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 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.

scholarly journals Re-emergence of dengue virus in regional Queensland: 2019 dengue virus outbreak in Rockhampton, Central Queensland, Australia

2021 ◽  
Vol 45 ◽  
Author(s):  
Jacina Walker ◽  
Alyssa Pyke ◽  
Paul Florian ◽  
Fred Moore ◽  
Nicolas Smoll ◽  
...  
Keyword(s):  
Public Health ◽  
Aedes Aegypti ◽  
Dengue Virus ◽  
Southeast Asia ◽  
Mosquito Control ◽  
Clinical Symptoms ◽  
Control Measures ◽  
Nucleotide Sequencing ◽  
Mosquito Vector ◽  
Vector Surveillance

Objective(s): To describe an autochthonous dengue virus type 2 (DENV-2) outbreak in Central Queensland from May 2019 and subsequent public health actions. Design and setting: Public health outbreak investigation of locally acquired DENV-2 cases in Rockhampton, Central Queensland. This included laboratory investigations, associated mosquito vector surveillance, and control measures implemented in response to the outbreak. Results: Twenty-one locally-acquired DENV-2 cases were identified during the Rockhampton outbreak (from 23 May to 7 October 2019): 13 laboratory-confirmed and eight probable cases. Clinical symptoms included lethargy (100%); fever (95%); headache (95%); and aches and pains (90%). Inspections of premises demonstrated that <i>Aedes aegypti</i> was present in 9.5% of those investigated which was more than half of the premises identified as containing mosquitoes. Nucleotide sequencing of a DENV-2 isolate recovered from the first confirmed case and DENV-2 RNA from an additional 5 patients indicated a single DENV-2 strain was responsible for the outbreak which was most closely related to DENV-2 strains from Southeast Asia. Conclusions: The 2019 DENV-2 outbreak in Rockhampton, Central Queensland, Australia, likely resulted from the importation of a strain, most closely related to DENV-2 strains from Southeast Asia and is the first reported outbreak in the region specifically implicating DENV-2. Given the presence of <i>Aedes aegypti</i> in Rockhampton, appropriate medical and mosquito avoidance advice; ongoing surveillance; and deployment of mosquito control strategies for the prevention of dengue and other mosquito-borne diseases should be priorities for this region.

The origins of dengue outbreaks in northern Queensland, Australia, 1990–2017

2018 ◽  
Vol 39 (2) ◽  
pp. 93 ◽  
Author(s):  
Alyssa T Pyke
Keyword(s):  
Public Health ◽  
Complex Dynamics ◽  
Genotypic Diversity ◽  
Health Concern ◽  
Mosquito Vector ◽  
Outbreak Management ◽  
Significant Public Health Concern ◽  
Dengue Outbreaks ◽  
Significant Public Health ◽  
Local Transmission

Dengue is one of the world's major infectious mosquito-borne diseases and although not endemic in Australia, is a significant public health concern. Queensland is vulnerable to outbreaks of dengue viruses (DENVs) and indeed, due to endemic populations of the mosquito vector Aedes aeypti, has been the only state since the 1950s to record local transmission. Determining DENV outbreak origins, and monitoring strain movement and diversity greatly assists outbreak management. It also confirms epidemiological links and potentially identifies incursions of rare or highly pathogenic viruses. There have been 73 DENV outbreaks recorded in northern Queensland within the past three decades and it has been the role of Public Health Virology, Department of Health, Queensland Government, to provide DENV genotyping and characterisation to facilitate this essential surveillance. This review summarises the likely origins of the recent northern Queensland outbreaks and describes the complex dynamics of DENV genotypic diversity that have characterised local transmission events.

scholarly journals Incidence of dengue in the Islands

2020 ◽  
Vol 7 (9) ◽  
pp. 3367
Author(s):  
Shivani Rao ◽  
Ajay Raj Sethuraman ◽  
Pandurang Vithal Thatkar
Keyword(s):  
Public Health ◽  
Aedes Aegypti ◽  
Prospective Study ◽  
Aedes Albopictus ◽  
Gradual Increase ◽  
Health Concern ◽  
Aedes Mosquito ◽  
Public Health Concern ◽  
Blood Samples ◽  
Health Centres

