understand its transmission dynamics in synanthropic and domesticated species living within villages is essential to quantify disease risk and assess the potential of zooprophylaxis. We developed a SI model of T. cruzi transmission in a multi-host community where vector reproduction and parasite transmission depend on a triatomine blood-feeding rate accounting for vector host preferences and interference while feeding. The model was parameterized to describe T. cruzi transmission in villages of the Yucatan peninsula, Mexico, using the information about Triatoma dimidiata vectors and host populations accumulated over the past 15 years. Extensive analyses of the model showed that dogs are key reservoirs and contributors to human infection, as compared to synanthropic rodents and cats, while chickens or other domesticated avian hosts dilute T. cruzi transmission despite increasing vector abundance. In this context, reducing the number of dogs or increasing avian hosts abundance decreases incidence in humans by up to 56% and 39%, respectively, while combining such changes reduces incidence by 71%. Although such effects are only reached over >10-years periods, they represent important considerations to be included in the design of cost-effective Integrated Vector Management. The concomitant reduction in T. cruzi vector prevalence estimated by simulating these zooprophylactic interventions could indeed complement the removal of colonies from the peridomiciles or the use of insect screens that lower vector indoor abundance by ~60% and ~80%. These new findings reinforce the idea that education and community empowerment to reduce basic risk factors is a cornerstone to reach and sustain the key objective of interrupting Chagas disease intra-domiciliary transmission.
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Affiliation(s)
- Alheli Flores-Ferrer
- UMR5096 ‘Laboratoire Génome et Développement des Plantes’, Université de Perpignan Via Domitia, Perpignan, France
| | - Etienne Waleckx
- Institut de Recherche pour le Développement, UMR INTERTRYP IRD, CIRAD, Université de Montpellier, Montpellier, France
- Laboratorio de Parasitología, Centro de Investigaciones Regionales ‘Dr. Hideyo Noguchi’, Universidad Autónoma deYucatán, Mérida, Yucatán, México
| | - Guilhem Rascalou
- UMR5096 ‘Laboratoire Génome et Développement des Plantes’, Université de Perpignan Via Domitia, Perpignan, France
| | - Eric Dumonteil
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, and Vector-Borne and Infectious Disease Research Center, Tulane University, New Orleans, Louisiana, United States of America
| | - Sébastien Gourbière
- UMR5096 ‘Laboratoire Génome et Développement des Plantes’, Université de Perpignan Via Domitia, Perpignan, France
- Centre for the Study of Evolution, School of Life Sciences, University of Sussex, Brighton, United Kingdom
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24
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Ucan-Mézquita A, Jimenez-Coello M, Guzmán-Marín E, Gutierrez-Blanco E, Chan-Pérez JI, Travi BL, Hernandez-Cortazar I, Ortega-Pacheco A. Efficacy of a topical combination of fipronil-permethrin against Rhodnius prolixus on dogs. Vet Parasitol 2019; 276:108978. [PMID: 31765865 DOI: 10.1016/j.vetpar.2019.108978] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/05/2019] [Accepted: 11/11/2019] [Indexed: 02/02/2023]
Abstract
A controlled clinical trial was carried out to assess the mortality and repellency of a new topical combination of fipronil-permethrin (Effitix® Virbac, Mexico) against Rhodnius prolixus in dogs. Ten medium-size dogs (10-15 kg) with short hair were used. The dogs were exposed to 8 adult triatomines once weekly for 7 weeks. On the control day (D0), the dogs were exposed to the insects without treatment. On D7, the dogs were immediately treated with a spot-on 2.2 ml pipette containing 134 mg of fipronil and 1200 mg permethrin after exposure to the insects. The dose was repeated after 4 weeks following the manufacturer's instructions. Repellency at D0 was, 0 % and the insects had a high blood content. After 12 h post-contact, repellency was 86.3 % and slowly decrease though D21 and D28. On D7, none of the insects survived after 3 h of feeding on the treated dogs. On D14, D35 and D42, all insects died within 12 h post-feeding, whereas no mortality was observed in the control D0 (P < 0.05). The results of this study indicated that administration of the product following the manufacturer's instructions was efficacious at inducing rapid mortality of R. prolixus and therefore could be useful to prevent the transmission of American trypanosomiasis in dogs.
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Affiliation(s)
- A Ucan-Mézquita
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Km 15.5 Carr. Merida-Xmatkuil, AP 4-116, Merida, Yucatan, Mexico
| | - M Jimenez-Coello
- Centro de Investigaciones Regionales "Dr. Hideyo Noguchi" Av. Itzaes Centro, Mérida, Yucatán, Mexico
| | - E Guzmán-Marín
- Centro de Investigaciones Regionales "Dr. Hideyo Noguchi" Av. Itzaes Centro, Mérida, Yucatán, Mexico
| | - E Gutierrez-Blanco
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Km 15.5 Carr. Merida-Xmatkuil, AP 4-116, Merida, Yucatan, Mexico
| | - J I Chan-Pérez
- Centro de Investigaciones Regionales "Dr. Hideyo Noguchi" Av. Itzaes Centro, Mérida, Yucatán, Mexico
| | - B L Travi
- University of Texas Medical Branch, Department of Internal Medicine - Division of Infectious Diseases, Galveston, TX, USA
| | - I Hernandez-Cortazar
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Km 15.5 Carr. Merida-Xmatkuil, AP 4-116, Merida, Yucatan, Mexico; Centro de Investigaciones Regionales "Dr. Hideyo Noguchi" Av. Itzaes Centro, Mérida, Yucatán, Mexico; University of Texas Medical Branch, Department of Internal Medicine - Division of Infectious Diseases, Galveston, TX, USA
| | - A Ortega-Pacheco
- Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Km 15.5 Carr. Merida-Xmatkuil, AP 4-116, Merida, Yucatan, Mexico.
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25
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Villalobos G, Nava-Bolaños A, De Fuentes-Vicente JA, Téllez-Rendón JL, Huerta H, Martínez-Hernández F, Rocha-Ortega M, Gutiérrez-Cabrera AE, Ibarra-Cerdeña CN, Córdoba-Aguilar A. A reduction in ecological niche for Trypanosoma cruzi-infected triatomine bugs. Parasit Vectors 2019; 12:240. [PMID: 31097007 PMCID: PMC6524312 DOI: 10.1186/s13071-019-3489-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 05/06/2019] [Indexed: 01/20/2023] Open
Abstract
Background Theory predicts that parasites can affect and thus drive their hosts’ niche. Testing this prediction is key, especially for vector-borne diseases including Chagas disease. Here, we examined the niche use of seven triatomine species that occur in Mexico, based on whether they are infected or not with Trypanosoma cruzi, the vectors and causative parasites of Chagas disease, respectively. Presence data for seven species of triatomines (Triatoma barberi, T. dimidiata, T. longipennis, T. mazzottii, T. pallidipennis, T. phyllosoma and T. picturata) were used and divided into populations infected and not infected by T. cruzi. Species distribution models were generated with Maxent 3.3.3k. Using distribution models, niche analysis tests of amplitude and distance to centroids were carried out for infected vs non-infected populations within species. Results Infected populations of bugs of six out of the seven triatomine species showed a reduced ecological space compared to non-infected populations. In all but one case (T. pallidipennis), the niche used by infected populations was close to the niche centroid of its insect host. Conclusions Trypanosoma cruzi may have selected for a restricted niche amplitude in triatomines, although we are unaware of the underlying reasons. Possibly the fact that T. cruzi infection bears a fitness cost for triatomines is what narrows the niche breadth of the insects. Our results imply that Chagas control programmes should consider whether bugs are infected in models of triatomine distribution. Electronic supplementary material The online version of this article (10.1186/s13071-019-3489-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Guiehdani Villalobos
- Hospital General "Dr. Manuel Gea González", Secretaría de Salud, Mexico City, Mexico.,Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Angela Nava-Bolaños
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - José A De Fuentes-Vicente
- Instituto de Ciencias Biológicas, Universidad de Ciencias y Artes de Chiapas, Tuxtla Gutiérrez, Chiapas, Mexico
| | - Juan Luis Téllez-Rendón
- Instituto de Diagnóstico y Referencia Epidemiológicos, Secretaría de Salud, Mexico City, Mexico
| | - Herón Huerta
- Instituto de Diagnóstico y Referencia Epidemiológicos, Secretaría de Salud, Mexico City, Mexico
| | | | - Maya Rocha-Ortega
- Hospital General "Dr. Manuel Gea González", Secretaría de Salud, Mexico City, Mexico
| | - Ana E Gutiérrez-Cabrera
- CONACyT-Centro de Investigación sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
| | - Carlos N Ibarra-Cerdeña
- Departamento de Ecología Humana, Centro de Investigación y Estudios Avanzados del IPN (Cinvestav), Unidad Mérida, 97310, Mérida, Yucatán, Mexico
| | - Alex Córdoba-Aguilar
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Mexico City, Mexico.
