scholarly journals Short Report: Adult Aedes abundance and risk of dengue transmission

2021 ◽  
Vol 15 (6) ◽  
pp. e0009475
Author(s):  
Janet Ong ◽  
Joel Aik ◽  
Lee Ching Ng
Keyword(s):  
Aedes Aegypti ◽  
Adult Female ◽  
Cluster Formation ◽  
Fold Increase ◽  
Short Report ◽  
Dengue Case ◽  
Vector Surveillance ◽  
Dengue Transmission ◽  
The Impact ◽  
Very High

Dengue is transmitted mainly by the adult female Aedes aegypti mosquito. However, little is known about the impact of adult Aedes abundance on the risk of dengue transmission. Here we analysed nationally representative dengue case and vector surveillance data collected from Singapore, to determine the effect of adult Aedes abundance on the risk of dengue transmission. A case was an area with active dengue transmission as indicated by the presence of dengue cluster. A control was an area where no dengue cluster was reported. Using multivariate logistic regression, we analysed 88 cases and 602 controls and estimated the odds of dengue cluster formation at various adult Aedes abundance levels, estimated by the mean number of adult female Aedes per Gravitrap per week and categorised into Low, Moderate, High and Very High abundance level. We found that the risk of dengue cluster formation was positively associated with adult Ae. aegypti abundance. We observed a three to four-fold increase in the odds of dengue clusters forming in areas with High (AOR: 3.40, 95% CI: 2.09, 5.52) and Very High (AOR: 3.99, 95% CI: 2.46, 6.46) adult Aedes aegypti abundance level compared to those with low Ae. aegypti abundance level. Our study strengthens the evidence for the use of adult Aedes indices for dengue risk assessment and early warning for dengue outbreaks. Entomological indicators of adult Ae. aegypti could be used to anticipate and prioritize areas for dengue control.

scholarly journals Entomological Risk Assessment for Dengue Virus Transmission during 2016–2020 in Kamphaeng Phet, Thailand

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1234
Author(s):  
Thanyalak Fansiri ◽  
Darunee Buddhari ◽  
Nattaphol Pathawong ◽  
Arissara Pongsiri ◽  
Chonticha Klungthong ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Dengue Virus ◽  
Case Reports ◽  
Virus Transmission ◽  
Denv Infection ◽  
Larval Abundance ◽  
Dengue Case ◽  
Vector Surveillance ◽  
Household Level ◽  
Dengue Transmission

Individual houses with high risks of dengue virus (DENV) transmission might be a source of virus transmission within the neighborhood. We conducted an entomological risk assessment for DENV transmission at the household level, comprising family cohort members residing in the same location, to assess the risk for dengue virus transmitted by mosquito vectors. The studies were conducted in Kamphaeng Phet Province, Thailand, during 2016–2020. Entomological investigations were performed in 35 cohort families on day 1 and day 14 after receiving dengue case reports. DENV was found in 22 Aedes samples (4.9%) out of 451 tested samples. A significantly higher DENV infection rate was detected in vectors collected on day 1 (6.64%) compared to those collected on day 14 (1.82%). Annual vector surveillance was carried out in 732 houses, with 1002 traps catching 3653 Aedes females. The majority of the 13,228 water containers examined were made from plastic and clay, with used tires serving as a primary container, with 59.55% larval abundance. Larval indices, as indicators of dengue epidemics and to evaluate disease and vector control approaches, were calculated. As a result, high values of larval indices indicated the considerably high risk of dengue transmission in these communities.

scholarly journals Establishment of wMel Wolbachia in Aedes aegypti mosquitoes and reduction of local dengue transmission in Cairns and surrounding locations in northern Queensland, Australia

2019 ◽  
Vol 3 ◽  
pp. 1547 ◽  
Author(s):  
Peter A. Ryan ◽  
Andrew P. Turley ◽  
Geoff Wilson ◽  
Tim P. Hurst ◽  
Kate Retzki ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Past History ◽  
Interrupted Time Series ◽  
Transmission Risk ◽  
Dengue Case ◽  
Model Estimate ◽  
Dengue Transmission ◽  
Before And After ◽  
History Of ◽  
Risk Areas

