scholarly journals The Use of Insecticide-Treated Curtains for Control ofAedes aegyptiand Dengue Virus Transmission in “Fraccionamiento” Style Houses in México

2018 ◽  
Vol 2018 ◽  
pp. 1-22
Author(s):  
Maria A. Loroño-Pino ◽  
Ana Uitz-Mena ◽  
Claudia M. Carrillo-Solís ◽  
Rocío J. Zapata-Gil ◽  
Dora M. Camas-Tec ◽  
...  
Keyword(s):  
Public Health ◽  
Dengue Virus ◽  
Rural Areas ◽  
Pyrethroid Resistance ◽  
Virus Transmission ◽  
Denv Infection ◽  
Mosquito Abundance ◽  
Suburban Areas ◽  
Significant Public Health ◽  
Study Sites

Dengue, chikungunya, yellow fever, and Zika viruses transmitted byAedes aegyptimosquitoes are major public health threats in the tropical and subtropical world. In México, construction of large tracts of “fraccionamientos” high density housing to accommodate population growth and urbanization has provided fertile ground forAe. aegypti-transmitted viruses. We investigated the utility of pyrethroid-treated window curtains to reduce both the abundance ofAe. aegyptiand to prevent dengue virus (DENV) transmission in fraccionamiento housing. Windows and doors of fraccionamiento homes in urban/suburban areas, whereAe. aegyptipyrethroid resistance associated with the Ile1016 knock down resistance (kdr) mutation in the voltage gated sodium channel gene was high, and in rural areas, where kdr resistance was low, were fitted with either insecticide-treated curtains (ITCs) or non-treated curtains (NTCs). The homes were monitored for mosquito abundance and DENV infection. ITCs reduced the indoor abundance ofAe. aegyptiand the number of DENV-infected mosquitoes in homes in rural but not in urban/suburban study sites.The presence of non-treated screens also was associated with reduced numbers of mosquitoes in homes. “Super-infested” homes, yielding more than 50 mosquitoes, including DENV-infected mosquitoes, provide a significant public health risk to occupants, visitors, and people in neighboring homes.

scholarly journals Field- and clinically derived estimates of Wolbachia-mediated blocking of dengue virus transmission potential in Aedes aegypti mosquitoes

2017 ◽  
Vol 115 (2) ◽  
pp. 361-366 ◽  
Author(s):  
Lauren B. Carrington ◽  
Bich Chau Nguyen Tran ◽  
Nhat Thanh Hoang Le ◽  
Tai Thi Hue Luong ◽  
Truong Thanh Nguyen ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Dengue Virus ◽  
Virus Transmission ◽  
Field Testing ◽  
Denv Infection ◽  
Ho Chi Minh City ◽  
Wild Type ◽  
Transmission Potential ◽  
Blood Meals ◽  
Increased Susceptibility

The wMel strain of Wolbachia can reduce the permissiveness of Aedes aegypti mosquitoes to disseminated arboviral infections. Here, we report that wMel-infected Ae. aegypti (Ho Chi Minh City background), when directly blood-fed on 141 viremic dengue patients, have lower dengue virus (DENV) transmission potential and have a longer extrinsic incubation period than their wild-type counterparts. The wMel-infected mosquitoes that are field-reared have even greater relative resistance to DENV infection when fed on patient-derived viremic blood meals. This is explained by an increased susceptibility of field-reared wild-type mosquitoes to infection than laboratory-reared counterparts. Collectively, these field- and clinically relevant findings support the continued careful field-testing of wMel introgression for the biocontrol of Ae. aegypti-born arboviruses.

scholarly journals Dengue NS1 antigen kit shows high sensitivity for detection of recombinant dengue virus-2 NS1 antigen spiked with Aedes aegypti mosquitoes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philip Raj Abraham ◽  
Bharathy R ◽  
Pradeep Kumar N ◽  
Ashwani Kumar
Keyword(s):  
Public Health ◽  
Aedes Aegypti ◽  
Dengue Virus ◽  
Infected Patient ◽  
Specific Treatment ◽  
High Sensitivity ◽  
Field Evaluation ◽  
Denv Infection ◽  
Ns1 Protein ◽  
Ns1 Antigen

