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1.
J Med Entomol ; 2024 Jul 06.
Article in English | MEDLINE | ID: mdl-38970363

ABSTRACT

Population genetic structure of arthropod disease vectors provides important information on vector movement and climate or other environmental variables that influence their distribution. This information is critical for data-driven vector control. In the first comprehensive study of the genetic structure of T. dimidiata s.l. (Latreille, 1811) we focus on an area of active transmission designated as a top priority for control. We examined a high number of specimens across a broad geographic area along the border of Guatemala and El Salvador including multiple spatial scales using a high number of genome-wide markers. Measuring admixture, pairwise genetic differentiation, and relatedness, we estimated the specimens represented three genetic clusters. We found evidence of movement (migration/gene flow) across all spatial scales with more admixture among locations in El Salvador than in Guatemala. Although there was significant isolation by distance, the 2 close villages in Guatemala showed either the most or least genetic variation indicating an additional role of environmental variables. Further, we found that social factors may be influencing the genetic structure. We demonstrated the power of genomic studies with a large number of specimens across a broad geographic area. The results suggest that for effective vector control movement must be considered on multiple spatial scales along with its contributing factors.

2.
Psychiatr Serv ; 74(8): 790-800, 2023 08 01.
Article in English | MEDLINE | ID: mdl-36718602

ABSTRACT

OBJECTIVE: This work aimed to assess the therapeutic and economic benefits of service dogs versus emotional support dogs for veterans with posttraumatic stress disorder (PTSD). METHODS: Veterans with PTSD (N=227) participating in a multicenter trial were randomly assigned to receive a service or emotional support dog; 181 veterans received a dog and were followed up for 18 months. Primary outcomes included overall functioning (assessed with World Health Organization Disability Assessment Scale II [WHODAS 2.0]) and quality of life (Veterans RAND 12-Item Health Survey [VR-12]). Secondary outcomes included PTSD symptoms (PTSD Checklist for DSM-5), suicidal ideation, depression, sleep quality, health care costs and utilization, medication adherence, employment, and productivity. RESULTS: Participants paired with a dog had a mean±SD age of 50.6±13.6 years (range 22-79), and most were male (80%), White (66%), and non-Hispanic (91%). Adjusted linear mixed repeated-measures models indicated no difference between the two groups on WHODAS 2.0 or VR-12 scores. Participants with service dogs had a 3.7-point greater reduction in PTSD symptoms versus participants with emotional support dogs (p=0.036). No reduced health care utilization or cost was associated with receiving a service dog. Veterans with service dogs had an increase of 10 percentage points in antidepressant adherence compared with those with emotional support dogs (p<0.01). CONCLUSIONS: Both groups appeared to benefit from having a service or emotional support dog. No significant differences in improved functioning or quality of life were observed between the groups. Those in the service dog group had a greater reduction in PTSD symptoms and better antidepressant adherence, improvements that should be explored further.


Subject(s)
Animal Assisted Therapy , Stress Disorders, Post-Traumatic , Veterans , Adult , Aged , Animals , Dogs , Female , Humans , Male , Middle Aged , Young Adult , Antidepressive Agents , Health Surveys , Quality of Life , Service Animals , Stress Disorders, Post-Traumatic/therapy , Stress Disorders, Post-Traumatic/psychology , Therapy Animals , Veterans/psychology
3.
Fed Pract ; 40(11 Suppl 5): S52-S56, 2023 Nov.
Article in English | MEDLINE | ID: mdl-38577306

ABSTRACT

Background: At the onset of COVID-19, essential supplies were not obtainable from manufacturers. This caused patients and clinicians to have additional risk and exposure to COVID-19 in some settings and the wasting of critical materials when testing was unavailable in other settings. Observations: The Veterans Health Administration (VHA) developed and enacted contingency plans for depleted supplies under both its First Mission-to care for veterans-and its Fourth Mission- to support the American health care system in times of crisis. A partnership among the VHA, US Food and Drug Administration, the National Institutes of Health, and America Makes addressed national shortages with the curation and development of designs, testing protocols, product evaluation, and product validation. VHA leveraged digital manufacturing to produce nasopharyngeal swabs onsite-3-dimensional-printed nasal swabs-and validate them to cover the gap between stockpile depletion and ramp up of traditional product manufacturing. Conclusions: This effort involved close collaboration between innovators and researchers within the organization and alongside government, industry, and academic partners. We illustrate this collaborative concept here with a use case of nasal swabs to demonstrate successes and lessons learned that are shaping how the VHA in conjunction with government and industry partners can shepherd this new strategy for crisis preparedness.