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26
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González-Rete B, Salazar-Schettino PM, Bucio-Torres MI, Córdoba-Aguilar A, Cabrera-Bravo M. Activity of the prophenoloxidase system and survival of triatomines infected with different Trypanosoma cruzi strains under different temperatures: understanding Chagas disease in the face of climate change. Parasit Vectors 2019; 12:219. [PMID: 31068226 PMCID: PMC6507061 DOI: 10.1186/s13071-019-3477-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 05/03/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Little is known about how human disease vectors will modify their life history patterns and survival capacity as a result of climate change. One case is that of Chagas disease, which has triatomine bugs and Trypanosoma cruzi as vectors and parasite, respectively. This work aimed to determine: (i) the activity of the prophenoloxidase system (prophenoloxidase and phenoloxidase activity, two indicators of immune ability) in three intestine regions (anterior midgut, posterior midgutand rectum) of the triatomine bug Meccus pallidipennis under three temperature conditions (20 °C, 30 °C and 34 °C) against two T. cruzi strains [ITRI/MX/14/CHIL (Chilpancingo) and ITRI/MX/12/MOR (Morelos)], and (ii) whether vector survival varies under these three temperatures after infection by these T. cruzi strains. RESULTS Our results indicate that prophenoloxidase activity was lower at higher temperatures, that the level of prophenoloxidase activity elicited by each strain was different (higher in Chilpancingo than in Morelos strains), and that prophenoloxidase activity was more intense in the anterior midgut than in the posterior midgut or rectum. Survival rates were lower in insects maintained at higher temperatures and infected by Chilpancingo strains. CONCLUSIONS These results indicate that climate change could lead to lower prophenoloxidase activity and survival rates in triatomines when infected with different T. cruzi strains, which could reduce the vector capacity of M. pallidipennis.
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Affiliation(s)
| | - Paz María Salazar-Schettino
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Martha I Bucio-Torres
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Alex Córdoba-Aguilar
- Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México, Apdo. P. 70-275, Circuito Exterior, Ciudad Universitaria, Coyoacán, 04510, Ciudad de México, Mexico.
| | - Margarita Cabrera-Bravo
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico.
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27
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Laiño MA, Cardinal MV, Enriquez GF, Alvedro A, Gaspe MS, Gürtler RE. An oral dose of Fluralaner administered to dogs kills pyrethroid-resistant and susceptible Chagas disease vectors for at least four months. Vet Parasitol 2019; 268:98-104. [PMID: 30981313 DOI: 10.1016/j.vetpar.2019.03.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 03/15/2019] [Accepted: 03/16/2019] [Indexed: 11/24/2022]
Abstract
New vector control tools that can fit into a broader integrated vector management strategy are notably lacking. We conducted a seven-month randomized trial to assess the efficacy of a single oral dose of Fluralaner (Bravecto®) administered to dogs on the blood-feeding success, engorgement levels and mortality of pyrethroid-resistant and -susceptible Triatoma infestans third- and fifth-instar nymphs. The trial included 10 Fluralaner-treated and 10 placebo-treated (control) outbred healthy dogs residing in rural houses of the Argentine Chaco. Most (92.7%) of the 3017 triatomines exposed were able to blood-feed. Generalized linear models showed that blood-feeding success was not significantly modified by Fluralaner treatment, time posttreatment and their interaction. However, pyrethroid-susceptible fifth instars blood-fed significantly more frequently than susceptible third instars, and no significant differences were observed between the latter and resistant fifth instars. Engorgement levels were not significantly modified by Fluralaner treatment, time posttreatment and their interaction. Nearly all the triatomines that blood-fed on treated dogs up to 60 days posttreatment (DPT) died within 24 h regardless of pyrethroid susceptibility status combined with bug stage. Cumulative bug mortality over 4 days postexposure remained high over 90-120 DPT (70-81% in susceptible third and fifth instars, and 47-49% in resistant fifth instars), and was virtually nil at 210 DPT. Triatomines that fed on control dogs suffered marginal mortality (0-4%) except at 4 and 30 DPT. Fluralaner and xenointoxication are eligible for Phase III efficacy trials alone or combined with other methods in the frame of an integrated vector management strategy in areas with or without pyrethroid resistance.
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Affiliation(s)
- M A Laiño
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - M V Cardinal
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina.
| | - G F Enriquez
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - A Alvedro
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - M S Gaspe
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
| | - R E Gürtler
- Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Laboratory of Eco-Epidemiology, Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad de Buenos Aires, Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina
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28
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Hodo CL, Hamer SA. Toward an Ecological Framework for Assessing Reservoirs of Vector-Borne Pathogens: Wildlife Reservoirs of Trypanosoma cruzi across the Southern United States. ILAR J 2018; 58:379-392. [PMID: 29106561 PMCID: PMC6019048 DOI: 10.1093/ilar/ilx020] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Accepted: 05/09/2017] [Indexed: 12/27/2022] Open
Abstract
Wildlife species are critical for both feeding vectors and serving as reservoirs of zoonotic vector-borne pathogens. Transmission pathways leading to disease in humans or other target taxa might be better understood and managed given a complete understanding of the relative importance of different reservoir species in nature. Using the conceptual framework of “reservoir potential,” which considers elements of both reservoir competence and vector-host contact, we review the wildlife reservoirs of Trypanosoma cruzi in the southern United States, where many species of triatomine vectors occur and wildlife maintain enzootic cycles that create a risk of spillover to humans, domestic dogs, and captive nonhuman primates that may develop Chagas disease. We reviewed 77 published reports of T. cruzi infection in at least 26 wildlife species across 15 southern states. Among the most well-studied and highly infected reservoirs are raccoon (Procyon lotor), woodrat (Neotoma spp.), and opossum (Didelphis virginiana), with aggregate overall infection prevalences of 36.4, 34.7, and 22.9%, respectively. Just over 60% of studies utilized methods from which an infectiousness index could be generated and show that raccoons and striped skunk (Mephitis mephitis) are among the most infectious wildlife hosts. Triatomine-host contact has sparsely been quantified in the southern United States, but 18 of the 24 host species previously identified to have been fed upon by triatomines are wildlife. Future studies to parameterize the reservoir potential model, especially to quantify wildlife infectiousness, vector-host contact, and the epidemiological importance of parasite strains maintained by wildlife, could open new doors for managing enzootic cycles and reducing T. cruzi spillover risk.
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Affiliation(s)
- Carolyn L Hodo
- Carolyn L. Hodo, DVM, DACVP, is a PhD candidate in the department of Veterinary Pathobiology at the Texas A&M University College of Veterinary Medicine and Biomedical Sciences in College Station, Texas. Sarah A. Hamer, PhD, DVM, DACVPM, is an assistant professor in the department of Veterinary Integrative Biosciences at the Texas A&M University College of Veterinary Medicine and Biomedical Sciences in College Station, Texas
| | - Sarah A Hamer
- Carolyn L. Hodo, DVM, DACVP, is a PhD candidate in the department of Veterinary Pathobiology at the Texas A&M University College of Veterinary Medicine and Biomedical Sciences in College Station, Texas. Sarah A. Hamer, PhD, DVM, DACVPM, is an assistant professor in the department of Veterinary Integrative Biosciences at the Texas A&M University College of Veterinary Medicine and Biomedical Sciences in College Station, Texas
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Lima-Cordón RA, Stevens L, Solórzano Ortíz E, Rodas GA, Castellanos S, Rodas A, Abrego V, Zúniga Valeriano C, Monroy MC. Implementation science: Epidemiology and feeding profiles of the Chagas vector Triatoma dimidiata prior to Ecohealth intervention for three locations in Central America. PLoS Negl Trop Dis 2018; 12:e0006952. [PMID: 30485265 PMCID: PMC6287883 DOI: 10.1371/journal.pntd.0006952] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/10/2018] [Accepted: 10/29/2018] [Indexed: 11/19/2022] Open
Abstract
The Ecohealth strategy is a multidisciplinary data-driven approach used to improve the quality of people's lives in Chagas disease endemic areas, such as regions of Central America. Chagas is a vector-borne disease caused by the parasite Trypanosoma cruzi. In Central America, the main vector is Triatoma dimidiata. Because successful implementation of the Ecohealth approach reduced home infestation in Jutiapa department, Guatemala, it was scaled-up to three localities, one in each of three Central American countries (Texistepeque, El Salvador; San Marcos de la Sierra, Honduras and Olopa, Guatemala). As a basis for the house improvement phase of the Ecohealth program, we determined if the localities differ in the role of sylvatic, synanthropic and domestic animals in the Chagas transmission cycle by measuring entomological indices, blood meal sources and parasite infection from vectors collected in and around houses. The Polymerase Chain Reaction (PCR) with taxa specific primers to detect both, blood sources and parasite infection, was used to assess 71 T. dimidiata from Texistepeque, 84 from San Marcos de la Sierra and 568 from Olopa. Our results show that infestation (12.98%) and colonization (8.95%) indices were highest in Olopa; whereas T. cruzi prevalence was higher in Texistepeque and San Marcos de la Sierra (>40%) than Olopa (8%). The blood meal source profiles showed that in Olopa, opossum might be important in linking the sylvatic and domestic Chagas transmission cycle, whereas in San Marcos de la Sierra dogs play a major role in maintaining domestic transmission. For Texistepeque, bird was the major blood meal source followed by human. When examining the different life stages, we found that in Olopa, the proportion bugs infected with T. cruzi is higher in adults than nymphs. These findings highlight the importance of location-based recommendations for decreasing human-vector contact in the control of Chagas disease.
