A strategy for entomo-virological surveillance of yellow fever, dengue, zika, and chikungunya viruses in field-collected mosquitoes.

Arboviruses transmitted by Culicidae insects are significant threats to human health, presenting dynamic transmission cycles and involving different vectors and hosts. The surveillance and characterization of the vectors involved in these cycles are crucial for understanding and preventing potential outbreaks. Therefore, we propose a strategy that we used for entomological surveillance of urban, rural, and sylvatic mosquitoes and to characterize natural infection by four major arboviruses.•Immature and adult mosquitoes were collected intra, peri and extradomicilie of urban and rural households, using different collection methodologies.•Mosquitoes were pooled or separated in head-thorax and abdomen, according to the species.•A multiplex nested RT-PCR (Reverse transcription polymerase chain reaction) method was used for the simultaneous detection of dengue virus (DENV), zika virus (ZIKV), chikungunya virus (CHIKV), and yellow fever virus (YFV).Overall, this strategy proved helpful for vectors surveillance at different ecosystems, as well as for implementing a low-cost molecular surveillance system that allows the early detection of potential outbreaks, and identify other potential vectors involved in viral transmission.

Improving knowledge, attitudes, and practices on dengue and diarrhea in rural primary school students, their parents, and teachers in Colombia: A cluster-randomized controlled trial.

BACKGROUND: Improved education on water-related diseases in schools could help to reduce disease burden. This paper presents specific results on knowledge, attitudes and practices (KAP) of a cluster-randomized controlled trial to reduce diarrheal disease and dengue entomological risk factors in rural primary schools in Colombia. The aim was to investigate whether enhanced educational interventions on dengue and diarrheal disease in schools could improve KAP scores related to these diseases in students and teachers in rural primary schools, as well as the students' parents. METHODOLOGY/PRINCIPAL FINDINGS: A factorial cluster-randomized controlled trial was carried out in 35 rural primary schools in two municipalities in Cundinamarca, central Colombia. Schools were randomized into four arms: interventions related to diarrheal disease (DIA), dengue (DEN), both (DIADEN), or no interventions (control, CON). Both educational and physical interventions to reduce risk factors of dengue and diarrhea were implemented. Comprehensive teachers' manuals were developed and deployed to guide the learning activities. The intervention was carried out over two school years. The knowledge scores of students receiving dengue interventions (DEN, DIADEN) increased by 1.16 point score (0.75-1.56, p<0.001) and those receiving diarrhea interventions (DIA, DIADEN) increased by 1.15 point score (0.67-1.63, p<0.001). The attitude and practice scores of students receiving the diarrhea interventions increased (Attitudes: 0.41 [0.11-0.71, p = 0.01]; Practices: 0.33 [0.01-0.65, p = 0.042]), but not for those receiving the dengue interventions (p = 0.31 and p = 0.08, respectively). CONCLUSIONS/SIGNIFICANCE: There were increases in knowledge scores among students, their teachers and their parents for both diseases. However, the attitudes and practices components were not affected to the same extent. The hypothesis that the students would disseminate knowledge acquired from the educational interventions to their parents was confirmed for dengue, but not for diarrhea. TRIAL REGISTRATION: ISRCTN40195031 The trial is registered in the Current Controlled Trials under Infections and Infestations category.

Multidisciplinary approach for surveillance and risk identification of yellow fever and other arboviruses in Colombia.

Arbovirus, a critical threat to human health, have complex and dynamic life cycles. With reports of Yellow fever virus (YFV) causing spillover from sylvatic transmission cycles, and dengue (DENV), chikungunya (CHIKV), and Zika (ZIKV) viruses expanding from urban to rural areas. We explored a multidisciplinary approach to analyze arbovirus transmission through vectors, and identify biological and sociodemographic determinants associated with their transmission risk in urban and rural areas in a Colombian municipality. We visited 178 urban and 97 rural households, registered sociodemographic characteristics and vaccination status for each of these households, collected adult and immature mosquitoes at the intra-, peri-, and extra-domicile, and surveyed forest patches in rural areas. Infections of YFV, DENV, ZIKV, and CHIKV in the mosquitoes collected in the wild were analyzed using a reverse transcriptase PCR. We identified various risk factors of transmission associated with a high Aedes aegypti infestation in urban areas and their presence in rural settlements and Haemagogus janthinomys and other sylvatic mosquitoes near urban areas. The collected Ae. aegypti females from urban areas had a high infection rate of YFV (5.8%) and CHIKV (58.8%), and those from rural settlements had a high infection rate of DENV (33%), CHIKV (16.7%), and ZIKV (16.7%). The infection rates of YFV in the thorax of the sylvatic mosquitoes H. janthinomys and Aedes serratus collected from the forest patches were 14.3 and 42.1%, respectively. We could discern the transmission determinants associated with climatic, socioeconomic, and anthropogenic factors and YFV vaccination status. This multidisciplinary approach for surveillance of arboviral diseases allowed us to independently detect and integrate factors indicating an early risk of rural transmission of DENV, CHIKV, and ZIKV and rural and urban outbreaks of YFV in the study area. This study provides a helpful tool for designing and focalizing prevention strategies.