AbstractDengue, caused by the dengue virus (DENV) is a significant vector-borne disease. In absence of a specific treatment and vaccine, dengue is becoming a rising threat to public health. Currently, control of dengue mainly focuses on the surveillance of the mosquito vectors. Improved surveillance methods for DENV in mosquito populations would be highly beneficial to the public health. However, current methods of DENV detection in mosquitoes requires specialized equipment and expensive reagents and highly trained personnel. As an alternative, commercially available dengue NS1 antigen ELISA kits could be used for detection of DENV infection in Aedes aegypti mosquitoes. In this study, we explored the utility of commercially available Dengue NS1 antigen kit (J. Mitra & Co. Pvt. Ltd) for the detection of recombinant dengue virus-2 (rDENV-2) NS1 protein and serum of dengue infected patient spiked with Ae. aegypti mosquito pools. The kit was found to be highly sensitive and specific towards detection of all serotypes of DENV. Further, it could detect as low as 750 femto gram rDENV-2 NS1 protein. It was also observed that rDENV-2 NS1 antigen spiked with blood-fed and unfed mosquito pools could be detected. In addition, the kit also detected dengue infected patient serum spiked with Ae. aegypti mosquito pools. Overall, the Dengue NS1 antigen kit displayed high sensitivity towards detection of recombinant as well as serum NS1 protein spiked with Ae. aegypti mosquito pools and could be considered for the dengue virus surveillance after a field evaluation in Ae. aegypti mosquitoes.

scholarly journals An agent-based model of dengue virus transmission shows how multiple uncertainties about vaccine efficacy influence public health impact projections

2016 ◽  
Author(s):  
T. Alex Perkins ◽  
Robert C. Reiner ◽  
Guido España ◽  
Quirine A. ten Bosch ◽  
Amit Verma ◽  
...  
Keyword(s):  
Public Health ◽  
Dengue Virus ◽  
Vaccine Efficacy ◽  
Denv Infection ◽  
Health Impact ◽  
Public Health Impact ◽  
Statistical Uncertainty ◽  
Dengue Vaccine ◽  
Agent Based ◽  
Biological Uncertainty

ABSTRACTGiven the limited effectiveness of strategies based solely on vector control to reduce dengue virus (DENV) transmission, it is expected that an effective vaccine could play a pivotal role in reducing the global disease burden of dengue. Of several dengue vaccines under development, Dengvaxia® from Sanofi Pasteur recently became the first to become licensed in select countries and to achieve WHO recommendation for use in certain settings, despite the fact that a number of uncertainties about its profile complicate projections of its public health impact. We used a stochastic, agent-based model for DENV transmission to perform simulations of the public health impact of dengue vaccines in light of two key uncertainties: (1) “statistical uncertainty” about the numerical value of the vaccine’s efficacy against disease, and (2) “biological uncertainty” about the extent to which its efficacy against disease derives from the amelioration of symptoms, blocking of DENV infection, or some combination thereof. Simulations of a generic dengue vaccine showed that the proportion of disease episodes averted following 20 years of routine vaccination of nine-year olds at 80% coverage was sensitive to both the numerical value of vaccine efficacy and to the extent to which efficacy derives from blocking of DENV infection. Simulations of a vaccine resembling Dengvaxia® took into account that vaccine trial results substantially reduced statistical uncertainty but did not address biological uncertainty, resulting in the proportion of disease episodes averted being more sensitive to biological uncertainty than to statistical uncertainty. Taken together, our results indicate limitations associated with the use of symptomatic disease as the primary endpoint of dengue vaccine trials and highlight the importance of considering multiple forms of uncertainty in projections of a vaccine’s public health impact.

scholarly journals Individual-based dengue virus surveillance in Aedes aegypti mosquitoes collected concurrently with suspected patients in Tarlac City, Philippines

2020 ◽  
Author(s):  
Jean Claude Balingit ◽  
Thaddeus M. Carvajal ◽  
Mariko Saito-Obata ◽  
Maribet Gamboa ◽  
Amalea Dulcene Nicolasora ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Dengue Virus ◽  
Phylogenetic Analyses ◽  
Simultaneous Detection ◽  
Denv Infection ◽  
Health Concern ◽  
Effective Control ◽  
Entomological Surveillance ◽  
Mosquito Abundance ◽  
Virus Surveillance

