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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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High Parasitic Loads Quantified in Sylvatic Triatoma melanica, a Chagas Disease Vector. Pathogens 2022; 11:pathogens11121498. [PMID: 36558833 PMCID: PMC9785645 DOI: 10.3390/pathogens11121498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 11/29/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022] Open
Abstract
Triatoma melanica is a sylvatic vector species in Brazil. In We aimed to characterize the Trypanosoma cruzi discrete typing units (DTUs), the parasitic loads, and the blood meal sources of insects collected in rocky outcrops in rural areas in the state of Minas Gerais. An optical microscope (OM) and kDNA-PCR were used to examine natural infection by T. cruzi, and positive samples were genotyped by conventional multilocus PCR. Quantification of the T. cruzi load was performed using qPCR, and the blood meal sources were identified by Sanger sequencing the 12S rRNA gene. A total of 141 T. melanica were captured. Of these, ~55% (61/111) and ~91% (63/69) were positive by OM and KDNA-PCR, respectively. We genotyped ~89% (56/63) of the T. cruzi-positive triatomines, with TcI (~55%, 31/56) being the most prevalent DTU, followed by TcIII (~20%, 11/56) and TcII (~7%, 4/56). Only TcI+TcIII mixed infections were detected in 10 (~18%) specimens. A wide range of variation in the parasitic loads of T. melanica was observed, with an overall median value of 104 parasites/intestine, with females having higher T. cruzi loads than N2, N4, and N5. TcII showed lower parasitic loads compared to TcI and TcIII. The OM positive diagnosis odds ratio between T. cruzi infection when the parasite load is 107 compared to 103 was approximately 29.1. The most frequent blood meal source was Kerodon rupestris (~58%), followed by Thrichomys apereoides (~18%), Wiedomys cerradensis (~8%), Galactis cuja (~8%) and Gallus gallus (~8%). Our findings characterize biological and epidemiological aspects of the sylvatic population of T. melanica in the study area, highlighting the need to extend surveillance and control to this vector.
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Characterization of triatomine bloodmeal sources using direct Sanger sequencing and amplicon deep sequencing methods. Sci Rep 2022; 12:10234. [PMID: 35715521 PMCID: PMC9205944 DOI: 10.1038/s41598-022-14208-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 06/02/2022] [Indexed: 11/17/2022] Open
Abstract
Knowledge of host associations of blood-feeding vectors may afford insights into managing disease systems and protecting public health. However, the ability of methods to distinguish bloodmeal sources varies widely. We used two methods—Sanger sequencing and amplicon deep sequencing—to target a 228 bp region of the vertebrate Cytochrome b gene and determine hosts fed upon by triatomines (n = 115) collected primarily in Texas, USA. Direct Sanger sequencing of PCR amplicons was successful for 36 samples (31%). Sanger sequencing revealed 15 distinct host species, which included humans, domestic animals (Canis lupus familiaris, Ovis aries, Gallus gallus, Bos taurus, Felis catus, and Capra hircus), wildlife (Rattus rattus, Incilius nebulifer, Sciurus carolinensis, Sciurus niger, and Odocoileus virginianus), and captive animals (Panthera tigris, Colobus spp., and Chelonoidis carbonaria). Samples sequenced by the Sanger method were also subjected to Illumina MiSeq amplicon deep sequencing. The amplicon deep sequencing results (average of 302,080 usable reads per sample) replicated the host community revealed using Sanger sequencing, and detected additional hosts in five triatomines (13.9%), including two additional blood sources (Procyon lotor and Bassariscus astutus). Up to four bloodmeal sources were detected in a single triatomine (I. nebulifer, Homo sapiens, C. lupus familiaris, and S. carolinensis). Enhanced understanding of vector-host-parasite networks may allow for integrated vector management programs focusing on highly-utilized and highly-infected host species.