4.
Acta Trop ; 235: 106655, 2022 Nov.
Article in English | MEDLINE | ID: mdl-35977598

ABSTRACT

Triatoma dimidiata is the main vector of Chagas disease in southern Mexico, Central America and northern South America. As a native vector, it moves readily among domestic, peri­domestic and sylvatic environments, making it difficult to control only using insecticide as this requires regular application, and re-infestation frequently occurs. Other social innovation alternatives such as those based on Ecohealth principles can be used to tackle the dynamics of the disease in an integral way. We asked whether an Ecohealth intervention, implemented beginning in 2001 in a highly infested village, 41.8%, in southeastern Guatemala, was sustainable in the long term. This intervention included initial insecticide treatments, followed by making low-cost house improvements to eliminate transmission risk factors such as repairing cracked walls, covering dirt floors with a cement-like substance and moving domestic animals outside. We assessed the long-term sustainability through entomological and house condition surveys, as well as an analysis of community satisfaction. We found over a 19-year period, infestation with T. dimidiata was reduced to 2.2% and maintained at a level below the level (8%) where vector transmission is unlikely. This long-term maintenance of low infestation coincided with a large proportion of villagers (88.6%) improving their houses and completing other aspects of the Ecohealth approach to maintain the village at low risk for Chagas transmission. There was unanimous satisfaction among the villagers with their houses, following improvements using the Ecohealth method, which likely played a role in the long-term persistence of the modifications. Although the infestation has remained low, 11 years following the last intervention and as the population grew there has been an increase in the proportion of "at-risk" houses, to 33%, pointing out the necessity of maintaining vigilance. The Ecohealth approach is a low-cost, sustainable approach for the long-term control of vector-borne Chagas disease. We recommend this approach including ongoing community monitoring and institutional response for the long-term, integrated control of Chagas disease.


Subject(s)
Chagas Disease , Insecticides , Triatoma , Animals , Chagas Disease/prevention & control , Guatemala/epidemiology , Housing , Insect Control/methods , Insect Vectors/physiology , Triatoma/physiology
5.
Transfusion ; 62(9): 1808-1817, 2022 09.
Article in English | MEDLINE | ID: mdl-35895440

ABSTRACT

BACKGROUND: Chagas disease is a parasitic infection that can insidiously cause non-ischemic cardiomyopathy. Given the largely silent nature of this progressive disease, asymptomatic blood donors pose potential blood transfusion risk. Blood donation screening has become an unintentional form of Chagas disease surveillance, with thousands of new cases identified since national surveillance was initiated in 2007. STUDY DESIGN AND METHODS: We recruited T. cruzi-positive blood donors identified from California and Arizona blood centers for confirmatory blood screening and assessment of lifetime infection risk. RESULTS: Among eight suspected cases, we identified four confirmed US autochthonous infections. The current manuscript details the transmission sources, healthcare-seeking behaviors post-blood donation resulting, and clinical course of disease among persons without any history of travel to endemic Latin American countries. DISCUSSION: This manuscript presents four additional US-acquired Chagas disease cases and identifies an opportunity for blood centers to assist in confronting barriers surrounding Chagas disease in the US.


Subject(s)
Chagas Disease , Trypanosoma cruzi , Blood Donors , Blood Transfusion , Chagas Disease/diagnosis , Chagas Disease/epidemiology , Chagas Disease/parasitology , Humans , Southwestern United States
6.
PLoS Negl Trop Dis ; 15(12): e0010043, 2021 12.
Article in English | MEDLINE | ID: mdl-34919556