Abstract Background Dengue virus (DENV) infection continues to be a major public health concern throughout tropical and subtropical regions of the world where Aedes aegypti mosquitoes, its primary vector, dwell. In the context of DENV transmission, effective control is reliant not only on knowledge of mosquito abundance, but also on mosquito infection. In the 2015 dengue season, we conducted a one-month entomological surveillance of adult Aedes aegypti mosquitoes around households of suspected dengue patients in Tarlac City, Philippines to assess the DENV infection rate in the local mosquito population, and to identify the DENV genotypes and serotypes concurrently co-circulating in mosquitoes and patients. Methods We performed a one-step multiplex real-time RT-PCR assay for the simultaneous detection and serotyping of DENV in patients and in individual female Aedes aegypti mosquito. Consequently, we performed sequencing and phylogenetic analyses to further characterize the detected DENVs in mosquitoes and patients at the genotype level. Results We collected a total of 583 adult Aedes aegypti mosquitoes, of which we tested 359 female mosquitoes individually for the presence of the DENV. Ten mosquitoes (2.8%) from amongst 359 female mosquitoes were confirmed to be positive for the presence of the DENV. We detected DENV-1, DENV-2, and DENV-4 in the field-collected mosquitoes, which were consistent with the serotypes concurrently infecting patients. Sequencing and phylogenetic analyses of the detected DENVs based on the partial envelope ( E ) gene revealed three genotypes concurrently present in the sampled mosquitoes and patients during the study period, namely: DENV-1 genotype IV, DENV-2 Cosmopolitan genotype and DENV-4 genotype II. Notably, we observed a random geographic distribution of DENVs in the study area suggesting the occurrence of active DENV transmission within and outside the vicinities of Tarlac City. Conclusions In this study, we demonstrate the utility of an individual-based DENV surveillance in field-collected mosquitoes and the importance of incorporating mosquito virus data in phylogenetic studies. Analyzing virus sequences from vector and host could potentially improve our understanding of the dynamics of DENV transmission.

scholarly journals Autochthonous dengue in two Dutch tourists visiting Département Var, southern France, July 2020

2020 ◽  
Vol 25 (39) ◽  
Author(s):  
Tom D Vermeulen ◽  
Johan Reimerink ◽  
Chantal Reusken ◽  
Sandra Giron ◽  
Peter J de Vries
Keyword(s):  
Public Health ◽  
Dengue Virus ◽  
Denv Infection ◽  
Diagnosis And Treatment ◽  
Southern Europe ◽  
Southern France ◽  
Delay In Diagnosis ◽  
Vector Borne Diseases ◽  
Vector Borne ◽  
Health Experts

We report dengue virus (DENV) infection in two Dutch tourists who visited Département Var, southern France, in July and August 2020. As some autochthonous dengue cases have occurred in Europe in recent years, awareness among physicians and public health experts about possible intermittent presence of DENV in southern Europe is important to minimise delay in diagnosis and treatment. Quick diagnosis can lead to timely action to contain the spread of vector-borne diseases and minimise transmission.

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.

Habitat model for baiting foxes in suburban areas to counteract Echinococcus multilocularis

2012 ◽  
Vol 39 (6) ◽  
pp. 488 ◽  
Author(s):  
Andreas König ◽  
Christof Janko ◽  
Bence Barla-Szabo ◽  
Diana Fahrenhold ◽  
Claudius Heibl ◽  
...  
Keyword(s):  
Public Health ◽  
Echinococcus Multilocularis ◽  
Rural Areas ◽  
Habitat Model ◽  
Suburban Areas ◽  
Separate Area ◽  
Community Area ◽  
Short Time ◽  
Do So

