Artículos Científicos
URI permanente para esta colecciónhttp://10.0.96.45:4000/handle/11056/14635
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Examinando Artículos Científicos por Materia "AEDES AEGYPTI"
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Ítem Características de los Egresos de una Unidad Hospitalaria de Atención de Dengue. Costa Rica, 1999–2002(Universidad Nacional de Costa Rica, 2009) Pacheco Acuña, Raúl; ROMERO-ZUÑIGA, JUAN JOSÉObjetivo: Caracterizar la población de pacientes egresados de la Unidad de Atención al Dengue del Hospital Monseñor Sanabria de Puntarenas. Materiales y Métodos: Se reunieron datos descriptivos del período de enero de 1999 a diciembre de 2002, así como los hallazgos clínicos y hematológicos de 267 pacientes egresados. Resultados: Los principales motivos de ingreso hospitalario fueron el mal estado general (35,0 %), conteo de plaquetas inferior a 100000/ul (31,5 %) y el torniquete positivo (21,3 %). El dengue afectó por igual a hombres y mujeres; fundamentalmente a adultos, con un promedio de 31 años de edad, así como a trabajadores remunerados, amas de casa y estudiantes (89,5 %). La mayor parte de pacientes provenían del área de mayor urbanización (75,7 %). El día promedio de ingreso, desde el inicio de los síntomas, fue de 3,7 días, y los síntomas más frecuentes fueron: fiebre, cefalea, mialgias, artralgias y dolor retroocular. El 39,7 % presentó algún tipo de manifestación hemorrágica, fuera provocado (26,2 %) o espontáneo (22,8 %), de los cuales el 7,2 % sangraron por más de un sitio. El principal sitio de sangrado fue la piel (52,4 %), seguido de las mucosas de nariz y la encías (35,7 %). La trombocitopenia se presentó en el 68,0 % de los casos. No hubo diferencia en el recuento plaquetario el día de ocurrencia de las manifestaciones hemorrágicas, entre los que sangraron y los que no. Se presentó leucopenia en el 40,5% de los casos. La estancia hospitalaria promedio fue de 3,3 días (rango: 1-12). Conclusión: Los hallazgos de este estudio deben considerarse para estimular la aplicación de la epidemiología descriptiva en el estudio de eventos como el dengue que afectan a nivel local, nacional o regional, y así contribuir al conocimiento de ellos.Ítem Hot temperatures can force delayed mosquito outbreaks via sequential changes in Aedes aegypti demographic parameters in autocorrelated environments(Elsevier B.V, 2014) Chaves, Luis Fernando; Scott, Thomas W.; Morrison, Amy; Takada, TakenoriAedes aegypti L. (Diptera: Culicidae) is a common pantropical urban mosquito, vector of dengue, Yellow Fever and chikungunya viruses. Studies have shown Ae. aegypti abundance to be associated with envi ronmental fluctuations, revealing patterns such as the occurrence of delayed mosquito outbreaks, i.e., sudden extraordinary increases in mosquito abundance following transient extreme high temperatures. Here, we use a two-stage (larvae and adults) matrix model to propose a mechanism for environmental signal canalization into demographic parameters of Ae. aegypti that could explain delayed high temper ature induced mosquito outbreaks. We performed model simulations using parameters estimated from a weekly time series from Thailand, assuming either independent or autocorrelated environments. For autocorrelated environments, we found that long delays in the association between the onset of “hot” environments and mosquito outbreaks (10 weeks, as observed in Thailand) can be generated when “hot” environments sequentially trigger a larval survival decrease and over-compensatory fecundity increase, which lasts for the whole “hot” period, in conjunction with a larval survival increase followed by a fecun dity decrease when the environment returns to “normal”. This result was not observed for independent environments. Finally, we discuss our results implications for prospective entomological research and vector management under changing environments.Ítem Increased adult Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) abundance in a dengue transmission hotspot, compared to a coldspot, within Kaohsiung City, Taiwan(MDPI, 2018-08-13) Ng, Ka Chon; Chaves, Luis Fernando; TSAI, KUN-HSIEN; Chuang, Ting-WuThe assumption that vector abundance differences might drive spatial and temporal heterogeneities in vector-borne disease transmission is common, though data supporting it is scarce. Here, we present data from two common mosquito species Aedes aegypti (Linnaeus) and Culex quinquefasciatus Say, biweekly sampled as adults, from March 2016 through December 2017, with BG-sentinel traps in two neighboring districts of Kaohsiung City (KC), Taiwan. One district has historically been a dengue transmission hotspot (Sanmin), and the other a coldspot (Nanzih). We collected a total 41,027 mosquitoes, and we found that average mosquito abundance (mean ± S.D.) was higher in Sanmin (Ae. aegypti: 9.03 ± 1.46; Cx. quinquefasciatus: 142.57 ± 14.38) than Nanzih (Ae. aegypti: 6.21 ± 0.47; Cx. quinquefasciatus: 63.37 ± 8.71) during the study period. In both districts, Ae. aegypti and Cx. quinquefasciatus population dynamics were sensitive to changes in temperature, the most platykurtic environmental variable at KC during the study period, a pattern predicted by Schmalhausen’s law, which states that organisms are more sensitive to small changes in environmental variables whose average value is more uncertain than its extremes. Our results also suggest that differences in Ae. aegypti abundance might be responsible for spatial differences in dengue transmission at KC. Our comparative approach, where we also observed a significant increment in the abundance of Cx. quinquefasciatus in the dengue transmission hotspot, suggests this area might be more likely to experience outbreaks of other vector borne diseases and should become a primary focus for vector surveillance and control.