Browsing by Author "Grijalva Cobo, Mario Javier"
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Absence of domestic triatomine colonies in an area of the coastal region of Ecuador where Chagas disease is endemic(2010) Grijalva Cobo, Mario Javier; Grijalva, Mario J.Rhodnius ecuadoriensis is considered the second most important vector of Chagas disease in Ecuador. It is distributed across six of the 24 provinces and occupies intradomiciliary, peridomiciliary and sylvatic habitats. This study was conducted in six communities within the coastal province of Guayas. Triatomine searches were conducted in domestic and peridomestic habitats and bird nests using manual searches, live-bait traps and sensor boxes. Synantrhopic mammals were captured in the domestic and peridomestic habitats. Household searches (n = 429) and randomly placed sensor boxes (n = 360) produced no live triatomine adults or nymphs. In contrast, eight nymphs were found in two out of six searched Campylorhynchus fasciatus (Troglodytidae) nests. Finally, Trypanosoma cruzi DNA was amplified from the blood of 10% of the 115 examined mammals. Environmental changes in land use (in- tensive rice farming), mosquito control interventions and lack of intradomestic adaptation are suggested among the possible reasons for the lack of domestic triatomine colonies.Item Open Access Abundance, Natural Infection with Trypanosomes, and Food Source of an Endemic Species of Triatomine, Panstrongylus howardi (Neiva 1911), on the Ecuadorian Central Coast(2015) Baus Carrera, Esteban Guillermo; Grijalva Cobo, Mario Javier; Ocaña Mayorga, Sofía Beatriz; Villacis Salazar, Anita Gabriela; Yumiseva Marín, César Alberto; Grijalva Cobo, Mario JavierThe elimination of domestic triatomines is the foundation of Chagas disease control. Regional initiatives are eliminating introduced triatomine species. In this scenario, endemic triatomines can occupy the ecological niches left open and become a threat to long-term Chagas disease control efforts. This study determined the abundance, colonization, and Trypanosoma cruzi infection rate of the endemic Panstrongylus howardi in 10 rural communities located in Ecuador's Manabí Province. In total, 518 individuals of P. howardi were collected. Infestation indices of 1.4% and 6.6% were found in the domestic and peridomestic environments, respectively. We determined a T. cruzi infection rate of 53.2% (N = 47) in this species. P. howardi has a high capacity to adapt to different habitats, especially in the peridomicile. This implies a considerable risk of transmission because of the frequency of intradomicile invasion. Therefore, this species needs to be taken into account in Chagas control and surveillance efforts in the region.Item Open Access Análisis de variabilidad fenotípica y diversidad genética de poblaciones sinantrópicas y silvestres de Rhodnius ecuadoriensis (Lent & León) en dos provincias endémicas para la enfermedad de Chagas en Ecuador(PUCE - Quito, 2011) Villacís Salazar, Anita Gabriela; Grijalva Cobo, Mario JavierLos estudios de morfometría, como los análisis moleculares, son herramientas que contribuyen al conocimiento de la estructura genética de los triatominos y generan información valiosa que ayuda a establecer estrategias de control. La información disponible de Rhodnius ecuadoriensis ha sido muy limitada. Durante los últimos años, el hallazgo de esta especie colonizando diferentes micro-ambientes en dos provincias del Ecuador (Loja y Manabí) con condiciones climáticas totalmente distintas, ha despertado el interés de ampliar su conocimiento y comprender su proceso de adaptación. Éste estudio comparó las poblaciones de R. ecuadoriensis encontradas en diferentes micro-ambientes (silvestre, peridomiciliar y domiciliar) en dos provincias endémicas para la Enfermedad de Chagas en el Ecuador, utilizando como herramientas de investigación: fenotipo antenal, morfometría geométrica alar, cruces experimentales y marcadores moleculares (mt ADN - Cyt b- y microsatélites). En cuanto al fenotipo se evidenció los siguientes aspectos: (i) Un marcado dimorfismo sexual en el tamaño alar en todas las sub-poblaciones (p < 0.001), presentando un mayor tamaño en las alas de las hembras. (ii) En el fenotipo antenal, el dimorfismo sexual solo fue evidente en hembras del hábitat domiciliar de Loja (p < 0.006). (iii) La geometría alar y el fenotipo antenal diferenciaron claramente las dos poblaciones geográficas de R. ecuadoriensis (p < 0.001). En cuanto al cruzamiento entre las dos poblaciones, se demostraron resultados: (i) Éxito en los cruces de un 87,5%. (ii) Viabilidad de un 32% de los huevos puestos por cruce. (iii) El tamaño alar de especímenes de Manabí, tanto en hembras y machos, fue mayor que los de Loja (parentales) y en la primera generación (F1) se encontró un tamaño alar compartido con los parentales (52% en