ABSTRACT

More than 100 years since the first description of Chagas Disease and with over 29,000 new cases annually due to vector transmission (in 2010), American Trypanosomiasis remains a Neglected Tropical Disease (NTD). This study presents the most comprehensive Trypanosoma cruzi sampling in terms of geographic locations and triatomine species analyzed to date and includes both nuclear and mitochondrial genomes. This addresses the gap of information from North and Central America. We incorporate new and previously published DNA sequence data from two mitochondrial genes, Cytochrome oxidase II (COII) and NADH dehydrogenase subunit 1 (ND1). These T. cruzi samples were collected over a broad geographic range including 111 parasite DNA samples extracted from triatomines newly collected across North and Central America, all of which were infected with T. cruzi in their natural environment. In addition, we present parasite reduced representation (Restriction site Associated DNA markers, RAD-tag) genomic nuclear data combined with the mitochondrial gene sequences for a subset of the triatomines (27 specimens) collected from Guatemala and El Salvador. Our mitochondrial phylogenetic reconstruction revealed two of the major mitochondrial lineages circulating across North and Central America, as well as the first ever mitochondrial data for TcBat from a triatomine collected in Central America. Our data also show that within mtTcIII, North and Central America represent an independent, distinct clade from South America, named here as mtTcIIINA-CA, geographically restricted to North and Central America. Lastly, the most frequent lineage detected across North and Central America, mtTcI, was also an independent, distinct clade from South America, noted as mtTcINA-CA. Furthermore, nuclear genome data based on Single Nucleotide Polymorphism (SNP) showed genetic structure of lineage TcI from specimens collected in Guatemala and El Salvador supporting the hypothesis that genetic diversity at a local scale has a geographical component. Our multiscale analysis contributes to the understanding of the independent and distinct evolution of T. cruzi lineages in North and Central America regions.


Subject(s)
Chagas Disease/parasitology , Mitochondria/genetics , Trypanosoma cruzi/classification , Trypanosoma cruzi/isolation & purification , Central America , Electron Transport Complex I/genetics , Electron Transport Complex I/metabolism , Electron Transport Complex IV/genetics , Electron Transport Complex IV/metabolism , Humans , Mitochondria/metabolism , Phylogeny , Protozoan Proteins/genetics , Protozoan Proteins/metabolism , South America , Trypanosoma cruzi/genetics
7.
Acta Trop ; 224: 106130, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34536368

ABSTRACT

Assays for parasite detection in insect vectors provide important information for disease control. American Trypanosomiasis (Chagas disease) is the most devastating vector-borne illness and the fourth most common in Central America behind HIV/AIDS and acute respiratory and diarrheal infections (Peterson et al., 2019). Under-detection of parasites is a general problem which may be influenced by parasite genetic variation; however, little is known about the genetic variation of the Chagas parasite, especially in this region. In this study we compared six assays for detecting the Chagas parasite, Trypanosoma cruzi: genomic reduced representation sequencing (here referred to as genotype-by-sequencing or GBS), two with conventional PCR (i.e., agarose gel detection), two with qPCR, and microscopy. Our results show that, compared to GBS genomic analysis, microscopy and PCR under-detected T. cruzi in vectors from Central America. Of 94 samples, 44% (50/94) were positive based on genomic analysis. The lowest detection, 9% (3/32) was in a subset assayed with microscopy. Four PCR assays, two with conventional PCR and two with qPCR showed intermediate levels of detection. Both qPCR tests and one conventional PCR test targeted the 195 bp repeat of satellite DNA while the fourth test targeted the 18S gene. Statistical analyses of the genomic and PCR results indicate that the PCR assays significantly under detect infections of Central American T. cruzi genotypes.


Subject(s)
Chagas Disease , Triatoma , Trypanosoma cruzi , Animals , Central America , Chagas Disease/diagnosis , Real-Time Polymerase Chain Reaction , Triatoma/genetics , Trypanosoma cruzi/genetics
8.
PLoS One ; 16(2): e0247068, 2021.
Article in English | MEDLINE | ID: mdl-33630885