Ítem Modeling the association between Aedes aegypti ovitrap egg counts, multi-scale remotely sensed environmental data and arboviral cases at Puntarenas, Costa Rica (2017–2018)(Elsevier, 2021-02) Chaves, Luis Fernando; Valerín Cordero, José Ángel; Delgado, Gabriela; Aguilar-Avendaño, Carlos; Maynes, Ezequías; Gutiérrez Alvarado, José Manuel; Ramírez Rojas, Melissa; Marín Rodríguez, Rodrigo; Romero-Vega, L. MarioProblems with vector surveillance are a major barrier for the effective control of vector-borne disease transmission through Latin America. Here, we present results from a 80-week longitudinal study where Aedes aegypti (L.) (Diptera: Culicidae) ovitraps were monitored weekly at 92 locations in Puntarenas, a coastal city in Costa Rica with syndemic Zika, chikungunya and dengue transmission. We used separate models to investigate the association of either Ae. aegypti-borne arboviral cases or Ae. aegypti egg counts with remotely sensed environmental variables. We also evaluated whether Ae. aegypti-borne arboviral cases were associated with Ae. aegypti egg counts. Using cross-correlation and time series modeling, we found that arboviral cases were not significantly associated with Ae. aegypti egg counts. Through model selection we found that cases had a non-linear response to multi-scale (1-km and 30-m resolution) measurements of temperature standard deviation (SD) with a lag of up to 4 weeks, while simultaneously increasing with finely-grained NDVI (30-m resolution). Meanwhile, median ovitrap Ae. aegypti egg counts increased, and respectively decreased, with temperature SD (1-km resolution) and EVI (30-m resolution) with a lag of 6 weeks. A synchrony analysis showed that egg counts had a travelling wave pattern, with synchrony showing cyclic changes with distance, a pattern not observed in remotely sensed data with 30-m and 10-m resolution. Spatially, using generalized additive models, we found that eggs were more abundant at locations with higher temperatures and where EVI was leptokurtic during the study period. Our results suggest that, in Puntarenas, remotely sensed environmental variables are associated with both Ae. aegyptiborne arbovirus transmission and Ae. aegypti egg counts from ovitraps.Ítem Nonlinear impacts of climatic variability on the density dependent regulation of an insect vector of disease(Blackwell, 2011-09) Chaves, Luis F; Morrison, Amy; KITRON, URIEL D.; SCOTT, THOMAS W.Aedes aegypti is one of the most common urban tropical mosquito species and an important vector of dengue, chikungunya, and yellow fever viruses. It is also an organism with a complex life history where larval stages are aquatic and adults are terrestrial. This ontogenetic niche shift could shape the density-dependent regulation of this and other mosquito species, because events that occur during the larval stages impact adult densities. Herein, we present results from simple density-dependent mathematical models fitted using maximum likelihood methods to weekly time series data from Puerto Rico and Thailand. Density-dependent regulation was strong in both populations. Analysis of climatic forcing indicated that populations were more sensitive to climatic variables with low kurtosis, i.e., climatic factors highly variable around the median, rainfall in Puerto Rico, and temperature in Thailand. Changes in environmental variability appear to drive sharp changes in the abundance of mosquitoes. The identification of den sity-independent (i.e., exogenous) variables forcing sharp changes in disease vector populations using the exogenous factors statistical properties, such as kurtosis, could be useful to assess the impacts of changing climate patterns on the transmission of vector-borne diseases.Ítem Prueba de torniquete como predictiva de sangrado espontáneo en casos de dengue clásico por den-2(Asociación Costarricense de Salud Pública, 2008) Pacheco Acuña, Raúl; ROMERO-ZUÑIGA, JUAN JOSÉObjetivo: Determinar el valor de la prueba de torniquete como predictiva de sangrado espontáneo en pacientes afectados por dengue clásico en un brote por el virus DEN-2. Materiales y métodos: Se realizó un estudio caso-control con una población de 267 pacientes egresados de la Unidad de Atención del Dengue del Hospital Monseñor Sanabria en Puntarenas, con diagnóstico de dengue clásico, en el periodo de julio de 1999 a junio de 2002, durante el brote de virus DEN-2 en la Región Pacífico Central de Costa Rica. Hubo un total de 61 pacientes con sangrado espontáneo (casos) y 181 pacientes sin el evento (controles). Se calculó la capacidad predictiva de la prueba de torniquete mediante una tabla de contingencia con la que se determinaron las características diagnósticas de la prueba así como la razón de posibilidades (Odds ratio) y la fracción etiológica, tomando como prueba de oro la condición de sangrado espontáneo. Resultados: La sensibilidad y especificidad de la prueba fueron 41.0% y 75.1%, respectivamente; asimismo, el valor predictivo positivo fue de 35.7%, mientras que el valor predictivo negativo fue de 79.1%. Los pacientes con diagnóstico de dengue por DEN-2 con la prueba de torniquete positivo tuvieron el doble de posibilidad de sufrir de sangrado espontáneo que aquellos con resultado negativo a la prueba (OR= 2.1; IC 95%: 1.1-3.9). Conclusión: La prueba de torniquete no es confiable para indicar fragilidad capilar y no debería utilizarse de manera definitiva para clasificar al paciente que requiere hospitalización por DEN-2.