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Affiliation(s)
- Raquel Asunción Lima-Cordón
- The Applied Entomology and Parasitology Laboratory at Biology School, Pharmacy Faculty, San Carlos University of Guatemala, Guatemala City, Guatemala
- Department of Biology, University of Vermont, Burlington, Vermont, United States of America
| | - Lori Stevens
- Department of Biology, University of Vermont, Burlington, Vermont, United States of America
| | - Elizabeth Solórzano Ortíz
- The Applied Entomology and Parasitology Laboratory at Biology School, Pharmacy Faculty, San Carlos University of Guatemala, Guatemala City, Guatemala
| | - Gabriela Anaité Rodas
- The Applied Entomology and Parasitology Laboratory at Biology School, Pharmacy Faculty, San Carlos University of Guatemala, Guatemala City, Guatemala
| | - Salvador Castellanos
- The Applied Entomology and Parasitology Laboratory at Biology School, Pharmacy Faculty, San Carlos University of Guatemala, Guatemala City, Guatemala
| | - Antonieta Rodas
- The Applied Entomology and Parasitology Laboratory at Biology School, Pharmacy Faculty, San Carlos University of Guatemala, Guatemala City, Guatemala
| | - Vianney Abrego
- Centro de Investigación y desarrollo en salud (CENSALUD-CID), Universidad de El Salvador, San Salvador, El Salvador
| | | | - María Carlota Monroy
- The Applied Entomology and Parasitology Laboratory at Biology School, Pharmacy Faculty, San Carlos University of Guatemala, Guatemala City, Guatemala
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Lopez PM, Abrahan LB, Ralph MR, Valentinuzzi VS. Circadian system responses to nocturnal and diurnal hosts in the kissing bug, Triatoma infestans. Chronobiol Int 2018; 35:1402-1412. [PMID: 29932744 DOI: 10.1080/07420528.2018.1486851] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Insects express diverse behavioral rhythms synchronized to environmental cycles. While circadian entrainment to light-dark cycles is ubiquitous in living organisms, synchronization to non-photic cycles may be critical for hematophagous bugs that depend on rhythmic hosts. The purpose was to determine whether Triatoma infestans are capable of synchronizing to the circadian rhythms of potential hosts with temporally distinct activity patterns; and, if so, if this synchronization occurs through masking or entrainment. Precise synchronization with the food source may be critical for the insects' survival due to the specific predatory or defensive nature of each host. Kissing bugs were housed in a compartment in constant dark, air-flow-connected to another compartment with a nocturnal or a diurnal host; both hosts were synchronized to a light-dark cycle. The activity rhythms of kissing bugs were modulated by the daily activity rhythms of the vertebrates. Effects were a decrease in the endogenous circadian period, independent of the host being nocturnal or diurnal; in some cases relative coordination occurred and in others synchronization was clearly achieved. Moreover, splitting and bimodality arose, phenomena that were also affected by the host presence. The results indicate that T. infestans were able to detect the non-photic cycle of their potential hosts, an ability that surely facilitates feeding and hinders predation risk. Understanding triatomines behavior is of fundamental importance to the design of population control methods.
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Affiliation(s)
- Pablo Martin Lopez
- a Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR) , Provincia de La Rioja, UNLAR, SEGEMAR, UNCa, CONICET , Anillaco , Argentina
| | - Luciana Beatriz Abrahan
- a Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR) , Provincia de La Rioja, UNLAR, SEGEMAR, UNCa, CONICET , Anillaco , Argentina
| | - Martin Roland Ralph
- b Centre for Biological Timing and Cognition, Department of Psychology , University of Toronto , Toronto , Canada
| | - Verónica Sandra Valentinuzzi
- a Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja (CRILAR) , Provincia de La Rioja, UNLAR, SEGEMAR, UNCa, CONICET , Anillaco , Argentina
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Flores-Ferrer A, Marcou O, Waleckx E, Dumonteil E, Gourbière S. Evolutionary ecology of Chagas disease; what do we know and what do we need? Evol Appl 2017; 11:470-487. [PMID: 29636800 PMCID: PMC5891055 DOI: 10.1111/eva.12582] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 11/19/2017] [Indexed: 01/02/2023] Open
Abstract
The aetiological agent of Chagas disease, Trypanosoma cruzi, is a key human pathogen afflicting most populations of Latin America. This vectorborne parasite is transmitted by haematophageous triatomines, whose control by large‐scale insecticide spraying has been the main strategy to limit the impact of the disease for over 25 years. While those international initiatives have been successful in highly endemic areas, this systematic approach is now challenged by the emergence of insecticide resistance and by its low efficacy in controlling species that are only partially adapted to human habitat. In this contribution, we review evidences that Chagas disease control shall now be entering a second stage that will rely on a better understanding of triatomines adaptive potential, which requires promoting microevolutionary studies and –omic approaches. Concomitantly, we show that our knowledge of the determinants of the evolution of T. cruzi high diversity and low virulence remains too limiting to design evolution‐proof strategies, while such attributes may be part of the future of Chagas disease control after the 2020 WHO's target of regional elimination of intradomiciliary transmission has been reached. We should then aim at developing a theory of T. cruzi virulence evolution that we anticipate to provide an interesting enrichment of the general theory according to the specificities of transmission of this very generalist stercorarian trypanosome. We stress that many ecological data required to better understand selective pressures acting on vector and parasite populations are already available as they have been meticulously accumulated in the last century of field research. Although more specific information will surely be needed, an effective research strategy would be to integrate data into the conceptual and theoretical framework of evolutionary ecology and life‐history evolution that provide the quantitative backgrounds necessary to understand and possibly anticipate adaptive responses to public health interventions.
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Affiliation(s)
- Alheli Flores-Ferrer
- UMR 228, ESPACE-DEV-IMAGES, 'Institut de Modélisation et d'Analyses en Géo-Environnement et Santé'Université de Perpignan Via Domitia Perpignan France.,UMR 5096 'Laboratoire Génome et Développement des Plantes' Université de Perpignan Via Domitia Perpignan France
| | - Olivier Marcou
- UMR 228, ESPACE-DEV-IMAGES, 'Institut de Modélisation et d'Analyses en Géo-Environnement et Santé'Université de Perpignan Via Domitia Perpignan France
| | - Etienne Waleckx
- Laboratorio de Parasitología, Centro de Investigaciones Regionales "Dr. Hideyo Noguchi" Universidad Autónoma de Yucatán Mérida Mexico
| | - Eric Dumonteil
- Department of Tropical Medicine School of Public Health and Tropical Medicine Tulane University New Orleans LA USA
| | - Sébastien Gourbière
- UMR 228, ESPACE-DEV-IMAGES, 'Institut de Modélisation et d'Analyses en Géo-Environnement et Santé'Université de Perpignan Via Domitia Perpignan France.,UMR 5096 'Laboratoire Génome et Développement des Plantes' Université de Perpignan Via Domitia Perpignan France
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Gürtler RE, Fernández MDP, Cecere MC, Cohen JE. Body size and hosts of Triatoma infestans populations affect the size of bloodmeal contents and female fecundity in rural northwestern Argentina. PLoS Negl Trop Dis 2017; 11:e0006097. [PMID: 29211791 PMCID: PMC5734792 DOI: 10.1371/journal.pntd.0006097] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 12/18/2017] [Accepted: 11/04/2017] [Indexed: 11/26/2022] Open
Abstract
Human sleeping quarters (domiciles) and chicken coops are key source habitats of Triatoma infestans—the principal vector of the infection that causes Chagas disease—in rural communities in northern Argentina. Here we investigated the links among individual bug bloodmeal contents (BMC, mg), female fecundity, body length (L, mm), host blood sources and habitats. We tested whether L, habitat and host blood conferred relative fitness advantages using generalized linear mixed-effects models and a multimodel inference approach with model averaging. The data analyzed include 769 late-stage triatomines collected in 120 sites from six habitats in 87 houses in Figueroa, Santiago del Estero, during austral spring. L correlated positively with other body-size surrogates and was modified by habitat type, bug stage and recent feeding. Bugs from chicken coops were significantly larger than pig-corral and kitchen bugs. The best-fitting model of log BMC included habitat, a recent feeding, bug stage, log Lc (mean-centered log L) and all two-way interactions including log Lc. Human- and chicken-fed bugs had significantly larger BMC than bugs fed on other hosts whereas goat-fed bugs ranked last, in consistency with average blood-feeding rates. Fecundity was maximal in chicken-fed bugs from chicken coops, submaximal in human- and pig-fed bugs, and minimal in goat-fed bugs. This study is the first to reveal the allometric effects of body-size surrogates on BMC and female fecundity in a large set of triatomine populations occupying multiple habitats, and discloses the links between body size, microsite temperatures and various fitness components that affect the risks of transmission of Trypanosoma cruzi. The few bug species of Triatominae that have become domesticated are the most important vectors of human Trypanosoma cruzi infection, which causes Chagas disease. Evolutionary theory predicts that the fitness of hematophagous species closely adapted to human habitations should increase with feeding on human hosts and insect body length (L). Testing these hypotheses is important for a better understanding of triatomine population dynamics, identifying key productive habitats, modeling parasite transmission and designing innovative vector control strategies. This study is the first to describe the distributions of L and total individual bloodmeal contents (BMC) of triatomines over bug stages and habitats in rural villages where Chagas disease is endemic, and provides a direct link between individual BMC and female fecundity, host-feeding choices and L. L positively and significantly correlated with other body-size surrogates and was modified by habitat and host associations. Feeding on humans was associated with larger BMC and maximal female fecundity in domestic triatomine populations. Human- and chicken-fed bugs had significantly larger BMC than bugs fed on other hosts. Goat-fed bugs ranked last over all habitats, in agreement with other evidence. This study demonstrates that identifiable habitat-host associations provide nearly optimal resources and conditions for T. infestans.