hembras y 82% en machos)...Item Open Access Análisis preliminar de la estructura genética de poblaciones sinantrópicas de Rhodnius ecuadoriensis (Lent & León) de la provincia de Manabí(PUCE - Quito, 2011) Muñoz Tobar, Sofía Isabel; Grijalva Cobo, Mario JavierLa Enfermedad de Chagas (ECh) o tripanosomiasis americana es una enfermedad producida por el protozoario flagelado Trypanosoma cruzi y transmitida principalmente a través de las heces de insectos vectores pertenecientes a la familia Reduviidae, subfamilia Triatominae (WHO, 2002). Esta enfermedad fue descubierta en 1909 por el médico brasileño Carlos Chagas, quien describió la enfermedad humana, el parásito y el vector (Rodriguez y Pinto, 2009). La transmisión vectorial constituye la principal forma de transmisión, aunque la ECh también puede ser adquirida a través de transfusiones sanguíneas, por vía oral, por transmisión congénita durante el embarazo o el parto y mediante trasplantes de órganos de pacientes portadores de la enfermedad (WHO, 2002; Teixeira et al., 2006). La transmisión vectorial de la ECh es exclusiva del continente americano, donde se encuentra presente desde el sur de los Estados Unidos hasta el sur de Argentina. La ECh afecta a entre 8 y 11 millones de personas (WHO, 2002; CDC, 2011). En el Ecuador, la enfermedad es endémica en la Amazonia, la Costa y las regiones subtropicales de los Andes ...Item Open Access Bats, trypanosomes, and triatomines in Ecuador: new insights into the diversity, transmission, and origins of Trypanosoma cruzi and chagas disease(2015-10-14) Grijalva Cobo, Mario Javier; Ocaña Mayorga, Sofía Beatriz; Pinto Báez, Christian Miguel; Villacis Salazar, Anita Gabriela; Pinto Báez, Christian MiguelThe generalist parasite Trypanosoma cruzi has two phylogenetic lineages associated almost exclusively with bats—Trypanosoma cruzi Tcbat and the subspecies T. c. marinkellei. We present new information on the genetic variation, geographic distribution, host associations, and potential vectors of these lineages. We conducted field surveys of bats and triatomines in southern Ecuador, a country endemic for Chagas disease, and screened for trypanosomes by microscopy and PCR. We identified parasites at species and genotype levels through phylogenetic approaches based on 18S ribosomal RNA (18S rRNA) and cytochrome b (cytb) genes and conducted a comparison of nucleotide diversity of the cytb gene. We document for the first time T. cruzi Tcbat and T. c. marinkellei in Ecuador, expanding their distribution in South America to the western side of the Andes. In addition, we found the triatominesCavernicola pilosa and Triatoma dispar sharing shelters with bats. The comparisons of nucleotide diversity revealed a higher diversity for T. c. marinkellei than any of the T. c. cruzigenotypes associated with Chagas disease. Findings from this study increased both the number of host species and known geographical ranges of both parasites and suggest potential vectors for these two trypanosomes associated with bats in rural areas of southern Ecuador. The higher nucleotide diversity of T. c. marinkellei supports a long evolutionary relationship between T. cruzi and bats, implying that bats are the original hosts of this important parasite.Item Open Access Comprehensive survey of domiciliary triatomine species capable of transmitting Chagas Disease in southern Ecuador(2015-10-06) Grijalva Cobo, Mario Javier; Villacís Salazar, Anita Gabriela; Yumiseva Marín, César Alberto; Moncayo Benalcázar, Ana Lucía; Baus Carrera, Esteban Guillermo; Ocaña Mayorga, Sofía Beatriz; Grijalva Cobo, Mario JavierChagas disease is a major health problem in Latin America. Its infectious agent, Trypanosoma cruzi, is transmitted mainly by the feces of insects called triatomines. Although great progress has been made in reducing transmission in the countries in the southern cone of South America, limited progress has been made in the Andean countries, partly because of lack of knowledge and partly because of limited resources and technical capability of control efforts. We report the first entomological survey conducted in southern Ecuador to learn the distribution of triatomines, their habitat and microhabitat preferences, and factors that favor their presence. The results of the study show that 9% of households in 92 rural communities harbor well-established triatomine populations. These rural areas in the southern Andean region are among the poorest in the country; most of the population lives in sub-standard housing, under conditions that favor the presence of Chagas disease vectors. These results, combined with recent reports of widespread triatomine infestation of wild animal nests in sylvatic areas throughout the region and frequent reports of reinfestation after control intervention, indicate the need for effective, monitored, and sustained