ABSTRACT

Scientific collections such as the U.S. National Museum (USNM) are critical to filling knowledge gaps in molecular systematics studies. The global taxonomic impediment has resulted in a reduction of expert taxonomists generating new collections of rare or understudied taxa and these large historic collections may be the only reliable source of material for some taxa. Integrated systematics studies using both morphological examinations and DNA sequencing are often required for resolving many taxonomic issues but as DNA methods often require partial or complete destruction of a sample, there are many factors to consider before implementing destructive sampling of specimens within scientific collections. We present a methodology for the use of archive specimens that includes two crucial phases: 1) thoroughly documenting specimens destined for destructive sampling-a process called electronic vouchering, and 2) the pipeline used for whole genome sequencing of archived specimens, from extraction of genomic DNA to assembly of putative genomes with basic annotation. The process is presented for eleven specimens from two different insect subfamilies of medical importance to humans: Anophelinae (Diptera: Culicidae)-mosquitoes and Triatominae (Hemiptera: Reduviidae)-kissing bugs. Assembly of whole mitochondrial genome sequences of all 11 specimens along with the results of an ortholog search and BLAST against the NCBI nucleotide database are also presented.


Subject(s)
Culicidae/genetics , DNA/genetics , Animals , Genomics/methods , Humans , Phylogeny , Sequence Analysis, DNA/methods , Triatoma/genetics , Triatominae/genetics
9.
Am J Trop Med Hyg ; 103(2): 735-744, 2020 08.
Article in English | MEDLINE | ID: mdl-32524965

ABSTRACT

Chagas disease is a lethal, neglected tropical disease. Unfortunately, aggressive insecticide-spraying campaigns have not been able to eliminate domestic infestation of Triatoma dimidiata, the native vector in Guatemala. To target interventions toward houses most at risk of infestation, comprehensive socioeconomic and entomologic surveys were conducted in two towns in Jutiapa, Guatemala. Given the exhaustively large search space associated with combinations of risk factors, traditional statistics are limited in their ability to discover risk factor interactions. Two recently developed statistical evolutionary algorithms, specifically designed to accommodate risk factor interactions and heterogeneity, were applied to this large combinatorial search space and used in tandem to identify sets of risk factor combinations associated with infestation. The optimal model includes 10 risk factors in what is known as a third-order disjunctive normal form (i.e., infested households have chicken coops AND deteriorated bedroom walls OR an accumulation of objects AND dirt floors AND total number of occupants ≥ 5 AND years of electricity ≥ 5 OR poor hygienic condition ratings AND adobe walls AND deteriorated walls AND dogs). Houses with dirt floors and deteriorated walls have been reported previously as risk factors and align well with factors currently targeted by Ecohealth interventions to minimize infestation. However, the tandem evolutionary algorithms also identified two new socioeconomic risk factors (i.e., households having many occupants and years of electricity ≥ 5). Identifying key risk factors may help with the development of new Ecohealth interventions and/or reduce the survey time needed to identify houses most at risk.


Subject(s)
Animals, Domestic , Chagas Disease/epidemiology , Construction Materials/statistics & numerical data , Housing, Animal , Housing/statistics & numerical data , Insect Vectors , Triatoma , Algorithms , Animals , Chagas Disease/transmission , Chickens , Dogs , Electric Wiring/statistics & numerical data , Family Characteristics , Guatemala/epidemiology , Humans , Hygiene , Insect Control , Insecticides , Pyrethrins , Risk Factors , Risk Reduction Behavior , Socioeconomic Factors
10.
Am J Med ; 133(1): 108-114.e13, 2020 01.
Article in English | MEDLINE | ID: mdl-31295438

ABSTRACT

BACKGROUND: Kissing bugs are common household pests in the Desert Southwest of the United States. These hematophagous bugs enter homes and suck blood from resident humans and pets. They are vectors of Trypanosoma cruzi, an enzootic parasite in small mammals and the cause of Chagas disease in humans. Autochthonous cases of Chagas disease are rare in the United States despite the presence of the vector and parasite. Environmental and biological factors accounting for this phenomenon need studying. METHODS: Homeowners in Bisbee and Tucson, Arizona captured kissing bugs inside homes during 2017-2018. Bugs were tested for presence of T. cruzi by polymerase chain reaction. Residents bitten by kissing bugs were tested for Chagas disease by serology. We evaluated invaded homes in the 2 cities. RESULTS: Three species of kissing bugs (n = 521) were collected in or near homes. Triatoma rubida was the most common triatomine in Tucson; T. recurva in Bisbee. T. protracta was uncommon. Seventeen percent of bugs captured in Bisbee and 51.1% in Tucson harbored T. cruzi. Bite victims (n = 105) recalled more than 2200 bites. Reactions to bites were common, including 32 episodes of anaphylaxis in 11 people (10.5%). Tests for Chagas disease (n = 116) were negative. Median age of houses was 91 years in Bisbee and 7 years in Tucson. Bisbee houses had pier and beam foundations. Tucson houses were built on concrete slabs. CONCLUSIONS: Kissing bugs harboring T. cruzi readily entered new and old homes. Bites of humans caused severe, life-threatening reactions. There was no serological evidence of Chagas disease among those bitten.


