Reacción paradojal secundaria a ingesta accidental de benzodiazepinas. Serie de casos / Paradoxical reaction secondary to accidental ingestion of benzodiazepines. Case series

Resumen Globalmente, los fármacos son el tipo de agente más frecuentemente implicado en las intoxicaciones pediátricas y las Ben-zodiacepinas el grupo farmacológico más frecuente. La reacción paradojal, secundaria a la exposición a Benzodiacepinas se caracteriza por la presencia de signosintomatología contraria a los efectos sedativos hipnóticos esperados, pudiendo presentarse con inquietud, ansiedad, hostilidad y alteraciones de la conducta, entre otros. La mayoría de los trabajos hallados acerca de este síndrome en pediatría lo describen secundario a Midazolam endovenoso, en contexto de sedación consciente para la realización de diferentes procedimientos. Las causas por los cuales se puede generar este fenómeno de desinhibición no han sido clarificadas, postulándose tres hipótesis: la desregulación colinérgica central, el aumento del tono gabaérgico en el sistema límbico, tálamo e hipotálamo y el desbalance de serotonina. Se expone una serie de 15 pacientes de entre 1 año y 5 años, expuestos accidentalmente a Benzodiacepinas, principalmente Clonazepam y Lorazepam, a fin de describir las características de esta reacción. En esta serie se observó con latencia breve y duración variable, de hasta 11 horas, la presencia en orden de frecuencia, de: ansiedad, irritabilidad, gritos, hostilidad y conductas agresivas, llanto inconsolable, incapacidad de contención por familiares, conductas irracionales, excitación psicomotriz, desinhibición emocional, alucinaciones y aumento de locuacidad, asociado frecuentemente a ataxia.

Abstract Globally, medicines are the most frequently toxins involved in pediatric poisonings, and Benzodiazepines are the most fre-quent pharmacological group in those poisonings. The paradoxical reaction, secondary to Benzodiazepines exposure, is characterized by the presence of contrary expected sedative-hypnotic effects, and may present with restlessness, increased anxiety, hostility, and behav-ioral alterations, among others. The studies we found about this syndrome in pediatric patients describe it most frequently secondary to endovenous Midazolam, in the context of the conscious sedation to perform different procedures. The reasons why this reaction is generated have not been clarified, three hypotheses are postulated: the central cholinergic dysregulation, the increased Gabaergic tone in the limbic system, thalamus and hypothalamus and the serotonin imbalance. A series of 15 patients, between 1 year and 5 years old, accidentally exposed to Benzodiazepines, mainly Clonazepam and Lorazepam, to describe the characteristics of the paradoxical reaction secondary to Benzodiazepines exposure. In this case series, we observed with short latency and variable duration, up to 11 hours, the presence in order of frequency of: anxiety, irritability, screams, hostility and aggressive behaviors, inconsolable crying, inability to con-tain by their family members, irrational behaviors and psychomotor excitement, emotional disinhibition, hallucinations and increased talkativeness, frequently associated with ataxia.

Intoxicación accidental por marihuana en pediatría. Serie de 3 casos / Accidental poisoning by marijuana in pediatrics. Series of 3 cases

Resumen La marihuana o cannabis es la sustancia psicoactiva ilícita de mayor consumo. Una consecuencia no deseada de la regulación de su cultivo y la difusión popular de su uso medicinal y recreativo, es su asociación con el aumento de la disponibilidad de cultivos en la población general y de productos, como alimentos y fármacos elaborados con infusiones de esta planta, con concentraciones desconocidas de delta-9-tetrahidrocannabinol (A9THC), su principal componente psicoactivo. Se presenta una serie de 3 pacientes expuestos a esta sustancia de forma no intencional, por vía digestiva, asistidos de forma presencial por los servicios de Toxicología y Emergencias del Hospital Interzonal de Agudos Especializado en Pediatría "Sor María Ludovica" de La Plata. A diferencia de la absorción por vía inhalatoria, por vía digestiva se producen concentraciones mucho más variables y ciclos temporales mayores de A9THC y sus metabolitos, que ejercen sus efectos sobre los receptores CB1, dispuestos en el sistema nervioso central, incluido tronco encefálico, región con mayor presencia de éstos en niños, lo que justifica las manifestaciones neurológicas frecuentes y de mayor gravedad en este grupo etario, en relación a los adultos. La sospecha clínica, la anamnesis y la detección temprana de cannabinoides en orina son los pilares fundamentales para establecer el diagnóstico temprano. El tratamiento consiste en medidas de sostén y sintomáticas, que se implementan según la gravedad del cuadro. Debe considerarse la posibilidad de exposición a esta sustancia frente a cuadros de letargo o somnolencia de aparición brusca, con ataxia, modificaciones del humor, alteraciones sensoperceptivas, convulsiones o coma, con o sin insuficiencia respiratoria, con taquicardia o bradicardia. Es de fundamental importancia la educación y concientización de los adultos a cargo de niños sobre estos riesgos.