Multilevel analysis of social, climatic and entomological factors that influenced dengue occurrence in three municipalities in Colombia.

According to the World Health Organization, dengue is a neglected tropical disease. Latin America, specifically Colombia is in alert regarding this arbovirosis as there was a spike in the number of reported dengue cases at the beginning of 2019. Although there has been a worldwide decrease in the number of reported dengue cases, Colombia has shown a growing trend over the past few years. This study performed a Poisson multilevel analysis with mixed effects on STATA® version 16 and R to assess sociodemographic, climatic, and entomological factors that may influence the occurrence of dengue in three municipalities for the period 2010-2015. Information on dengue cases and their sociodemographic variables was collected from the National Public Health Surveillance System (SIVIGILA) records. For climatic variables (temperature, relative humidity, and precipitation), we used the information registered by the weather stations located in the study area, which are managed by the Instituto de Hidrologia, Meteorologia y Estudios Ambientales (IDEAM) or the Corporación Autónoma Regional (CAR). The entomological variables (house index, container index, and Breteau index) were provided by the Health office of the Cundinamarca department. SIVIGILA reported 1921 dengue cases and 56 severe dengue cases in the three municipalities; of them, three died. One out of four cases occurred in rural areas. The age category most affected was adulthood, and there were no statistical differences in the number of cases between sexes. The Poisson multilevel analysis with the best fit model explained the presentation of cases were temperature, relative humidity, precipitation, childhood, live in urban area and the contributory healthcare system. The temperature had the biggest influence on the presentation of dengue cases in this region between 2010 and 2015.

Prevalence of dengue antibodies in healthy children and adults in different Colombian endemic areas.

OBJECTIVES: Colombia is a dengue hyperendemic country; however, the prevalence of antibodies against dengue in the general population including the inhabitants of rural areas is unknown. This study aimed to determine the prevalence of dengue IgM and IgG antibodies in healthy children and adults in urban and rural areas of seven different endemic regions in Colombia between 2013 and 2015. DESIGN OR METHOD: Blood samples from healthy volunteers (1,318) were processed by serology (by indirect IgG and capture IgM and IgG ELISA) and molecular tests to detect viral RNA and circulating serotypes. RESULTS: The seroprevalence of IgG for dengue were 85% in children and over 90% for adults. In addition to the high IgM positive rate (14.9%) and secondary recent infection marker rate (capture IgG, 16%), 8.4% of the healthy volunteers were positive for dengue virus (DENV) RNA. CONCLUSION: This study confirmed the broad and permanent circulation of DENV in Colombia and the high rates of infection and reinfection suffered by its inhabitants. This information can be used by the health authorities to strengthen vector control and vaccine policies and review the algorithms of diagnosis and disease management in children and adults.

Knowledge, attitudes, and practices about dengue among pupils from rural schools in an endemic area in Colombia / Conocimientos, actitudes y prácticas sobre dengue en estudiantes de escuelas rurales de un área endémica en Colombia

INTRODUCTION: Dengue is a public health problem in tropical and subtropical regions of the world. Studies on dengue in rural areas are scarce since the disease is considered mainly urban. OBJECTIVE: To determine the knowledge (K), attitudes (A) and practices (P) of dengue in an endemic area in Colombia. MATERIALS AND METHODS: We conducted a cross-sectional study with 515 pupils (7-16 years old) in 34 rural schools in Anapoima and La Mesa municipalities during 2011. Each KAP category was evaluated independently by a scoring system and then categorized into high, medium or low. RESULTS: Pupils recognized knowledge variables such as the symptoms (fever, bone pain), transmission route (mosquito bites), and mosquito breeding sites (uncovered water tanks, solid waste). Average scores on attitude were high in both municipalities indicating a well-developed perception of disease severity. Seeking treatment in medical centers and self-medication for fever management and the use of mosquito net and space-spraying of insecticides were the most frequently identified practices. DISCUSSION: This is the first KAP dengue study performed in a rural area in Colombia and as such it contributes to the understanding of dengue perceptions by the inhabitants of these areas. It showed a medium level of knowledge about dengue and a lower level of preventive practices in pupils from rural schools. It also showed that pupils considered space-spraying as crucial for vector control. The presence of the vector in rural areas of the country underlines the need to improve surveillance and education to more effectively control the vector and promote prevention methods including community participation.

