Comparación de pruebas moleculares para el diagnóstico de Leishmania spp. en lesiones cutáneas con baja carga parasitaria

Introducción: La leishmaniasis cutánea (LC) es un problema grave de salud pública en Panamá. El diagnóstico de esta parasitosis ha sido siempre desafiante, no sólo debido a su similitud con otras infecciones dérmicas, sino también a características particulares de las lesiones, como cargas parasitarias bajas. ​Materiales y Métodos: En este estudio, se evaluaron mediante cuatro métodos moleculares, 235 muestras de ADN procedentes de lesiones con frotis negativos por LC obtenidas durante el período 2015-2019. Resultados: Los resultados señalan que las sensibilidades encontradas fueron de 75.6% (IC 0.6234-0.8709) para la PCR kDNA-Género específico, de 66.7% (IC 0.5359-0.776) para la PCR Hsp70-Género específico y de 77.6% (IC 0.645-0.8949) para la qPCR 18S ribosomal. Todas las pruebas obtuvieron un valor predictivo positivo de 100%, mientras que el valor predictivo negativo más alto fue con la qPCR (80.58%) y el más bajo con el PCR Hsp70-Género específico (73.2%). En cuanto a la precisión de diagnóstico se obtuvo un rango mayor del 82% en todas las pruebas evaluadas. Conclusión: Este estudio confirma la buena sensibilidad de la PCR kDNA-Viannia para el análisis de lesiones de LC con baja carga parasitaria. Esta metodología es relativamente fácil de estandarizar, por lo que se recomienda su uso en laboratorios clínicos regionales de Panamá. Aun cuando la qPCR 18S ribosomal presentó una sensibilidad relativamente menor, el uso de esta metodología debe ser también considerada por su facilidad de uso, menor tiempo de ejecución y capacidad de cuantificación. (provisto por Infomedic International)

Introduction: Cutaneous leishmaniasis (CL) is a serious public health problem in Panama. The diagnosis of this parasitosis has always been challenging, not only because of its similarity to other dermal infections, but also because of characteristics of the lesions, such as low parasite loads. Materials and Methods: In this study, 235 DNA samples from smear-negative lesions by LC obtained during the period 2015-2019 were evaluated by four molecular methods. Results: The results indicate that the sensitivities found were 75.6% (CI 0.6234-0.8709) for kDNA-Gene-specific PCR, 66.7% (CI 0.5359-0.776) for Hsp70-Gene-specific PCR and 77.6% (CI 0.645-0.8949) for 18S ribosomal qPCR. All tests obtained a positive predictive value of 100%, while the highest negative predictive value was with qPCR (80.58%) and the lowest with Hsp70-Gene-specific PCR (73.2%). In terms of diagnostic accuracy, a range greater than 82% was obtained in all the tests evaluated. Conclusion: This study confirms the good sensitivity of kDNA-Viannia PCR for the analysis of LC lesions with low parasite load. This methodology is relatively easy to standardize, so it is recommended for use in regional clinical laboratories in Panama. Although 18S ribosomal qPCR showed a relatively lower sensitivity, the use of this methodology should also be considered because of its ease of use, shorter execution time and quantification capacity. (provided by Infomedic International)

Factores de riesgo asociados con la leishmaniasis cutánea en dos comunidades rurales de Panamá Oeste

Introducción: La leishmaniasis cutánea (LC) es una enfermedad zoonótica endémica en Panamá. Su agente causal son protozoarios del género Leishmania y la transmiten insectos flebotominos. Objetivo: Evaluar los factores de riesgos asociados con la LC y la diversidad de flebotominos en dos comunidades rurales de Panamá Oeste. Metodología: Se seleccionaron dos comunidades endémicas para LC: Trinidad de las Minas (TM), de alta incidencia y Las Pavas (LP), de baja incidencia. Los factores de riesgo asociados con la LC fueron evaluados mediante una encuesta aplicada a100 personas (TM: n=50; LP: n=50). Se colectaron flebotominos con trampas CDC durante tres noches consecutivas en temporada lluviosa y seca. Resultados: La mayoría de las personas confirmó conocer sobre la LC (TM: 96% y LP: 68%). No se encontraron diferencias significativas entre las características sociodemográficas, estructura de las viviendas, composición del peridomicilio y abundancia/diversidad de animales domésticos en ambas comunidades. El reporte de perezosos cercanos al peridomicilio fue mayor en TM (70%) vs LP (32%). La especie de flebotomino antropofílica más abundante durante la temporada seca fue Lutzomyia gomezi (TM: 40.1% y LP: 10.4%). Durante la temporada lluviosa fue Nyssomyia trapidoi (43.4%) en TM y Psychodopygus panamensis (75.7%) en LP. Las especies zoofílicas más comunes en ambas comunidades fueron Trichopygomyia triramula y Pressatia dysponeta. Conclusión: La mayor incidencia de LC en TM podría estar condicionada a su ecología montañosa, con una cobertura boscosa cercana más extensa y una mayor frecuencia de mamíferos reservorios silvestres. Se confirmó la presencia de vectores de LC en el peridomicilio de ambas comunidades. (provisto por Infomedic International)