Abstract Marijuana or cannabis is the illicit psychoactive substance most widely used. An unwanted consequence of the regula-tion of its cultivation and the popular diffusion of its medicinal and recreational use, is the association with an increase in the avail-ability of crops in the general population, products, foods and medicines made with cannabis infusions, with unknown concentra-tions of delta-9-tetrahydrocannabinol (A9THC), the most important psychoactive component. We present a series with 3 patients with unintentional exposure to this substance through the digestive tract, assisted by the Toxicology and Emergency services of the Interzonal Hospital for Acute Specialized in Pediatrics "Sor María Ludovica". Unlike absorption through the inhalation route, more variable concentrations and greater temporal cycles of A9THC and its metabolites are produced through the digestive route, which exert their effects on CB1 receptors, arranged in the central nervous system, including brainstem, the region with greatest presence of this receptors in children, that justifies the frequent and more serious neurological manifestations in children, compared to adults. Clinical suspicion, anamnesis and early detection of cannabinoids in urine are the fundamental pillars to establish an early diagnosis. Treatment consists in supportive and symptomatic measures, that are implemented according to the severity of the condition. The possibility of exposure to this substance must be estimated in the face of sudden onset of lethargy or drowsi-ness, with ataxia, mood modifications, sensory-perceptual disturbances, seizures or coma, with or without respiratory failure, with tachycardia or bradycardia. The education and awareness of caretakers adults, about these risks is of fundamental importance.

Yeast Smell Like What They Eat: Analysis of Volatile Organic Compounds of Malassezia furfur in Growth Media Supplemented with Different Lipids.

Malassezia furfur is part of the human skin microbiota. Its volatile organic compounds (VOCs) possibly contribute to the characteristic odour in humans, as well as to microbiota interaction. The aim of this study was to investigate how the lipid composition of the liquid medium influences the production of VOCs. Growth was performed in four media: (1) mDixon, (2) oleic acid (OA), (3) oleic acid + palmitic acid (OA+PA), and (4) palmitic acid (PA). The profiles of the VOCs were characterized by HS-SPME/GC-MS in the exponential and stationary phases. A total number of 61 VOCs was found in M. furfur, among which alkanes, alcohols, ketones, and furanic compounds were the most abundant. Some compounds previously reported for Malassezia (γ-dodecalactone, 3-methylbutan-1-ol, and hexan-1-ol) were also found. Through our experiments, using univariate and multivariate unsupervised (Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA)) and supervised (Projection to Latent Structures Discriminant Analysis (PLS-DA)) statistical techniques, we have proven that each tested growth medium stimulates the production of a different volatiles profile in M. furfur. Carbon dioxide, hexan-1-ol, pentyl acetate, isomer5 of methyldecane, dimethyl sulphide, undec-5-ene, isomer2 of methylundecane, isomer1 of methyldecane, and 2-methyltetrahydrofuran were established as differentiating compounds among treatments by all the techniques. The significance of our findings deserves future research to investigate if certain volatile profiles could be related to the beneficial or pathogenic role of this yeast.

Exophiala psychrophila: A new agent of chromoblastomycosis.

Chromoblastomycosis is a chronic cutaneous and subcutaneous mycosis, is caused by dematiaceous fungi, the most frequently implicated are Fonsecaea, Phialophora, Cladophialophora, Rhinocladiella and Exophiala. We report a woman who was treated before with mycological cure, but she experience a relapse requiring treatment again. Direct microscopic examination and skin biopsy with culture were necessary to identify a Exophiala psychrophila, and for our knowledge this is the first case reported.

Lack of correlation of ECV and outcome in an in vivo murine model of systemic fusariosis.

The efficacy of liposomal amphotericin B and voriconazole was evaluated against the systemic infection by Fusarium oxysporum species complex or Fusarium keratoplasticum. Although MIC values were within the epidemiological cutoff values (ECVs) recently stablished for Fusarium spp., no efficacy was obtained, indicating that ECVs for Fusarium are not relevant for in vivo efficacy.