Background: The wMel strain of Wolbachia has been successfully introduced into Aedes aegypti mosquitoes and subsequently shown in laboratory studies to reduce transmission of a range of viruses including dengue, Zika, chikungunya, yellow fever, and Mayaro viruses that cause human disease. Here we report the entomological and epidemiological outcomes of staged deployment of Wolbachia across nearly all significant dengue transmission risk areas in Australia. Methods: The wMel strain of Wolbachia was backcrossed into the local Aedes aegypti genotype (Cairns and Townsville backgrounds) and mosquitoes were released in the field by staff or via community assisted methods. Mosquito monitoring was undertaken and mosquitoes were screened for the presence of Wolbachia. Dengue case notifications were used to track dengue incidence in each location before and after releases. Results: Empirical analyses of the Wolbachia mosquito releases, including data on the density, frequency and duration of Wolbachia mosquito releases, indicate that Wolbachia can be readily established in local mosquito populations, using a variety of deployment options and over short release durations (mean release period 11 weeks, range 2-22 weeks). Importantly, Wolbachia frequencies have remained stable in mosquito populations since releases for up to 8 years. Analysis of dengue case notifications data demonstrates near-elimination of local dengue transmission for the past five years in locations where Wolbachia has been established. The regression model estimate of Wolbachia intervention effect from interrupted time series analyses of case notifications data prior to and after releases, indicated a 96% reduction in dengue incidence in Wolbachia treated populations (95% confidence interval: 84 – 99%). Conclusion: Deployment of the wMel strain of Wolbachia into local Ae. aegypti populations across the Australian regional cities of Cairns and most smaller regional communities with a past history of dengue has resulted in the reduction of local dengue transmission across all deployment areas.

scholarly journals Establishment of wMel Wolbachia in Aedes aegypti mosquitoes and reduction of local dengue transmission in Cairns and surrounding locations in northern Queensland, Australia

2020 ◽  
Vol 3 ◽  
pp. 1547 ◽  
Author(s):  
Peter A. Ryan ◽  
Andrew P. Turley ◽  
Geoff Wilson ◽  
Tim P. Hurst ◽  
Kate Retzki ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Past History ◽  
Interrupted Time Series ◽  
Transmission Risk ◽  
Dengue Case ◽  
Model Estimate ◽  
Dengue Transmission ◽  
Before And After ◽  
History Of ◽  
Risk Areas

Background: The wMel strain of Wolbachia has been successfully introduced into Aedes aegypti mosquitoes and subsequently shown in laboratory studies to reduce transmission of a range of viruses including dengue, Zika, chikungunya, yellow fever, and Mayaro viruses that cause human disease. Here we report the entomological and epidemiological outcomes of staged deployment of Wolbachia across nearly all significant dengue transmission risk areas in Australia. Methods: The wMel strain of Wolbachia was backcrossed into the local Aedes aegypti genotype (Cairns and Townsville backgrounds) and mosquitoes were released in the field by staff or via community assisted methods. Mosquito monitoring was undertaken and mosquitoes were screened for the presence of Wolbachia. Dengue case notifications were used to track dengue incidence in each location before and after releases. Results: Empirical analyses of the Wolbachia mosquito releases, including data on the density, frequency and duration of Wolbachia mosquito releases, indicate that Wolbachia can be readily established in local mosquito populations, using a variety of deployment options and over short release durations (mean release period 11 weeks, range 2-22 weeks). Importantly, Wolbachia frequencies have remained stable in mosquito populations since releases for up to 8 years. Analysis of dengue case notifications data demonstrates near-elimination of local dengue transmission for the past five years in locations where Wolbachia has been established. The regression model estimate of Wolbachia intervention effect from interrupted time series analyses of case notifications data prior to and after releases, indicated a 96% reduction in dengue incidence in Wolbachia treated populations (95% confidence interval: 84 – 99%). Conclusion: Deployment of the wMel strain of Wolbachia into local Ae. aegypti populations across the Australian regional cities of Cairns and most smaller regional communities with a past history of dengue has resulted in the reduction of local dengue transmission across all deployment areas.

scholarly journals A Report on Vector Surveillance for Zika/Dengue at CCS International Airport, Lucknow, India

2021 ◽  
Vol 53 (03) ◽  
pp. 76-79
Author(s):  
Shaukat Kamal ◽  
Keyword(s):  
Aedes Aegypti ◽  
Case Fatality ◽  
Health Department ◽  
Limited Resources ◽  
Vector Surveillance ◽  
Entomological Surveillance ◽  
Vector Density ◽  
International Airport ◽  
Intervention Measures ◽  
Very High