Introducción. El dengue es un problema de salud pública en las regiones tropicales y subtropicales del mundo. Los estudios sobre la enfermedad en áreas rurales son escasos debido a que se presenta principalmente en los núcleos urbanos. Objetivo. Determinar los conocimientos, las actitudes y las prácticas sobre el dengue en un área rural endémica en Colombia. Materiales y métodos. Se hizo un estudio transversal con 515 estudiantes, entre los 7 y los 16 años de edad en 34 escuelas rurales de los municipios de Anapoima y La Mesa en el 2011. Cada categoría se evaluó por separado con un puntaje clasificado como alto, medio o bajo. Resultados. Los estudiantes reconocieron los síntomas (fiebre, dolor de huesos), la ruta de transmisión (picadura de mosquitos) y los criaderos (depósitos de agua destapados, residuos sólidos). El promedio de los puntajes de actitudes fue alto en ambos municipios, lo que indica que percibían la gravedad del dengue. Las prácticas más frecuentes de tratamiento de la fiebre fueron la consulta médica y la automedicación, en tanto que los métodos de control más frecuentes fueron el uso de mosquiteros y el rociamiento con insecticidas. Discusión. Este es el primer estudio de conocimientos, actitudes y prácticas sobre el dengue en un área rural de Colombia. Los resultados contribuyen a entender las percepciones de la enfermedad en sus habitantes y evidenciaron niveles medios de conocimiento y puntuaciones bajas en cuanto a las prácticas entre los estudiantes de las escuelas rurales. Los estudiantes consideraron que la fumigación es importante para el control del vector. La presencia del mosquito en áreas rurales del país resalta la necesidad de mejorar la vigilancia y la educación para lograr un control efectivo del vector y promover métodos de prevención que incluyan la participación comunitaria.

Knowledge, attitudes and practices about dengue among pupils from rural schools in Colombia / Conocimientos, actitudes y prácticas sobre dengue en estudiantes de escuelas rurales en Colombia

Abstract Introduction: Dengue is a public health problem in tropical and subtropical regions of the world. Studies on dengue in rural areas are scarce since the disease is considered mainly urban. Objective: To determine the knowledge (K), attitudes (A) and practices (P) of dengue in an endemic area in Colombia. Materials and methods: We conducted a cross-sectional study with 515 pupils (7-16 years old) in 34 rural schools in Anapoima and La Mesa municipalities during 2011. Each KAP category was evaluated independently by a scoring system and then categorized into high, medium or low. Results: Pupils recognized knowledge variables such as the symptoms (fever, bone pain), transmission route (mosquito bites), and mosquito breeding sites (uncovered wáter tanks, solid waste). Average scores on attitude were high in both municipalities indicating a well-developed perception of disease severity. Seeking treatment in medical centers and self-medication for fever management and the use of mosquito net and space-spraying of insecticides were the most frequently identified practices. Discussion: This is the first KAP dengue study performed in a rural area in Colombia and as such it contributes to the understanding of dengue perceptions by the inhabitants of these areas. It showed a medium level of knowledge about dengue and a lower level of preventive practices in pupils from rural schools. It also showed that pupils considered space-spraying as crucial for vector control. The presence of the vector in rural areas of the country underlines the need to improve surveillance and education to more effectively control the vector and promote prevention methods including community participation.

Resumen Introducción. El dengue es un problema de salud pública en las regiones tropicales y subtropicales del mundo. Los estudios sobre la enfermedad en áreas rurales son escasos debido a que se presenta principalmente en los núcleos urbanos. Objetivo. Determinar los conocimientos, las actitudes y las prácticas sobre el dengue en un área rural endémica en Colombia. Materiales y métodos. Se hizo un estudio transversal con 515 estudiantes, entre los 7 y los 16 años de edad en 34 escuelas rurales de los municipios de Anapoima y La Mesa en el 2011. Cada categoría se evaluó por separado con un puntaje clasificado como alto, medio o bajo. Resultados. Los estudiantes reconocieron los síntomas (fiebre, dolor de huesos), la ruta de transmisión (picadura de mosquitos) y los criaderos (depósitos de agua destapados, residuos sólidos). El promedio de los puntajes de actitudes fue alto en ambos municipios, lo que indica que percibían la gravedad del dengue. Las prácticas más frecuentes de tratamiento de la fiebre fueron la consulta médica y la automedicación, en tanto que los métodos de control más frecuentes fueron el uso de mosquiteros y el rociamiento con insecticidas. Discusión. Este es el primer estudio de conocimientos, actitudes y prácticas sobre el dengue en un área rural de Colombia. Los resultados contribuyen a entender las percepciones de la enfermedad en sus habitantes y evidenciaron niveles medios de conocimiento y puntuaciones bajas en cuanto a las prácticas entre los estudiantes de las escuelas rurales. Los estudiantes consideraron que la fumigación es importante para el control del vector. La presencia del mosquito en áreas rurales del país resalta la necesidad de mejorar la vigilancia y la educación para lograr un control efectivo del vector y promover métodos de prevención que incluyan la participación comunitaria.