Background: Dengue is transmitted mainly by bite of Aedes mosquito namely Aedes aegypti and Aedes albopictus posing major public health concern. The objective of the study is to study incidence of dengue in Andaman and Nicobar Islands.Methods: Prospective study from January 2012 to December 2018 from all primary, community and tertiary health centres of Andaman and Nicobar Islands.Results: Out of a total of 5255 blood samples tested from 2012 to 2018 the total dengue positive cases were 525 (9.99%).Conclusions: There has been gradual increase in number of dengue cases from 2012 to 2016 thereafter there has been reduction of cases.

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 Inferring the ecological drivers of arboviral outbreaks

2019 ◽  
Author(s):  
Warren Tennant ◽  
Trevelyan McKinley ◽  
Mario Recker
Keyword(s):  
Public Health ◽  
Health Planning ◽  
Disease Incidence ◽  
Ecological Factors ◽  
Current Control ◽  
Control Measures ◽  
Health Concern ◽  
Mosquito Vector ◽  
Global Public Health ◽  
Incidence Data

AbstractThe emergence and wide-spread circulation of mosquito-transmitted viral diseases, such as dengue, Zika and Chikungunya, is a global public health concern. In the absence of effective vaccines, current control measures are mostly targeted against the mosquito vector and have so far only shown limited success. The reliance on mosquitoes for transmission also imposes strong ecological constraints that can introduce significant spatial and temporal variations in disease incidence. However, the way that epidemiological and ecological factors interact and determine population-level disease dynamics is only partially understood. Here we fit a spatially-explicit individual based model defined within a Bayesian framework to Zika incidence data from Feira de Santana, allowing us to more precisely quantify the relationships between socio-ecological factors and arboviral outbreaks. Our results further demonstrated that the virus was likely introduced into multiple spatially segregated locations at the start of the outbreak, highlighting the benefits that spatio-temporal incidence data would bring in making modelling approaches more realistic for public health planning.

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 A proposed framework for the development and qualitative evaluation of West Nile virus models and their application to local public health decision-making

2021 ◽  
Vol 15 (9) ◽  
pp. e0009653
Author(s):  
Alexander C. Keyel ◽  
Morgan E. Gorris ◽  
Ilia Rochlin ◽  
Johnny A. Uelmen ◽  
Luis F. Chaves ◽  
...  
Keyword(s):  
Public Health ◽  
Decision Making ◽  
West Nile Virus ◽  
Qualitative Evaluation ◽  
The United States ◽  
Coarse Grained ◽  
Health Concern ◽  
Mosquito Vector ◽  
Model Assessment ◽  
West Nile

West Nile virus (WNV) is a globally distributed mosquito-borne virus of great public health concern. The number of WNV human cases and mosquito infection patterns vary in space and time. Many statistical models have been developed to understand and predict WNV geographic and temporal dynamics. However, these modeling efforts have been disjointed with little model comparison and inconsistent validation. In this paper, we describe a framework to unify and standardize WNV modeling efforts nationwide. WNV risk, detection, or warning models for this review were solicited from active research groups working in different regions of the United States. A total of 13 models were selected and described. The spatial and temporal scales of each model were compared to guide the timing and the locations for mosquito and virus surveillance, to support mosquito vector control decisions, and to assist in conducting public health outreach campaigns at multiple scales of decision-making. Our overarching goal is to bridge the existing gap between model development, which is usually conducted as an academic exercise, and practical model applications, which occur at state, tribal, local, or territorial public health and mosquito control agency levels. The proposed model assessment and comparison framework helps clarify the value of individual models for decision-making and identifies the appropriate temporal and spatial scope of each model. This qualitative evaluation clearly identifies gaps in linking models to applied decisions and sets the stage for a quantitative comparison of models. Specifically, whereas many coarse-grained models (county resolution or greater) have been developed, the greatest need is for fine-grained, short-term planning models (m–km, days–weeks) that remain scarce. We further recommend quantifying the value of information for each decision to identify decisions that would benefit most from model input.

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.

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