scholarly journals Exploring the utility of social-ecological and entomological risk factors for dengue infection as surveillance indicators in the dengue hyper-endemic city of Machala, Ecuador

2021 ◽  
Vol 15 (3) ◽  
pp. e0009257
Author(s):  
Catherine A. Lippi ◽  
Anna M. Stewart-Ibarra ◽  
Timothy P. Endy ◽  
Mark Abbott ◽  
Cinthya Cueva ◽  
...  
Keyword(s):  
Risk Factors ◽  
Aedes Aegypti ◽  
Dengue Infection ◽  
Good Condition ◽  
Ecological Factors ◽  
Dengue Case ◽  
Infection Status ◽  
Household Level ◽  
Targeted Interventions ◽  
Social Ecological

The management of mosquito-borne diseases is a challenge in southern coastal Ecuador, where dengue is hyper-endemic and co-circulates with other arboviral diseases. Prior work in the region has explored social-ecological factors, dengue case data, and entomological indices. In this study, we bring together entomological and epidemiological data to describe links between social-ecological factors associated with risk of dengue transmission at the household level in Machala, Ecuador. Households surveys were conducted from 2014–2017 to assess the presence of adult Aedes aegypti (collected via aspiration) and to enumerate housing conditions, demographics, and mosquito prevention behaviors. Household-level dengue infection status was determined by laboratory diagnostics in 2014–2015. Bivariate analyses and multivariate logistic regression models were used to identify social-ecological variables associated with household presence of female Ae. aegypti and household dengue infection status, respectively. Aedes aegypti presence was associated with interruptions in water service and weekly trash collection, and household air conditioning was protective against mosquito presence. Presence of female Ae. aegypti was not associated with household dengue infections. We identified shaded patios and head of household employment status as risk factors for household-level dengue infection, while window screening in good condition was identified as protective against dengue infection. These findings add to our understanding of the systems of mosquito-borne disease transmission in Machala, and in the larger region of southern Ecuador, aiding in the development of improved vector surveillance efforts, and targeted interventions.

scholarly journals Exploring the utility of social-ecological and entomological risk factors for dengue infection as surveillance indicators in the dengue hyper-endemic city of Machala, Ecuador

2020 ◽  
Author(s):  
Catherine Lippi ◽  
Anna M. Stewart-Ibarra ◽  
Timothy P. Endy ◽  
Mark Abbott ◽  
Cinthya Cueva ◽  
...  
Keyword(s):  
Risk Factors ◽  
Aedes Aegypti ◽  
Dengue Infection ◽  
Good Condition ◽  
Ecological Factors ◽  
Dengue Case ◽  
Infection Status ◽  
Household Level ◽  
Targeted Interventions ◽  
Social Ecological

The management of mosquito-borne diseases is a challenge in southern coastal Ecuador, where dengue is hyper-endemic and co-circulates with other arboviral diseases. Prior work in the region has explored social-ecological factors, dengue case data, and entomological indices. In this study, we bring together entomological and epidemiological data to describe links between social-ecological factors associated with risk of dengue transmission at the household level in Machala, Ecuador. Households surveys were conducted from 2014-2016 to assess the presence of adult Aedes aegypti (collected via aspiration) and to enumerate housing conditions, demographics, and mosquito prevention behaviors. Household-level dengue infection status was determined by laboratory diagnostics in 2014-2015. Logistic models and multimodel selection were used to identify social-ecological variables associated with household presence of female Ae. aegypti and household dengue infection status, respectively. We identified significant risk factors for household-level dengue infection reflecting household condition, including bamboo cane construction material, shaded patios, and adjacency to abandoned properties, while housing structures in good condition were identified as protective against dengue infection. Aedes aegypti presence was associated with a greater than average number people per household and interrupted water supply, but was not associated with household level dengue infections. Models of Ae. aegypti presence were unstable, and not well resolved in ranking of competing models, suggesting that highly localized entomological surveillance indicators may not be indicative of risk in communities with hyperendemic dengue fever. These findings add to our understanding of the systems of mosquito-borne disease transmission in Machala, and in the larger region of southern Ecuador, aiding in the development of improved vector surveillance efforts, and targeted interventions.