[Spatial distribution of Aedes aegypti (Diptera: Culicidae) in the rural area of two municipalities of Cundinamarca, Colombia].

INTRODUCTION: It is difficult to adapt or create new strategies for dengue control in rural areas due to the dispersion of homes and the lack of knowledge about the presence and behavior of the vector in these areas. Spatial data analysis could help understand time and space dynamics related to the transmission of vector-borne diseases in rural areas and, thus, contribute to the prevention and control of dengue. OBJECTIVE: To determine the probability of the presence of the dengue vector Aedes aegypti in the rural area of the municipalities of Anapoima and La Mesa, in the central area of Colombia. MATERIALS AND METHODS: The probability of the presence or absence of the vector in the study area was determined by means of the kriging spatial interpolation method. RESULTS: The region with the highest probability of the presence of the vector was located in the central part, close to the urban centers of both municipalities. CONCLUSION: This study shows the importance of geostatistics for the surveillance of vector-borne diseases and the analysis of time and space dynamics of vector insects and of diseases transmitted by them.

Dengue virus detection in Aedes aegypti larvae and pupae collected in rural areas of Anapoima, Cundinamarca, Colombia.

INTRODUCTION: There is a high incidence and prevalence of dengue in the department of Cundinamarca, and recently Aedes aegypti, the main vector of dengue virus (DENV), was detected in some of its rural areas. OBJECTIVE: To evaluate viral transovarial transmission in larvae and pupae collected in rural areas of the municipality of Anapoima, Cundinamarca. MATERIALS AND METHODS: Live larvae and pupae were collected from 53 homes and later they were taken to the laboratory in Anapoima, where they were classified, pooled and frozen. In Bogotá, they were homogenized, RNA was extracted with Trizol™, and RT-PCR and conventional PCR were performed. The amplified products were analyzed on 2% agarose gels. RESULTS: In 54.7% of the houses we found A. aegypti in immature stages, and DENV-1 was the most frequent serotype. However, the simultaneous presence of DENV 1 and 2, DENV 1 and 3, DENV 1 and 4, and DENV 1, 2 and 3 serotypes was detected in some pools. CONCLUSION: The results confirmed the natural vertical transmission of the virus in the rural area under study. These findings confirmed the vector capacity of A. aegypti, and partly explains the persistence of the virus in the region and the possibility of transmission by the vector during adulthood without having ingested infected blood. This situation increases the risk of DENV infection in Colombia and the need for prevention and control programs in all areas where the mosquito is present.

Distribución espacial de Aedes aegypti (Diptera: Culicidae) en el área rural de dos municipios de Cundinamarca, Colombia / Spatial distribution of Aedes aegypti (Diptera: Culicidae) in the rural area of two municipalities of Cundinamarca, Colombia

Resumen Introducción. Es difícil adaptar o formular nuevas estrategias para el control del dengue en las áreas rurales debido a la dispersión de los hogares y a la falta de conocimiento sobre la presencia y el comportamiento del vector en estas áreas. El análisis de los datos espaciales podría ayudar a comprender las dinámicas temporales y espaciales relacionadas con la transmisión de enfermedades transmitidas por vectores en las zonas rurales y, por lo tanto, contribuir a la prevención y el control del dengue. Objetivo. Determinar la probabilidad de la presencia del vector del dengue, Aedes aegypti, en el área rural de los municipios de Anapoima y La Mesa, Cundinamarca, Colombia. Materiales y métodos. Se visitaron 102 viviendas del área rural, se inspeccionaron los criaderos potenciales del mosquito A. aegypti y se capturaron las formas adultas encontradas en su interior. La probabilidad de la presencia o la ausencia del vector en el área de estudio, se estableció mediante el método de interpolación espacial kriging. Resultados. La región con mayor probabilidad para la presencia del vector se encontró en la parte central, cerca de los centros urbanos de los dos municipios. Conclusión. Los análisis de las dinámicas espacio-temporales de los vectores de enfermedades pueden utilizarse en los sistemas para su vigilancia, con el fin de complementar los métodos usados actualmente, optimizar la determinación de las áreas de intervención de control vectorial y ahorrar recursos.

Abstract Introduction: It is difficult to adapt or create new strategies for dengue control in rural areas due to the dispersion of homes and the lack of knowledge about the presence and behavior of the vector in these areas. Spatial data analysis could help understand time and space dynamics related to the transmission of vector-borne diseases in rural areas and, thus, contribute to the prevention and control of dengue. Objective: To determine the probability of the presence of the dengue vector Aedes aegypti in the rural area of the municipalities of Anapoima and La Mesa, in the central area of Colombia. Materials and methods: The probability of the presence or absence of the vector in the study area was determined by means of the kriging spatial interpolation method. Results: The region with the highest probability of the presence of the vector was located in the central part, close to the urban centers of both municipalities. Conclusion: This study shows the importance of geostatistics for the surveillance of vector-borne diseases and the analysis of time and space dynamics of vector insects and of diseases transmitted by them.