Subject(s)
Chagas Disease/epidemiology , Insect Bites and Stings/epidemiology , Insect Vectors/parasitology , Triatoma/parasitology , Trypanosoma cruzi/isolation & purification , Adolescent , Adult , Aged , Aged, 80 and over , Anaphylaxis/epidemiology , Anaphylaxis/etiology , Animals , Arizona/epidemiology , Female , Humans , Hypersensitivity/epidemiology , Hypersensitivity/etiology , Insect Bites and Stings/complications , Male , Middle Aged , United States/epidemiology , Young Adult
11.
Rev. cuba. med. trop ; 71(3): e380, sept.-dic. 2019. tab, graf
Article in English | LILACS, CUMED | ID: biblio-1093576

ABSTRACT

Introduction: The Mesoamerican endemic specieTriatoma dimidiata is the main vector of Chagas disease in Central America, after the elimination of an introduced vector Rhodnius prolixus. The traditional method of vector control using insecticides results in reinfestation. An integrated Ecohealth approach, including education, house improvements and domestic animal management was shown effective for long-term control ofT. dimidiata, and it was applied in several villages in Guatemala. Objective: To evaluate the changes in community practices after an Ecohealth intervention in La Prensa, Olopa Chiquimula. Methods: Through three surveys, we measured risk factors associated withT. dimidiatainfestation, the infestation index, blood sources of T. dimidiata, the presence of Trypanosoma cruzi were analyzed using PCR. Statistics analysis included Wilcoxon signed-rank tests, Mc-Nemar test, Chi-square test and Fisher exact test to compare the surveys. Results: Over the years, risk factors associated with the presence of T. dimidiata and population density of the vector were observed. We found a decrease in consumption of human blood and the parasite in the vector population. However, we found the consumption of bird blood meal increased Conclusions: Our results provide evidence that an ecohealth approach for an endemic Chagas vector has impact on reducing vector-human contact, possibly by influencing people's behavior. Increasing the community knowledge about these risk factors can be an effective strategy to further reduce the risk of house reinfestation and Chagas transmission(AU)


Introducción: La especie endémica mesoamericana Triatoma dimidiata es el vector principal de la enfermedad de Chagas en América Central, después de la eliminación de un vector introducido Rhodnius prolixus. El método tradicional de control de vectores que utiliza insecticidas resulta en reinfestación. Se demostró que un enfoque integrado de ecosalud, que incluye la educación, mejorías en el hogar y manejo de animales domésticos, es efectivo para el control a largo plazo del T. dimidiata, y se aplicó en varias aldeas de Guatemala. Objetivo: evaluar los cambios en las prácticas comunitarias después de una intervención de ecosalud en La Prensa, Olopa Chiquimula. Métodos: a través de tres encuestas, se midieron los factores de riesgo asociados con la infestación de T. dimidiata, el índice de infestación, las fuentes sanguíneas de T. dimidiata y la presencia de Trypanosoma cruzi. Estas encuestas se analizaron mediante PCR. El análisis estadístico incluyó pruebas de Wilcoxon de rango con signo, la prueba de Mc-Nemar, la prueba de Chi-cuadrado y la prueba exacta de Fisher para comparar las encuestas. Resultados: A lo largo de los años, se observaron factores de riesgo asociados con la presencia de T. dimidiata y la densidad de población del vector. Encontramos una disminución del parásito en la población de vectores y en el consumo de sangre humana. Sin embargo, encontramos que aumentó el consumo de harina de sangre de aves. Conclusiones: Nuestros resultados proporcionan evidencia de que un enfoque de ecosalud para un vector de Chagas endémico impacta en la reducción del contacto vector-humano, posiblemente al influir en el comportamiento de las personas. Aumentar el conocimiento de la comunidad sobre estos factores de riesgo puede ser una estrategia efectiva para reducir aun más el riesgo de reinfestación en la casa y la transmisión de Chagas(AU)