vector control to reduce the high risk of infection to which approximately 100,000 people living in rural areas of southern Ecuador are exposed.Item Metadata only Conocimientos, actitudes y prácticas sobre la vacuna de influenza durante el embarazo en Quito-EcuadorErazo Checa, Carlos Vinicio; Moncayo Benalcázar, Ana LucíaApresentação/Introdução: La vacunación es la forma más efectiva para prevenir la infección y las consecuencias graves causadas por el virus de la influenza en mujeres embarazadas y sus hijos. El Ministerio de Salud del Ecuador provee la vacuna de influenza libre de costo a través de campañas anuales durante los meses de diciembre a febrero; sin embargo, bajas coberturas de vacunación se han reportado en mujeres embarazadas. Objetivos: Determinar los conocimientos, actitudes y prácticas relacionados con la vacuna de influenza durante el embarazo y los factores asociados con la vacunación. Metodología: Se realizó un estudio transversal con 842 mujeres que fueron captadas durante el periodo post-parto en los tres principales hospitales gineco-obstétricos de la ciudad Quito durante los años 2016-2017. A dichas mujeres se les administró un cuestionario para obtener información sobre datos demográficos, socio-económicos, cuidado prenatal, condiciones de riesgo y conocimientos, actitudes y prácticas sobre la vacuna de influenza durante el embarazo. Para la evaluación de los factores asociados con la vacunación se empleó un modelo de regresión log-binomial y como medida de efecto se obtuvo la Razón de Prevalencia e Intervalos de Confianza al 95%. Resultados: Se observó una baja cobertura de vacunación contra influenza durante el embarazo en Quito (36,6%). Las mujeres vacunadas percibieron la vacunación como segura y efectiva en una mayor proporción que las mujeres no vacunadas. Conclusões/Considerações: Los resultados evidencian que la recomendación de los profesionales de salud y el cuidado prenatal afectan la cobertura de vacunación, reflejando su importancia para el éxito de las campañas de vacunación. Por lo tanto, es necesario desarrollar estudios para entender las barreras relacionadas con la recomendación de la vacuna de influenza por los profesionales de salud para de esta manera implementar programas educacionales.Item Open Access Determinación de linajes y dinámica de la transmisión de Trypanosoma cruzi en dos provincias endémicas para la Enfermedad de Chagas en Ecuador(PUCE - Quito, 2010) Ocaña Mayorga, Sofía Beatriz; Grijalva Cobo, Mario JavierTrypanosoma cruzi, el agente etiológico de la Enfermedad de Chagas, es un parásito altamente diverso y su transmisión se lleva a cabo dentro de tres ciclos (doméstico, peridoméstico y silvestre). En Ecuador, esta enfermedad constituye un problema de salud pública, sin embargo, la dinámica de la transmisión de la enfermedad es desconocida. Este estudio se llevó a cabo en dos provincias endémicas para la enfermedad: (10 comunidades en la provincia de Manabí y 92 en la provincia de Loja) con el objetivo de determinar la dinámica de las poblaciones de T. cruzi provenientes de los tres hábitats: domiciliar (dentro de las viviendas), peridomiciliar (cerca de las viviendas o en lugares asociados a actividades humanas) y silvestre (zonas alejadas de viviendas al menos 20 metros). Además, se incluyó en el análisis una amplia variedad de hospederos (vectores y reservorios). Se realizó la caracterización de los linajes circulantes y el análisis de 10 microsatélites polimórficos. Todos los aislados analizados, independientemente de su origen geográfico, hábitat y hospedero, fueron caracterizados dentro del linaje TcI. En Manabí, se encontraron altos índices de infección en las especies de vectores Panstrongylus howardi (peridomicilio) y Rhodnius ecuadoriensis (peridomicilio y silvestre); así como en marsupiales (Didelphis marsupialis y Philander opossum) en peridomicilio. La dinámica poblacional en esta región no pudo ser definida debido a la a la alta multiclonalidad de los aislados obtenidos, por lo que se recomienda el aislamiento de clones para futuros análisis. En Loja, el vector con mayor infección fue R. ecuadoriensis, y fue la única especie que se encontró colonizando todos los hábitats (domicilio, peridomicilio y silvestre), mientras que los roedores (Mus musculus) y marsupiales (D. marsupialis) en el domicilio y peridomicilio, respectivamente, fueron los principales reservorios. En esta provincia se identificaron dos poblaciones discretas, las cuales presentan ciclos de transmisión diferentes: LOJADom/Peri (aislados de hábitat domiciliar y peridomiciliar) y LOJASilv (aislados del hábitat silvestre). Se encontró una fuerte correlación entre la distancia geográfica y genética de los aislados LOJASilv, mientras que, los datos de los aislados LOJADom/Peri sugieren que existe un flujo genético constante entre estas poblaciones y que