A cross-sectional survey of Aedes aegypti immature abundance in urban and rural household containers in central Colombia.

BACKGROUND: Aedes aegypti, the major vector of dengue, breeds in domestic water containers. The development of immature mosquitoes in such containers is influenced by various environmental, ecological and socioeconomic factors. Urban and rural disparities in water storage practices and water source supply may affect mosquito immature abundance and, potentially, dengue risk. We evaluated the effect of water and container characteristics on A. aegypti immature abundance in urban and rural areas. Data were collected in the wet season of 2011 in central Colombia from 36 urban and 35 rural containers, which were either mosquito-positive or negative. Immature mosquitoes were identified to species. Data on water and container characteristics were collected from all containers. RESULTS: A total of 1452 Aedes pupae and larvae were collected of which 81% were A. aegypti and 19% A. fluviatilis. Aedes aegypti immatures were found in both urban and rural sites. However, the mean number of A. aegypti pupae was five times higher in containers in the urban sites compared to those in the rural sites. One of the important factors associated with A. aegypti infestation was frequency of container washing. Monthly-washed or never-washed containers were both about four times more likely to be infested than those washed every week. There were no significant differences between urban and rural sites in frequency of washing containers. Aedes aegypti immature infestation was positively associated with total dissolved solids, but negatively associated with dissolved oxygen. Water temperature, total dissolved solids, ammonia, nitrate, and organic matter were significantly higher in urban than in rural containers, which might explain urban-rural differences in breeding of A. aegypti. However, many of these factors vary substantially between studies and in their degree of association with vector breeding, therefore they may not be reliable indices for vector control interventions. CONCLUSIONS: Although containers in urban areas were more likely to be infested with A. aegypti, rural containers still provide suitable habitats for A. aegypti. Containers that are washed more frequent are less likely to produce A. aegypti. These results highlight the importance of container washing as an effective vector control tool in both urban and rural areas. In addition, alternative designs of the highly productive washbasins should continue to be explored. To control diseases such as dengue, Zika and chikungunya, effective vector breeding site control must be implemented in addition to other interventions.

A Cluster-Randomized Controlled Trial to Reduce Diarrheal Disease and Dengue Entomological Risk Factors in Rural Primary Schools in Colombia.

BACKGROUND: As many neglected tropical diseases are co-endemic and have common risk factors, integrated control can efficiently reduce disease burden and relieve resource-strained public health budgets. Diarrheal diseases and dengue fever are major global health problems sharing common risk factors in water storage containers. Where provision of clean water is inadequate, water storage is crucial. Fecal contamination of stored water is a common source of diarrheal illness, but stored water also provides breeding sites for dengue vector mosquitoes. Integrating improved water management and educational strategies for both diseases in the school environment can potentially improve the health situation for students and the larger community. The objective of this trial was to investigate whether interventions targeting diarrhea and dengue risk factors would significantly reduce absence due to diarrheal disease and dengue entomological risk factors in schools. METHODOLOGY/PRINCIPAL FINDINGS: A factorial cluster randomized controlled trial was carried out in 34 rural primary schools (1,301 pupils) in La Mesa and Anapoima municipalities, Cundinamarca, Colombia. Schools were randomized to one of four study arms: diarrhea interventions (DIA), dengue interventions (DEN), combined diarrhea and dengue interventions (DIADEN), and control (CON). Interventions had no apparent effect on pupil school absence due to diarrheal disease (p = 0.45) or on adult female Aedes aegypti density (p = 0.32) (primary outcomes). However, the dengue interventions reduced the Breteau Index on average by 78% (p = 0.029), with Breteau indices of 10.8 and 6.2 in the DEN and DIADEN arms, respectively compared to 37.5 and 46.9 in the DIA and CON arms, respectively. The diarrhea interventions improved water quality as assessed by the amount of Escherichia coli colony forming units (CFU); the ratio of Williams mean E. coli CFU being 0.22, or 78% reduction (p = 0.008). CONCLUSIONS/SIGNIFICANCE: Integrated control of dengue and diarrhea has never been conducted before. This trial presents an example for application of control strategies that may affect both diseases and the first study to apply such an approach in school settings. The interventions were well received and highly appreciated by students and teachers. An apparent absence of effect in primary outcome indicators could be the result of pupils being exposed to risk factors outside the school area and mosquitoes flying in from nearby uncontrolled breeding sites. Integrated interventions targeting these diseases in a school context remain promising because of the reduced mosquito breeding and improved water quality, as well as educational benefits. However, to improve outcomes in future integrated approaches, simultaneous interventions in communities, in addition to schools, should be considered; using appropriate combinations of site-specific, effective, acceptable, and affordable interventions. TRIAL REGISTRATION: ClinicalTrials.gov no. ISRCTN40195031.