scholarly journals Social-ecological factors and preventive actions decrease the risk of dengue infection at the household-level: results from a prospective dengue surveillance study in Machala, Ecuador

2017 ◽  
Author(s):  
Aileen Kenneson ◽  
Efraín Beltrán-Ayala ◽  
Mercy J. Borbor-Cordova ◽  
Mark E. Polhemus ◽  
Sadie J. Ryan ◽  
...  
Keyword(s):  
Public Health ◽  
Risk Factors ◽  
Vector Control ◽  
Disease Outbreaks ◽  
Ecological Factors ◽  
Bed Nets ◽  
Household Level ◽  
Social Ecological ◽  
Piped Water ◽  
Abandoned Properties

ABSTRACTBackgroundIn Ecuador, dengue virus (DENV) infections transmitted by the Aedes aegypti mosquito are among the greatest public health concerns in urban coastal communities. Community- and household-level vector control is the principal means of controlling disease outbreaks. This study aimed to assess the impact of knowledge, attitudes, and practices (KAPs) and social-ecological factors on the presence or absence of DENV infections in the household..MethodsIn 2014 and 2015, individuals with DENV infections from sentinel clinics were invited to participate in the study, as well as members of their household and members of four neighboring households located within 200 meters. We conducted diagnostic testing for DENV on all study participants; we surveyed heads of households (HOHs) regarding demographics, housing conditions and KAPs. We compared KAPs and social-ecological factors between households with (n=139) versus without (n=80) DENV infections, using bivariate analyses and multivariate logistic regression models with and without interactions.ResultsSignificant risk factors in multivariate models included proximity to abandoned properties, interruptions in piped water, and shaded patios (p<0.05). Significant protective factors included use of mosquito bed nets, fumigation inside the home, piped water inside the home (p<0.05). In bivariate analyses (but not multivariate modeling), DENV infections was positively associated with HOHs who were male, employed, and of younger age than households without infections (p<0.05). DENV infections were not associated with knowledgeattitude, or reported barriers to prevention activities.DiscussionSpecific actions that can be considered to decrease the risk of DENV infections in the household include targeting vector control in highly shaded properties, fumigating inside the home, and use of mosquito bed nets. Community-level interventions include clean-up of abandoned properties, daily trash pick-up, and reliable piped water inside houses. These findings can inform interventions to reduce the risk of other diseases transmitted by the Ae. aegypti mosquito, such as chikungunya and Zika fever.Author summaryDengue, chikungunya and Zika viruses are transmitted to people primarily by the Aedes aegypti mosquitoes in tropical and subtropical regions. Diseases transmitted by the Ae. aegypti mosquito are a growing public health concern. Mosquito control is the principal means of preventing and controlling disease outbreaks. In this study, we compared the characteristics of households with and without DENV infections in the city of Machala, Ecuador. We found that risk factors for DENV infection included proximity to abandoned properties, interruptions in the piped water supply, and a highly shaded patio. Protective factors included the use of mosquito bed nets, fumigation inside the home, and piped water inside the home. These findings can be used to inform targeted vector control interventions by the public health sector at the household and community levels.

scholarly journals Household-Level Risk Factors for Aedes aegypti Pupal Density in Guayaquil, Ecuador

2020 ◽  
Author(s):  
Thien-An Ha ◽  
Tomás M. León ◽  
Karina Lalangui ◽  
Patricio Ponce ◽  
John M. Marshall ◽  
...  
Keyword(s):  
Risk Factors ◽  
Aedes Aegypti ◽  
Vector Control ◽  
Negative Binomial Regression Model ◽  
Control Methods ◽  
Municipal Services ◽  
Breeding Sites ◽  
Household Level ◽  
Level Model ◽  
The Impact