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Affiliation(s)
- Ricardo E. Gürtler
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
- * E-mail:
| | - María del Pilar Fernández
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - María Carla Cecere
- Laboratorio de Eco-Epidemiología, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- Instituto de Ecología, Genética y Evolución de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Joel E. Cohen
- Laboratory of Populations, Rockefeller and Columbia Universities, New York, New York, United States of America
- Earth Institute and Department of Statistics, Columbia University, New York, New York, United States of America
- Department of Statistics, University of Chicago, Chicago, Illinois, United States of America
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Georgieva AY, Gordon ER, Weirauch C. Sylvatic host associations of Triatominae and implications for Chagas disease reservoirs: a review and new host records based on archival specimens. PeerJ 2017; 5:e3826. [PMID: 28948106 PMCID: PMC5609523 DOI: 10.7717/peerj.3826] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 08/29/2017] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The 152 extant species of kissing bug include important vectors of the debilitating, chronic, and often fatal Chagas disease, which affects several million people mainly in Central and South America. An understanding of the natural hosts of this speciose group of blood-feeding insects has and will continue to aid ongoing efforts to impede the spread of Chagas disease. However, information on kissing bug biology is piecemeal and scattered, developed using methods with varying levels of accuracy over more than 100 years. Existing host records are heavily biased towards well-studied primary vector species and are derived from primarily three different types of observations, associational, immunological or DNA-based, with varying reliability. METHODS We gather a comprehensive and unparalleled number of sources reporting host associations via rigorous targeted searches of publication databases to review all known natural, or sylvatic, host records including information on how each record was collected. We integrate this information with novel host records obtained via attempted amplification and sequencing of a ∼160 base pair (bp) region of the vertebrate 12S mitochondrial gene from the gastrointestinal tract of 64 archival specimens of Triatominae representing 19 species collected primarily in sylvatic habitats throughout the southern United States and Central and South America during the past 10 years. We show the utility of this method for uncovering novel and under-studied groups of Triatominae hosts, as well as detecting the presence of the Chagas disease pathogen via Polymerase Chain Reaction (PCR) of a ∼400 bp sequence of the trypanosome 18S gene. RESULTS New host associations for several groups of arboreal mammals were determined including sloths, New World monkeys, coatis, arboreal porcupines and, for the first time as a host of any Triatominae, tayras. A thorough review of previously documented sylvatic hosts, organized by triatomine species and the type of observation (associational, antibody-based, or DNA-based), is presented in a phylogenetic context and highlights large gaps in our knowledge of Triatominae biology. CONCLUSION The application of DNA-based methods of host identification towards additional species of Triatominae, including rarely collected species that may require use of archival specimens, is the most efficient and promising way to resolve recognized shortfalls.
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Affiliation(s)
- Anna Y. Georgieva
- Department of Entomology, University of California, Riverside, CA, United States of America
| | - Eric R.L. Gordon
- Department of Entomology, University of California, Riverside, CA, United States of America
| | - Christiane Weirauch
- Department of Entomology, University of California, Riverside, CA, United States of America
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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.
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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
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Tomasini N, Ragone PG, Gourbière S, Aparicio JP, Diosque P. Epidemiological modeling of Trypanosoma cruzi: Low stercorarian transmission and failure of host adaptive immunity explain the frequency of mixed infections in humans. PLoS Comput Biol 2017; 13:e1005532. [PMID: 28481887 PMCID: PMC5440054 DOI: 10.1371/journal.pcbi.1005532] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 05/22/2017] [Accepted: 04/24/2017] [Indexed: 01/27/2023] Open
Abstract
People living in areas with active vector-borne transmission of Chagas disease have multiple contacts with its causative agent, Trypanosoma cruzi. Reinfections by T. cruzi are possible at least in animal models leading to lower or even hardly detectable parasitaemia. In humans, although reinfections are thought to have major public health implications by increasing the risk of chronic manifestations of the disease, there is little quantitative knowledge about their frequency and the timing of parasite re-inoculation in the course of the disease. Here, we implemented stochastic agent-based models i) to estimate the rate of re-inoculation in humans and ii) to assess how frequent are reinfections during the acute and chronic stages of the disease according to alternative hypotheses on the adaptive immune response following a primary infection. By using a hybrid genetic algorithm, the models were fitted to epidemiological data of Argentinean rural villages where mixed infections by different genotypes of T. cruzi reach 56% in humans. To explain this percentage, the best model predicted 0.032 (0.008-0.042) annual reinfections per individual with 98.4% of them occurring in the chronic phase. In addition, the parasite escapes to the adaptive immune response mounted after the primary infection in at least 20% of the events of re-inoculation. With these low annual rates, the risks of reinfection during the typically long chronic stage of the disease stand around 14% (4%-18%) and 60% (21%-70%) after 5 and 30 years, with most individuals being re-infected 1-3 times overall. These low rates are better explained by the weak efficiency of the stercorarian mode of transmission than a highly efficient adaptive immune response. Those estimates are of particular interest for vaccine development and for our understanding of the higher risk of chronic disease manifestations suffered by infected people living in endemic areas.
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Affiliation(s)
- Nicolás Tomasini
- Instituto de Patología Experimental, Facultad de Ciencias de la Salud, CONICET, Universidad Nacional de Salta, Salta, Argentina
| | - Paula Gabriela Ragone
- Instituto de Patología Experimental, Facultad de Ciencias de la Salud, CONICET, Universidad Nacional de Salta, Salta, Argentina
| | - Sébastien Gourbière
- UMR 228 ESPACE-DEV-IMAGES, ‘Institut de Modélisation et d'Analyses en Géo-Environnement et Santé’, Université de Perpignan Via Domitia, Perpignan, France
| | - Juan Pablo Aparicio
- Instituto de Investigaciones en Energía no Convencional, CONICET, Universidad Nacional de Salta, Salta, Argentina
| | - Patricio Diosque
- Instituto de Patología Experimental, Facultad de Ciencias de la Salud, CONICET, Universidad Nacional de Salta, Salta, Argentina
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Al-Asuoad N, Pleasant T, Shillor M, Munugala H, Coffield DJ, Spagnuolo AM. Simulations of a logistic-type model with delays for Chagas disease with insecticide spraying. INT J BIOMATH 2017. [DOI: 10.1142/s1793524517500334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This work studies and numerically simulates a logistic-type model for the dynamics of Chagas disease, which is caused by the parasite T. cruzi and affects millions of humans and domestic mammals throughout rural areas in Central and South America. A basic model for the disease dynamics that includes insecticide spraying was developed in Spagnuolo et al. (2010) [27] and consists of a delay-differential equation for the vectors and three nonlinear ordinary differential equations for the populations of the infected vectors, infected humans and infected domestic mammals. In this work, the vector equation is modified by using a logistic term with zero, one or two delays or time lags. The aim of this study is three-fold: to numerically study the effects of using different numbers of delays on the model behavior; to find if twice yearly insecticide spraying schedules improve vector control; and to study the sensitivity of the system to the delays in the case of two delays, by introducing randomness in the delays. It is found that the vector equation with different number of delays has very different solutions. The “best” day of spraying is the middle of Spring and twice annual sprayings cause only minor improvements in disease control. Finally, the model is found to be insensitive to the values of the delays, when the delays are randomly distributed within rather narrow intervals or ranges centered on the parameter values used in Coffield et al. (2014) [8].
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Affiliation(s)
- Nofe Al-Asuoad
- Department of Mathematics and Statistics, Oakland University, Rochester MI 48309, USA
| | | | - Meir Shillor
- Department of Mathematics and Statistics, Oakland University, Rochester MI 48309, USA
| | | | - Daniel J. Coffield
- Mathematics Department, University of Michigan-Flint, Flint MI 48502, USA
| | - Anna Maria Spagnuolo
- Department of Mathematics and Statistics, Oakland University, Rochester MI 48309, USA
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The TcTASV proteins are novel promising antigens to detect active Trypanosoma cruzi infection in dogs. Parasitology 2016; 143:1382-9. [PMID: 27173912 DOI: 10.1017/s0031182016000822] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In regions where Chagas disease is endemic, canine Trypanosoma cruzi infection is highly correlated with the risk of transmission of the parasite to humans. Herein we evaluated the novel TcTASV protein family (subfamilies A, B, C), differentially expressed in bloodstream trypomastigotes, for the detection of naturally infected dogs. A gene of each TcTASV subfamily was cloned and expressed. Indirect enzyme-linked immunosorbent assays (ELISA) were developed using recombinant antigens individually or mixed together. Our results showed that dogs with active T. cruzi infection differentially reacted against the TcTASV-C subfamily. The use of both TcTASV-C plus TcTASV-A proteins (Mix A+C-ELISA) enhanced the reactivity of sera from dogs with active infection, detecting 94% of the evaluated samples. These findings agree with our previous observations, where the infected animals exhibited a quick anti-TcTASV-C antibody response, coincident with the beginning of parasitaemia, in a murine model of the disease. Results obtained in the present work prove that the Mix A+C-ELISA is a specific, simple and cheap technique to be applied in endemic areas in screening studies. The Mix A+C-ELISA could help to differentially detect canine hosts with active infection and therefore with high impact in the risk of transmission to humans.