Introduction: Cutaneous leishmaniasis (CL) is a zoonotic disease endemic in Panama. Its causal agent are protozoa of the genus Leishmania and is transmitted by phlebotomine sandflies. Objective: To evaluate the risk factors associated with CL and the diversity of phlebotomine sandflies in two rural communities in western Panama. Methodology: Two CL endemic communities were selected: Trinidad de las Minas (TM), with high incidence and Las Pavas (LP), with low incidence. The risk factors associated with CL were assessed by means of a survey applied to 100 people (TM: n=50; LP: n=50). Phlebotomine sandflies were collected with CDC traps during three consecutive nights in rainy and dry season. Results: The majority of people confirmed knowledge about CL (TM: 96% and LP: 68%). No significant differences were found between sociodemographic characteristics, housing structure, peridomicile composition and abundance/diversity of domestic animals in both communities. The report of sloths near the peridomicile was higher in TM (70%) vs LP (32%). The most abundant anthropophilic phlebotomine species during the dry season was Lutzomyia gomezi (TM: 40.1% and LP: 10.4%). During the rainy season it was Nyssomyia trapidoi (43.4%) in TM and Psychodopygus panamensis (75.7%) in LP. The most common zoophilic species in both communities were Trichopygomyia triramula and Pressatia dysponeta. Conclusion: The higher incidence of CL in TM could be conditioned to its mountainous ecology, with a more extensive nearby forest cover and a higher frequency of wild mammal reservoirs. The presence of CL vectors in the peridomicile of both communities was confirmed. (provided by Infomedic International)

Evaluation of cytochrome b sequence to identify Leishmania species and variants: the case of Panama

BACKGROUND The genetic heterogeneity of Leishmania parasites is a major factor responsible for the wide variety of Leishmania-associated manifestations. Consequently, understanding the genetic make-up of Leishmania species using suitable molecular markers is an important component of realising local and regional scale disease risk. The cytochrome b (cytb) is frequently used to type New World Leishmania species. However, its potential to discriminate Leishmania species and variants requires further evaluation. OBJECTIVES To explore the capacity of cytb gene to identify New World Leishmania species and variants and to develop an approach able to type local Leishmania species and variants. METHODS We retrieved 360 partial and complete Leishmania cytb gene sequences publicly available in GenBank database to study all single nucleotide polymorphisms (SNPs) across the cytb gene that differentiate New World Leishmania species. This information was used to develop an approach based upon the polymorphisms found in a DNA segment of 948bp. We also compared the typing results found with this technique with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) profiling obtained using HSP70 gene as target. One hundred Panamanian isolates were used to both typed Leishmania species and assess local genetic variability. FINDINGS We found complete agreement between our cytb approach and the PCR-RFLP profiling method based on HSP70 for Leishmania species identification. Ninety-two isolates were identified as L. panamensis, although other Viannia species were found circulating at a lower frequency. Three L. panamensis haplotypes were identified in Panamanian provinces. We also provide an initial report of L. guyanensis haplotypes circulating in Panama. MAIN CONCLUSIONS Cytb gene sequence encompasses key main SNPs that aid to identify Leishmania species. The cytb approach developed with this information was able to identify and assess genetic variability of local Leishmania species found in this study.

Conocimientos, actitudes y prácticas sobre la malaria en la población indígena guna de la comarca de Madungandí, Panamá, 2012 / Knowledge, attitudes and practices regarding malaria in the indigenous Guna population of the Madungandí region, Panamá, 2012

Introducción. Las encuestas sobre comportamientos, actitudes y prácticas permiten determinar el grado de conocimiento de la población sobre la malaria o paludismo, así como las actitudes y prácticas que contribuyen a su transmisión. Objetivo. Identificar los conocimientos, actitudes y prácticas que favorecen la transmisión de la malaria en la población indígena guna de Madungandí. Materiales y métodos. Se hizo un estudio transversal mediante una encuesta a los jefes de familia de una muestra de 40 % de las viviendas en tres comunidades con alta incidencia de malaria. La encuesta se hizo con encuestadores gunas e integrantes del equipo de investigación, y con la ayuda de un traductor. El análisis se hizo en Epi-Info 6.04. Resultados. El rango de edad de los encuestados fluctuaba entre los 20 y los 70 años. Todos los encuestados indicaron pertenecer a la etnia guna y hablar su lengua; 64 % eran del sexo masculino y 30 % eran analfabetas. La mitad de los encuestados (51 %) manifestó haber enfermado de malaria, por lo menos, una vez en los últimos ocho años y 89 % reconoció la enfermedad como un problema de salud. El 63 % manifestó que el médico tradicional "inadule" curaba la malaria, y 78 % practicaba la "fuma de la pipa" y la "quema del cacao" para prevenirla. Conclusión. Dado el limitado conocimiento sobre la malaria y su vector, así como la actitud de colaboración de la población guna, es necesario iniciar programas educativos y de participación comunitaria para mejorar las prácticas de prevención y control en las comunidades, y disminuir así la incidencia de la enfermedad en la comarca de Madungandí.