AbstractBackgroundVector-borne diseases are a major cause of disease burden in Guayaquil, Ecuador, especially arboviruses spread by Aedes aegypti mosquitoes. Understanding which household characteristics and risk factors lead to higher Ae. aegypti densities and consequent disease risk can help inform and optimize vector control programs.MethodsCross-sectional entomological surveys were conducted in Guayaquil between 2013 and 2016, covering household demographics, municipal services, potential breeding containers, presence of Ae. aegypti larvae and pupae, and history of using mosquito control methods. A zero-truncated negative binomial regression model was fitted to data for estimating the household pupal index. An additional model assessed the factors of the most productive breeding sites across all of the households.ResultsOf surveyed households, 610 satisfied inclusion criteria. The final household-level model found that collection of large solid items (e.g., furniture and tires) and rainfall the week of and 2 weeks before collection were negatively correlated with average pupae per container, while bed canopy use, unemployment, container water volume, and the interaction between large solid collection and rainfall 2 weeks before the sampling event were positively correlated. Selection of these variables across other top candidate models with ΔAICc < 1 was robust, with the strongest effects from large solid collection and bed canopy use. The final container-level model explaining the characteristics of breeding sites found that contaminated water is positively correlated with Ae. aegypti pupae counts while breeding sites composed of car parts, furniture, sewerage parts, vases, ceramic material, glass material, metal material, and plastic material were all negatively correlated.ConclusionHaving access to municipal services like bulky item pickup was effective at reducing mosquito proliferation in households. Association of bed canopy use with higher mosquito densities is unexpected, and may be a consequence of large local mosquito populations or due to limited use or effectiveness of other vector control methods. The impact of rainfall on mosquito density is multifaceted, as it may both create new habitat and “wash out” existing habitat. Providing services and social/technical interventions focused on monitoring and eliminating productive breeding sites is important for reducing aquatic-stage mosquito densities in households at risk for Ae. aegypti-transmitted diseases.

scholarly journals Dengue fever and Aedes aegypti risk in the Galápagos Islands, Ecuador

2017 ◽  
Author(s):  
Ryan Nightingale ◽  
Catherine Lippi ◽  
Sadie J. Ryan ◽  
Mercy J. Borbor-Cordova ◽  
Marilyn Cruz B ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Dengue Fever ◽  
Mosquito Control ◽  
Dengue Infection ◽  
Human Movement ◽  
Galapagos Islands ◽  
Housing Conditions ◽  
Galápagos Islands ◽  
Household Level ◽  
Attitudes And Practices

AbstractIntroductionDengue fever is an emerging infectious disease in the Galápagos Islands of Ecuador, with the first cases reported in 2002 and periodic outbreaks since then. Here we report the results of a pilot study conducted in two cities in 2014: Puerto Ayora (PA) on Santa Cruz Island, and Puerto Baquerizo Moreno (PB) on Santa Cristobal Island. The aims of this study were to assess the social-ecological risk factors associated with dengue and mosquito presence at the household-level.MethodsIn 2014 we conducted 100 household surveys (50 on each island) in neighborhoods with prior reported dengue. Adult mosquitoes were collected inside and outside the home, larval indices were determined through container surveys, and heads of households were interviewed to determine demographics, prior dengue infections, housing conditions, and knowledge, attitudes and practices regarding dengue. Multimodel selection methods were used to derive best-fit generalized linear regression (GLM) models of prior dengue infection, and the presence of Ae. aegypti in the home.ResultsWe found that 24% of PB and 14% of PA respondents self-reported a prior dengue infection, and more PB homes than PA homes had Ae. aegypti. The top-ranked model for prior dengue infection included human movement – travel between neighborhoods, between islands, and to the mainland; demographics including salary level and education of the head of household, and increase with more people per room in a house, house condition, access to water quality issues, and dengue awareness. The top-ranked model for the presence of Ae. aegypti included housing conditions, including the presence of window screens and air conditioners, mosquito control actions, and dengue risk perception.Discussion/conclusionTo our knowledge, this is the first study of dengue risk and Aedes aegypti in the Galápagos Islands. The findings that human movement within and between islands, and to and from the mainland, were important to reported dengue cases confirms concerns of this route of introduction and repeated transmission.

scholarly journals The social and spatial ecology of dengue presence and burden during an outbreak in Guayaquil, Ecuador, 2012