Subject(s)
Humans , Triatominae , Chagas Disease/prevention & control , Communication , Community Participation
12.
Infect Genet Evol ; 74: 104000, 2019 10.
Article in English | MEDLINE | ID: mdl-31408767

ABSTRACT

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and transmitted by triatomine insect vectors. In Guatemala, insecticide spraying is an integral part of management of the main vector, Triatoma dimidiata. Spraying typically has low efficacy, which may be due to incomplete elimination from infested houses, within-village dispersal, or influx from other villages or sylvan environments. To evaluate how these mechanisms contribute to reinfestation, we conducted a time-course analysis of T. dimidiata infestation, abundance and household genetic structure in two nearby villages in Jutiapa, Guatemala; houses in the first village were surveyed, treated with insecticide if infested and then re-surveyed at eight and 22 months following spraying, while the second village served as an untreated control to quantify changes associated with seasonal dispersal. Insects were genotyped at 2-3000 SNP loci for kinship and population genetic analyses. Insecticide application reduced overall infestation and abundance, while the untreated village was stable over time. Nevertheless, within two years 35.5% of treated houses were reinfested and genetic diversity had largely recovered. Insects collected from reinfested houses post-spraying were most closely related to pre-spray collections from the same house, suggesting that infestations had not been fully eliminated. Immigration by unrelated insects was also detected within a year of spraying; when it occurred, dispersal was primarily local from neighboring houses. Similar dispersal patterns were observed following the annual dispersal season in the untreated village, with high-infestation houses serving as sources for neighboring homes. Our findings suggest that the efficacy of pyrethroid application is rapidly diminished by both within-house breeding by survivors and annual cycles of among-house movement. Given these patterns, we conclude that house structural improvements, an integral part of the Ecohealth approach that makes houses refractory to vector colonization and persistence, are critical for long-term reduction of T. dimidiata infestation.


Subject(s)
Insecticide Resistance , Insecticides/pharmacology , Polymorphism, Single Nucleotide , Pyrethrins/pharmacology , Triatoma/growth & development , Animals , DNA/genetics , Female , Genotyping Techniques/methods , Guatemala , Insect Control , Male , Population Dynamics , Triatoma/drug effects , Triatoma/genetics
13.
Mem Inst Oswaldo Cruz ; 114: e190047, 2019.
Article in English | MEDLINE | ID: mdl-31166422

ABSTRACT

OBJECTIVES: We tested a rapid and specific immunochromatographic assay (that detects human blood in forensic samples) to determine if human blood was present in triatomines and their fecal excreta. METHODS: We fed Triatoma rubida human blood (positive control) or mouse blood (negative control) and performed the assay on the abdominal contents and fecal excreta. Triatomine field specimens collected in and around human habitations and excreta were also tested. FINDINGS: The assay was positive in triatomines fed human blood (N = 5/5) and fecal excreta from bugs known to have ingested human blood (N = 5/5). Bugs feeding on mice (N = 15/15) and their fecal excreta (N = 8/8) were negative for human blood. Human blood was detected in 47% (N = 23/49) triatomines, representing six different species, collected in the field. MAIN CONCLUSIONS: The pilot study shows that this rapid and specific test may have applications in triatomine research. Further study is needed to determine the sensitivity of this assay compared to other well-established techniques, such as DNA- and proteomics-based methodologies and the assay's application in the field.


Subject(s)
Blood , Feces/chemistry , Immunoassay/methods , Triatominae , Animals , Chagas Disease/transmission , Humans , Mice , Pilot Projects , Reference Standards , Reference Values , Reproducibility of Results , Time Factors
15.
Zookeys ; (820): 51-70, 2019.
Article in English | MEDLINE | ID: mdl-30728739

ABSTRACT

A new species of the genus Triatoma Laporte, 1832 (Hemiptera, Reduviidae) is described based on specimens collected in the department of Huehuetenango, Guatemala. Triatomahuehuetenanguensis sp. n. is closely related to T.dimidiata (Latreille, 1811), with the following main morphological differences: lighter color; smaller overall size, including head length; and width and length of the pronotum. Natural Trypanosomacruzi (Chagas, 1909) infection, coupled with its presence in domestic habitats, makes this species a potentially important vector of Trypanosomacruzi in Guatemala.