In view of reports of Zika outbreak from Gujarat & Rajasthan states, an entomological surveillance of Aedes aegypti vector was carried out at Adani Chaudhary Charan Singh (CCS) International Airport, Lucknow and its adjoining areas between 2016 to 2019. The regular monitoring of the vector and effective intervention measures prevented the invasion of new pathogen of Zika and Yellow fever pathogen (virus) by bringing down the Aedes aegypti vector density at lowest level. The entomological indices worked out in 2016 as the premise index in the month of February, June and August, were remained positive for Aedes aegypti and container index (CI) was found 14.14. The House Index (HI), Container Index (CI) & Breteau Index (BI) were 24.50, 17.51 & 25.27, respectively in residential colony of Air Port Staff located at a distance of 0.50 km, whereas, indices were found very high i.e. 37.50, 25.50 & 57.62, respectively in Farrukhabad/Chillawan civil inhabitation located at a distance of 2.0 Kilometre. With the dedicated efforts of Airport Authority of India and State Health Department, Aedes aegypti indices gradually declined to very low level as the premise were positive for Aedes aegypti larvae but container index inside & outside airport premise became 2.70 & 4.37 respectively in early half of 2019. The HI, CI & BI were found 2.57, 2.69 & 3.09 in the airport residential colony and 3.15, 2.57 & 2.77, respectively in civil inhabitation i.e. Farrukhabad/Chillawan area in early half of 2019. The collateral impact of low vector density resulted drastic decline in dengue morbidity by 83.73% & 74.74% and in mortality by 88.89% & 94.44%, during 2017 & 2018 respectively in comparison to 2016 and the case fatality rate (CFR) declined from 0.65% in 2016 to 0.14% in 2018. However no death was documented due to Chikungunya in Lucknow and the morbidity though was doubled in 2017 & declined again to the level of 2016, but remained very less in comparison to dengue, as only 44, 80 & 47 cases of Chikungunya were reported during 2016, 2017 & 2018, respectively. The Airport also achieved the dividend in the form of conferring the title of Best Airport of the year 2018 in size & region managing the cleanliness in increased thrust of passengers’ load to more than double in limited resources.

scholarly journals Establishment of Wolbachia strain wAlbB in Malaysian populations of Aedes aegypti for dengue control

2019 ◽  
Author(s):  
W. A. Nazni ◽  
A. A. Hoffmann ◽  
A. Noor Afizah ◽  
Y. L. Cheong ◽  
M. V. Mancini ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Virus Transmission ◽  
Larval Rearing ◽  
Kuala Lumpur ◽  
Novel Approach ◽  
Dengue Transmission ◽  
Vector Mosquito ◽  
Primary Vector ◽  
Dengue Control ◽  
Very High

AbstractDengue has enormous health impacts globally. A novel approach to decrease dengue incidence involves the introduction of Wolbachia endosymbionts that block dengue virus transmission into populations of the primary vector mosquito, Aedes aegypti. The wMel Wolbachia strain has previously been trialed in open releases of Ae. aegypti; however the wAlbB strain has been shown to maintain higher density than wMel at high larval rearing temperatures. Releases of Ae. aegypti mosquitoes carrying wAlbB were carried out in 6 diverse sites in greater Kuala Lumpur, Malaysia, with high endemic dengue transmission. The strain was successfully established and maintained at very high population frequency at some sites, or persisted with additional releases following fluctuations at other sites. Based on passive case monitoring, reduced human dengue incidence was observed in the release sites when compared to control sites. The wAlbB strain of Wolbachia provides a promising option as a tool for dengue control, particularly in very hot climates.

scholarly journals Increased Adult Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) Abundance in a Dengue Transmission Hotspot, Compared to a Coldspot, within Kaohsiung City, Taiwan

Insects ◽  
2018 ◽  
Vol 9 (3) ◽  
pp. 98 ◽  
Author(s):  
Ka-Chon Ng ◽  
Luis Chaves ◽  
Kun-Hsien Tsai ◽  
Ting-Wu Chuang
Keyword(s):  
Aedes Aegypti ◽  
Culex Quinquefasciatus ◽  
Disease Transmission ◽  
Mosquito Species ◽  
Comparative Approach ◽  
Vector Surveillance ◽  
Mosquito Abundance ◽  
Dengue Transmission ◽  
Vector Borne ◽  
Kaohsiung City

