Extended stage duration and diminished fecundity in deltamethrin-resistant Triatoma infestans (Klug, 1834) of the Argentinean Chaco.

Pyrethroid-resistance is an emergent trait in populations of various insect species. For Triatoma infestans (Klug, 1834) (Heteroptera: Reduviidae), the major vector of Chagas disease in the southern part of South America, hotspot areas of pyrethroid-resistance have recently been found in the Chaco Province of Argentina. Resistant condition can reduce fitness of individuals in the absence of insecticide exposure, that is, fitness costs. We evaluated the existence of developmental and/or reproductive costs in T. infestans collected from two areas of pyrethroid-resistance in Chaco Province, Argentina. Three toxicological groups were defined from field-collected insects: susceptible (survival <20%), moderately resistant (survival between 20% and 80%) and highly resistant (survival >80%). Cohorts of the three toxicological groups were followed-up to study life cycle and reproductive parameters. Additionally, we parameterized matrix population growth models. First and IV nymphal stages of the resistant groups exhibited a longer stage duration than susceptible ones. The reproductive days and hatching success showed significant lower values revealing reproductive costs for the resistant groups. Matrix analysis showed lower population growth rates for the resistant groups. Our results support developmental and reproductive costs for pyrethroid-resistant individuals. This trait could be interpreted as lower population recovery ability for pyrethroid-resistant individuals compared to susceptible insects after alternative vector control actions.

Neurolinguistics evidence of oral discourse in schizophrenic patients. Comparative analysis with Wernicke's aphasia

Introduction: In schizophrenia, the presence of a digressive oral discourse is very frequent, plenty of paraphasias and neologisms, provoked by the alterations of thought, which is common in thisillness. This form of empty oral discourse, full of paraphasias and neologisms, is one of the characteristic clinical manifestations of Wernicke's aphasia; with the difference that, in thesepatients, the symptomatology is linguistic, not secondary to alterations of thought. What cognitive mechanisms lead to similar verbal behaviors in both groups of patients? Objective: The purpose of this research was to obtain empirical evidence about cognitive mechanisms that underlie the alterations of verbal communication in both types of patients, from the comparative analysis of their execution in neurocognitive and neurolinguistic tests. Method: The study was implemented in a population of 70 patients organized into two groups: 35 aphasics and 35 schizophrenics. Both groups were subjected to the tests of Semantic Matching of Images, Identification of Homonymous Images and Oral Denomination of Images and Comics. Data processing involved descriptive statistics and Student's t-test for comparative analysis between groups. Results: Indicate that there are no significant differences between groups in semantic processing. In the formation of lexical concepts, schizophrenics show worse performance; while aphasics perform worse on neurolinguistic examination tests. Conclusions: Empirical evidence shows that the oral discourse of both groups of patients is markedly digressive and empty, with paraphasias and neologisms, but linguistically different.

Introducción: En la esquizofrenia es muy frecuente la presencia de un discurso oral digresivo, lleno de parafasias y neologismos, provocado por las alteraciones del pensamiento común en esta enfermedad.Esta forma de discurso oral vacío, lleno de parafasias y neologismos, es una de las manifestaciones clínicas características de la afasia de Wernicke,con la diferencia de que en estos pacientes la sintomatología es lingüística, no secundaria a alteraciones del pensamiento.¿Qué mecanismos cognitivos conducen a conductas verbales similares en ambos grupos de pacientes? Objetivo: Obtener evidencia empírica sobre los mecanismos cognitivos que subyacen a las alteraciones de la comunicación verbal en ambos tipos de pacientes, a partir del análisis comparativo de su ejecución en pruebas neurocognitivas y neurolingüísticas. Método: El estudio se implementó en una población de 70 pacientes organizados en dos grupos: 35 afásicos y 35 esquizofrénicos.Ambos grupos fueron sometidos a las pruebas de Coincidencia Semántica de Imágenes, Identificación de Imágenes Homónimas y Denominación Oral de Imágenes y Cómics.El procesamiento de datos involucró estadística descriptiva y prueba t de Student para análisis comparativo entre grupos. Resultados: Indican que no existen diferencias significativas entre grupos en el procesamiento semántico.En la formación de conceptos léxicos, los esquizofrénicos muestran peor desempeño;mientras que los afásicos obtienen peores resultados en las pruebas de examen neurolingüístico. Conclusiones: La evidencia empírica muestra que el discurso oral de ambos grupos de pacientes es marcadamente digresivo y vacío, con parafasias y neologismos, pero lingüísticamente diferentes.