16.
J Med Entomol ; 56(3): 651-655, 2019 04 16.
Article in English | MEDLINE | ID: mdl-30597032

ABSTRACT

Kissing bugs in the genus Triatoma are obligate blood feeders that feed mainly on vertebrate blood and have lost the predatory lifestyle found in other reduviid bugs. They occasionally also feed on the hemolymph of arthropods, especially during the first and second instar stages. The largest kissing bug species in the United States, Triatoma recurva (Stål) (Hemiptera: Reduviidae), is poorly known and was chosen to investigate its ability to feed and develop on a diet of cockroach hemolymph. Molting from first instar individuals to second instars readily occurred at approximately the same rate reported for the species feeding on mammalian blood. Subsequent instars also fed on and survived on cockroach hemolymph with some individuals maturing to adults. In the larger instars, development time and survival rates were reduced relative to the results reported in the literature for mammalian-blood-fed individuals. Two other species of kissing bugs, Triatoma protracta (Uhler) and T. rubida (Uhler) failed to survive on cockroach hemolymph with most individuals failing to molt from the first instar stage. Although T. recurva does not thrive on a diet limited to hemolymph of cockroaches, it appears to be an unusual species in which cockroaches might be a primary source of nutrition for smaller individuals and are a viable exclusive source of nutrition for all immatures. At a minimum during times of limited availability of vertebrate blood sources, the presence of cockroaches enhances survival opportunities. Efforts to control populations of this kissing bug species likely will be improved with additional control of cockroach populations in the environment.


Subject(s)
Diet , Food Chain , Hemolymph , Insect Control , Periplaneta , Triatoma/growth & development , Animals , Female , Male , Nymph/growth & development
17.
Mem. Inst. Oswaldo Cruz ; 114: e190047, 2019. tab, graf
Article in English | LILACS | ID: biblio-1012677

ABSTRACT

BACKGROUND DNA- and proteomics-based techniques are currently used to identify a triatomine human blood meal. These methods are time consuming, require access to laboratories with sophisticated equipment, and trained personnel. OBJECTIVES We tested a rapid and specific immunochromatographic assay (that detects human blood in forensic samples) to determine if human blood was present in triatomines and their fecal excreta. METHODS We fed Triatoma rubida human blood (positive control) or mouse blood (negative control) and performed the assay on the abdominal contents and fecal excreta. Triatomine field specimens collected in and around human habitations and excreta were also tested. FINDINGS The assay was positive in triatomines fed human blood (N = 5/5) and fecal excreta from bugs known to have ingested human blood (N = 5/5). Bugs feeding on mice (N = 15/15) and their fecal excreta (N = 8/8) were negative for human blood. Human blood was detected in 47% (N = 23/49) triatomines, representing six different species, collected in the field. MAIN CONCLUSIONS The pilot study shows that this rapid and specific test may have applications in triatomine research. Further study is needed to determine the sensitivity of this assay compared to other well-established techniques, such as DNA- and proteomics-based methodologies and the assay's application in the field.


Subject(s)
Humans , Immunoassay , Chromatography, Affinity/methods , Triatominae , Pilot Projects
18.
PLoS Negl Trop Dis ; 12(10): e0006730, 2018 10.
Article in English | MEDLINE | ID: mdl-30335763