Introduction: Knowledge, attitudes and practices surveys allow to determine the degree of knowledge on the management of malaria in a given population, as well as the attitudes and practices that contribute or not to its transmission. Objective: To identify the knowledge, attitudes and practices that favor or not the transmission of malaria in the indigenous Guna population of Madungandí. Materials and methods: A cross-sectional study was conducted by applying a survey to the heads of the families in a sample of 40% of households in three communities with high malaria incidence. Local Guna residents and translators were part of the research team that applied the questionnaires. The statistical analysis was performed in Epi-Info 6.04. Results: The age range of those surveyed was between 20 and 70 years. All responders indicated that they belonged to and spoke the language of the Guna ethnic group, 64% were male and 30% were illiterate. Half (51%) of the responders declared they had suffered malaria at least once in the last eight years, and 89% accepted that malaria was a health problem. Sixty-three per cent responded that their traditional doctors, “inadule”, cured malaria and 7.0 % practiced the “pipe smoking” and “cocoa burn” rituals to prevent the disease. Conclusion: Considering the limited knowledge about malaria and its vector, as well as the willingness to collaborate shown by the Guna population, it is essential to initiate educational and participative programs to improve control and prevention activities in the communities aimed at achieving a reduction in malaria incidence in the Madungandí indigenous region.

Risk factors associated with Trypanosoma cruziexposure in domestic dogs from a rural community in Panama

Chagas disease, caused by Trypanosoma cruziinfection, is a zoonosis of humans, wild and domestic mammals, including dogs. In Panama, the main T. cruzivector is Rhodnius pallescens, a triatomine bug whose main natural habitat is the royal palm, Attalea butyracea. In this paper, we present results from three T. cruziserological tests (immunochromatographic dipstick, indirect immunofluorescence and ELISA) performed in 51 dogs from 24 houses in Trinidad de Las Minas, western Panama. We found that nine dogs were seropositive (17.6% prevalence). Dogs were 1.6 times more likely to become T. cruziseropositive with each year of age and 11.6 times if royal palms where present in the peridomiciliary area of the dog’s household or its two nearest neighbours. Mouse-baited-adhesive traps were employed to evaluate 12 peridomestic royal palms. All palms were found infested with R. pallescenswith an average of 25.50 triatomines captured per palm. Of 35 adult bugs analysed, 88.6% showed protozoa flagellates in their intestinal contents. In addition, dogs were five times more likely to be infected by the presence of an additional domestic animal species in the dog’s peridomiciliary environment. Our results suggest that interventions focused on royal palms might reduce the exposure to T. cruzi infection.

Conocimientos y factores de riesgo relacionados con la enfermedad de Chagas en dos comunidades panameñas donde Rhodnius pallescens es el vector principal / Knowledge and risk factors related to Chagas´ disease in two Panamanian communities where Rhodnius pallescens is the main vector

Introducción. La implementación de los programas de vigilancia, prevención y control de la enfermedad de Chagas requiere una aproximación integral. La sostenibilidad de los programas depende de la participación comunitaria amparada en un conocimiento básico del problema. Objetivo. Evaluar los conocimientos de los entrevistados que facilitan o limitan la vigilancia, prevención y control de la enfermedad de Chagas en dos comunidades endémicas de Panamá donde Rhodnius pallescens es el vector principal. Materiales y métodos. Mediante un cuestionario se evaluaron los conocimientos y los factores de riesgo relacionados con la enfermedad de Chagas en 201 personas mayores de 10 años de las comunidades endémicas de Las Pavas y Lagartera Grande, ubicadas en la ribera oeste del Canal de Panamá. Con ayuda de los moradores también se evaluó la presencia de chinches triatominos en 93 viviendas a lo largo de un año. Resultados. De las personas entrevistadas, 69,2 % (139/201) tenía pocos o muy pocos conocimientos sobre la enfermedad de Chagas y 93 % (187/201) estaba expuesto a factores de riesgo moderados o altos. Se capturaron chinches triatominos en 20,4 % (19/93) de las viviendas evaluadas, de los cuales, el 86,8 % (66/76) era R. pallescens. Se encontró asociación significativa entre la presencia de chinches dentro de las viviendas y las viviendas catalogadas como precarias (p<0,01). Conclusión. A pesar de que en estas dos comunidades se han desarrollado programas de educación sanitaria, es necesario reforzar los conocimientos básicos sobre la enfermedad de Chagas antes de establecer medidas de prevención y vigilancia que involucren la participación activa de sus habitantes.