2017 ◽  
Author(s):  
Catherine A. Lippi ◽  
Anna M. Stewart-Ibarra ◽  
Ángel G. Muñoz ◽  
Mercy J. Borbor ◽  
Raúl Mejía ◽  
...  
Keyword(s):  
Risk Factors ◽  
Dengue Fever ◽  
Garbage Collection ◽  
Significant Risk ◽  
Dengue Case ◽  
List Type ◽  
Housing Conditions ◽  
Social Ecological ◽  
Piped Water ◽  
Block Level

AbstractDengue fever, a mosquito-borne viral disease, is an ongoing public health problem in Ecuador and throughout the tropics, yet we have a limited understanding of the disease transmission dynamics in these regions. The objective of this study was to characterize the spatial dynamics and social-ecological risk factors associated with a recent dengue outbreak in Guayaquil, Ecuador. We examined georeferenced dengue cases (n = 4,248) and block-level census data variables to identify potential social-ecological variables associated with the presence and burden of dengue fever in Guayaquil in 2012. We applied LISA and Moran’s I tests to analyze hotspots of dengue cases and used multimodel selection in R computing language to identify covariates associated with dengue incidence at the census zone level. Significant hotspots of dengue transmission were found near the North Central and Southern portions of Guayaquil. Significant risk factors for presence of dengue included poor housing conditions (e.g., poor condition of ceiling, floors, and walls), access to paved roads, and receipt of remittances. Counterintuitive positive correlations with dengue presence were observed with several municipal services such as garbage collection and access to piped water. Risk factors for the increased burden of dengue included poor housing conditions, garbage collection, receipt of remittances, and sharing a property with more than one household. Social factors such as education and household demographics were negatively correlated with increased dengue burden. Our findings elucidate underlying differences with dengue presence and burden and indicate the potential to develop dengue vulnerability and risk maps to inform disease prevention and control - information that is also relevant for emerging epidemics of chikungunya and zika.HighlightsIn 2012, Guayaquil, Ecuador had a large outbreak of dengue casesDengue case presence and burden exhibited spatial heterogeneity at the census block levelSocial-ecological drivers of case presence and burden differed in this outbreak, highlighting the need to model both types of epidemiological dataAccess to municipal resources such as garbage collection and piped water had counterintuitive relationships with dengue presence, but poor housing, garbage collection and remittances correlated to dengue burden.Our findings inform risk mapping and vector control and surveillance allocation, relevant to this and other concurrent emergent epidemics such as chikungunya and zika

scholarly journals Associations between Household-Level Exposures and All-Cause Diarrhea and Pathogen-Specific Enteric Infections in Children Enrolled in Five Sentinel Surveillance Studies

2020 ◽  
Vol 17 (21) ◽  
pp. 8078
Author(s):  
Josh M. Colston ◽  
Abu S. G. Faruque ◽  
M. Jahangir Hossain ◽  
Debasish Saha ◽  
Suman Kanungo ◽  
...  
Keyword(s):  
Risk Factors ◽  
Diarrheal Disease ◽  
Pathogen Transmission ◽  
Childhood Mortality ◽  
Infection Status ◽  
Surveillance Studies ◽  
Household Level ◽  
Caregiver Education ◽  
Combining Data ◽  
Enteric Infections

Diarrheal disease remains a major cause of childhood mortality and morbidity causing poor health and economic outcomes. In low-resource settings, young children are exposed to numerous risk factors for enteric pathogen transmission within their dwellings, though the relative importance of different transmission pathways varies by pathogen species. The objective of this analysis was to model associations between five household-level risk factors—water, sanitation, flooring, caregiver education, and crowding—and infection status for endemic enteric pathogens in children in five surveillance studies. Data were combined from 22 sites in which a total of 58,000 stool samples were tested for 16 specific enteropathogens using qPCR. Risk ratios for pathogen- and taxon-specific infection status were modeled using generalized linear models along with hazard ratios for all-cause diarrhea in proportional hazard models, with the five household-level variables as primary exposures adjusting for covariates. Improved drinking water sources conferred a 17% reduction in diarrhea risk; however, the direction of its association with particular pathogens was inconsistent. Improved sanitation was associated with a 9% reduction in diarrhea risk with protective effects across pathogen species and taxa of around 10–20% risk reduction. A 9% reduction in diarrhea risk was observed in subjects with covered floors, which were also associated with decreases in risk for zoonotic enteropathogens. Caregiver education and household crowding showed more modest, inconclusive results. Combining data from diverse sites, this analysis quantified associations between five household-level exposures on risk of specific enteric infections, effects which differed by pathogen species but were broadly consistent with hypothesized transmission mechanisms. Such estimates may be used within expanded water, sanitation, and hygiene (WASH) programs to target interventions to the particular pathogen profiles of individual communities and prioritize resources.