Context Foxes are carriers of many zoonoses, such as the fox tapeworm. Treating foxes with medication of edible bait is often the only way of protecting people. Whereas bait can be distributed very effectively by aeroplane in rural areas, in settled areas it must be distributed by hand. In doing so it is important to get as close as possible to the foxes. Aims In suburban areas it is important to ensure that it is mainly foxes that take the bait and that they do so within a short time. In order to achieve this, a habitat model was developed for the baiting of foxes in suburban areas. Methods In Grünwald, a suburb of Munich, 12 foxes were radio-collared and observed to see which gardens they visited more frequently or for longer periods. At the same time, the community area was divided up by a grid. At each point on the grid, two gardens were selected: one garden known to be visited by foxes, and a control garden in which no fox had been observed. In this way the structure of average gardens in the community could be compared with those used by foxes. On this basis a model of garden use by foxes was developed and checked by a program of phototrapping in a separate area. Key results Using sources of food, bushes and garden houses as variables, a habitat model was developed with the categories ‘unsuitable’, ‘less suitable’ and ‘very suitable’ for foxes. This correlated closely with the appearance of foxes in gardens (P < 0.001). Conclusion The model helps to identify gardens preferred by foxes. Implications This study shows us how to reach foxes in suburban environments quickly with bait containing medication and so contributes to improving public health. The method described, of checking a model in an area not used in the development of the model, can also be seen as a contribution towards the universalisation of models.

scholarly journals Dengue Virus Antibodies Enhance Zika Virus Infection

2016 ◽  
Author(s):  
Lauren M. Paul ◽  
Eric R. Carlin ◽  
Meagan M. Jenkins ◽  
Amanda L. Tan ◽  
Carolyn M. Barcellona ◽  
...  
Keyword(s):  
Public Health ◽  
Dengue Virus ◽  
Disease Severity ◽  
Zika Virus ◽  
Severe Disease ◽  
Denv Infection ◽  
Zikv Infection ◽  
Developmental Problems ◽  
Transmitted Virus ◽  
The Impact

AbstractBackgroundFor decades, human infections with Zika virus (ZIKV), a mosquito-transmitted flavivirus, were sporadic, associated with mild disease, and went underreported since symptoms were similar to other acute febrile diseases endemic in the same regions. Recent reports of severe disease associated with ZIKV, including Guillain-Barré syndrome and severe fetal abnormalities, have greatly heightened awareness. Given its recent history of rapid spread in immune naïve populations, it is anticipated that ZIKV will continue to spread in the Americas and globally in regions where competent Aedes mosquito vectors are found. Globally, dengue virus (DENV) is the most common mosquito-transmitted human flavivirus and is both well-established and the source of outbreaks in areas of recent ZIKV introduction. DENV and ZIKV are closely related, resulting in substantial antigenic overlap. Through a mechanism known as antibody-dependent enhancement (ADE), anti-DENV antibodies can enhance the infectivity of DENV for certain classes of immune cells, causing increased viral production that correlates with severe disease outcomes. Similarly, ZIKV has been shown to undergo ADE in response to antibodies generated by other flaviviruses. However, response to DENV antibodies has not yet been investigated.Methodology / Principal FindingsWe tested the neutralizing and enhancing potential of well-characterized broadly neutralizing human anti-DENV monoclonal antibodies (HMAbs) and human DENV immune sera against ZIKV using neutralization and ADE assays. We show that anti-DENV HMAbs, cross-react, do not neutralize, and greatly enhance ZIKV infection in vitro. DENV immune sera had varying degrees of neutralization against ZIKV and similarly enhanced ZIKV infection.Conclusions / SignificanceOur results suggest that pre-existing DENV immunity will enhance ZIKV infection in vivo and may increase disease severity. A clear understanding of the interplay between ZIKV and DENV will be critical in informing public health responses in regions where these viruses co-circulate and will be particularly valuable for ZIKV and DENV vaccine design and implementation strategies.Author SummaryRecent reports of severe disease, including developmental problems in newborns, have greatly heightened public health awareness of Zika virus (ZIKV), a mosquito-transmitted virus for which there is no vaccine or treatment. It is anticipated that ZIKV will continue to spread in the Americas and globally in regions where competent mosquitoes are found. Dengue virus (DENV), a closely related mosquito-transmitted virus is well-established in regions of recent ZIKV introduction and spread. It is increasingly common that individuals living in these regions may have had a prior DENV infection or may be infected with DENV and ZIKV at the same time. However, very little is known about the impact of DENV infections on ZIKV disease severity. In this study, we tested the ability of antibodies against DENV to prevent or enhance ZIKV infection in cell culture-based assays. We found that DENV antibodies can greatly enhance ZIKV infection in cells.Our results suggest that ZIKV infection in individuals that had a prior DENV infection may experience more severe clinical manifestations. The results of this study provide a better understanding of the interplay between ZIKV and DENV infections that can serve to inform public health responses and vaccine strategies.