Introduction: The implementation of surveillance, control and prevention measures for Chagas´ disease requires an integrated approach. The sustainability of programs depends on community participation supported on a basic understanding of the problem. Objective: To evaluate the knowledge of people interviewed which facilitates or limits the surveillance, prevention and control of Chagas´ disease in two endemic Panamanian communities where Rhodnius pallescens is the main vector. Materials and methods: A questionnaire assessed the knowledge and risk factors related to Chagas´ disease in 201 people over 10 years of age from the endemic communities of Las Pavas and Lagartera Grande located on the western shore of Panama Canal. Additionally, with the help of the residents, the presence of triatomine bugs in 93 dwellings was evaluated during a year. Results: Of those interviewed, 69.2% (139/201) had poor or very poor knowledge about Chagas´ disease. Nearly 93% (187/201) was exposed to moderate or high risk factors. Triatomine bugs were collected in 20.4% (19/93) of the evaluated homes; 80% (66/76) of them were R. pallescens . Significant association was found between the presence of triatomines inside the houses and precarious housing (p<0.01). Conclusion: Despite having been exposed to health education-related programs, it is necessary to strengthen the basic knowledge about Chagas´ disease in the two communities before establishing prevention and surveillance measures which involve active participation of its inhabitants.

Caracterización de la transmisión de la malaria por Plasmodium vivax en la región fronteriza de Panamá con Costa Rica en el municipio de Barú, Panamá / Characterization of Plasmodium vivax malaria transmission at the border of Panamá and Costa Rica

Introducción. Pocos estudios describen los factores asociados con la dinámica de transmisión de la malaria, o paludismo, por Plasmodium vivax en las regiones endémicas de Panamá. Objetivo. Caracterizar la dinámica de transmisión de la malaria producida por P. vivax en la región fronteriza de Panamá con Costa Rica. Materiales y métodos. Se llevó a cabo un estudio observacional, descriptivo y transversal. Se evaluaron la incidencia parasitaria anual, el índice de láminas positivas y el índice anual de exámenes de sangre. Se identificaron los anofelinos vectores, y se caracterizaron sus criaderos preferenciales, densidad larvaria e índice de picada/hombre/noche. Se hizo búsqueda pasiva y activa de casos sospechosos mediante examen de gota gruesa. Resultados. De 10.401 muestras de gota gruesa, 83 resultaron positivas para P. vivax. El 84 % de los casos provenía de zonas rurales, el 79 % constituía una población económicamente activa, la mediana de edad fue de 36 años y, la media, de 30 años. El 58,5 % de los casos fueron de sexo masculino. La incidencia parasitaria anual fue de 4,1 por 1.000 habitantes; el índice de láminas positivas fue de 0,8 % y el índice anual de exámenes de sangre fue de 51,9 %. El 65,0 % de los casos diagnosticados registró entre 100 y 2.000 parásitos/μl de sangre. Se identificaron los mosquitos vectores Anopheles albimanus y An. punctimacula. Conclusión. Es necesario el seguimiento de estudios entomológicos, el fortalecimiento de la vigilancia epidemiológica, la consideración de los factores de riesgo y la realización de un trabajo en coordinación con las autoridades de salud de Costa Rica, para controlar la malaria en esta región.

Introduction. Few studies have described the factors associated with Plasmodium vivax transmission dynamics in endemic regions from Panamá. Objective. Malaria transmission dynamics produced by P. vivax were characterized at the border between Panamá and Costa Rica. Materials and methods. In the municipality of Barú, an observational, descriptive and cross-sectional study was undertaken to measure the annual parasite index (API), slide positivity index (SPR), and the annual blood examination rate (ABER). The most frequent symptoms and signs in malaria patients were recorded. The anopheline species were identified in the area and the preferred larval habitats, the density of larval populations in the larval habitats and the bites/human/night were characterized. Results. Of a total of 10,401 thick smear blood samples, 83 were positive for P. vivax. Of these, 84% came from rural areas and 79% were from economically active individuals. The median and average ages were 36 and 30 years, respectively, and 58.5% of the malaria cases were male. API was 4.1/1,000 inhabitants; SPR was 0.8% and ABER was 51.9%. Of the diagnosed cases, 54% showed blood parasitemias ranging between 100-2,000 parasites/μl. The majority of the cases were observed in May and June. Two mosquito vector species were identified-- Anopheles albimanus and An. punctimacula. Conclusion. These observations indicate the advisibility of continued entomological studies, strengthening of epidemiological surveillance, consideration of additional risk factors and evaluation of work performance in the border region. This will require coordination with health authorities of both countries to control malaria in this region.