scholarly journals Household and climate factors influence Aedes aegypti risk in the arid city of Huaquillas, Ecuador

2020 ◽  
Author(s):  
James L. Martin ◽  
Anna M. Stewart-Ibarra ◽  
Efraín Beltrán Ayala ◽  
Erin A. Mordecai ◽  
Rachel Sippy ◽  
...  
Keyword(s):  
Public Health ◽  
Aedes Aegypti ◽  
High Temperatures ◽  
Health Concern ◽  
Septic Systems ◽  
Mosquito Vector ◽  
Household Level ◽  
Social Ecological ◽  
Heads Of Household ◽  
Water Tanks

AbstractArboviruses transmitted by Aedes aegypti (e.g., dengue, chikungunya, Zika) are of major public health concern on the arid coastal border of Ecuador and Peru. This high transit border is a critical disease surveillance site due to human movement-associated risk of transmission. Local level studies are thus integral to capturing the dynamics and distribution of vector populations and social-ecological drivers of risk, to inform targeted public health interventions. Our study examines factors associated with household-level Ae. aegypti presence in Huaquillas, Ecuador, while accounting for spatial and temporal effects. From January to May of 2017, adult mosquitoes were collected from a cohort of households (n = 63) in clusters (n = 10), across the city of Huaquillas, using aspirator backpacks. Household surveys describing housing conditions, demographics, economics, travel, disease prevention, and city services were conducted by local enumerators. This study was conducted during the normal arbovirus transmission season (January - May), but during an exceptionally dry year. Household level Ae. aegypti presence peaked in February, and counts were highest in weeks with high temperatures and a week after increased rainfall. Presence of Ae. aegypti was highly variable between clusters. Hierarchical generalized linear models were used to explore household social-ecological variables and female Ae. aegypti presence. Houses with Ae. aegypti used larvicide in water tanks and had high awareness of dengue transmission. We found that homes were more likely to have Ae. aegypti when heads of household had lived in the neighborhoods for longer than average (>22 years), when households had more occupants than average (>4.5), had a female head of household, and received more frequent garbage collection. Ae. aegypti presence was less likely in households with reliable water supply and septic systems. Based on our findings, infrastructure access, urban occupancy patterns, and seasonal climate are important considerations for vector control in this city, and even in dry years, this arid environment supports Ae. aegypti breeding habitat.Author summaryMosquito transmitted infectious diseases are a growing concern around the world. The yellow fever mosquito (Aedes aegypti) has been responsible for recent major outbreaks of disease, including dengue fever and Zika. This mosquito prefers to bite humans and lay its eggs in artificial containers such as water tanks and planters. This makes Ae. aegypti well suited to become established in growing urban areas. Controlling these mosquitoes has been an important way to reduce the risk of disease transmission. Studies that are undertaken to understand local factors that contribute to the continued survival of the mosquito can be used to inform control practices. We conducted a study in the largest city on the border of Ecuador and Peru where we collected adult mosquitoes from houses and surveyed household members about their behaviors, perceptions, and housing infrastructure associated with the mosquito vector. Mosquitoes were most numerous in weeks with high temperatures and a week after increased rainfall. Larvicide was a commonly used control strategy in homes where Ae. aegypti was present. We found that houses that had more people, female heads of household, heads of household that had lived in the neighborhood for a long time, and had unreliable water service, were more likely have mosquitoes present, while houses that used septic systems were less likely to have mosquitoes present.