implicaría a una influencia antropogénica en la dispersión del parásito. Además se observó un flujo genético, aunque no frecuente, entre las poblaciones selváticas y domésticas/peridomésticas en la que los mamíferos sinantrópicos podrían actuar como factores vinculantes entre ambos ambientes. Finalmente, los análisis genéticos demostraron en LOJADom/Peri la primera evidencia de sexualidad en una población natural de T. cruzi. Dos aspectos importantes se derivan de los resultados obtenidos en este trabajo. El primero se relaciona con la aplicación práctica de la información molecular en el diseño de estrategias de control, tomando en cuenta que la dinámica poblacional de los parásitos está influenciada por las características intrínsecas locales y que debe ser analizada en una escala geográfica restringida. En segundo lugar, se rompe con el paradigma de la clonalidad de T. cruzi, como ha sucedido en otros parásitos de importancia médica, lo que puede tener consecuencias significativas en la epidemiología de este importante patógeno.Item Open Access Development of Peptide-Based Lineage-Specific Serology for Chronic Chagas Disease: Geographical and Clinical Distribution of Epitope Recognition.(2014) Grijalva Cobo, Mario Javier; Bhattacharyya, Tapan.Chagas disease, caused by infection with the protozoan Trypanosoma cruzi, remains a serious public health issue in Latin America. Genetically diverse, the species is sub-divided into six lineages, known as Tcl-TcVI, which have disparate geographical and ecological distributions. TcII, TcV, and TcVI are associated with severe human disease in the Southern Cone countries, whereas TcI is associated with cardiomyopathy north of the Amazon. T. cruzi persists as a chronic infection, with cardiac and/or gastrointestinal symptoms developing years or decades after initial infection. Identifying an individual´s history of T. cruzi lineage infection directly by genotyping of the parasite is complicated by the low parasitaemia and sequestration in the host tissues. We have appllied here serology against lineage-specific epitopes of the T. cruzi surface antigen TSSA, as an indirect approach to allow identification of infecting lineage. Chagasic sera from chronic patients from a range of endemic countries were tested by ELISA against synthetic peptides representing lineage-specific TSSA epitopes bound to avidin-coated ELISA plates via a biotin labelled polyethylene glycol-glycine spacer to increase rotation and ensure each amino acid side chain could freely interact with their antibodies. 79/113 (70%) of samples from Brazil, Bolivia, and Argentina recognised the TSSA epitope common to lineages TcII/TcV/TcVI. Comparison with clinical information showed that a higher proportion of Brazilian TSSApep-II/V/VI responders had ECG abnormalities than non-responders (38% vs 17%; p<0.0001). Among northern chagasic sera 4/20 (20%) from Ecuador reacted with this peptide; 1/12 Venezuelan and 1/34 Colombian samples reacted with TSSApep-IV. In addition, a proposed TcI-specific epitope, described elsewhere, was demonstrated herre to be highly conserved across lineages and therefore not applicable to lineage-specific serology. These resultas demonstrate the considerable potential for synthetic peptide serology to investigate the infection history of individuals, geographical and clinical associations of T. cruzi lineagesItem Metadata only Distribution of triatomine species in domestic and peridomestic environments in central coastal Ecuador(2017) Baus Carrera, Esteban Guillermo; Grijalva Cobo, Mario Javier; Moncayo Benalcázar, Ana Lucía; Ocaña Mayorga, Sofía Beatriz; Villacis Salazar, Anita Gabriela; Yumiseva Marín, César Alberto; Baus Carrera, Esteban GuillermoBackground: Although the central coast of the Ecuador is considered endemic for Chagas disease, few studies have focused on determining the risk of transmission in this region. In this study we describe the triatomine household infestation in Manabí province (Central Coast region), determine the rate of Trypanosoma cruzi infection and study the risk factors associated with infestation by Rhodnius ecuadoriensis. Methodology/principal findings: An entomological survey found three triatomine species (Rhodnius ecuadoriensis, Panstrongylus rufotuberculatus and P. howardi) infesting domiciles in 47.4% of the 78 communities visited (total infestation rate of 4.5%). Four percent of domiciles were infested, and nymphs were observed in 77% of those domiciles. The three species were found in altitudes below 500 masl and in all ecological zones except cloud forest. Within the domicile, we found the three species mostly in bedrooms. Rhodnius ecuadoriensis and P. rufotuberculatus were abundant in bird nests, including chicken coops and P. howardi associated with rats in piles of bricks, in the peridomicile. Triatomine infestation was