Aedes aegypti en el área rural: implicaciones en salud pública / Aedes aegypti in areas rural: public health implications

El mosquito Aedes aegypti (L) es considerado como el vector primario de los virus del dengue, del chikungunya, del zika y de la fiebre amarilla urbana en el continente americano. La especie también ha sido incriminada como posible vector urbano de la encefalitis equina venezolana. El papel de A. aegypti como transmisor de enfermedades al hombre fue demostrado por el médico estadounidense Walter Reed en 1901, confirmando la hipótesis planteada por el médico cubano Carlos Finlay en el sentido de que A. aegypti era el vector de la fiebre amarilla.

Schools as Potential Risk Sites for Vector-Borne Disease Transmission: Mosquito Vectors in Rural Schools in Two Municipalities in Colombia.

Dengue and other vector-borne diseases are of great public health importance in Colombia. Vector surveillance and control activities are often focused at the household level. Little is known about the importance of nonhousehold sites, including schools, in maintaining vector-borne disease transmission. The objectives of this paper were to determine the mosquito species composition in rural schools in 2 municipalities in Colombia and to assess the potential risk of vector-borne disease transmission in school settings. Entomological surveys were carried out in rural schools during the dry and rainy seasons of 2011. A total of 12 mosquito species were found: Aedes aegypti, Anopheles pseudopunctipennis, Culex coronator, Cx. quinquefasciatus, and Limatus durhamii in both immature and adult forms; Ae. fluviatilis, Cx. nigripalpus, Cx. corniger, and Psorophora ferox in immature forms only; and Ae. angustivittatus, Haemagogus equinus, and Trichoprosopon lampropus in adult forms only. The most common mosquito species was Cx. quinquefasciatus. Classrooms contained the greatest abundance of adult female Ae. aegypti and Cx. quinquefasciatus. The most common Ae. aegypti breeding sites were containers classified as "others" (e.g., cans), followed by containers used for water storage. A high level of Ae. aegypti infestation was found during the wet season. Our results suggest that rural schools are potentially important foci for the transmission of dengue and other mosquito-borne diseases. We propose that public health programs should be implemented in rural schools to prevent vector-borne diseases.

Resultados de un conjunto de intervenciones integradas para reducir la diarrea y el riesgo entomológico para dengue en las escuelas rurales del municipio de Apulo, Cundinamarca, Colombia / Results of a set of integrated interventions to reduce diarrhea and dengue entomological risk in rural schools in the municipality of Apulo, Cundinamarca, Colombia

Determinar si un conjunto de intervenciones integradas implementadas en las instituciones educativas rurales del municipio de Apulo, Cundinamarca, mejoran la calidad del agua para consumo y reducen la infestación del mosquito vector, reduciendo los factores de riesgo para diarrea y dengue. Materiales y métodos. Se llevó a cabo un estudio cuasiexperimental, antes y después de la intervención, en el cual participaron 350 estudiantes de 14 instituciones rurales del municipio. Se implementó un conjunto de intervenciones para la prevención de las dos enfermedades: para diarrea, instalación de filtros, lavado y tapado de tanques de agua para consumo, y prácticas de higiene; para dengue, tapado de tanques y albercas, y manejo de los residuos sólidos. Resultados. Los índices de infestación de las escuelas por formas inmaduras de Aedes aegypti y de pupas por persona, fueron menores después de la intervención, siendo el último estadísticamente significativo. Con relación a la calidad del agua para consumo, después de la intervención se logró reducir el porcentaje de muestras positivas y la media geométrica de la concentración de las muestras positivas para Escherichia coli, tanto en el total de las muestras, como en las tomadas en los tanques y en las tomadas antes y después de filtrar. Estas diferencias no fueron estadísticamente significativas entre los dos periodos. Después de las intervenciones, se observó una reducción significativa en las tasas de ausentismo general por enfermedad, específicamente, por diarrea e infecciones respiratorias agudas. Conclusión. Se evaluó un conjunto de intervenciones integradas para la prevención de la diarrea y el dengue, enfermedades que tienen en común las prácticas inadecuadas en el almacenamiento del agua para consumo...

To determine if a set of integrated interventions implemented in rural education institutions in the municipality of Apulo, Cundinamarca, improve the quality of potable water and reduce the infestation of the mosquito vector, reducing risk factors for diarrhea and dengue. Materials and methods: A quasi-experimental study, pre and post intervention, with the participation of 350 students from 14 rural education institutions in the municipality was carried out. A set of interventions for the prevention of the two diseases was implemented; for diarrhea: installation of filters, cleaning and covering of potable water tanks, and hygiene practices, and for dengue: covering of tanks and reservoirs and management of solid waste. Results: Infestation rates in schools by immature forms of Aedes aegypti and of pupa/person were less in the post-intervention stage, being this last one statistically significant. In relation to the quality of potable water in the post-intervention stage, a reduction in the percentage of positive samples was achieved, as well as in the geometric mean of the positive samples for Escherichia coli in the totality of samples, in the samples taken in the tanks, and in the samples taken before and after filtering. These differences were not statistically significant between the two periods. A significant reduction in the general absenteeism rates was observed due to illness; specifically, due to diarrhea and acute respiratory diseases. Conclusion: This study evaluated a set of integrated interventions for the prevention of diarrhea and dengue, diseases that share inadequate practices in the storage of drinkable water...