Antibacterial Activities of Azole Complexes Combined with Silver Nanoparticles.

Growing antimicrobial resistance is considered a potential threat for human health security by health organizations, such as the WHO, CDC and FDA, pointing to MRSA as an example. New antibacterial drugs and complex derivatives are needed to combat the development of bacterial resistance. Six new copper and cobalt complexes of azole derivatives were synthesized and isolated as air-stable solids and characterized by melting point analyses, elemental analyses, thermogravimetric analyses (TGA), and infrared and ultraviolet/visible spectroscopy. The analyses and spectral data showed that the complexes had 1:1 (M:L) stoichiometries and tetrahedral geometries, the latter being supported by DFT calculations. The antibacterial activities of the metal complexes by themselves and combined with silver nanoparticles (AgNPs; 2 µg mL-1) were assessed in vitro by broth microdilution assays against eight bacterial strains of clinical relevance. The results showed that the complexes alone exhibited moderate antibacterial activities. However, when the metal complexes were combined with AgNPs, their antibacterial activities increased (up to 10-fold in the case of complex 5), while human cell viabilities were maintained. The minimum inhibitory concentration (MIC50) values were in the range of 25-500 µg mL-1. This study thus presents novel approaches for the design of materials for fighting bacterial resistance. The use of azole complexes combined with AgNPs provides a new alternative against bacterial infections, especially when current treatments are associated with the rapid development of antibiotic resistance.

Lipid Metabolic Versatility in Malassezia spp. Yeasts Studied through Metabolic Modeling.

Malassezia species are lipophilic and lipid-dependent yeasts belonging to the human and animal microbiota. Typically, they are isolated from regions rich in sebaceous glands. They have been associated with dermatological diseases such as seborrheic dermatitis, pityriasis versicolor, atopic dermatitis, and folliculitis. The genomes of Malassezia globosa, Malassezia sympodialis, and Malassezia pachydermatis lack the genes related to fatty acid synthesis. Here, the lipid-synthesis pathways of these species, as well as of Malassezia furfur, and of an atypical M. furfur variant were reconstructed using genome data and Constraints Based Reconstruction and Analysis. To this end, the genomes of M. furfur CBS 1878 and the atypical M. furfur 4DS were sequenced and annotated. The resulting Enzyme Commission numbers and predicted reactions were similar to the other Malassezia strains despite the differences in their genome size. Proteomic profiling was utilized to validate flux distributions. Flux differences were observed in the production of steroids in M. furfur and in the metabolism of butanoate in M. pachydermatis. The predictions obtained via these metabolic reconstructions also suggested defects in the assimilation of palmitic acid in M. globosa, M. sympodialis, M. pachydermatis, and the atypical variant of M. furfur, but not in M. furfur. These predictions were validated via physiological characterization, showing the predictive power of metabolic network reconstructions to provide new clues about the metabolic versatility of Malassezia.

Genotyping of Fusarium Isolates from Onychomycoses in Colombia: Detection of Two New Species Within the Fusarium solani Species Complex and In Vitro Antifungal Susceptibility Testing.

Fusariosis have been increasing in Colombia in recent years, but its epidemiology is poorly known. We have morphologically and molecularly characterized 89 isolates of Fusarium obtained between 2010 and 2012 in the cities of Bogotá and Medellín. Using a multi-locus sequence analysis of rDNA internal transcribed spacer, a fragment of the translation elongation factor 1-alpha (Tef-1α) and of the RNA-dependent polymerase subunit II (Rpb2) genes, we identified the phylogenetic species and circulating haplotypes. Since most of the isolates studied were from onychomycoses (nearly 90 %), we carried out an epidemiological study to determine the risk factors associated with such infections. Five phylogenetic species of the Fusarium solani species complex (FSSC), i.e., F. falciforme, F. keratoplasticum, F. lichenicola, F. petroliphilum, and FSSC 6 as well as two of the Fusarium oxysporum species complex (FOSC), i.e., FOSC 3 and FOSC 4, were identified. The most prevalent species were FOSC 3 (38.2%) followed by F. keratoplasticum (33.7%). In addition, our isolates were distributed into 23 haplotypes (14 into FOSC and nine into FSSC). Two of the FSSC phylogenetic species and two haplotypes of FSSC were not described before. Our results demonstrate that recipients of pedicure treatments have a lower probability of acquiring onychomycosis than those not receiving such treatments. The antifungal susceptibility of all the isolates to five clinically available agents showed that amphotericin B was the most active drug, while the azoles exhibited lower in vitro activity.