characterized by high rates of colonization, especially in peridomicile. Flagelates infection was detected in only 12% of the samples by microscopy and Trypanosoma cruzi infection in 42% of the examined triatomines by PCR (n = 372). The most important risk factors for house infestation by R. ecuadoriensis were ecological zone (w = 0.99) and presence of chickens (w = 0.96). Determinants of secondary importance were reporting no insecticide applications over the last twelve months (w = 0.86) and dirt floor (w = 0.70). On the other hand, wood as wall material was a protective factor (w = 0.85). Conclusion/significance: According the results, approximately 571,000 people would be at high risk for T. cruzi infection in Manabí province. A multidisciplinary approximation and the adhesion to a periodic integrated vector management (IVM) program are essential to guarantee sustainable preventive and control strategies for Chagas disease in this region.Item Open Access Dynamics of Sylvatic Chagas Disease Vectors in Coastal Ecuador Is Driven by Changes in Land Cover.(2014) Grijalva Cobo, Mario Javier; Grijalva Cobo, Mario JavierGlobally, more than 10 million people are infected with Trypanosoma cruzi. The emergence and perpetuation of Chagas disease in some endemic countries, such as Ecuador, depends largely on sylvatic populations of T. cruzi-infected vectors that frequently infest houses after insecticide treatment thereby hampering long-term control prospects in vast geographical areas. Our study describes, for the first time in an agricultural landscape, how the temporal dynamics of sylvatic vector, host, and pathogen populations interact spatially in a farming community of coastal Ecuador. In particular, we found that land cover changes due to both farming activities and vegetation phenology affect rodent host distribution and consequently the relative abundance of vectors involved in the transmission cycle of T. cruzi.Item Open Access Ecological factos related to the widespread distribution of sylvatic Rhodnius ecuadoriensis populations in southern Ecuador.(2012) Grijalva Cobo, Mario Javier; Grijalva Cobo, Mario JavierChagas disease transmission risk is a function of the presence of triatomines in domestic habitats. Rhodnius ecuadoriensis is one of the main vectors implicated in transmission of Trypanosoma cruzi in Ecuador. This triatomine species is present in domestic, peridomestic and sylvatic habitats in the country. To determine the distribution of sylvatic populations of R. ecuadoriensis and the factors related to this distribution, triatomine searches were conducted between 2005 and 2009 in southern Ecuador. Manual triatomine searches were conducted by skilled bug collectors in 23 communities. Sylvatic searched sites were selected by a) directed sampling, where microhabitats were selected by the searchers and b) random sampling, where sampling points where randomly generated. Domiciliary triatomine searches were conducted using the one man-hour method. Natural trypanosome infection was determined by microscopic examination and PCR. Generalized linear models were used to test the effect of environmental factors on the presence of sylvatic triatomines. n total, 1,923 sylvatic individuals were collected representing a sampling effort of 751 man-hours. Collected sylvatic triatomines were associated with mammal and bird nests. The 1,219 sampled nests presented an infestation index of 11.9%, a crowding of 13 bugs per infested nest, and a colonization of 80% of the nests. Triatomine abundance was significantly higher in squirrel (Sciurus stramineus) nests located above five meters from ground level and close to the houses. In addition, 8.5% of the 820 examined houses in the same localities were infested with triatomines. There was a significant correlation between R. ecuadoriensis infestation rates found in sylvatic and synanthropic environments within communities (p = 0.012). Parasitological analysis revealed that 64.7% and 15.7% of the sylvatic bugs examined (n = 300) were infected with Trypanosoma cruzi and T. rangeli respectively, and 8% of the bugs presented mixed infections. The wide distribution of sylvatic R. ecuadoriensis populations may jeopardize the effectiveness of control campaigns conducted to eliminate domestic populations of this species. Also, the high T. cruzi infection rates found in sylvatic R. ecuadoriensis populations in southern Ecuador could constitute a risk for house re- infestation and persistent long-term Chagas disease transmission in the region.Item Metadata only Efecto de un programa de transferencia monetaria condicionada en la mortalidad de niños menores de 5 años en el EcuadorMoncayo Benalcázar, Ana LucíaIntroducción: A pesar de que la tasa de mortalidad en menores de cinco años (TMM5) ha disminuido considerablemente en el Ecuador, miles de niños continúan