scholarly journals Investigating differences in village-level heterogeneity of malaria infection and household risk factors in Papua New Guinea

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Desmond Gul ◽  
Daniela Rodríguez-Rodríguez ◽  
Elma Nate ◽  
Alma Auwan ◽  
Mary Salib ◽  
...  
Keyword(s):  
Risk Factors ◽  
Spatial Heterogeneity ◽  
Papua New Guinea ◽  
New Guinea ◽  
Malaria Prevalence ◽  
Malaria Risk ◽  
Cross Sectional ◽  
Household Level ◽  
Targeted Interventions ◽  
Spatial Risk

AbstractMalaria risk is highly heterogeneous. Understanding village and household-level spatial heterogeneity of malaria risk can support a transition to spatially targeted interventions for malaria elimination. This analysis uses data from cross-sectional prevalence surveys conducted in 2014 and 2016 in two villages (Megiar and Mirap) in Papua New Guinea. Generalised additive modelling was used to characterise spatial heterogeneity of malaria risk and investigate the contribution of individual, household and environmental-level risk factors. Following a period of declining malaria prevalence, the prevalence of P. falciparum increased from 11.4 to 19.1% in Megiar and 12.3 to 28.3% in Mirap between 2014 and 2016, with focal hotspots observed in these villages in 2014 and expanding in 2016. Prevalence of P. vivax was similar in both years (20.6% and 18.3% in Megiar, 22.1% and 23.4% in Mirap) and spatial risk heterogeneity was less apparent compared to P. falciparum. Within-village hotspots varied by Plasmodium species across time and between villages. In Megiar, the adjusted odds ratio (AOR) of infection could be partially explained by household factors that increase risk of vector exposure, such as collecting outdoor surface water as a main source of water. In Mirap, increased AOR overlapped with proximity to densely vegetated areas of the village. The identification of household and environmental factors associated with increased spatial risk may serve as useful indicators of transmission hotspots and inform the development of tailored approaches for malaria control.

scholarly journals Household and climate factors influence Aedes aegypti presence in the arid city of Huaquillas, Ecuador

2021 ◽  
Vol 15 (11) ◽  
pp. e0009931
Author(s):  
James L. Martin ◽  
Catherine A. Lippi ◽  
Anna M. Stewart-Ibarra ◽  
Efraín Beltrán Ayala ◽  
Erin A. Mordecai ◽  
...  
Keyword(s):  
Public Health ◽  
Aedes Aegypti ◽  
Disease Surveillance ◽  
Local Level ◽  
Human Movement ◽  
Breeding Habitat ◽  
Health Concern ◽  
Septic Systems ◽  
Household Level ◽  
Social Ecological

Arboviruses transmitted by Aedes aegypti (e.g., dengue, chikungunya, Zika) are of major public health concern on the arid coastal border of Ecuador and Peru. This high transit border is a critical disease surveillance site due to human movement-associated risk of transmission. Local level studies are thus integral to capturing the dynamics and distribution of vector populations and social-ecological drivers of risk, to inform targeted public health interventions. Our study examines factors associated with household-level Ae. aegypti presence in Huaquillas, Ecuador, while accounting for spatial and temporal effects. From January to May of 2017, adult mosquitoes were collected from a cohort of households (n = 63) in clusters (n = 10), across the city of Huaquillas, using aspirator backpacks. Household surveys describing housing conditions, demographics, economics, travel, disease prevention, and city services were conducted by local enumerators. This study was conducted during the normal arbovirus transmission season (January—May), but during an exceptionally dry year. Household level Ae. aegypti presence peaked in February, and counts were highest in weeks with high temperatures and a week after increased rainfall. Univariate analyses with proportional odds logistic regression were used to explore household social-ecological variables and female Ae. aegypti presence. We found that homes were more likely to have Ae. aegypti when households had interruptions in piped water service. Ae. aegypti presence was less likely in households with septic systems. Based on our findings, infrastructure access and seasonal climate are important considerations for vector control in this city, and even in dry years, the arid environment of Huaquillas supports Ae. aegypti breeding habitat.

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