Draft Genome Sequence of the Animal and Human Pathogen Malassezia pachydermatis Strain CBS 1879.

Malassezia pachydermatis is a basidiomycetous yeast that causes infections in humans and animals. Here, we report the genome sequence of Malassezia pachydermatis strain CBS 1879, which will facilitate the study of mechanisms underlying pathogenicity of the only non-lipid-dependent Malasezzia species.

Seborrheic dermatitis: predisposing factors and ITS2 secondary structure for Malassezia phylogenic analysis.

Seborrheic dermatitis (SD) is a chronic, widespread skin condition, which is considered a multifactorial disease influenced, in part, by Malassezia spp. opportunistic activities, as well as various endogenous and exogenous factors. Malassezia species are lipophilic, lipid-dependent yeasts that are members of the normal mycobiota of the human skin. Their isolation from SD lesions varies around the world and the study of the relationship among factors such as gender, age, immunosuppressive condition of the patient and SD development, can lead to a better understanding of this disease. To elucidate the association of age and gender with the development of SD and to precisely determine the Malassezia species involved in the disease, samples were obtained from 134 individuals, including individuals without lesions, human immunodeficiency virus positive patients, individuals with seborrheic dermatitis, and HIV patients with seborrheic dermatitis. Malassezia spp. were identified by phenotypic and genotypic methods and a phylogenetic analysis was performed using Bayesian inference. This study revealed that age and gender are not predisposing factors for SD development, and that the most frequent species of Malassezia related to SD development among the Colombian population is M. restricta. We also report the isolation of M. yamatoensis for the first time in Colombia, and propose an ITS2 secondary structure from Malassezia taxa that can be used for precise identification and to establish more robust phylogenetic relationships.

Quiste óseo aneurismático en columna cervical / Bone Cysts Aneurysmal

Presentamos el caso de un quiste óseo aneurismático en la columna cervical que se manejó con embolización intravascular con partículas. Se obtuvo una muy buena respuesta y una marcada disminución de su tamaño, por lo que no se llevó a resección quirúrgica.

A case of aneurysmal bone cyst of the cervical spine treated with particulate embolization with a very good answer and marked involution of the mass, for which it doesn’t lead to surgical resection.

Infestation by Triatoma pallidipennis (Hemiptera: Reduviidae: Triatominae) is associated with housing characteristics in rural Mexico.

Long-term control of Chagas disease requires not only interruption of the human transmission cycle of Trypanosoma cruzi Schyzotrypanum, Chagas, 1909 by controlling its domestic triatomine vectors but also surveillance to prevent reinfestation of residences from sylvatic or persistent peridomestic populations. Although a number of potential risk factors for infestation have been implicated in previous studies, the explanatory power of resulting models has been low. Two years after cessation of triatomine vector control efforts in the town of Chalcatzingo, Morelos, 78 environmental, socioecological, and spatial variables were analyzed for association with infestation by Triatoma pallidipennis Stal 1872 (Hemiptera: Reduviidae: Triatominae), the principal vector of T. cruzi. We studied 712 residences in this rural community to identify specific intradomestic and peridomestic risk factors that predicted infestation with T. pallidipennis. From numerous characteristics that were identified as correlated with infestation, we derived multivariate logistic regression models to predict residences that were more or less likely to be infested with T. pallidipennis. The most important risk factors for infestation included measurements of house age, upkeep, and spatial location in the town. The effects of certain risk factors on infestation were found to be modified by spatial characteristics of residences. The results of this study provide new information regarding risk factors for infestation by T. pallidipennis that may aid in designing sustainable disease control programs in rural Mexico.