Control de diarrea y dengue en escuelas primarias rurales de Colombia: protocolo de estudio para un ensayo aleatorio y controlado por conglomerados / Diarrhea and dengue control in rural primary schools in Colombia: study protocol for a randomized controlled trial

Antecedentes. Las enfermedades diarreicas y el dengue son graves problemas de salud pública a nivel global. Cuando el suministro de agua potable es inadecuado, el almacenamiento de agua es crucial. La contaminación fecal del agua almacenada es una fuente común de las enfermedades diarreicas y, al mismo tiempo, el agua almacenada proporciona criaderos para los mosquitos vectores del dengue. Un manejo deficiente del agua doméstica y del saneamiento son, por lo tanto, determinantes potenciales de ambas enfermedades. Poco se sabe de la importancia del agua almacenada para el riesgo combinado de la diarrea y el dengue, sin embargo, una intervención compartida podría ser importante para el desarrollo de esfuerzos en gestión y control integrado. Aun menos conocidos son los efectos de un control integrado de estas enfermedades en los entornos escolares. El objetivo de este estudio fue investigar si las intervenciones contra la diarrea y el dengue reducían significativamente las enfermedades diarreicas y los factores de riesgo entomológico de dengue, en las escuelas primarias rurales de dos municipios de Cundinamarca. Metodología y diseño. Se trata de un ensayo por conglomerados, factorial de 2 x 2, controlado y de asignación aleatoria. Las instituciones elegibles fueron las escuelas rurales de los municipios de La Mesa y Anapoima en el departamento de Cundinamarca. Los estudiantes elegibles fueron los niños de las escuelas de los grados 0 a 5. Las escuelas fueron asignadas aleatoriamente a uno de los cuatro grupos del estudio: intervenciones de diarrea, intervenciones de dengue, las dos intervenciones, diarrea y dengue, y control. Las escuelas fueron estratificadas por municipio y asignadas mediante un acto público al inicio del ensayo. La variable de respuesta primaria para la diarrea fue la tasa de incidencia de diarrea en los niños de las escuelas, y para dengue, la densidad de adultos hembra de Aedes aegypti por escuela. Aproximadamente...

Background: Diarrheal diseases and dengue fever are major global health problems. Where provision of clean water is inadequate, water storage is crucial. Fecal contamination of stored water is a common source of diarrheal illness, but stored water also provides breeding sites for dengue vector mosquitoes. Poor household water management and sanitation are therefore potential determinants of both diseases. Little is known of the role of stored water for the combined risk of diarrhea and dengue, yet a joint role would be important for developing integrated control and management efforts. Even less is known of the effect of integrating control of these diseases in school settings. The objective of this trial was to investigate whether interventions against diarrhea and dengue will significantly reduce diarrheal disease and dengue entomological risk factors in rural primary schools. Methods/design: This is a 2×2 factorial cluster randomized controlled trial. Eligible schools were rural primary schools in La Mesa and Anapoima municipalities, Cundinamarca, Colombia. Eligible pupils were school children in grades 0 to 5. Schools were randomized to one of four study arms: diarrhea interventions (DIA); dengue interventions (DEN); combined diarrea and dengue interventions (DIADEN); and control (C). Schools were allocated publicly in each municipality (strata) at the start of the trial, obviating the need for allocation concealment. The primary outcome for diarrea is incidence rate of diarrhea in school children and for dengue it is density of adult female Aedes aegypti per school. Approximately 800 pupils from 34 schools were enrolled in the trial with eight schools in the DIA arm, nine in the DEN, eight in the DIADEN, and nine in the control arms. The trial was funded by the Research Council of Norway and the Lazos de Calandaima Foundation. Discussion: This is the first trial investigating...

Diarrhea and dengue control in rural primary schools in Colombia: study protocol for a randomized controlled trial.