Evaluación de la actividad tóxica de los insecticidas piretroides deltametrina y lambdacihalotrina en dos poblaciones de campo de Rhodnius pallescens (Hemíptera: Reduviidae) de Panamá / Evaluation of the toxic activity of the pyrethroid insecticides deltamethrin and lambdacyhalothrin in two Panamanian field populations of Rhodnius pallescens (Hem¨ªptera: Reduviidae)

Introducción. La evaluación de la sensibilidad de las poblaciones de Rhodnius pallescens permite detectar y vigilar los grados de resistencia en el transcurso del tiempo, con el fin de evaluar los efectos de las estrategias de control y manejo de la resistencia. Objetivo. Determinar la línea base de sensibilidad de los principios activos deltametrina y lambdacihalotrina en ninfas de estadios I y V, en dos poblaciones de campo de R. pallescens. Materiales y métodos. Los bioensayos se realizaron tomando como referencia el protocolo estandarizado de aplicación tópica para R. prolixus y adaptado para R. pallescens. Resultados. Con la aplicación tópica del insecticida lambdacihalotrina en ninfas de estadio I en R. pallescens (Chilibre) y R. pallescens (Cerro Cama), los valores de la dosis letal 50 (DL50) expresados en nanogramos por insecto fueron de DL50=0,129 y DL50=0,109, respectivamente. En ninfas de estadio V los valores fueron de DL50=1,712 y DL50=3,478, respectivamente. Por su parte, la aplicación tópica de deltametrina en ninfas de estadio I, registró valores de DL50=0,022 y DL50=0,021 y, en ninfas de estadio V, de DL50=2,110 y DL50=1,548. Conclusiones. En ninfas de estadios I y V de ambas poblaciones de R. pallescens, se observó mediante los valores obtenidos de factor de resistencia que no existen ninguna diferencia significativa en el efecto tóxico de los insecticidas estudiados. Esto permite establecer que las dos cepas de R. pallescens son sensibles a los insecticidas deltametrina y lambdacihalotrina.

Introduction. Systematic evaluation of the susceptibility of disease vectors to insecticides permits the detection of the development of insecticide resistance over time. This is necessary to evaluate the effectiveness of control methods and to plan management strategies of the resistance.Objective. The baseline susceptibility was determined for I and V instar nymphs of Rhodnius pallescens to the active ingredients of the insecticides deltamethrin and lambdacyhalothrin.Materials and methods. The bioassays were applied to two field populations of R. pallescens collected in Chilibre and Cerro Cama, Panam¨¢. A standard protocol for topical application was adapted from that developed for Rhodnius prolixus. Bioassays were performed using topical applications on the dorsal abdominal surface, with volumes of 0.1 ¦Ìl and 0.5 ¦Ìl acetone solution of insecticide for nymphs of stage I and V respectively, using 5 ¦Ìl and 25 ¦Ìl Hamilton microsyringes with a repeating dispenser. Ten nymphs were used for each insecticide concentration.Results. With the topical application of lambdacyhalothrin on first-instar nymphs from Chilibre and Cerro Cama, the LD50 values expressed in ng/insect were 0.13 and 0.11 respectively. In fifth-instar nymphs the LD50 values were 1.71 and 3.48, respectively. For deltamethrin, the topical application on first-instar nymphs resulted in LD50 values of 0.02 and 0.02, and in fifth-instar nymphs the LD50 values were 2.11 and 1.55, respectively.Conclusions. In I and V instar nymphs from the two R. pallescens populations, resistance factor values demonstrated no significant difference in the toxic effects of the two insecticides and indicated that the R. pallescens populations were susceptible them.

In vitro and in vivo experimental models for drug screening and development for Chagas disease

Chagas disease, a neglected illness, affects nearly 12-14 million people in endemic areas of Latin America. Although the occurrence of acute cases sharply has declined due to Southern Cone Initiative efforts to control vector transmission, there still remain serious challenges, including the maintenance of sustainable public policies for Chagas disease control and the urgent need for better drugs to treat chagasic patients. Since the introduction of benznidazole and nifurtimox approximately 40 years ago, many natural and synthetic compounds have been assayed against Trypanosoma cruzi, yet only a few compounds have advanced to clinical trials. This reflects, at least in part, the lack of consensus regarding appropriate in vitro and in vivo screening protocols as well as the lack of biomarkers for treating parasitaemia. The development of more effective drugs requires (i) the identification and validation of parasite targets, (ii) compounds to be screened against the targets or the whole parasite and (iii) a panel of minimum standardised procedures to advance leading compounds to clinical trials. This third aim was the topic of the workshop entitled Experimental Models in Drug Screening and Development for Chagas Disease, held in Rio de Janeiro, Brazil, on the 25th and 26th of November 2008 by the Fiocruz Program for Research and Technological Development on Chagas Disease and Drugs for Neglected Diseases Initiative. During the meeting, the minimum steps, requirements and decision gates for the determination of the efficacy of novel drugs for T. cruzi control were evaluated by interdisciplinary experts and an in vitro and in vivo flowchart was designed to serve as a general and standardised protocol for screening potential drugs for the treatment of Chagas disease.