The assumption that vector abundance differences might drive spatial and temporal heterogeneities in vector-borne disease transmission is common, though data supporting it is scarce. Here, we present data from two common mosquito species Aedes aegypti (Linnaeus) and Culex quinquefasciatus Say, biweekly sampled as adults, from March 2016 through December 2017, with BG-sentinel traps in two neighboring districts of Kaohsiung City (KC), Taiwan. One district has historically been a dengue transmission hotspot (Sanmin), and the other a coldspot (Nanzih). We collected a total 41,027 mosquitoes, and we found that average mosquito abundance (mean ± S.D.) was higher in Sanmin (Ae. aegypti: 9.03 ± 1.46; Cx. quinquefasciatus: 142.57 ± 14.38) than Nanzih (Ae. aegypti: 6.21 ± 0.47; Cx. quinquefasciatus: 63.37 ± 8.71) during the study period. In both districts, Ae. aegypti and Cx. quinquefasciatus population dynamics were sensitive to changes in temperature, the most platykurtic environmental variable at KC during the study period, a pattern predicted by Schmalhausen’s law, which states that organisms are more sensitive to small changes in environmental variables whose average value is more uncertain than its extremes. Our results also suggest that differences in Ae. aegypti abundance might be responsible for spatial differences in dengue transmission at KC. Our comparative approach, where we also observed a significant increment in the abundance of Cx. quinquefasciatus in the dengue transmission hotspot, suggests this area might be more likely to experience outbreaks of other vector borne diseases and should become a primary focus for vector surveillance and control.

scholarly journals Decreased dengue transmission in migrant worker populations in Singapore attributable to SARS-CoV-2 quarantine measures

2020 ◽  
Author(s):  
Jue Tao Lim ◽  
Borame Lee Dickens ◽  
Janet Ong ◽  
Joel Aik ◽  
Vernon J Lee ◽  
...  
Keyword(s):  
Relative Risk ◽  
Migrant Workers ◽  
Migrant Worker ◽  
Dengue Case ◽  
Working Population ◽  
Social Distancing ◽  
Weather Patterns ◽  
Risk Increase ◽  
Dengue Transmission ◽  
The Impact

Abstract Background We examined the impact of SARS-CoV-2 social distancing and quarantine policies on dengue transmission in the general and migrant worker populations in Singapore. Methods We utilized all nationally reported dengue cases in the general and migrant worker populations from 1 January 2013 to 31 May 2020. A difference-in-difference identification strategy was used to determine the effects of social distancing and quarantine policies on reported dengue case counts over time, whilst controlling for weather patterns, seasonality, age and population size. Results A reduction of 4.8 dengue cases per age band among migrant workers was attributable to quarantine policies, corresponding to a total reduction of around 432 reported dengue cases over 10 weeks. In the general working population, an increase of 14.5 dengue cases per age band was observed, which corresponds to a total increase of around 1450 reported dengue cases in the same time period. There is an expected relative risk reduction in dengue transmission for the migrant worker population at 0.635 due to quarantine policy and a relative risk increase for the general working population due to social distancing policies at 0.685. Conclusions Migrant workers experienced a reduced risk of dengue when they were confined to their dormitories as part of the COVID-19 social distancing measures. Our study highlights the vulnerability of migrant workers under normal working conditions.

Novel Applications of Nanotechnology in Controlling HIV and HSV Infections

2020 ◽  
Vol 12 ◽  
Author(s):  
Sai Akilesh M ◽  
Ashish Wadhwani
Keyword(s):  
Drug Delivery ◽  
Viral Infections ◽  
Polymeric Nanoparticles ◽  
Volume Ratio ◽  
Fold Increase ◽  
Multi Drug Resistance ◽  
Health Crisis ◽  
Pharmaceutical Properties ◽  
Simplex Virus ◽  
The Impact

: Infectious diseases have been prevalent since many decades and viral pathogens have caused global health crisis and economic meltdown on a devastating scale. High occurrence of newer viral infections in the recent years, in spite of the progress achieved in the field of pharmaceutical sciences defines the critical need for newer and more effective antiviral therapies and diagnostics. The incidence of multi-drug resistance and adverse effects due to the prolonged use of anti-viral therapy is also a major concern. Nanotechnology offers a cutting edge platform for the development of novel compounds and formulations for biomedical applications. The unique properties of nano-based materials can be attributed to the multi-fold increase in the surface to volume ratio at the nano-scale, tunable surface properties of charge and chemical moieties. Idealistic pharmaceutical properties such as increased bioavailability and retention times, lower toxicity profiles, sustained release formulations, lower dosage forms and most importantly, targeted drug delivery can be achieved through the approach of nanotechnology. The extensively researched nano-based materials are metal and polymeric nanoparticles, dendrimers and micelles, nano-drug delivery vesicles, liposomes and lipid based nanoparticles. In this review article, the impact of nanotechnology on the treatment of Human Immunodeficiency Virus (HIV) and Herpes Simplex Virus (HSV) viral infections during the last decade are outlined.