Introdução: Na esquizofrenia é muito frequente a presença de um discurso oral digressivo, repleto de parafasias e neologismos, provocados pelas alterações de pensamento comuns nesta doença.Essa forma de discurso oral vazio, repleto de parafasias e neologismos, é uma das manifestações clínicas características da afasia de Wernicke,com a diferença de que, nesses pacientes, a sintomatologia é linguística e não secundária a alterações do pensamento.Que mecanismos cognitivos levam a comportamentos verbais semelhantes em ambos os grupos de pacientes? Objetivos: Obter evidências empíricas sobre os mecanismos cognitivos subjacentes às alterações da comunicação verbal em ambos os tipos de pacientes, a partir da análise comparativa da sua execução em testes neurocognitivos e neurolinguísticos. Métodos: O estudo foi implementado numa população de 70 pacientes organizados em dois grupos: 35 afásicos e 35 esquizofrênicos.Ambos os grupos foram submetidos aos testes de Emparelhamento Semântico de Imagens, Identificação de Imagens Homônimas e Denominação Oral de Imagens e Quadrinhos.O processamento dos dados envolveu estatística descritiva e teste t de Student para análise comparativa entre grupos. Resultados: Indicam que não há diferenças significativas entre os grupos no processamento semântico.Na formação de conceitos lexicais, os esquizofrênicos apresentam pior desempenho;enquanto os afásicos apresentam pior desempenho nos testes de exame neurolinguístico.Conclusões:a evidência empírica mostra que o discurso oral de ambos os grupos de pacientes é marcadamente digressivo e vazio, com parafasias e neologismos, mas linguisticamente diferente.

Spatial distribution of Taenia solium porcine cysticercosis within a rural area of Mexico.

Cysticercosis is caused by Taenia solium, a parasitic disease that affects humans and rurally bred pigs in developing countries. The cysticercus may localize in the central nervous system of the human, causing neurocysticercosis, the most severe and frequent form of the disease. There appears to be an association between the prevalence of porcine cysticercosis and domestic pigs that wander freely and have access to human feces. In order to assess whether the risk of cysticercosis infection is clustered or widely dispersed in a limited rural area, a spatial analysis of rural porcine cysticercosis was applied to 13 villages of the Sierra de Huautla in Central Mexico. Clustering of cases in specific households would indicate tapeworm carriers in the vicinity, whereas their dispersal would suggest that the ambulatory habits of both humans and pigs contribute to the spread of cysticercosis. A total of 562 pigs were included in this study (August-December 2003). A global positioning system was employed in order to plot the geographic distribution of both cysticercotic pigs and risk factors for infection within the villages. Prevalence of pig tongue cysticercosis varied significantly in sampled villages (p = 0.003), ranging from 0% to 33.3% and averaging 13.3%. Pigs were clustered in households, but no differences in the clustering of cysticercotic and healthy pigs were found. In contrast, the presence of pigs roaming freely and drinking stagnant water correlated significantly with porcine cysticercosis (p = 0.07), as did the absence of latrines (p = 0.0008). High prevalence of porcine cysticercosis proves that transmission is still quite common in rural Mexico. The lack of significant differentiation in the geographical clustering of healthy and cysticercotic pigs weakens the argument that focal factors (e.g., household location of putative tapeworm carriers) play an important role in increasing the risk of cysticercosis transmission in pigs. Instead, it would appear that other wide-ranging biological, physical, and cultural factors determine the geographic spread of the disease. Extensive geographic dispersal of the risk of cysticercosis makes it imperative that control measures be applied indiscriminately to all pigs and humans living in this endemic area.

Inexpensive anti-cysticercosis vaccine: S3Pvac expressed in heat inactivated M13 filamentous phage proves effective against naturally acquired Taenia solium porcine cysticercosis.

In search of reducing vaccine production costs', a recombinant M13 phage version of the anti-cysticercosis tripeptide vaccine (S3Pvac) was developed. The efficacy of S3Pvac-Phage vs. placebo was evaluated in a randomized trial that included 1,047 rural pigs in 16 villages of Central Mexico. Three to five months after vaccination 530 pigs were examined by tongue inspection. At 5-27 months of age, 331 pigs (197 vaccinated/134 controls) were inspected at necropsy. Vaccination reduced 70% the frequency of tongue cysticercosis and, based on necropsy, 54% of muscle-cysticercosis and by 87% the number of cysticerci.