Polimorfismos genéticos de aislamientos del género Malassezia obtenidos en Colombia de pacientes con lesión dermatológica y sin ella / Genetic polymorphism of Malassezia spp. yeast isolates from individuals with and without

Introducción. Las especies del género Malassezia se consideran levaduras oportunistas emergentes de gran importancia. Han sido asociadas a diferentes patologías dermatológicas y sistémicas de las cuales se aislan una o más especies de este género. El papel de estas levaduras en las enfermedades dermatológicas no se ha aclarado completamente, ya que la Malassezia spp. pertenece a la flora normal de la piel. Objetivo. Buscar marcadores genéticos en los aislamientos de Malassezia spp. que permitan correlacionar las lesiones dermatológicas con las especies aisladas. Materiales y métodos. Se obtuvieron 103 aislamientos de Malassezia spp. a partir de muestras de pacientes con pitiriasis versicolor, dermatitis seborreica, dermatitis seborreica en pacientes positivos para VIH, dermatitis atópica, y de individuos sanos. Para los controles se usaron ocho cepas del Centraalbureau voor Schimmelcultures (CBS), Holanda. El perfil genético se realizó utilizando la técnica de ADN polimórfico amplificado aleatorio (RAPD) con tres iniciadores (OPA2, OPA4, OPA13). Los datos obtenidos se analizaron con los programas Diversity Database y SYN-TAX-PC. Resultados. Se observó heterogeneidad genética intraespecífica en Malassezia furfur, Malassezia globosa, Malassezia restricta, Malassezia slooffiae y Malassezia obtusa, mientras que Malassezia sympodialis mostró mayor homogeneidad. Conclusión. No se determinó ningún patrón genético específico mediante la técnica de RAPD para las especies de Malassezia que se pudiera relacionar con la entidad dermatológica implicada

Malassezia yeast species isolated from patients with dermatologic lesions.

INTRODUCTION: Yeasts of the genus Malassezia form a normal component of skin flora, but are also associated with several dermatological disorders. Since 1996, the description of new species in this genus have led to new questions about their epidemiology and pathogenicity. OBJECTIVE: Herein, the frequency of Malassezia species in individuals with pityriasis versicolor, atopic dermatitis, seborrhoeic dermatitis, seborrhoeic dermatitis was compared in HIV patients and healthy individuals. Three body sites were selected for examination--head, thorax, and upper and lower extremities. MATERIAL AND METHODS: The 154 Malassezia species were isolated from 112 individuals and grouped as follows: 39 with seborrhoeic dermatitis (20 were HIV-positive patients), 18 with pityriasis versicolor, 18 with atopic dermatitis and 37 without dermatological leisions. HIV patient samples were examined microscopically, and specimens from both patients and healthy subjects were cultured on modified Dixon agar medium. Subsequently, isolates were identified by macroscopic, microscopic and physiological characteristics. RESULTS: The most commonly isolated species were Malassezia globosa (37.5%), M. sympodialis (31.3%) and M. furfur (31.3%). Malazzerzia globosa predominated in patients with pityriasis versicolor (67%) and in HIV-positive patients with seborrhoeic dermatitis (85%). In non-HIV patients with atopic dermatitis or seborrhoeic dermatitis, M. furfur and M. restricta were isolated in 72% and 26% of the cases, respectively. CONCLUSION: Several conclusions were evident. First, Malassezia species was present in subjects with and without dermatological pathologies. Second, the species frequency in the sampled population differed from frequencies reported from other geographic areas. Third, Malassezia globosa was involved at high frequency in patients with dermatological pathologies, suggesting a higher pathogenicity of this species. Additional studies on each species are recommended to clarify their pathogenic roles in association with HIV-positive and normal subjects.

Malassezia yeast species isolated from patients with dermatologic lesions / Especies de Malassezia aisladas de pacientes con lesiones dermatológicas

Introducción. Las levaduras del género Malassezia forman parte de la flora normal de la piel y se asocian con varios tipos de lesiones dermatológicas. Desde 1996, la descripción de nuevas especies dentro de este género planteó numerosos interrogantes sobre su epidemiología y patogenicidad. Objetivo. El fin de este trabajo fue encontrar la frecuencia de las diferentes especies de Malassezia en individuos con pitiriasis versicolor, dermatitis atópica, dermatitis seborreica, dermatitis seborreica en pacientes positivos para VIH, y en individuos sin lesiones a partir de tres zonas corporales (cabeza, tórax, extremidades inferiores y superiores). Materiales y métodos. Se identificaron 154 aislamientos de especies de Malassezia de 112 individuos: 39 con dermatitis seborreica de los cuales 20 eran positivos para VIH, 18 con pitiriasis versicolor, 18 con dermatitis atópica y 37 individuos sin lesión dermatológica (controles). Las escamas de piel de los pacientes se observaron microscópicamente y las muestras de pacientes y controles se cultivaron en agar Dixon modificado. Posteriormente, se observaron las colonias y se identificaron según sus características macroscópicas, microscópicas y fisiológicas. Resultados. Las especies más frecuentemente aisladas en el total de los grupos estudiados fueron: Malassezia globosa (37,5 por ciento), M. sympodialis (31,3 por ciento) y M. furfur (31,3 por ciento). M. globosa predominó en los aislamientos de pacientes con pitiriasis versicolor (67 por ciento) y en pacientes positivos para VIH con dermatitis seborreica (85 por ciento). En pacientes con dermatitis atópica y dermatitis seborreica sin diagnóstico de VIH, se aislaron M. furfur y M. restricta en el 72 por ciento y el 26 por ciento de los casos, respectivamente. Conclusiones. Las diferentes especies de Malassezia pueden aislarse de pacientes con lesiones dermatológicas o sin ellas. Además, la frecuencia de especies en la población muestreada difiere de lo reportado en otras zonas geográficas. Se destaca la alta frecuencia de M. globosa en pacientes con lesiones lo que podría indicar la mayor patogenicidad de esta especie. No obstante, se requieren estudios adicionales para determinar el papel de las diferentes especies del género Malassezia, asociadas con estas patologías