muriendo por causas relacionadas a la pobreza. Un programa social conocido como “Bono de Desarrollo Humano (BDH)” fue instaurado para garantizar un nivel de consumo mínimo para las familias y para reducir la desnutrición crónica y enfermedades prevenibles en la niñez. Objetivos: Evaluar el efecto del BDH en la mortalidad de niños menores de 5 años en el Ecuador, específicamente por causas relacionadas con la pobreza como malnutrición, diarrea e infecciones respiratorias. Metodología: El estudio tiene un diseño ecológico mixto, comprendió el periodo del 2009 al 2014 (años posteriores fueron excluidos por falta de información) e incluyó a 144 cantones con estadísticas vitales de calidad intermedia y adecuada. Las TMM5 y otros indicadores fueron calculados para cada cantón y cada año. Las fuentes de información fueron: el Instituto Nacional de Estadísticas y Censos y el Sistema Nacional de Información. Se crearon dos indicadores de cobertura del BDH, el primero relacionado a la población total y el segundo a la población elegible de cada cantón. El análisis se basó en una regresión para datos en panel utilizando modelos de regresión binomial negativa con efectos fijos. Resultados: Por cada incremento de 1% en la cobertura del BDH, calculado de la población total (PT) o la población elegible (PE), existiría una disminución en la tasa de mortalidad por malnutrición en niños menores de 5 años de 3% (RR 0,971, IC 95% 0,953-0,989) y 1,5% (RR 0,985, IC 95% 0,973-0,998), respectivamente. Se observó un efecto menor del BDH en la mortalidad por infecciones respiratorias (cobertura BDH-PT: RR 0,992, IC 95% 0,984-0,999 y cobertura BDH-PE: RR 0,994, IC 95% 0,989-0,999). No se encontró un efecto del BDH en la TMM5 por todas las causas ni en la mortalidad por diarrea. EL BDH también redujo las tasas de egresos hospitalarios en menores de cinco años, tanto la general como por diarrea. Conclusiones: Un programa de transferencia monetaria condicionada como el Bono de Desarrollo Humano puede contribuir con la reducción de la mortalidad debido a causas relacionadas con la pobreza, como desnutrición e infecciones respiratorias. El Ecuador, al ser un país que ha incrementado recientemente el monto del BDH, requiere realizar un cuidadoso monitoreo y evaluación del impacto del programa para asegurar que realmente reduzca las inequidades y mejore la salud.Item Open Access Factores sociales asociados con la utilización de los servicios de atención prenatal en Ecuador(2016-11) Costales Cordero, Jaime Alfredo; Grijalva Cobo, Mario JavierObjetivos: La atención prenatal es uno de los pilares de la salud pública y permite el acceso a intervenciones tales como la prevención de la transmisión materno-infantil del VIH y de la sífilis congénita. Este artículo tiene como objetivo describir los factores sociales asociados con la utilización de los servicios de atención prenatal en Ecuador. Métodos. Entre 2011 y 2012, se realizó un análisis de la información procedente de las historias clínicas y de la entrevista a las participantes, que integraron una muestra probabilística a nivel nacional de 5 998 mujeres atendidas por parto o aborto en 15 servicios sanitarios en Ecuador con el objetivo de estimar la prevalencia de VIH, sífilis, enfermedad de Chagas y la cobertura de atención prenatal. Resultados. El estudio mostró que 94,1% de las mujeres había acudido a algún control prenatal, pero la asistencia al menos a cuatro controles fue 73,1%. Se encontró que el menor nivel educativo, el mayor número de embarazos, la ocupación en el sector agrícola o ganadero y la pertenencia a los grupos étnicos indígena, afroecuatoriano u otros minoritarios fueron factores asociados con la falta de uso (ningún control prenatal) o al uso inadecuado de la atención prenatal (menos de cuatro controles o primer control después de las 20 semanas de gestación) en Ecuador. Conclusiones. Estos resultados apuntan a la persistencia de desigualdades marcadas en el acceso y en la utilización de servicios de atención prenatal atribuibles a factores socioeconómicos y a la necesidad de fortalecer las estrategias para su abordaje para alcanzar la meta de la cobertura universal de atención prenatalItem Open Access HIV and syphilis infection in pregnant women in Ecuador: prevalence and characteristics of antenatal care(2014) Grijalva Cobo, Mario JavierObjectives This study aimed to obtain nationally representative estimates of HIV and syphilis prevalence and coverage of preventive antenatal services in pregnant women in Ecuador, in order to develop a national strategy for the elimination of mother-to-child transmission of HIV and syphilis. Methods A national probability sample of 5988 women presenting for delivery or miscarriage services was selected from 15 healthcare facilities during 2011–2012, using a two-stage cluster sample technique. Biological specimens were