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Cecere MC, Leporace M, Fernández MP, Zárate JE, Moreno C, Gürtler RE, Cardinal MV. Host-Feeding Sources and Infection With Trypanosoma cruzi of Triatoma infestans and Triatoma eratyrusiformis (Hemiptera: Reduviidae) From the Calchaqui Valleys in Northwestern Argentina. JOURNAL OF MEDICAL ENTOMOLOGY 2016; 53:666-673. [PMID: 26849898 DOI: 10.1093/jme/tjw002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 01/11/2016] [Indexed: 06/05/2023]
Abstract
We assessed the prevalence of infection with Trypanosoma cruzi, parasite genotypes (discrete typing units, DTUs), and the host-feeding sources of domestic and peridomestic Triatoma infestans Klug and Triatoma eratyrusiformis Del Ponte in eight rural communities of the subandean Calchaqui valleys in northwestern Argentina. We sought to analyze their epidemiological role in the context of routine vector surveillance and control actions. Infection with T. cruzi was determined by optic microscopy or polymerase chain reaction (PCR) amplification of the hypervariable region of kinetoplast DNA minicircles. Parasite genotypes were identified through a multi PCR-based strategy. Bloodmeal contents were tested with a direct ELISA assay against nine antisera. Human sleeping quarters (domiciles) and peridomestic dry-shrub fences concentrated most of the T. infestans and T. eratyrusiformis infected with T. cruzi, respectively. The most frequent host-feeding sources of T. infestans were chickens (73.1%) in peridomiciles and humans (73.3%) in domiciles, whereas T. eratyrusiformis fed more often on cavid rodents (92.6%), which thrived in the dry-shrub fences. The main T. cruzi DTU identified in both vectors was T. cruzi I (TcI). Triatoma eratyrusiformis was implicated in the local circulation of TcI among cavies and perhaps mice, but infection with other typically domestic DTUs (TcVI and TcII/TcV/TcVI) indicated overlap between (peri)domestic transmission cycles in both vector species. Because dry-shrub fences were not targeted for routine insecticide spraying, they may act as sources of (peri)domestic reinfestation. Triatoma eratyrusiformis is an emergent secondary vector of T. cruzi and plays a significant role in the local transmission of T. cruzi.
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Affiliation(s)
- M C Cecere
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires-Instituto de Ecología, Genética y Evolución (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; ; ),
| | - M Leporace
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires-Instituto de Ecología, Genética y Evolución (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; ; )
- Laboratorio de Control de Vectores Entomológicos de Importancia Sanitaria (LaCVEIS), Fundación Barceló, Centeno y Rivadavia. Santo Tomé, Corrientes, Argentina, and
| | - M P Fernández
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires-Instituto de Ecología, Genética y Evolución (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; ; )
| | - J E Zárate
- Coordinación Nacional de Control de Vectores (CNCV), Italia 1971, San Miguel de Tucumán, Tucumán, Argentina (; )
| | - C Moreno
- Coordinación Nacional de Control de Vectores (CNCV), Italia 1971, San Miguel de Tucumán, Tucumán, Argentina (; )
| | - R E Gürtler
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires-Instituto de Ecología, Genética y Evolución (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; ; )
| | - M V Cardinal
- Laboratorio de Eco-Epidemiología, Departamento de Ecología, Genética y Evolución, Universidad de Buenos Aires-Instituto de Ecología, Genética y Evolución (IEGEBA), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET),Ciudad Universitaria, C1428EHA, Buenos Aires, Argentina (; ; ; ; )
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Mesk M, Mahdjoub T, Gourbière S, Rabinovich JE, Menu F. Invasion speeds of Triatoma dimidiata, vector of Chagas disease: An application of orthogonal polynomials method. J Theor Biol 2016; 395:126-143. [PMID: 26807809 DOI: 10.1016/j.jtbi.2016.01.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 12/12/2015] [Accepted: 01/06/2016] [Indexed: 11/18/2022]
Abstract
Demographic processes and spatial dispersal of Triatoma dimidiata, a triatomine species vector of Chagas disease, are modeled by integrodifference equations to estimate invasion capacity of this species under different ecological conditions. The application of the theory of orthogonal polynomials and the steepest descent method applied to these equations, allow a good approximation of the abundance of the adult female population and the invasion speed. We show that: (1) under the same mean conditions of demography and dispersal, periodic spatial dispersal results in an invasion speed 2.5 times larger than the invasion speed when spatial dispersal is continuous; (2) when the invasion speed of periodic spatial dispersal is correlated to adverse demographic conditions, it is 34.7% higher as compared to a periodic dispersal that is correlated to good demographic conditions. From our results we conclude, in terms of triatomine population control, that the invasive success of T. dimidiata may be most sensitive to the probability of transition from juvenile to adult stage. We discuss our main theoretical predictions in the light of observed data in different triatomines species found in the literature.
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Affiliation(s)
- Mohammed Mesk
- Laboratoire d'Analyse Non Linéaire et Mathématiques Appliquées, Université de Tlemcen, BP 119 Imama (Pôle2), Tlemcen 13000, Algeria.
| | - Tewfik Mahdjoub
- Laboratoire d'Analyse Non Linéaire et Mathématiques Appliquées, Université de Tlemcen, BP 119 Imama (Pôle2), Tlemcen 13000, Algeria.
| | - Sébastien Gourbière
- Université de Perpignan Via Domitia, EA 4218 ׳Institut de Modélisation et d׳Analyse en Géo-Environnements et Santé' (IMAGES), Perpignan 66100, France.
| | - Jorge E Rabinovich
- Centro de Estudios Parasitológicos y de Vectores, Universidad Nacional de La Plata, La Plata, Provincia de Buenos Aires, Argentina.
| | - Frédéric Menu
- Laboratoire de Biométrie et Biologie Evolutive (UMR 5558), Université de Lyon, Université Lyon 1, UMR CNRS 5558, 43 Bd du 11 Novembre 1918, 69 622 Villeurbanne Cedex, France.
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Ramirez-Sierra MJ, Dumonteil E. Infection Rate by Trypanosoma cruzi and Biased Vertebrate Host Selection in the Triatoma dimidiata (Hemiptera: Reduvidae) Species Complex. JOURNAL OF MEDICAL ENTOMOLOGY 2016; 53:20-25. [PMID: 26474882 DOI: 10.1093/jme/tjv157] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 09/17/2015] [Indexed: 06/05/2023]
Abstract
Chagas disease is a vector-borne disease, caused by the protozoan parasite Trypanosoma cruzi and transmitted by hematophagous insects. Triatoma dimidiata (Hemiptera: Reduvidae (Latreille 1811)) is one of the main vectors, and recent molecular studies indicate that it is a species complex, with potentially different vectorial competences. We investigated the differences in natural T. cruzi infection rate within T. dimidiata complex in Yucatan, Mexico. ITS-2 hybrid bugs had a twofold higher infection rate than ITS-2 Groups 2 and 3 bugs, and this pattern was consistent over time and in several villages. To test if T. dimidiata ITS-2 hybrid bugs could feed more frequently on T. cruzi-infected hosts, we evaluated their host-seeking behavior in a dual-choice chamber. Group 2 and 3 bugs were equally attracted to T. cruzi-infected or uninfected mice. On the contrary, ITS-2 hybrid bugs reached three times more frequently the T. cruzi-infected mouse, compared to the uninfected one, indicating a significant bias toward an infected host. This behavior may explain in part their higher natural infection rate. Further studies should explore the complex and unique interactions among T. cruzi, triatomines vectors, and mammalian hosts, as this may led to new strategies to interfere with transmission cycles and improve Chagas disease control.
