Dengue fever transmission between construction site and its surrounding communities in China

Abstract Background: Due to more mosquito habitats and the lack of basic mosquito control facilities, construction sites are more likely to have secondary cases after case importation, which may increase the number of cases entering the community and the chance of community transmission. For example, the outbreak in Zhanjiang Prefecture, China, 2018, started at a construction site, then occurred in the surrounding communities. This study aims to investigate how to effectively reduce the dengue transmission risk related to construction sites and the neighboring communities.Methods: The study was based on an outbreak of dengue fever (DF) occurred in Zhanjiang Prefecture, Guangdong Province in 2018. We simulated the transmission of dengue virus between human and mosquitoes at the construction site and in the neighboring community separately, as well between them by assuming human movement between the construction site and the neighboring community. Susceptible-Exposed-Infectious/Asymptomatic-Recovered (SEIAR) model was used for the human, while SEI model was used for the mosquitoes. We obtained the transmissibility parameters by fitting the model to observed number of locally acquired cases before local interventions started and the coefficient of determination (R2) was used to quantify the significance of the fit. We then evaluated the effectiveness of different intervention scenarios targeting at reducing the transmissibility between different human and mosquito subpopulations at different locations (i.e. construction sites and community) quantified by the total attack rate (TAR) and duration of the outbreak (DO).Results: A total of 467 DF cases were reported in Zhanjiang Prefecture in 2018, among which 102 were located at a construction site and 131 were located in the surrounding community. The values of R2 were 0.829 (P < 0.001) and 0.878 (P < 0.001) for the construction site and the community, respectively. The modelling outcome indicated that without interventions, the number of cases on the construction site would reach to 156, yielding a total attack rate (TAR) of 31.25% (95% confidence interval [CI]: 27.18%- 35.31%). In the community, the number of the cases would be much more than the reported data and up to 10796, yielding a TAR of 21.59% (95%CI: 21.23%- 21.95%). When the transmission route from mosquitoes to people is cut off in the community, the number of cases in the community would decrease to a minimum of 33 compared with other situations we simulated, yielding a TAR of 0.068% (95%CI: 0.05%- 0.09%) and a duration of outbreak (DO) of 60 days. When the transmission route from infectious mosquitoes in the community and the construction site to susceptible people on the construction site is cut off at the same time, the number of cases in the construction site would drop to a minimum of 74, yielding a TAR of 14.88% (95%CI: 11.76%- 18.00%) and a DO of 66 days.Conclusions: Without intervention, DF could spread rapidly in the densely populated communities around the construction site. To control the outbreak effectively for both the construction site and the community, interventions need to be taken to reduce the transmission within the community and from the community to the construction site. Only controlling the transmission within the construction site could not reduce the number of cases on the construction site, and controlling the transmission route within the construction site or between the construction site and the community could not lead to a reduction in the number of cases in the community.

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Dengue fever transmission between construction site and its surrounding communities in China

10.21203/rs.3.rs-37245/v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Xingchun Liu ◽

Meng Zhang ◽

Qu Cheng ◽

Yingtao Zhang ◽

Guoqiang Ye ◽

...

Keyword(s):