collected and an interview and review of medical records were performed. Agreement between these last two sources was measured. Estimates were adjusted for the sampling design. Results Estimated national HIV prevalence (0.60%) was higher than confirmed syphilis infection prevalence (0.25%). In the coastal region, HIV prevalence (1.13%) exceeded the threshold that defines a generalised epidemic and syphilis prevalence reached 0.37%. An estimated 5.9% of women did not use antenatal care services while 73.0% completed at least four consultations. HIV testing coverage (89.9%) was higher than for syphilis (71.6%). Agreement between medical records and interviews was mostly moderate (0.40–0.75). Important variables were frequently not recorded, such as timing of syphilis testing, which was not recorded in 49.6%. Conclusions The concentration of HIV and syphilis infections in the coastal region of Ecuador highlights the need for intensified prevention and a response tailored to local epidemic conditions. Major challenges for the elimination initiative include achieving universal, early access to antenatal care, improving coverage of HIV and syphilis testing, and improving the quality of medical records to support progress monitoring.Item Metadata only Influence of ecological factors on the presence of a triatomine species associated with the arboreal habitat of a host of Trypanosoma cruzi(2018) Crespo Pérez, María Verónica; Grijalva Cobo, Mario Javier; Ocaña Mayorga, Sofía Beatriz; Pinto Báez, Christian Miguel; Villacis Salazar, Anita Gabriela; Crespo Pérez, María VerónicaBackground: The white-naped squirrel, Simosciurus nebouxii (previously known as Sciurus stramineus), has recently been identified as an important natural host for Trypanosoma cruzi in Ecuador. The nests of this species have been reported as having high infestation rates with the triatomine vector Rhodnius ecuadoriensis. The present study aims to determine the levels of nest infestation with R. ecuadoriensis, the ecological variables that are influencing the nest site selection, and the relationship between R. ecuadoriensis infestation and trypanosome infection. Results: The study was carried out in transects in forest patches near two rural communities in southern Ecuador. We recorded ecological information of the trees that harbored squirrel nests and the trees within a 10 m radius. Manual examinations of each nest determined infestation with triatomines. We recorded 498 trees (n = 52 with nests and n = 446 without nests). Rhodnius ecuadoriensis was present in 59.5% of the nests and 60% presented infestation with nymphs (colonization). Moreover, we detected T. cruzi in 46% of the triatomines analyzed. Conclusions: We observed that tree height influences nest site selection, which is consistent with previous observations of squirrel species. Factors such as the diameter at breast height and the interaction between tree height and tree species were not sufficient to explain squirrel nest presence or absence. However, the nest occupancy and tree richness around the nest were significant predictors of the abundance of triatomines. Nevertheless, the variables of colonization and infection were not significant, and the data observed could be expected because of chance alone (under the null hypothesis). This study ratifies the hypothesis that the ecological features of the forest patches around rural communities in southern Ecuador favor the presence of nesting areas for S. nebouxii and an increase of the chances of having triatomines that maintain T. cruzi populations circulating in areas near human dwellings. Additionally, these results highlight the importance of including ecological studies to understand the dynamics of T. cruzi transmission due to the existence of similar ecological and land use features along the distribution of the dry forest of southern Ecuador and northern Peru, which implies similar challenges for Chagas disease control.Item Open Access Late Pleistocene environmental changes lead to unstable demography and population divergence of Anopheles albumanus in the northern Neotropics(2010) Grijalva Cobo, Mario Javier; Loaiza, Jose.We investigated the historical demography of Anopheles albimanus using mosquitoes from five countries and three different DNA regions, the mitochondrial cytochrome oxidase subunit I gene (COI), the single copy nuclear white gene and the ribosomal internal transcribed spacer two (ITS2). All the molecular markers supported the taxonomic status of a single species of An. albimanus. Furthermore, agreement between the COI and the white genes suggested a scenario of Pleistocene geographic fragmentation (i.e., population contraction) and subsequent range expansion across southern Central America.Item Metadata only Life cycle, feeding, and defecation patterns of Panstrongylus chinai (Hemiptera: Reduviidae: Triatominae) under laboratory conditions(2016-07) Villacis Salazar, Anita Gabriela; Grijalva Cobo, Mario Javier; Villacis Salazar, Anita GabrielaChagas disease is caused by the protozoan Trypanosoma cruzi. Panstrongylus chinai (Del Ponte) is highly domiciliated in the Peruvian and Ecuadorian Andes and has been found naturally infected with T. cruzi. The objective of this study was to describe the life cycle, feeding, and defecation patterns of P. chinai in the Loja province within southern Ecuador. To characterize its life cycle, a cohort of 70 individuals was followed from egg to adult. At each stage of development, prefeeding time, feeding time, weight of ingested meal, proportional weight increase, and the time to the first defecation were recorded. Panstrongylus chinai completed its development in 371.4 ± 22.3 d, (95% CI 355.4–387.4), which means that it is likely a univoltine species. Prefeeding time, feeding time, and weight of ingested meal increased as individuals developed through nymphal stages. Moreover, time to first defecation was shortest in the early nymphal stages, suggesting higher vector potential in the early developmental stages. Data obtained in this study represent an important advance in our knowledge of the biology of P. chinai, which should be considered as a secondary Chagas disease vector species in the Andean valleys of Loja (Ecuador) and in the north of Peru, and included in entomological surveillance programs.Item Metadata only Life cycle, feeding, and defecation patterns of Triatoma carrioni (Hemiptera: Reduviidae), under laboratory conditions(2019-04) Grijalva Cobo, Mario Javier; Moncayo Benalcázar, Ana Lucía; Villacis Salazar, Anita Gabriela; Grijalva Cobo, Mario JavierChagas disease is caused by Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae). It is transmitted to humans primarily through contaminated feces of blood-sucking vectors of the subfamily Triatominae, known in Ecuador as 'chinchorros'. Some Triatominae species can adapt to domiciliary and peridomiciliary environments where T. cruzi can be transmitted to humans. Triatoma carrioni (Larrousse 1926) colonizes domestic and peridomestic habitats up to 2,242 m above sea level (masl) in southern Ecuador (Loja Province) and northern Peru. This study describes the life cycle, feeding, and defecation patterns of T. carrioni under controlled laboratory conditions using mice as hosts. Specimens were collected in Loja Province, Ecuador, and maintained in the laboratory. The life cycle was approximately 385.7 ± 110.6 d. There was a high mortality rate, 40.9% for first instars and 38.9% for fifth instars (NV). Feeding and defecation patterns for each life stage were examined by recording: insertion time of the proboscis into the host, total feeding time, time to first defecation, and weight of the bloodmeal. Total feeding time varied between 20.6 ± 11.4 min for first instars (NI) and 48.9 ± 19.0 min for adult females. The time to first defecation was variable but ranged from 9.8 ± 10.6 min for NI to 39.4 ± 24.7 min for NV during feeding. This suggests that T. carrioni has an annual life cycle and is a potential vector of T. cruzi in Loja Province. Improved knowledge of populations of T. carrioni in domestic and peridomestic environments of Ecuador can have a significant impact on the prevention and control of Chagas disease.Item Open Access Limitations of selective deltamethrin application for triatomine control in central coastal Ecuador(2011) Baus Carrera, Esteban Guillermo; Grijalva Cobo, Mario Javier; Villacís Salazar, Anita Gabriela; Yumiseva Marin, César Alberto; Grijalva, Mario J.This year-long study evaluated the effectiveness of a strategy involving selective deltamethrin spraying and community education for control of Chagas disease vectors in domestic units located in rural communities of coastal Ecuador. Surveys for triatomines revealed peridomestic infestation with Rhodnius ecuadoriensis and Panstrogylus howardi, with infestation indices remaining high during the study (13%, 17%, and 10%, at initial, 6-month, and 12-month, visits, respectively), which indicates a limitation of this stratefy for triatomine population control. Infestation was found 6 and 12 months after spraying with deltamethrin. In addition, a large number of previously vector-free domestic units also were found infested at the 6- and 12-month surveys, which indicates new infestations by sylvatic triatomines. The predominance of young nymphs and adults suggests new infestation events, likely from sylvatic foci. In addition, infection with Trypanosoma cruzi was found in 65%, 21% and 29% at initial, 6-month and 12-month visits, respectively. All parasites isolated (n=20) were identified as Tcl. New vector control stratefies need to ve devised and evaluated for reduction of T. cruzi transmission in this region.