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Trypanosoma cruzi infection in the wild Chagas disease vector, Mepraia spinolai: Parasitic load, discrete typing units, and blood meal sources. Acta Trop 2022; 229:106365. [PMID: 35150641 DOI: 10.1016/j.actatropica.2022.106365] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 12/30/2022]
Abstract
BACKGROUND Mepraia spinolai, a wild vector of Trypanosoma cruzi in Chile, is an abundant triatomine species that is frequently infected by the parasite that causes Chagas disease. The aim of this study was to determine if the parasitic load of T. cruzi in M. spinolai is related to its blood meal source and the infecting DTUs of T. cruzi. METHODS The vector was captured in rural areas. In the laboratory, DNA was extracted from its abdomen and T. cruzi was quantified using qPCR. Real time PCR assays for four T. cruzi DTUs were performed. Blood meal sources were identified by real-time PCR amplification of vertebrate cytochrome b gene sequences coupled with high resolution melting (HRM). RESULTS Trypanosoma cruzi was detected in 735 M. spinolai; in 484 we identified one blood meal source, corresponding to human, sylvatic, and domestic species. From these, in 224 we were able to discriminate the infecting DTU. When comparing the parasitic loads between the unique blood meal sources, no significant differences were found, but infections with more than one DTU showed higher parasitic loads than single infections. DTU TcI was detected in a high proportion of the samples. CONCLUSIONS Higher parasitic loads are related to a greater number of T. cruzi DTUs infecting M. spinolai, and this triatomine seems to have a wide span of vertebrate species in its diet.
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Carmona-Galindo VD, Marín Recinos MF, Gámez Hidalgo SA, Recinos Paredes G, Posada Vaquerano EE, Romero Magaña AL, Castillo Ayala AK. Morphological variability and ecological characterization of the Chagas disease vector Triatoma dimidiata (Hemiptera: Reduviidae) in El Salvador. Acta Trop 2020; 205:105392. [PMID: 32061627 DOI: 10.1016/j.actatropica.2020.105392] [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] [Received: 07/16/2019] [Revised: 02/08/2020] [Accepted: 02/08/2020] [Indexed: 11/24/2022]
Abstract
There are 8 million people with Chagas disease worldwide and in El Salvador approximately 39% of the population is at risk of contracting the disease. One of the principal challenges in mitigating Chagas is evaluating the role of the vector ecology of triatomine species in the transmission of the Trypanosoma cruzi parasite in anthropogenically modified habitats, where new patterns of transmission frequently arise. Field studies of triatomine vector ecology in El Salvador have largely focused on describing parameters that contribute to infestation patterns, which may themselves be rooted in the morphological variability that exists in triatomine populations. The objective of this study was to evaluate the morphology of the vector species Triatoma dimidiata with respect to the characteristics of the ecological landscape the vector inhabits throughout El Salvador. We used image analyses to evaluate T. dimidiata morphological variability and then used Geographic Information Systems to intersect the morphological point-data with map layers containing different environmental characteristics. Our study found that the variation in the size, shape, and coloration of T. dimidiata varied in relation to elevation, Holdridge life zone, soil type and land use. We further characterize the local morphological adaptations of T. dimidiata with respect to the local ecological, biological, and geographical conditions in El Salvador. We suggest that future studies consider a molecular exploration of local T. dimidiata species complex in El Salvador, especially since morphological studies of triatomine species complex have found that variability correlate with the genetic variability of the population.
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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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Mendes-Sousa AF, Araújo LDND, Sousa SSD, Alencar SDC, Sousa Júnior WAD, Sousa LMD, Rocha SMD, Maia JCDS, Marques MMM, Pinheiro TG, Silva ELD, Barros VC, Pacheco ACL. Triatomine bugs (Hemiptera, Reduviidae, Triatominae) in the Domiciles of the Guaribas Valley Territory, in Northeastern Brazil. Rev Soc Bras Med Trop 2020; 53:e20200177. [PMID: 32935785 PMCID: PMC7491561 DOI: 10.1590/0037-8682-0177-2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 05/26/2020] [Indexed: 11/22/2022] Open
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