[Genetic polymorphism of Malassezia spp. yeast isolates from individuals with and without dermatological lesions]. / Polimorfismos genéticos de aislamientos del género Malassezia obtenidos en Colombia de pacientes con lesión dermatológica y sin ella.

INTRODUCTION: Malassezia spp. yeasts are opportunistic and newly emergent diseases. One or more species have been isolated in association with dermatological pathology and systemic disease. Their pathological role has not been fully elucidated since Malassezia spp. are common in normal skin flora. OBJECTIVE: In the current study, a search was undertaken for genetic markers in the Malassezia spp. isolates that correlate with each type of dermatologic lesion. MATERIALS AND METHODS: A total of 103 strains of Malassezia spp were isolated from patients with pytiriasis versicolor, seborrheic dermatitis, seborrheic dermatitis HIV (+), and atopic dermatitis, as well as from healthy individuals. Eight isolates from CBS Centraalbureau voor Schimmelcultures (Netherlands) were used as controls. Fingerprinting was done using random amplification of polymorphic DNA technique (RAPD) with three primers (OPA2, OPA4, OPA13). The data were analyzed with Diversity Database and SYN-TAX-PC programs. RESULTS: Intraspecies genetic heterogeneity in M. furfur, M. globosa, M. restricta, M. slooffiae, M. obtusa was observed, whereas M. sympodialis showed the greatest homogeneity. CONCLUSION: The dermatological disease caused by these different species was not associated with distinctive RAPD fingerprints.

Efficacy of pyrethroid insecticides against domestic and peridomestic populations of Triatoma pallidipennis and Triatoma barberi (Reduviidae:Triatominae) vectors of Chagas' disease in Mexico.

A single village control trial for Triatoma pallidipennis and T. barberi was conducted using three synthetic pyrethroids (bifenthrin, cyfluthrin, and deltamethrin), evaluated as residual treatments in separate sectors, with complete coverage indoors and in peridomiciliary areas. Spray intervention was preceded by a preintervention entomological evaluation and household survey, followed by four postintervention evaluations at 1, 3, 6, and 12 mo of > 96% of houses. Overall preintervention adjusted infestation index was 38%, 17% of which represented intradomicile infestation. Dose verification using high-performance liquid chromatography (HPLC) demonstrated correct spray doses for all but deltamethrin treatments. There was between a 6- and 13-fold decrease in intradomicile live bug infestation for cyfluthrin- and bifenthrin-treated areas, resulting at 1 mo in 0 and 0.6% infestation, respectively. Intradomicile infestation recovered somewhat, terminating at 20 and 50% of preintervention levels at 12 mo, respectively, while peridomicile infestation recovered preintervention levels within 3-6 mo. Households with persistent live peridomiciliary infestation had 1.9 times the risk of having a persistent intradomiciliary infestation, while 80% of peridomicile infestations for both triatomine species were in houses not having a previous infestation. New or reinfestation of households did not occur consistent with a sylvan source, and unconstructed lots were not a significant source of bugs. Houses with persistent peridomicile infestation did represent a significant risk for surrounding uninfested houses by cluster analysis (P < 0.05). Along with the increased prevalence of T. cruzi infection after intervention, the data indicate that a sylvan reservoir source, probably peridomicile small rodent nests, represent the major risk factor for persistent and new infestations.