“Factores de riesgo asociados a la infestación domiciliaria por Triatoma infestans, vector de la Enfermedad de Chagas”

TesisLa ciudad de Arequipa es una zona endémica de la enfermedad de Chagas donde la enfermedad ha llegado a ser un problema urbano. El Ministerio de Salud llevó a cabo campañas orientadas a interrumpir la transmisión vectorial de la enfermedad mediante el uso de insecticidas piretroides para eliminar al Triatoma infestans, el insecto vector de esta enfermedad. El objetivo fue determinar los factores de riesgo asociados a la infestación domiciliaria por T. infestans en localidades periurbanas de Alto Selva Alegre. Se analizó la base de datos colectada a partir de encuestas entomológicas realizadas en 7 localidades del distrito de Alto Selva Alegre en el año 2014. Se estudiaron 25 variables como la zona de estudio, demográficas, materiales de la vivienda y presencia de animales en intradomicilio y peridomicilio. Se realizó el análisis estadístico mediante regresiones logísticas, lineales y regresión logística múltiple para determinar las covariables asociadas a la infestación y el tamaño poblacional de las colonias del vector. Los resultados muestran que, el Índice de Infestación Domiciliario (IID) en las localidades estudiadas varía entre 0.4% y 23.4%, siendo la localidad de Pampa Chica la que presentó el valor más alto. El análisis de regresión múltiple determinó que los principales factores de riesgo que facilitan la infestación por T. infestans son la localidad de Pampa Chica (OR=4.3), el peridomicilio inadecuado (OR=6.7), la presencia de material noble sin estucar en la construcción (OR=2.9), el material pircado (OR=5.7) y la presencia de animales (OR=1.5). Tambien se identificaron como variables que facilitan el crecimiento de las colonias de insectos a: el peridomicilio inadecuado (p=0.0014), la mezcla de material noble y pircado en el intradomicilio (p=0.0044) y la presencia de un elevado número de animales en el peridomicilio (p=0.03). Se concluye que la interacción entre estos factores facilita la infestación y el crecimiento poblacional del vector en las viviendas de una localidad y pueden ser considerados para mejorar las estrategias de control y vigilancia entomológica del vector en zonas endémicas

Dispersal patterns of Trypanosoma cruzi in Arequipa, Peru.

Anthropogenic environmental alterations such as urbanization can threaten native populations as well as create novel environments that allow human pests and pathogens to thrive. As the number and size of urban environments increase globally, it is more important than ever to understand the dispersal dynamics of hosts, vectors and pathogens of zoonotic disease systems. For example, a protozoan parasite and the causative agent of Chagas disease in humans, Trypanosoma cruzi, recently colonized and spread through the city of Arequipa, Peru. We used population genomic and phylogenomic tools to analyze whole genomes of 123 T. cruzi isolates derived from vectors and non-human mammals throughout Arequipa to determine patterns of T. cruzi dispersal. The data show significant population genetic structure within city blocks-parasites in the same block tend to be very closely related-but no population structure among blocks within districts-parasites in neighboring blocks are no more closely related to one another than to parasites in distant districts. These data suggest that T. cruzi dispersal within a block occurs regularly and that occasional long-range dispersal events allow the establishment of new T. cruzi populations in distant blocks. Movement of domestic animals may be the primary mechanism of inter-block and inter-district T. cruzi dispersal

Sexual reproduction in a natural Trypanosoma cruzi population.