Dengue Fever ◽

Attack Rate ◽

Transmission Risk ◽

Coefficient Of Determination ◽

Transmission Route ◽

Construction Site ◽

Construction Sites ◽

Effective Measure ◽

Incident Cases ◽

Sei Model

Abstract Background: Because of the urbanization and the lack of basic mosquito control facilities, constructions sites might increase the transmission risk of dengue. For example, the outbreak in Zhanjiang Prefecture, China, 2018, started at a construction site, then spread to surrounding communities. This study aims to investigate how to effectively reduce the dengue transmission risk related to construction sites.Methods: The study was based on an outbreak of dengue fever (DF) occurred in Zhanjiang Prefecture, Guangdong Province in 2018. We simulated the transmission of dengue virus between human and mosquitoes at the construction site and in the neighboring community separately, as well between them by assuming human movement between the construction site and the neighboring community. Susceptible-Exposed-Infectious/Asymptomatic-Recovered (SEIAR) model was used for the human, while SEI model was used for the mosquitoes. We obtained the transmissibility parameters by fitting the model to observed number of incident cases before local interventions started and the coefficient of determination (R2) was used to quantify the significance of the fit. We then evaluated the effectiveness of different intervention scenarios targeting at reducing the transmissibility between different human and mosquito subpopulations at different locations (i.e. construction sites and community) quantified by the total attack rate (TAR) and duration of the outbreak (DO).Results: A total of 467 cases of dengue fever were reported in Zhanjiang Prefecture in 2018, among which 102 were located at a construction site and 131 were located in the surrounding community. The values of R2 were 0.829 (P < 0.001) and 0.878 (P < 0.001) for the construction site and the community, respectively. The modelling outcome indicated that without interventions, the number of cases on the construction site would reach to 156, yielding a total attack rate (TAR) of 31.25% (95% confidence interval [CI]: 27.18%- 35.31%). In the community, the number of the cases would be much more than the reported data and up to 10796, yielding a TAR of 21.59% (95%CI: 21.23%- 21.95%). When the transmission route from mosquitoes to people is cut off in the community, the number of cases in the community would decrease to a minimum of 33 compared with other situations we simulated, yielding a TAR of 0.068% (95%CI: 0.05%- 0.09%) and a duration of outbreak (DO) of 60 days. When the transmission route from infectious mosquitoes in the community and the construction site to susceptible people on the construction site is cut off at the same time, the number of cases in the construction site would drop to a minimum of 74, yielding a TAR of 14.88% (95%CI: 11.76%- 18.00%) and a DO of 66 days.Conclusions: Construction sites may facilitate the dengue outbreaks into neighboring communities, SEIAR-SEI model can be efficiently applied to simulate outbreaks of dengue fever. Cutting off the transmission routes and properly controlling vectors in communities is an effective measure to control this disease.

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Dengue fever transmission between a construction site and its surrounding communities in China

Parasites & Vectors ◽

10.1186/s13071-020-04463-x ◽

2021 ◽

Vol 14 (1) ◽

Author(s):

Xingchun Liu ◽

Meng Zhang ◽

Qu Cheng ◽

Yingtao Zhang ◽

Guoqiang Ye ◽

...

Keyword(s):

Dengue Fever ◽

Attack Rate ◽

Mosquito Control ◽

Community Interventions ◽

Transmission Route ◽

Construction Site ◽

Construction Sites ◽

Initial Infection ◽

Community Transmission ◽

Sei Model

Abstract Background Due to an increase in mosquito habitats and the lack facilities to carry out basic mosquito control, construction sites in China are more likely to experience secondary dengue fever infection after importation of an initial infection, which may then increase the number of infections in the neighboring communities and the chance of community transmission. The aim of this study was to investigate how to effectively reduce the transmission of dengue fever at construction sites and the neighboring communities. Methods The Susceptible-Exposed-Infectious/Asymptomatic-Recovered (SEIAR) model of human and SEI model of mosquitoes were developed to estimate the transmission of dengue virus between humans and mosquitoes within the construction site and within a neighboring community, as well between each of these. With the calibrated model, we further estimated the effectiveness of different intervention scenarios targeting at reducing the transmissibility at different locations (i.e. construction sites and community) with the total attack rate (TAR) and the duration of the outbreak (DO). Results A total of 102 construction site-related and 131 community-related cases of dengue fever were reported in our area of study. Without intervention, the number of cases related to the construction site and the community rose to 156 (TAR: 31.25%) and 10,796 (TAR: 21.59%), respectively. When the transmission route from mosquitoes to humans in the community was cut off, the number of community cases decreased to a minimum of 33 compared with other simulated scenarios (TAR: 0.068%, DO: 60 days). If the transmission route from infectious mosquitoes in the community and that from the construction site to susceptible people on the site were cut off at the same time, the number of cases on the construction site dropped to a minimum of 74 (TAR: 14.88%, DO: 66 days). Conclusions To control the outbreak of dengue fever effectively on both the construction site and in the community, interventions needed to be made both within the community and from the community to the construction site. If interventions only took place within the construction site, the number of cases on the construction site would not be reduced. Also, interventions implemented only within the construction site or between the construction site and the community would not lead to a reduction in the number of cases in the community.

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Dengue fever transmission between construction site and its surrounding communities in China

10.21203/rs.3.rs-37245/v3 ◽

2020 ◽

Author(s):

Xingchun Liu ◽

Meng Zhang ◽

Qu Cheng ◽

Yingtao Zhang ◽

Guoqiang Ye ◽

...

Keyword(s):

Dengue Virus ◽

Attack Rate ◽

Mosquito Control ◽

Community Interventions ◽

Transmission Route ◽

Construction Site ◽

Construction Sites ◽

Dengue Transmission ◽

Community Transmission ◽

Sei Model

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

10.1101/113829 ◽

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.