scholarly journals Do Prospective Teachers Care About PISA Studies? A Pilot Study among University Students in Germany

2017 ◽  
Vol 10 (5) ◽  
pp. 26 ◽  
Author(s):  
Olga Ioannidou ◽  
Despoina Georgiou ◽  
Andreas Obersteiner ◽  
Nilufer Deniz Bas ◽  
Christine Mieslinger
Keyword(s):  
Teacher Education ◽  
University Students ◽  
Prospective Teachers ◽  
International Student ◽  
Teacher Education Program ◽  
Student Assessment ◽  
International Student Assessment ◽  
The Impact ◽  
Very High ◽  
Expected Outcomes

The results of international comparison studies such as the Program for International Student Assessment (PISA) have initiated intense discussions about educational reforms in Germany. Although in-service and pre-service teachers are an essential part of such reforms, little is known about their attitudes towards PISA studies. The present study aims to fill this gap through the investigation of pre-service teachers’ awareness, interest, perception, and attitudes towards PISA. A questionnaire was used to survey a sample of 107 university students who were participating in a teacher education program. The results reveal that 100% of the participants are aware of PISA. Nearly 69% of the participants think that the impact of PISA is rather high or very high, while 41% of them believe that PISA results are reliable. Accordingly, half of the participants seem to be interested in PISA results for their country. The present study discusses these findings in the light of the expected outcomes as proposed in standards for teacher education.

scholarly journals Administrative Coding Methods Impact Surgical Site Infection Rates

2020 ◽  
Vol 41 (S1) ◽  
pp. s111-s112
Author(s):  
Mohammed Alsuhaibani ◽  
Mohammed Alzunitan ◽  
Kyle Jenn ◽  
Daniel Diekema ◽  
Michael Edmond ◽  
...  
Keyword(s):  
Cesarean Section ◽  
Surgical Procedures ◽  
Hip Prosthesis ◽  
Knee Prosthesis ◽  
Surgical Site Infections ◽  
Fold Increase ◽  
Abdominal Hysterectomy ◽  
Absolute Difference ◽  
Coding Method ◽  
The Impact

Background: Surveillance for surgical site infections (SSI) is recommended by the CDC. Currently, colon and abdominal hysterectomy SSI rates are publicly available and impact hospital reimbursement. However, the CDC NHSN allows surgical procedures to be abstracted based on International Classification of Diseases, Tenth Revision (ICD-10) or current procedural terminology (CPT) codes. We assessed the impact of using ICD and/or CPT codes on the number of cases abstracted and SSI rates. Methods: We retrieved administrative codes (ICD and/or CPT) for procedures performed at the University of Iowa Hospitals & Clinics over 1 year: October 2018–September 2019. We included 10 procedure types: colon, hysterectomy, cesarean section, breast, cardiac, craniotomy, spinal fusion, laminectomy, hip prosthesis, and knee prosthesis surgeries. We then calculated the number of procedures that would be abstracted if we used different permutations in administration codes: (1) ICD codes only, (2) CPT codes only, (3) both ICD and CPT codes, and (4) at least 1 code from either ICD or CPT. We then calculated the impact on SSI rates based on any of the 4 coding permutations. Results: In total, 9,583 surgical procedures and 180 SSIs were detected during the study period using the fourth method (ICD or CPT codes). Denominators varied according to procedure type and coding method used. The number of procedures abstracted for breast surgery had a >10-fold difference if reported based on ICD only versus ICD or CPT codes (104 vs 1,109). Hip prosthesis had the lowest variation (638 vs 767). For SSI rates, cesarean section showed almost a 3-fold increment (2.6% when using ICD only to 7.32% with both ICD & CPT), whereas abdominal hysterectomy showed nearly a 2-fold increase (1.14% when using CPT only to 2.22% with both ICD & CPT codes). However, SSI rates remained fairly similar for craniotomy (0.14% absolute difference), hip prosthesis (0.24% absolute difference), and colon (0.09% absolute difference) despite differences in the number of abstracted procedures and coding methods. Conclusions: Denominators and SSI rates vary depending on the coding method used. Variations in the number of procedures abstracted and their subsequent impact on SSI rates were not predictable. Variations in coding methods used by hospitals could impact interhospital comparisons and benchmarking, potentially leading to disparities in public reporting and hospital penalties.Funding: NoneDisclosures: None

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