BackgroundSexual reproduction provides an evolutionary advantageous mechanism that combines favorable mutations that have arisen in separate lineages into the same individual. This advantage is especially pronounced in microparasites as allelic reassortment among individuals caused by sexual reproduction promotes allelic diversity at immune evasion genes within individuals which is often essential to evade host immune systems. Despite these advantages, many eukaryotic microparasites exhibit highly-clonal population structures suggesting that genetic exchange through sexual reproduction is rare. Evidence supporting clonality is particularly convincing in the causative agent of Chagas disease, Trypanosoma cruzi, despite equally convincing evidence of the capacity to engage in sexual reproduction.Methodology/ principle findingsIn the present study, we investigated two hypotheses that can reconcile the apparent contradiction between the observed clonal population structure and the capacity to engage in sexual reproduction by analyzing the genome sequences of 123 T. cruzi isolates from a natural population in Arequipa, Peru. The distribution of polymorphic markers within and among isolates provides clear evidence of the occurrence of sexual reproduction. Large genetic segments are rearranged among chromosomes due to crossing over during meiosis leading to a decay in the genetic linkage among polymorphic markers compared to the expectations from a purely asexually-reproducing population. Nevertheless, the population structure appears clonal due to a high level of inbreeding during sexual reproduction which increases homozygosity, and thus reduces diversity, within each inbreeding lineage.Conclusions/ significanceThese results effectively reconcile the apparent contradiction by demonstrating that the clonal population structure is derived not from infrequent sex in natural populations but from high levels of inbreeding. We discuss epidemiological consequences of this reproductive strategy on genome evolution, population structure, and phenotypic diversity of this medically important parasite

Immigration and establishment of Trypanosoma cruzi in Arequipa, Peru.

Changing environmental conditions, including those caused by human activities, reshape biological communities through both loss of native species and establishment of non-native species in the altered habitats. Dynamic interactions with the abiotic environment impact both immigration and initial establishment of non-native species into these altered habitats. The repeated emergence of disease systems in urban areas worldwide highlights the importance of understanding how dynamic migratory processes affect the current and future distribution and abundance of pathogens in urban environments. In this study, we examine the pattern of invasion of Trypanosoma cruzi-the causative agent of human Chagas disease-in the city of Arequipa, Peru. Phylogenetic analyses of 136 T. cruzi isolates from Arequipa and other South American locations suggest that only one T. cruzi lineage established a population in Arequipa as all T. cruzi isolated from vectors in Arequipa form a recent monophyletic group within the broader South American phylogeny. We discuss several hypotheses that may explain the limited number of established T. cruzi lineages despite multiple introductions of the parasite

Externado de Medicina Interna - ME212 - 202102

Curso de la carrera de medicina, de carácter teórico-práctico del ciclo 9, en el que los estudiantes presentan una historia clínica con su respectivo plan diagnóstico, terapéutico y de procedimientos en un paciente con una condición médica, a través de la realización de actividades de simulación y metodología activa. El curso del externado de medicina interna busca desarrollar la competencia general de comunicación escrita (nivel 3) y las competencias específicas de práctica clínica (nivel 3) y profesionalismo(nivel 3). El externado de medicina al estudiante le permitirá plantear un adecuado tratamiento y plan de trabajo según el diagnóstico de los principales problemas médicos que le servirá en su futura vida profesional.

Externado de Medicina Interna - ME212 - 202101

Curso de la carrera de medicina, de carácter teórico-práctico del ciclo 9, en el que los estudiantes presentan una historia clínica con su respectivo plan diagnóstico, terapéutico y de procedimientos en un paciente con una condición médica, a través de la realización de actividades de simulación y metodología activa. El curso del externado de medicina interna busca desarrollar la competencia general de comunicación escrita (nivel 3) y las competencias específicas de práctica clínica-diagnóstico(nivel 3) y profesionalismo-sentido ético y legal y responsabilidad profesional(nivel 3). El externado de medicina al estudiante le permitirá plantear un adecuado tratamiento y plan de trabajo según el diagnóstico de los principales problemas médicos que le servirá en su futura vida profesional

Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger Observatory

The Advanced LIGO and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short gamma-ray burst (GRB) that followed the merger of this binary was also recorded by the Fermi Gamma-ray Burst Monitor (Fermi-GBM), and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), indicating particle acceleration by the source. The precise location of the event was determined by optical detections of emission following the merger. We searched for high-energy neutrinos from the merger in the GeV–EeV energy range using the Antares, IceCube, and Pierre Auger Observatories. No neutrinos directionally coincident with the source were detected within ±500 s around the merger time. Additionally, no MeV neutrino burst signal was detected coincident with the merger. We further carried out an extended search in the direction of the source for high-energy neutrinos within the 14 day period following the merger, but found no evidence of emission. We used these results to probe dissipation mechanisms in relativistic outflows driven by the binary neutron star merger. The non-detection is consistent with model predictions of short GRBs observed at a large off-axis angle