BACKGROUND: Diarrheal diseases and dengue fever are major global health problems. Where provision of clean water is inadequate, water storage is crucial. Fecal contamination of stored water is a common source of diarrheal illness, but stored water also provides breeding sites for dengue vector mosquitoes. Poor household water management and sanitation are therefore potential determinants of both diseases. Little is known of the role of stored water for the combined risk of diarrhea and dengue, yet a joint role would be important for developing integrated control and management efforts. Even less is known of the effect of integrating control of these diseases in school settings. The objective of this trial was to investigate whether interventions against diarrhea and dengue will significantly reduce diarrheal disease and dengue entomological risk factors in rural primary schools. METHODS/DESIGN: This is a 2×2 factorial cluster randomized controlled trial. Eligible schools were rural primary schools in La Mesa and Anapoima municipalities, Cundinamarca, Colombia. Eligible pupils were school children in grades 0 to 5. Schools were randomized to one of four study arms: diarrhea interventions (DIA); dengue interventions (DEN); combined diarrhea and dengue interventions (DIADEN); and control (C). Schools were allocated publicly in each municipality (strata) at the start of the trial, obviating the need for allocation concealment. The primary outcome for diarrhea is incidence rate of diarrhea in school children and for dengue it is density of adult female Aedes aegypti per school. Approximately 800 pupils from 34 schools were enrolled in the trial with eight schools in the DIA arm, nine in the DEN, eight in the DIADEN, and nine in the control arms. The trial status as of June 2012 was: completed baseline data collections; enrollment, randomization, and allocation of schools. The trial was funded by the Research Council of Norway and the Lazos de Calandaima Foundation. DISCUSSION: This is the first trial investigating the effect of a set of integrated interventions to control both dengue and diarrhea. This is also the first trial to study the combination of diarrhea-dengue disease control in school settings. TRIAL REGISTRATION: Current Controlled Trials ISRCTN40195031.

Caracterización preliminar de los sitios de cría de Aedes (Stegomyia) albopictus (Skuse, 1894) (Diptera: Culicidae) en el municipio de Leticia, Amazonas, Colombia / Characterization of Aedes albopictus (Skuse, 1894) (Diptera: Culicidae) larval habitats near the Amazon River in Colombia

Introducción. Dada la importancia de Aedes albopictus en la salud pública, es necesario caracterizar los criaderos para establecer medidas de control. Objetivo. Caracterizar en función de los parámetros físico-químicos y grupos de organismos presentes, los criaderos de los estadios inmaduros de Ae. albopictus en Leticia, Amazonas. Materiales y métodos. Se inspeccionaron 154 viviendas en el área urbana en diciembre 2002 y enero 2003, para buscar criaderos de Ae. albopictus y otros dípteros con estadios acuáticos inmaduros. En los criaderos con resultados positivos se tomaron datos físico-químicos cualitativos y cuantitativos: exposición al sol, ubicación, tamaño, material, conductividad, turbidez, oxígeno disuelto, temperatura y presencia de macroinvertebrados y plancton. Los resultados se compararon mediante análisis descriptivos, análisis de componentes principales, dendrogramas de clasificación e índices de diversidad. Resultados. Se encontraron 21 criaderos con larvas de dípteros, 13 con Ae. albopictus; 92% de ellos estaban ubicados en el peridomicilio, en recipientes pequeños o medianos, dispuestos en la sombra, con baja turbidez y conductividad, bajos índices de diversidad para macroinvertebrados y altos para organismos productores de plancton. En el análisis de componentes principales, se encontró correlación significativa con ácaros, oligoquetos y hemípteros (macroinvertebrados), y con bacilarofíceas, clorofíceas y cianofíceas (plancton). En presencia de otros culícidos, las larvas de Ae. albopictus fueron escasas. Conclusión. En este estudio se encontró que las hembras de Ae. albopictus depositan sus huevos en depósitos de agua recién establecidos con disponibilidad suficiente de recurso, baja conductividad y turbidez, y menor competencia intraespecífica e interespecífica.

Introduction. Because the role of Aedes albopictus as an incriminated vector of several viral pathogens, its control is important to human health. To establish appropriate control methods, characterization of the larval habitats is a necessary first step. Objective. Habitats of the immature stages of Ae. albopictus were characterized with respect to physical-chemical parameters and by floral and faunal arrays present. Materials and methods. Leticia is located at the southern most tip of Colombia on the banks of the Amazon River. In the urban area, 154 houses were inspected in December 2002 and January 2003. Physical-chemical data were collected, including exposure to sunlight, location, container size and material, water conductivity, and dissolved oxygen. Macroinvertebrates and plankton samples were taken at each positive larval site. The results were compared using descriptive analysis, principal component analysis, classification dendrograms, and diversity indexes. Results. Twenty-one habitats were found positive for Diptera, and 13 were positive for Ae. albopictus larvae. Most of the positive habitats (92%) were located near the houses-they were small or medium size receptacles located in the shade. This water generally had low conductivity and low turbidity, although high values of these parameters were also identified. The habitats had low diversity indexes for macroinvertebrates and high diversity indexes for plankton. In the principal component analysis, significant correlation was found with mites, oligochaetes and hemipterans (the macroinvertebrates) and with bacilarophyceaes, clorophyceaes and cianophyceas (the algal forms). Conclusion. In Leticia, females of Ae. albopictus were found in newly established habitats with sufficient availability of resources, low conductivity, and turbidity, lower intra-and interspecific competition.