Prevalencia de autoanticuerpos contra receptores autonómicos en pacientes panameños con cardiopatía chagásica crónica y con otras formas de cardiopatía / Prevalence of autoantibodies against autonomic receptors in patients with chronic cardiopathies

Introducción. La enfermedad de Chagas es la principal causa de cardiomiopatía crónica en Centroamérica. Existe controversia sobre los mecanismos causantes de la patología cardiaca observada durante la fase crónica de esta parasitosis. Varios estudios han detectado la presencia de autoanticuerpos circulantes dirigidos contra receptores beta-adrenérgicos y colinérgicos muscarínicos del miocardio en pacientes chagásicos, que pueden desencadenar señales intracelulares y alterar la función cardiaca durante el curso de la enfermedad. Objetivo. Nuestro objetivo principal fue comparar la frecuencia sérica de estos autoanticuerpos en pacientes chagásicos crónicos con la observada en pacientes con otras formas de cardiopatía y en controles sanos. Materiales y métodos. Se determinó la prevalencia de autoanticuerpos contra receptores beta-adrenérgicos y colinérgicos muscarínicos en cuatro grupos de pacientes panamelos: 53 pacientes chagásicos, 25 pacientes seronegativos con insuficiencia cardiaca, 25 pacientes con diferentes tipos de arritmia cardiaca y 25 controles sanos. Resultados. Los autoanticuerpos contra receptores autonómicos fueron más frecuentes en el grupo de pacientes con cardiopatía chagásica crónica (24,5%) comparados con el grupo de insuficiencia cardiaca (20,0%) y con el grupo con arritmias cardiacas (16,0%). Al comparar la proporción de autoanticuerpos entre el grupo de pacientes con cardiopatía chagásica crónica y los controles sanos, se detectaron diferencias muy significativas (24,5% versus 0%; p=0,0015). De los 53 pacientes con infección crónica, 48 (90,6%) presentaron algún grado de alteración cardiaca. Conclusiones. En comparación con el grupo de controles sanos, la frecuencia de los autoanticuerpos contra receptores autonómicos se encuentra significativamente aumentada en pacientes con enfermedad de Chagas crónica y con otras formas de cardiopatía.

Introduction. ChagasL disease is the main cause of chronic myocardiopathy in Central America. The mechanisms proposed for this cardiac pathology during the chronic phase remain controversial. Several studies have detected the presence of circulating autoantibodies against ƒÀ-adrenergic and cholinergic muscarinic receptors of the myocardium in patients with Chagas disease. These autoantibodies can trigger intracellular signals and modify the cardiac function during the progression of the disease. Objectives. The serological frequency of these autoantibodies was compared among patients with chronic Chagas disease, patients with other cardiopathies and healthy controls. Materials and methods. The prevalence of autoantibodies against ƒÀ-adrenergic and cholinergic muscarinic receptors was determined in four groups of Panamenian patients: 53 chagasic patients, 25 serologically negative patients with cardiac insufficiency, 25 patients with cardiac arrhythmia and 25 healthy individuals. Results. The antibodies against autonomic receptors were more frequently observed in patients with chronic chagasic cardiomyopathy (24.5%) compared to the cardiac insufficiency group (20.0%) and the cardiac arrhythmia group (16.0%). The proportion of autoantibodies was significantly different between the groups with chronic chagasic cardiomyopathy and healthy controls (24.5% versus 0%; p=0.015). Of the 53 chronically infected chagasic patients, 48 (90%) showed some degree of cardiac dysfunction. Conclusions. The frequency of autoantibodies against autonomic receptors is significantly increased in patients with chronic Chagas disease and in patients with other cardiopathies.

Feeding sources and trypanosome infection index of Rhodnius pallescens in a Chagas disease endemic area of Amador County, Panama

The sylvatic triatomine Rhodnius pallescens is considered to be the most important and widespread vector of Trypanosoma cruzi and Trypanosoma rangeli in Panama. However, its behavior and biological characteristics have only been partially investigated. Thus, to achieve sustainable and efficient control over Chagas disease in Panama, a better understanding of the ecology and biology of R. pallescens is essential. In this study we evaluated R. pallescens host feeding sources using a dot-blot assay, and the trypanosome infection index by PCR analysis in a Chagas disease endemic area of central Panama. It was found that in peridomestic palm trees, 20.3 percent of the examined bugs had fed on opossums (Didelphis marsupialis). However, we observed an increased anthropophagy (25.4 percent) for those bugs collected inside houses. Considering the domestic and peridomestic habitats as a whole, the proportion of collected R. pallescens infected with trypanosomes was 87.4 percent. In the two habitats the predominant infection was with T. cruzi (80-90 percent). Between 47-51 percent of the analyzed triatomines were infected with T. rangeli. Mixed infections (40-51 percent) were also detected. These findings provide a better basis for the implementation of a rational control and surveillance program for Chagas disease in regions where R. pallescens is endemic.