ABSTRACT

Chagas disease, considered a neglected disease by the World Health Organization, is caused by the protozoan parasite Trypanosoma cruzi, and transmitted by >140 triatomine species across the Americas. In Central America, the main vector is Triatoma dimidiata, an opportunistic blood meal feeder inhabiting both domestic and sylvatic ecotopes. Given the diversity of interacting biological agents involved in the epidemiology of Chagas disease, having simultaneous information on the dynamics of the parasite, vector, the gut microbiome of the vector, and the blood meal source would facilitate identifying key biotic factors associated with the risk of T. cruzi transmission. In this study, we developed a RADseq-based analysis pipeline to study mixed-species DNA extracted from T. dimidiata abdomens. To evaluate the efficacy of the method across spatial scales, we used a nested spatial sampling design that spanned from individual villages within Guatemala to major biogeographic regions of Central America. Information from each biotic source was distinguished with bioinformatics tools and used to evaluate the prevalence of T. cruzi infection and predominant Discrete Typing Units (DTUs) in the region, the population genetic structure of T. dimidiata, gut microbial diversity, and the blood meal history. An average of 3.25 million reads per specimen were obtained, with approximately 1% assigned to the parasite, 20% to the vector, 11% to bacteria, and 4% to putative blood meals. Using a total of 6,405 T. cruzi SNPs, we detected nine infected vectors harboring two distinct DTUs: TcI and a second unidentified strain, possibly TcIV. Vector specimens were sufficiently variable for population genomic analyses, with a total of 25,710 T. dimidiata SNPs across all samples that were sufficient to detect geographic genetic structure at both local and regional scales. We observed a diverse microbiotic community, with significantly higher bacterial species richness in infected T. dimidiata abdomens than those that were not infected. Unifrac analysis suggests a common assemblage of bacteria associated with infection, which co-occurs with the typical gut microbial community derived from the local environment. We identified vertebrate blood meals from five T. dimidiata abdomens, including chicken, dog, duck and human; however, additional detection methods would be necessary to confidently identify blood meal sources from most specimens. Overall, our study shows this method is effective for simultaneously generating genetic data on vectors and their associated parasites, along with ecological information on feeding patterns and microbial interactions that may be followed up with complementary approaches such as PCR-based parasite detection, 18S eukaryotic and 16S bacterial barcoding.


Subject(s)
DNA/genetics , DNA/isolation & purification , Feeding Behavior , Gastrointestinal Microbiome , Triatoma/genetics , Trypanosoma cruzi/isolation & purification , Animals , Archaea/genetics , Archaea/isolation & purification , Bacteria/genetics , Bacteria/isolation & purification , Central America , Cluster Analysis , Computational Biology , Fungi/genetics , Fungi/isolation & purification , High-Throughput Nucleotide Sequencing , Humans , Nematoda/genetics , Nematoda/isolation & purification , Phylogeny , Sequence Analysis, DNA , Triatoma/microbiology , Triatoma/parasitology , Triatoma/physiology , Trypanosoma cruzi/genetics , Viruses/genetics , Viruses/isolation & purification
19.
Zookeys ; (775): 69-95, 2018.
Article in English | MEDLINE | ID: mdl-30057472

ABSTRACT

In this paper, Triatoma mopansp. n. is described based on five males and six females collected in the Rio Frio cave, Cayo District, Belize. This species is similar to Triatoma dimidiata (Latreille), but can be distinguished by characters found on the pronotum, legs, and abdomen. Geometric morphometry and phylogenetic comparisons are also provided. Presently, the species is known only from the type locality and is a potential Chagas vector.

20.
Mol Phylogenet Evol ; 120: 144-150, 2018 03.
Article in English | MEDLINE | ID: mdl-29248626

ABSTRACT

To date, the phylogeny of Triatoma dimidiata sensu lato (s. l.) (Hemiptera: Reduviidae: Triatominae), the epidemiologically most important Chagas disease vector in Central America and a secondary vector in Mexico and northern South America, has only been investigated by one multi-copy nuclear gene (Internal Transcribed Spacer - 2) and a few mitochondrial genes. We examined 450 specimens sampled across most of its native range from Mexico to Ecuador using reduced representation next-generation sequencing encompassing over 16,000 single nucleotide polymorphisms (SNPs). Using a combined phylogenetic and species delimitation approach we uncovered two distinct species, as well as a well-defined third group that may contain multiple species. The findings are discussed with respect to possible drivers of diversification and the epidemiological importance of the distinct species and groups.


Subject(s)
Genetic Variation , Genome , Triatoma/genetics , Animals , Central America , Chagas Disease/parasitology , Chagas Disease/pathology , DNA/chemistry , DNA/isolation & purification , DNA/metabolism , Genes, Mitochondrial , Humans , Insect Vectors/genetics , Phylogeny , Polymorphism, Single Nucleotide , Triatoma/classification , Triatoma/parasitology , Trypanosoma cruzi/physiology
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