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Affiliation(s)
- M J Ramirez-Sierra
- Laboratorio de Parasitología, Centro de Investigaciones Regionales ''Dr. Hideyo Noguchi'', Universidad Autónoma de Yucatán, 97000 Mérida, Yucatán, México
| | - E Dumonteil
- Laboratorio de Parasitología, Centro de Investigaciones Regionales ''Dr. Hideyo Noguchi'', Universidad Autónoma de Yucatán, 97000 Mérida, Yucatán, México , Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, 70112, New Orleans, LA, and
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Gürtler RE, Cardinal MV. Reservoir host competence and the role of domestic and commensal hosts in the transmission of Trypanosoma cruzi. Acta Trop 2015; 151:32-50. [PMID: 26051910 DOI: 10.1016/j.actatropica.2015.05.029] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 05/25/2015] [Accepted: 05/31/2015] [Indexed: 12/30/2022]
Abstract
We review the epidemiological role of domestic and commensal hosts of Trypanosoma cruzi using a quantitative approach, and compiled >400 reports on their natural infection. We link the theory underlying simple mathematical models of vector-borne parasite transmission to the types of evidence used for reservoir host identification: mean duration of infectious life; host infection and infectiousness; and host-vector contact. The infectiousness of dogs or cats most frequently exceeded that of humans. The host-feeding patterns of major vectors showed wide variability among and within triatomine species related to their opportunistic behavior and variable ecological, biological and social contexts. The evidence shows that dogs, cats, commensal rodents and domesticated guinea pigs are able to maintain T. cruzi in the absence of any other host species. They play key roles as amplifying hosts and sources of T. cruzi in many (peri)domestic transmission cycles covering a broad diversity of ecoregions, ecotopes and triatomine species: no other domestic animal plays that role. Dogs comply with the desirable attributes of natural sentinels and sometimes were a point of entry of sylvatic parasite strains. The controversies on the role of cats and other hosts illustrate the issues that hamper assessing the relative importance of reservoir hosts on the basis of fragmentary evidence. We provide various study cases of how eco-epidemiological and genetic-marker evidence helped to unravel transmission cycles and identify the implicated hosts. Keeping dogs, cats and rodents out of human sleeping quarters and reducing their exposure to triatomine bugs are predicted to strongly reduce transmission risks.
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Affiliation(s)
- Ricardo E Gürtler
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires-IEGEBA (CONICET-UBA), Buenos Aires, Argentina.
| | - M V Cardinal
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires-IEGEBA (CONICET-UBA), Buenos Aires, Argentina
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Alroy KA, Huang C, Gilman RH, Quispe-Machaca VR, Marks MA, Ancca-Juarez J, Hillyard M, Verastegui M, Sanchez G, Cabrera L, Vidal E, Billig EMW, Cama VA, Náquira C, Bern C, Levy MZ. Prevalence and Transmission of Trypanosoma cruzi in People of Rural Communities of the High Jungle of Northern Peru. PLoS Negl Trop Dis 2015; 9:e0003779. [PMID: 26000770 PMCID: PMC4441511 DOI: 10.1371/journal.pntd.0003779] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Accepted: 04/22/2015] [Indexed: 11/18/2022] Open
Abstract
Background Vector-borne transmission of Trypanosoma cruzi is seen exclusively in the Americas where an estimated 8 million people are infected with the parasite. Significant research in southern Peru has been conducted to understand T. cruzi infection and vector control, however, much less is known about the burden of infection and epidemiology in northern Peru. Methodology A cross-sectional study was conducted to estimate the seroprevalence of T. cruzi infection in humans (n=611) and domestic animals [dogs (n=106) and guinea pigs (n=206)] in communities of Cutervo Province, Peru. Sampling and diagnostic strategies differed according to species. An entomological household study (n=208) was conducted to identify the triatomine burden and species composition, as well as the prevalence of T. cruzi in vectors. Electrocardiograms (EKG) were performed on a subset of participants (n=90 T. cruzi infected participants and 170 age and sex-matched controls). The seroprevalence of T. cruzi among humans, dogs, and guinea pigs was 14.9% (95% CI: 12.2 – 18.0%), 19.8% (95% CI: 12.7- 28.7%) and 3.3% (95% CI: 1.4 – 6.9%) respectively. In one community, the prevalence of T. cruzi infection was 17.2% (95% CI: 9.6 - 24.7%) among participants < 15 years, suggesting recent transmission. Increasing age, positive triatomines in a participant's house, and ownership of a T. cruzi positive guinea pig were independent correlates of T. cruzi infection. Only one species of triatomine was found, Panstrongylus lignarius, formerly P. herreri. Approximately forty percent (39.9%, 95% CI: 33.2 - 46.9%) of surveyed households were infested with this vector and 14.9% (95% CI: 10.4 - 20.5%) had at least one triatomine positive for T. cruzi. The cardiac abnormality of right bundle branch block was rare, but only identified in seropositive individuals. Conclusions Our research documents a substantial prevalence of T. cruzi infection in Cutervo and highlights a need for greater attention and vector control efforts in northern Peru. Chagas disease causes significant morbidity and mortality throughout Central and South America. The epidemiology and control of this disease is subject to unique regional particularities, including the behavior and ecology of the local insect vector species. Significant resources have been allocated towards research and control efforts in southern Peru, yet very little is known about the prevalence and epidemiology of Trypanosoma cruzi in northern Peru. Our study highlights significant T. cruzi infection in northern Peru and is one of the first to document substantial transmission by the insect Panstrongylus lignarius. Our results illustrate major gaps in knowledge and the need for public health interventions targeted at Chagas disease in the region of Cutervo Province of northern Peru.
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Affiliation(s)
- Karen A. Alroy
- American Association for the Advancement of Science (AAAS) Science & Technology Policy Fellow at the Division of Environmental Biology, National Science Foundation, Arlington, Virginia, United States of America
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Christine Huang
- Department of Pediatrics and Department of Emergency Medicine, University of Arizona, Tucson, Arizona, United States of America
| | - Robert H. Gilman
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
- Faculty of Science and Philosophy Alberto Cazorla Talleri, Urbanización Ingeniería, University Peruana Cayetano Heredia, Lima, Peru
| | - Victor R. Quispe-Machaca
- Faculty of Science and Philosophy Alberto Cazorla Talleri, Urbanización Ingeniería, University Peruana Cayetano Heredia, Lima, Peru
| | - Morgan A. Marks
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Jenny Ancca-Juarez
- Faculty of Science and Philosophy Alberto Cazorla Talleri, Urbanización Ingeniería, University Peruana Cayetano Heredia, Lima, Peru
| | - Miranda Hillyard
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Manuela Verastegui
- Faculty of Science and Philosophy Alberto Cazorla Talleri, Urbanización Ingeniería, University Peruana Cayetano Heredia, Lima, Peru
| | - Gerardo Sanchez
- Faculty of Science and Philosophy Alberto Cazorla Talleri, Urbanización Ingeniería, University Peruana Cayetano Heredia, Lima, Peru
| | - Lilia Cabrera
- Faculty of Science and Philosophy Alberto Cazorla Talleri, Urbanización Ingeniería, University Peruana Cayetano Heredia, Lima, Peru
| | - Elisa Vidal
- Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, United States of America
| | - Erica M. W. Billig
- Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Vitaliano A. Cama
- Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - César Náquira
- Faculty of Science and Philosophy Alberto Cazorla Talleri, Urbanización Ingeniería, University Peruana Cayetano Heredia, Lima, Peru
| | - Caryn Bern
- Department of Epidemiology and Biostatistics, School of Medicine, University of California, San Francisco, San Francisco, California, United States of America
| | - Michael Z. Levy
- Faculty of Science and Philosophy Alberto Cazorla Talleri, Urbanización Ingeniería, University Peruana Cayetano Heredia, Lima, Peru
- Center for Clinical Epidemiology and Biostatistics, Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Castillo-Neyra R, Chou Chu L, Quispe-Machaca V, Ancca-Juarez J, Malaga Chavez FS, Bastos Mazuelos M, Naquira C, Bern C, Gilman RH, Levy MZ. The potential of canine sentinels for reemerging Trypanosoma cruzi transmission. Prev Vet Med 2015; 120:349-56. [PMID: 25962956 DOI: 10.1016/j.prevetmed.2015.04.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 03/23/2015] [Accepted: 04/22/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Chagas disease, a vector-borne disease transmitted by triatomine bugs and caused by the parasite Trypanosoma cruzi, affects millions of people in the Americas. In Arequipa, Peru, indoor residual insecticide spraying campaigns are routinely conducted to eliminate Triatoma infestans, the only vector in this area. Following insecticide spraying, there is risk of vector return and reinitiation of parasite transmission. Dogs are important reservoirs of T. cruzi and may play a role in reinitiating transmission in previously sprayed areas. Dogs may also serve as indicators of reemerging transmission. METHODS We conducted a cross-sectional serological screening to detect T. cruzi antibodies in dogs, in conjunction with an entomological vector collection survey at the household level, in a disease endemic area that had been treated with insecticide 13 years prior. Spatial clustering of infected animals and vectors was assessed using Ripley's K statistic, and the odds of being seropositive for dogs proximate to infected colonies was estimated with multivariate logistic regression. RESULTS There were 106 triatomine-infested houses (41.1%), and 45 houses infested with T. cruzi-infected triatomine insects (17.4%). Canine seroprevalence in the area was 12.3% (n=154); all seropositive dogs were 9 months old or older. We observed clustering of vectors carrying the parasite, but no clustering of seropositive dogs. The age- and sex-adjusted odds ratio between seropositivity to T. cruzi and proximity to an infected triatomine (≤50m) was 5.67 (95% CI: 1.12-28.74; p=0.036). CONCLUSIONS Targeted control of reemerging transmission can be achieved by improved understanding of T. cruzi in canine populations. Our results suggest that dogs may be useful sentinels to detect re-initiation of transmission following insecticide treatment. Integration of canine T. cruzi blood sampling into existing interventions for zoonotic disease control (e.g., rabies vaccination programs) can be an effective method of increasing surveillance and improving understanding of disease distribution.