O triatomíneo silvestre Rhodnius pallescens é considerado o mais importante vetor do Trypanosoma cruzi e Trypanosoma rangeli no Panamá. Entretanto, seu comportamento e características biológicas são pouco estudados. Para controlar a doença de Chagas no Panamá é necessário melhorar a compreensão dos aspectos eco-biológicos do R. pallescens. Neste estudo, investigaram-se as fontes de alimentação de R. pallescens usando dot-blot e o índice de infecção por Trypanosoma por metodologia molecular, em área endêmica da doença de Chagas na região central do Panamá. Foi observado que 20,3 por cento dos barbeiros coletados em palmeiras peridomésticas se alimentavam de gambás (Didelphis marsupialis). Contudo, barbeiros coletados dentro das residências apresentaram antropofagia aumentada (25,4 por cento). Considerando o ambiente doméstico e peridoméstico juntos, o percentual de R. pallescens infectados com Trypanosoma foi de 87,4 por cento. Nos ambientes doméstico e peridoméstico, a infecção por T. cruzi foi de 80,4 por cento e 90 por cento; a infecção por T. rangeli foi de 47 por cento e 51 por cento, respectivamente. Observou-se infecção mista em 43 por cento dos triatomíneos coletados em ambiente doméstico e em 51 por cento dos triatomíneos peridomésticos. Estes achados fornecem embasamento para a implementação de um controle adequado e um programa de vigilância para a doença de Chagas em regiões onde o R. pallescens é endêmico.

Chromosome variability in the Chagas disease vector Rhodnius pallescens (Hemiptera, Reduviidae, Rhodniini)

Rhodnius pallescens is the main vector of Trypanosoma cruzi in Panama and one of the most relevant secondary vectors in Colombia. Despite the importance of this species, there is limited knowledge about the genetic variability along its geographical distribution. In order to evaluate the degree of karyotype variability we analyzed the meiotic behavior and banding pattern of the chromosomes of 112 males of R. pallescens coming from different regions of Colombia and Panama. Using the C-banding technique we identified two chromosomal patterns or cytotypes characterized by differences in the amount, size and distribution of constitutive heterochromatic regions in the chromosome complement (2n = 20 autosomes plus XY in males). The individuals can be easily classified in each cytotype by the analysis of the chromosomes during first meiotic prophase. The frequencies of the cytotypes are variable according to the geographic origin of the populations. This chromosomal divergence together with morphological data supports the existence of three genetically different populations of R. pallescens and provides new information to understand the distribution dynamics of this species.

Protozoarios enteropatógenos asociados con diarrea en niños menores de cinco años, provincia de Panamá, 2006-2007 / Protoza enteropathogen associated with diarrhea in children less than five years, province of Panama, 2006-2007

La diarrea infantil continúa siendo un grave problema de salud a nivel mundial principalmente en países en vías de desarrollo como Panamá. Sin embargo, los parásitos y otros agentes asociados a los episodios de diarrea en niños menores de cinco años han sido poco estudiados en nuestro medio. En este sentido se propuso realizar la presente investigación a fin de determinar la frecuencia de la infección con protozoarios enteropatógenos en heces diarreicas de niños menores de cinco años de la provincia de Panamá. La metodología utilizada consistió en análisis microscópico (directo y tinción de kinyoun) y detección de coproantígenos (ELISA). Se encontró que el 37.3% (132/354) de las muestras de diarrea evaluadas presentaron infecciones con protozoarios. El 65.9% (87/132) de las muestras positivas provienen de niños menores de dos años de edad. La infección con Cryptosporidium spp.estuvo frecuentemente asociada (24.6%) a los casos de diarrea infantil provenientes del distrito de la Chorrera. Se estima que el 77.6% de los casos de giardiasis y el 100% de los casos de criptospidiosis no estan siendo identificados en los laboratorios investigados. La baja frecuencia de los casos de Entamoeba sp.(>5%) sugiere una relación de menor importancia para los casos de diarreas estudiados.Por otro lado los resultados obtenidos con una prueba de aglutinación demostraron una frecuencia relativamente baja (13%,46/354) para la infección con rotavirus. Los resultados obtenidos en este estudio deben alertar a los directores y trabajadores de la salud en la provincia de Panamá.

Molecular characterization of human Trypanosoma cruzi isolates from endemic areas in Panama

The present work provides information on Trypanosoma cruzi genotype circulating in endemic areas of Chagas disease in Panama. A total of 26 crude stocks of T. cruzi, isolated from the blood of persons with different clinical profiles of Chagas disease were collected and crio-conserved until used. Most of the stocks had been characterized by means of isoenzyme electrophoresis on cellulose acetate membranes. The clinical profiles of infected persons included 9 (34.6 percent) asymptomatic and 17 acute (65.4 percent) including 5 (19.2 percent) fatal cases, 2 under 5 years old and 3 adults. A multiplex-PCR assay based on the amplification of the non-transcribed spacer of the mini-exon gene was performed. All stocks of T. cruzi included in the study were found to correspond to Tc I group. This result supports the predominance of T. cruzi-I in the transmission cycles affecting the human population in the Republic of Panama.