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Development of IoT-Based Particulate Matter Monitoring System for Construction Sites

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph182111510 ◽

2021 ◽

Vol 18 (21) ◽

pp. 11510

Author(s):

Hyunsik Kim ◽

Sungho Tae ◽

Pengfei Zheng ◽

Geonuk Kang ◽

Hanseung Lee

Keyword(s):

Real Time ◽

Monitoring System ◽

Field Application ◽

Coefficient Of Determination ◽

Scattering Method ◽

Construction Site ◽

Construction Sites ◽

Accuracy Of Measurements ◽

Wide Range ◽

Internet Of Things Technology

Particulate matters (PMs) generated on construction sites can pose serious health risks to field workers and residents living near construction sites. PMs are generated in a wide range of locations; therefore, they must be managed in real time at various locations within construction sites for practical management of the PMs. However, no such systems exist currently. Therefore, this study aims to develop a system that can manage PMs in real time at multiple locations in a construction site using the Internet of Things technology. Accordingly, measuring instrument, network, and program services were developed as system components, while considering the characteristics of construction sites, and the construction site PM monitoring system was developed by integrating these components. Finally, performance certification and field application tests were performed to verify the developed system. The construction site PM monitoring system (CPMS) achieved grade 1 for reproducibility, relative precision, and data acquisition rate, and grade 2 for accuracy and coefficient of determination. Thus, it received a performance certification of grade 2, in total. In particular, regarding accuracy, which is a shortcoming of the light-scattering method and represents the accuracy of measurements, the CPMS was found to have an accuracy of 74.2%.

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Investigating Male Aedes aegypti (Diptera: Culicidae) Attraction to Different Oviposition Containers Using Various Configurations of the Sound Gravid Aedes Trap

Journal of Medical Entomology ◽

10.1093/jme/tjz229 ◽

2019 ◽

Vol 57 (3) ◽

pp. 957-961

Author(s):

Kyran M Staunton ◽

Barukh B Rohde ◽

Michael Townsend ◽

Jianyi Liu ◽

Mark Desnoyer ◽

...

Keyword(s):

Aedes Aegypti ◽

Zika Virus ◽

Disease Transmission ◽

Urban Landscape ◽

Mosquito Control ◽

Transmission Risk ◽

Northern Australia ◽

Control Programs ◽

Male Dispersal ◽

Olfactory Attractant

Abstract Aedes aegypti (Linnaeus), the primary vectors of the arboviruses dengue virus and Zika virus, continue to expand their global distributions. In efforts to better control such species, several mosquito control programs are investigating the efficacy of rearing and releasing millions of altered male Aedes throughout landscapes to reduce populations and disease transmission risk. Unfortunately, little is known about Ae. aegypti, especially male, dispersal behaviors within urban habitats. We deployed Sound-producing Gravid Aedes Traps (SGATs) in Cairns, northern Australia, to investigate male Ae. aegypti attraction to various oviposition container configurations. The traps were arranged to include: 1) water only, 2) organically infused water, 3) infused water and L3 larvae, 4) infused water and a human-scented lure, and lastly 5) no water or olfactory attractant (dry). Our data suggest that males were more attracted to SGATs representing active larval sites than potential larval sites, but were equally attracted to dry SGATs relative to those containing water and/or infusion. Additionally, we found that female Ae. aegypti were equally attracted to wet SGATs, with or without infusion, but not dry ones. These results suggest that male Ae. aegypti within northern Australia are more attracted to active larval sites and equally attracted to dry containers as wet or infused ones. Additionally, female Ae. aegypti are unlikely to enter dry containers. Such findings contribute to our understanding of potentially attractive features for local and released Ae. aegypti throughout the northern Australian urban landscape.

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Use of Functional Response Modeling to Evaluate the Effect of Temperature on Predation of Amblyseius swirskii (Acari: Phytoseiidae) Adults Preying on Tetranychus urticae (Acari: Tetranychidae) Nymphs

Journal of Economic Entomology ◽

10.1093/jee/toab171 ◽

2021 ◽

Author(s):

Azadeh Farazmand ◽

Masood Amir-Maafi

Keyword(s):