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Affiliation(s)
- Ricardo Castillo-Neyra
- Center for Clinical Epidemiology & Biostatistics - Department of Biostatistics & Epidemiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA; Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru.
| | - Lily Chou Chu
- Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Jenny Ancca-Juarez
- Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | | | - Cesar Naquira
- Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Caryn Bern
- School of Medicine, University of California, San Francisco, CA, USA
| | - Robert H Gilman
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Michael Z Levy
- Center for Clinical Epidemiology & Biostatistics - Department of Biostatistics & Epidemiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA.
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Floridia-Yapur N, Vega-Benedetti AF, Rumi MM, Ragone P, Lauthier JJ, Tomasini N, d'Amato AMA, Lopez-Quiroga I, Diosque P, Marcipar I, Nasser JR, Cimino RO. Evaluation of recombinant antigens of Trypanosoma cruzi to diagnose infection in naturally infected dogs from Chaco region, Argentina. Parasite Immunol 2015; 36:694-9. [PMID: 25201522 DOI: 10.1111/pim.12144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 09/03/2014] [Indexed: 11/28/2022]
Abstract
Dogs are considered the main mammal reservoir of Trypanosoma cruzi in domiciliary environments. Consequently, accurate detection of T. cruzi infection in canine populations is epidemiologically relevant. Here, we analysed the utility of the T. cruzi recombinant antigens FRA, SAPA, CP1, Ag1 and a SAPA/TSSA VI mixture, in an ELISA format. We used a positive control group of sera obtained from 38 dogs from the Chaco region in Argentina with positive homogenate-ELISA reaction, all of them also positive by xenodiagnosis and/or PCR. The negative group included 19 dogs from a nonendemic area. Sensitivity, specificity, area under the curve (AUC) of the receiver operating charactheristic (ROC) curve and Kappa index were obtained to compare the diagnostic efficiency of the tests. The SAPA/TSSA VI had the highest performance, with a sensitivity of 94.7% and an AUC ROC of 0.99 that indicates high accuracy. Among individual antigens, SAPA-ELISA yielded the highest sensitivity (86.8%) and AUC ROC (0.96), whereas FRA-ELISA was the least efficient test (sensitivity = 36.8%; AUC ROC = 0.53). Our results showed that the use of SAPA/TSSA VI in ELISAs could be a useful tool to study dogs naturally infected with T. cruzi in endemic areas.
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Affiliation(s)
- N Floridia-Yapur
- Cátedra de Química Biológica, Facultad de Ciencias Naturales, Universidad Nacional de Salta, Salta, Argentina; Instituto de Investigaciones de Enfermedades Tropicales, Sede Regional Orán, Universidad Nacional de Salta (IIET), Salta, Argentina
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Castillo-Neyra R, Barbu CM, Salazar R, Borrini K, Naquira C, Levy MZ. Host-seeking behavior and dispersal of Triatoma infestans, a vector of Chagas disease, under semi-field conditions. PLoS Negl Trop Dis 2015; 9:e3433. [PMID: 25569228 PMCID: PMC4287539 DOI: 10.1371/journal.pntd.0003433] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 11/23/2014] [Indexed: 11/19/2022] Open
Abstract
Chagas disease affects millions of people in Latin America. The control of this vector-borne disease focuses on halting transmission by reducing or eliminating insect vector populations. Most transmission of Trypanosoma cruzi, the causative agent of Chagas disease, involves insects living within or very close to households and feeding mostly on domestic animals. As animal hosts can be intermittently present it is important to understand how host availability can modify transmission risk to humans and to characterize the host-seeking dispersal of triatomine vectors on a very fine scale. We used a semi-field system with motion-detection cameras to characterize the dispersal of Triatoma infestans, and compare the behavior of vector populations in the constant presence of hosts (guinea pigs), and after the removal of the hosts. The emigration rate – net insect population decline in original refuge – following host removal was on average 19.7% of insects per 10 days compared to 10.2% in constant host populations (p = 0.029). However, dispersal of T. infestans occurred in both directions, towards and away from the initial location of the hosts. The majority of insects that moved towards the original location of guinea pigs remained there for 4 weeks. Oviposition and mortality were observed and analyzed in the context of insect dispersal, but only mortality was higher in the group where animal hosts were removed (p-value <0.01). We discuss different survival strategies associated with the observed behavior and its implications for vector control. Removing domestic animals in infested areas increases vector dispersal from the first day of host removal. The implications of these patterns of vector dispersal in a field setting are not yet known but could result in movement towards human rooms. Chagas disease is transmitted by triatomine bugs that actively disperse by walking and flying. The control of this vector-borne disease focuses on reducing or eliminating the insect vector populations. Most transmission of Trypanosoma cruzi, the causative agent of Chagas disease, involves insects living within or very close to households and feeding mostly on domestic animals. As animal hosts can be removed due to migration, slaughter, or death, it is important to understand how host availability can modify transmission risk to humans and to characterize the dispersal of triatomine vectors on a very fine scale. We used a semi-field system to characterize the dispersal of Triatoma infestans, and compare the behavior of vector populations in the constant presence of hosts and after the removal of the hosts. The emigration rate – net insect population decline in original refuges – following host removal was on average 19.7% of insects per 10 days compared to 10.2% in constant host populations. Activity of insects was significantly increased when hosts were removed. The removal of domestic animals in infested areas increases vector dispersal, possibly towards nearby human sleeping spaces.
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Affiliation(s)
- Ricardo Castillo-Neyra
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America
- Center for Clinical Epidemiology & Biostatistics - Department of Biostatistics & Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
| | - Corentin M. Barbu
- Center for Clinical Epidemiology & Biostatistics - Department of Biostatistics & Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Renzo Salazar
- School of Science and Philosophy, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Katty Borrini
- School of Science and Philosophy, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Cesar Naquira
- School of Science and Philosophy, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Michael Z. Levy
- Center for Clinical Epidemiology & Biostatistics - Department of Biostatistics & Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, United States of America
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Otálora-Luna F, Guerin PM. Amines from vertebrates guide triatomine bugs to resources. JOURNAL OF INSECT PHYSIOLOGY 2014; 71:52-60. [PMID: 25260571 DOI: 10.1016/j.jinsphys.2014.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 07/16/2014] [Accepted: 09/03/2014] [Indexed: 06/03/2023]
Abstract
Most triatomine bugs (Heteroptera: Reduviidae) are nest-living insects that require vertebrate blood or invertebrate haemolymph to complete their life cycle. Vertebrates accumulate excretory products in or near their nesting sites and we hypothesize that triatomines use emanations from such host wastes when searching for resources. Here we recount how triatomine bugs increase upwind locomotion on a servosphere in response to volatile amine constituents of vertebrate excretions. Fresh chicken faeces is strongly attractive to Rhodnius prolixus nymphs. Ammonia induces attraction and an increase in both speed and total path length by R. prolixus on the servosphere. Whereas ethylamine and dimethylamine attract R. prolixus, Triatoma infestans and Panstrongylus geniculatus, other amine constituents of vertebrate excretions such as isobutylamine and hexylamine induce R. prolixus nymphs to walk faster and for a longer period. These amines are derived from generally occurring metabolites of vertebrates and from gut flora metabolism. We conclude that amines and other products associated with nesting hosts serve as signals for foraging triatomines.
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Affiliation(s)
- Fernando Otálora-Luna
- Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2009 Neuchâtel, Switzerland.
| | - Patrick M Guerin
- Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2009 Neuchâtel, Switzerland
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Provecho YM, Gaspe MS, del Pilar Fernández M, Enriquez GF, Weinberg D, Gürtler RE. The peri-urban interface and house infestation with Triatoma infestans in the Argentine Chaco: an underreported process? Mem Inst Oswaldo Cruz 2014; 109:923-34. [PMID: 25410997 PMCID: PMC4296498 DOI: 10.1590/0074-0276140225] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 09/10/2014] [Indexed: 02/08/2023] Open
Abstract
Peri-urban infestations with triatomine bugs, their sources and their dynamics have
rarely been investigated. Here, we corroborated the reported occurrence of
Triatoma infestans in a peri-urban area and in neighbouring rural
houses in Pampa del Indio, in the Argentine Chaco, and identified its putative
sources using spatial analysis and demographic questionnaires. Peri-urban
householders reported that 10% of their premises had triatomines, whereas T.
infestans was collected by timed manual searches or community-based
surveillance in only nine (3%) houses. Trypanosoma cruzi-infected
T. infestans and Triatoma sordida were collected
indoors only in peri-urban houses and were infected with TcV
and TcI, respectively. The triatomines fed on chickens,
cats and humans. Peri-urban infestations were most frequent in a squatter settlement
and particularly within the recently built mud houses of rural immigrants, with
large-sized households, more dogs and cats and more crowding. Several of the observed
infestations were most likely associated with passive bug transport from other
sources and with active bug dispersal from neighbouring foci. Thus, the households in
the squatter settlement were at a greater risk of bug invasion and colonisation. In
sum, the incipient process of domestic colonisation and transmission, along with
persistent rural-to-urban migratory flows and unplanned urbanisation, indicate the
need for active vector surveillance and control actions at the peri-urban interface
of the Gran Chaco.