Predominance of Trypanosoma rangeli infection in children from a Chagas disease endemic area in the west-shore of the Panama canal

A total of 206 serum samples from children (3-14 years old) living in the Amador County (La Chorrera District, Province of Panama) were screened by indirect immunofluorescence antibody test (IFAT) for the presence of antibodies against Trypanosoma cruzi. Positive sera were confirmed by recombinant enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. The presence of blood trypanosomes was investigated by hemoculture and subsequently identify by a duplex polymerase chain reaction (PCR) followed by dot blot hybridization. The results indicated a prevalence of 9.7 percent for trypanosome infections, a seroprevalence of 2.9 percent against T. cruzi and a predominance of T. rangeli infection (6.8 percent). The immunological and clinical implications of these findings are discussed.

Eco-epidemiological aspects of Trypanosoma cruzi, Trypanosoma rangeli and their vector (Rhodnius pallescens) in Panama

A epidemiologia da infecção do T. cruzi foi investigada na margem oriental do canal do Panamá, na região central da Republica do Panamá. A informação obtida durante o estudo avaliou fatores de risco da doença de Chagas nesta área. Entre 1999 e 2000, 1110 triatomíneos foram coletados: 1050 triatomíneos (94,6) em palmeiras, 27 (2,4) em habitats periurbanos e 33 (3,0) no interior de casas. Todos os espécimens foram identificados como R. pallescens. Não havia nenhuma evidência de domiciliação do vetor. O exame de glândulas salivares de 380 R. pallescens revelaram taxa de infecção natural por Trypanosoma de 7,6, mas o conteúdo da ampola rectal de 373 triatomíneos mostrou 45 de positividade. Os perfis de isoenzimas em Trypanosomas isolados demonstraram que 85,4 (n = 88) eram T. cruzi e 14,6 (n = 15) eram T. rangeli. A análise da refeição de sangue de 829 R. pallescens demonstrou comportamento zoofílico do vetor, sendo os gambás a fonte preferencial de sangue. Soroprevalência nos seres humanos de ambos locais de estudo foi menos que 2. Nossos resultados demonstram que T. cruzi sobrevive na área em associação equilibrada com R. pallescens e com diversas espécies diferentes de mamíferos em seus nichos naturais. Entretanto, a área é um risco eminente de infecção para sua população, pelo que é importante executar um programa educacional na comunidade a respeito das medidas, do conhecimento e do controle da doença.

Cesarean childbirth in Puerto Rico: the facts

According to the last Island-wide survey carried out in 1982 in Puerto Rico, the cesarean rate for the trienium of 1980-82 was estimated in 27 percent. Since 1989, an item about the type of delivery has been included in the live birth certificate. These data indicate that the incidence of cesarean deliveries continued to increase and by 1994 it amounted to 31 percent, undoubtedly the highest rate of the world. However, its fluctuation since 1990 suggests that this type of delivery has finally steadied in Puerto Rico. The high proportion of repeated cesareans and the low percentage of vaginal birth after cesarean (VBAC) deliveries were important factors contributing to the overall rate. Unexpectedly high risk mothers such as, adolescents, unwed and those of the lower socioeconomic status had highest cesarean rates than most adequate prenatal care had the highest percentages of surgical deliveries. In spite of dealing with a selected clientele, the cesarean rate in private hospitals was more than their encounterparts. Similarly, mothers who had the twice that of public institutions. In fact, a multiple correlation analysis demonstrate that the type of hospital of delivery was the most important correlate of a cesarean

Out of the wedlock childbearing in Puerto Rico

In 1978, the proportion of out of the wedlock childbearing amounted to 18 percent, the lowest figure ever recorded in Puerto Rico. Since then, a consistent upward trend has been observed and in 1994 almost 42 percent of all live births was attributed to non-legally married mothers; 32 percent to mothers in consensualunions and ten percent to unwed mothers (not cohabiting with her child's father). Out of the wedlock childbearing is higher among adolescents and mothers of the lowest socioeconomic status as well as, among mothers out of the labor force. As compared with the legally married out of the wedlock mothers received a poorer prenatal care; those not cohabiting with their child's father receiving the poorest. Among out of the wedlock mothers the proportions of low birthweight newborns, preterm and depressed are higher than among the legally married, as well as their infant mortality rates.

Apgar score and infant mortality in Puerto Rico

This study has as its objectives: 1) to examine the association between Apgar score and a set of demographic and sociodemographic variables so as to assess its usefulness as an indicator of the physical conditions of the newborn; 2) to determine if Apgar score in Puerto Rico is a good predictor of the newborn probability of surviving during his first year of life. For this purpose the 1990 live births and infant deaths data was utilized. The results indicate a direct relation between Apgar score with mother's schooling, father's occupation, and number of prenatal visits. Apgar score shows, also, an U curve type relationship with birthweight and gestational age, while it was found to be higher in private than in public hospitals. One of the most important findings was the strong association between infant mortality and Apgar score, even when the effect of other important independent variables such as birthweight and gestational age were held constant. These results demonstrate that, in spite of its criticisms Apgar score seems to be an excellent indicator of the newborn conditions at birth and a very good predictor of infant mortality in Puerto Rico