Functional Response ◽

Tetranychus Urticae ◽

Attack Rate ◽

Handling Time ◽

Effect Of Temperature ◽

Coefficient Of Determination ◽

Temperature Threshold ◽

Amblyseius Swirskii ◽

Functional Responses ◽

Wide Range

Abstract In this research, functional responses of Amblyseius swirskii Athias-Henriot preying on different Tetranychus urticae Koch nymphal densities (2, 4, 8, 16, 32, 64, and 128) were studied at eight constant temperatures (15, 20, 25, 27.5, 30, 32.5, 35 and 37.5°C) in a circular Petri dish (3-cm diameter × 1-cm height) under lab conditions. At all temperatures, the logistic regression showed a type II functional response. A nonlinear relationship was found between temperature and attack rate and the reciprocal of handling time. The reciprocal of handling time decreased exponentially with increasing temperature. In contrast, the attack rate grew rapidly with increasing temperatures up to an optimum, showing a decreasing trend at higher temperatures. In order to quantify the functional response of A. swirskii over a broad range of temperatures and to gain a better estimation of attack rate and handling time, a temperature-settled functional response equation was suited to our data. Our model showed that the number of prey consumed increased with rising prey density. Also, the predation rates increased with increasing temperatures but decreased at extremely high temperatures. Based on our model, the predation rate begins at the lower temperature threshold (11.73°C) and reaches its peak at upper temperature threshold (29.43°C). The coefficient of determination (R2) of the random predator model was 0.99 for all temperatures. The capability of A. swirskii to search and consume T. urticae over a wide range of temperatures makes it a good agent for natural control of T. urticae in greenhouses.

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Safety Assessment and Risk Management in Indian Building Construction Sites

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d1003.1284s219 ◽

2019 ◽

Vol 8 (4S2) ◽

pp. 8-12

Keyword(s):

Safety Assessment ◽

Building Construction ◽

Construction Site ◽

Construction Sites ◽

Safety Measures ◽

Severity Rating ◽

Key Factor ◽

Incident Rate ◽

Observation Method ◽

Unsafe Condition

Construction sites records high accident and incident rate due to lack of safety measures. Safety assessment rating is significant for every construction site to know safety status of the particular site. In this research TR safety observation method is used to assess the site performance. As unsafe condition is the key factor in every construction site, this research considers the possible unsafe conditions to assess the site performance. A questionnaire survey is done with the workers to know the existing safe conditions. Results showed that the safety performance of the site is 39%. Then every unsafe condition is ranked with respect to severity rating for detailed analysis. Furthermore bowtie analysis is used to identify the causes and consequences of the unsafe conditions. Through this analysis the owner can reduce the risk of every event and improve the site performance.

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Tumbuhan Obat: Pendekatan Alternatif dalam Pengendalian Nyamuk Aedes aegypti dan Virus Dengue Penyebab Demam Dengue

JURNAL BIOLOGI PAPUA ◽

10.31957/jbp.541 ◽

2018 ◽

Vol 4 (2) ◽

pp. 83-90

Author(s):

Ign Joko Suyono ◽

Aditya K. Karim

Keyword(s):

Medicinal Plant ◽

Aedes Aegypti ◽

Dengue Fever ◽

Mosquito Control ◽

Dengue Shock Syndrome ◽

Viral Disease ◽

Mosquito Vector ◽

Major Health ◽

Alternative Approach ◽

Control And Prevention

Dengue is the most important emerging tropical viral disease of humans in the world today. Aedes aegypti is a major mosquito vector responsible for transmitting many viral diseases and this mosquito that spreads major health problems like dengue fever. The resistance of Ae. aegypti to insecticides is already widespread and represents a serious problem for programmes aimed at the control and prevention of dengue in tropical countries. The search for compounds extracted from medicinal plant preparations as alternatives insecticide for mosquito control is in immediate need. Alternative approach for control Ae. aegypti dan virus dengue using the medicinal plant will be discussed in this paper.Key words: Medicinal plant, Aedes aegypti, dengue fever, dengue haemorragi fever, dengue shock syndrome

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Rebar Worker Analysis Using a 3-Axis Accelerometer

Frontiers in Built Environment ◽

10.3389/fbuil.2021.721742 ◽

2021 ◽

Vol 7 ◽

Author(s):

Takuma Akaki ◽

Tomoyuki Gondo

Keyword(s):

Body Movement ◽

Building Construction ◽

Accelerometer Data ◽

Construction Site ◽

Work Intensity ◽

Construction Sites ◽

Repetitive Tasks ◽

The Difference ◽

Total Body ◽

Large Building

The purpose of the present study is to grasp the situation of construction sites easily by distinguishing the movements of construction workers at construction sites from the accelerometer data attached to their waists. For the construction manager to accurately perceive the active or inactive state of his workers, their movements were classified into three distinct categories: walking, standing, and sitting. We tracked and observed two rebar workers for 5 days at a large building construction site. Their movements were classified by two-axis plots of (1) the difference between the maximum and minimum absolute values and (2) the value of acceleration at each second, and visualized by a heatmap among others for this trial. The results showed that despite the difficulty in distinguishing rebar work without a total body movement while sitting, the accuracy of discrimination was 60–80% in walking and sitting. From this analysis, we were able to identify repetitive tasks and the differences between morning and afternoon tasks. Furthermore, by applying simple visualization, we could concisely represent changes in work intensity over a relatively long period.

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