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Affiliation(s)
- Yael M Provecho
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, National Council of Scientific and Technological Research, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - M Sol Gaspe
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, National Council of Scientific and Technological Research, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - M del Pilar Fernández
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, National Council of Scientific and Technological Research, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gustavo F Enriquez
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, National Council of Scientific and Technological Research, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Ricardo E Gürtler
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, National Council of Scientific and Technological Research, Universidad de Buenos Aires, Buenos Aires, Argentina
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Gürtler RE, Cecere MC, Fernández MDP, Vazquez-Prokopec GM, Ceballos LA, Gurevitz JM, Kitron U, Cohen JE. Key source habitats and potential dispersal of triatoma infestans populations in Northwestern Argentina: implications for vector control. PLoS Negl Trop Dis 2014; 8:e3238. [PMID: 25299653 PMCID: PMC4191936 DOI: 10.1371/journal.pntd.0003238] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 09/04/2014] [Indexed: 11/18/2022] Open
Abstract
Background Triatoma infestans —the principal vector of the infection that causes Chagas disease— defies elimination efforts in the Gran Chaco region. This study identifies the types of human-made or -used structures that are key sources of these bugs in the initial stages of house reinfestation after an insecticide spraying campaign. Methodology and Principal Findings We measured demographic and blood-feeding parameters at two geographic scales in 11 rural communities in Figueroa, northwest Argentina. Of 1,297 sites searched in spring, 279 (21.5%) were infested. Bug abundance per site and female fecundity differed significantly among habitat types (ecotopes) and were highly aggregated. Domiciles (human sleeping quarters) had maximum infestation prevalence (38.7%), human-feeding bugs and total egg production, with submaximal values for other demographic and blood-feeding attributes. Taken collectively peridomestic sites were three times more often infested than domiciles. Chicken coops had greater bug abundance, blood-feeding rates, engorgement status, and female fecundity than pig and goat corrals. The host-feeding patterns were spatially structured yet there was strong evidence of active dispersal of late-stage bugs between ecotopes. Two flight indices predicted that female fliers were more likely to originate from kitchens and domiciles, rejecting our initial hypothesis that goat and pig corrals would dominate. Conclusions and Significance Chicken coops and domiciles were key source habitats fueling rapid house reinfestation. Focusing control efforts on ecotopes with human-fed bugs (domiciles, storerooms, goat corrals) would neither eliminate the substantial contributions to bug population growth from kitchens, chicken coops, and pig corrals nor stop dispersal of adult female bugs from kitchens. Rather, comprehensive control of the linked network of ecotopes is required to prevent feeding on humans, bug population growth, and bug dispersal simultaneously. Our study illustrates a demographic approach that may be applied to other regions and triatomine species for the design of innovative, improved vector control strategies. The major vectors of Chagas disease are species of triatomine bugs adapted to human sleeping quarters and peridomestic annexes where they feed on humans and domestic or synanthropic mammals or birds. Knowledge of the demography and nutritional status of Triatominae in real-life settings is still fragmentary, and this affects our ability to prevent or reduce house reinfestation after insecticide spraying. In addition to showing where the bugs are likely to live (occupancy and density information), our observations and analysis of flight dispersal provide insights into where bugs are likely to originate. Data on nymphal and adult sex ratios, nutritional status, and female fecundity point to the key ecotopes and sites driving the population growth of the bugs and fueling house reinfestation. Focusing control efforts on the three ecotopes (human sleeping quarters, storerooms, and goat corrals) that housed reactive, human-fed bugs would neither eliminate the substantial contributions to bug population growth from kitchens, chicken coops, and pig corrals nor stop dispersal of adult female bugs from kitchens. Rather, comprehensive control of the linked network of ecotopes in a typical house compound and community is required to prevent feeding on humans, bug population growth, and bug dispersal simultaneously.
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Affiliation(s)
- Ricardo E. Gürtler
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires-IEGEBA (CONICET-UBA), Buenos Aires, Argentina
- * E-mail:
| | - María C. Cecere
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires-IEGEBA (CONICET-UBA), Buenos Aires, Argentina
| | - María del Pilar Fernández
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires-IEGEBA (CONICET-UBA), Buenos Aires, Argentina
| | - Gonzalo M. Vazquez-Prokopec
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires-IEGEBA (CONICET-UBA), Buenos Aires, Argentina
- Department of Environmental Studies, Emory University, Atlanta, Georgia, United States of America
| | - Leonardo A. Ceballos
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires-IEGEBA (CONICET-UBA), Buenos Aires, Argentina
| | - Juan M. Gurevitz
- Laboratory of Eco-Epidemiology, Department of Ecology, Genetics and Evolution, Universidad de Buenos Aires-IEGEBA (CONICET-UBA), Buenos Aires, Argentina
| | - Uriel Kitron
- Department of Environmental Studies, Emory University, Atlanta, Georgia, United States of America
| | - Joel E. Cohen
- Laboratory of Populations, Rockefeller and Columbia Universities, New York, New York, United States of America
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Rodríguez C, Lobbia P, Nattero J, Catalá S, Crocco L. Effect of feeding frequency on the reproductive efficiency of two species of Triatoma with different epidemiological importance. Rev Soc Bras Med Trop 2014; 47:430-6. [PMID: 25229282 DOI: 10.1590/0037-8682-0111-2014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 07/08/2014] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION In Triatominae, reproductive efficiency is an important factor influencing population dynamics, and a useful parameter in measuring a species' epidemiological significance as a vector of Trypanosoma cruzi (Chagas, 1909). The reproductive efficiency of triatomines is affected by food availability; hence, we measured and compared the effects of feeding frequency on the reproductive parameters of Triatoma patagonica (Del Ponte, 1929) and Triatoma infestans (Klug, 1934), and the effects of starvation on T. patagonica. METHODS Couples from both species were fed weekly, or every 3 weeks; in addition, females in couples of T. patagonica were not fed. Each couple was observed weekly and reproductive efficiency was assessed on the following parameters: fecundity (eggs/female), fertility (eggs hatched/eggs laid), initiation and end of oviposition, initiation of mating, number of matings/week, and number of reproductive weeks. Relative meal size index (RMS), blood consumption index (CI), and E values (eggs/mg blood) were also calculated. RESULTS Changes in feeding frequency affected the reproductive parameters of T. patagonica only, with a decrease in fecundity and number of reproductive weeks for those fed every 3 weeks, or not fed. The reproductive period, RMS index, and CI were lower for T. patagonica than T. infestans. However, despite the lower fecundity of T. patagonica, this species required less blood to produce eggs, with an E values of 2 compared to 2.94 for T. infestans. CONCLUSIONS Our results suggest that the differences in fecundity observed between species reflect the availability of food in their natural ecotopes.
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Affiliation(s)
- Claudia Rodríguez
- Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Patricia Lobbia
- Centro de Referencias de Vectores, Pabellón Rawson, Hospital Colonia de Santa María de Punilla, Santa María de Punilla, Córdoba, Argentina
| | - Julieta Nattero
- Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Silvia Catalá
- Centro Regional de Investigaciones Científicas y Transferencia Tecnológica de La Rioja, La Rioja, Argentina
| | - Liliana Crocco
- Físicas y Naturales, Universidad Nacional de Córdoba, Córdoba, Argentina
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Ecological, social and biological risk factors for continued Trypanosoma cruzi transmission by Triatoma dimidiata in Guatemala. PLoS One 2014; 9:e104599. [PMID: 25170955 PMCID: PMC4149347 DOI: 10.1371/journal.pone.0104599] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 07/15/2014] [Indexed: 11/24/2022] Open
Abstract
Background Chagas disease transmission by Triatoma dimidiata persists in Guatemala and elsewhere in Central America under undefined ecological, biological and social (eco-bio-social) conditions. Methodology Eco-bio-social risk factors associated with persistent domiciliary infestation were identified by a cross-sectional survey and qualitative participatory methods. Quantitative and qualitative data were generated regarding Trypanosoma cruzi reservoirs and triatomine hosts. Blood meal analysis and infection of insects, dogs and rodents were determined. Based on these data, multimodel inference was used to identify risk factors for domestic infestation with the greatest relative importance (>0.75). Principal Findings Blood meal analysis showed that 64% of 36 bugs fed on chickens, 50% on humans, 17% on dogs; 24% of 34 bugs fed on Rattus rattus and 21% on Mus musculus. Seroprevalence among 80 dogs was 37%. Eight (17%) of 46 M. musculus and three (43%) of seven R. rattus from households with infected triatomines were infected with T. cruzi Distinct Typing Unit I. Results from interviews and participatory meetings indicated that vector control personnel and some householders perceived chickens roosting and laying eggs in the house as bug infestation risk factors. House construction practices were seen as a risk factor for bug and rodent infestation, with rodents being perceived as a pest by study participants. Multimodel inference showed that house infestation risk factors of high relative importance are dog density, mouse presence, interior wall plaster condition, dirt floor, tile roofing and coffee tree presence. Conclusions/Significance Persistent house infestation is closely related to eco-bio-social factors that maintain productive T. dimidiata habitats associated with dogs, chickens and rodents. Triatomine, dog and rodent infections indicate active T. cruzi transmission. Integrated vector control methods should include actions that consider the role of peridomestic animals in transmission and community memberś level of knowledge, attitudes and practices associated with the disease and transmission process.
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