scholarly journals Human antibody responses after dengue virus infection are highly cross-reactive to Zika virus

2016 ◽  
Vol 113 (28) ◽  
pp. 7852-7857 ◽  
Author(s):  
Lalita Priyamvada ◽  
Kendra M. Quicke ◽  
William H. Hudson ◽  
Nattawat Onlamoon ◽  
Jaturong Sewatanon ◽  
...  
Keyword(s):  
Immune Responses ◽  
Dengue Virus ◽  
Zika Virus ◽  
Denv Infection ◽  
Cross Reactivity ◽  
Health Concern ◽  
Human Antibody ◽  
Functional Quality ◽  
Significant Public Health

Zika virus (ZIKV) is an emerging mosquito-borne flavivirus of significant public health concern. ZIKV shares a high degree of sequence and structural homology compared with other flaviviruses, including dengue virus (DENV), resulting in immunological cross-reactivity. Improving our current understanding of the extent and characteristics of this immunological cross-reactivity is important, as ZIKV is presently circulating in areas that are highly endemic for dengue. To assess the magnitude and functional quality of cross-reactive immune responses between these closely related viruses, we tested acute and convalescent sera from nine Thai patients with PCR-confirmed DENV infection against ZIKV. All of the sera tested were cross-reactive with ZIKV, both in binding and in neutralization. To deconstruct the observed serum cross-reactivity in depth, we also characterized a panel of DENV-specific plasmablast-derived monoclonal antibodies (mAbs) for activity against ZIKV. Nearly half of the 47 DENV-reactive mAbs studied bound to both whole ZIKV virion and ZIKV lysate, of which a subset also neutralized ZIKV. In addition, both sera and mAbs from the dengue-infected patients enhanced ZIKV infection of Fc gamma receptor (FcγR)-bearing cells in vitro. Taken together, these findings suggest that preexisting immunity to DENV may impact protective immune responses against ZIKV. In addition, the extensive cross-reactivity may have implications for ZIKV virulence and disease severity in DENV-experienced populations.

scholarly journals Trends in the prevalence of adult overweight and obesity in Australia, and its association with geographic remoteness

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Syed Afroz Keramat ◽  
Khorshed Alam ◽  
Mohammed Khaled Al-Hanawi ◽  
Jeff Gow ◽  
Stuart J. H. Biddle ◽  
...  
Keyword(s):  
Public Health ◽  
Rural Areas ◽  
Urban Areas ◽  
Overweight And Obesity ◽  
Health Concern ◽  
Major City ◽  
Individual Level ◽  
Significant Public Health ◽  
Nationally Representative ◽  
Geographic Remoteness

AbstractThe prevalence of overweight and obesity has been increasing globally and has become a significant public health concern in Australia in the two past decades. This study explores the most recent national prevalence and trends of adult overweight and obesity in Australia. It will also investigate geographic remoteness as a potential risk factor for an individual being overweight or obese in adulthood. A retrospective longitudinal study that utilised 14 successive waves (wave 6 through 19) of a nationally representative linked individual-level survey. Data was obtained from the Household, Income and Labour Dynamics in Australia survey. The data on 199,675 observations from 26,713 individuals aged ≥ 15 years over the period 2006 to 2019 was analysed. Random-effects logit model was employed to estimate the association between geographic remoteness and the risk of excessive weight gain. The results reveal that the prevalence of overweight, obesity and combined overweight and obesity among Australian adults in 2019 were 34%, 26% and 60%, respectively. The analysis shows that the prevalence of overweight and obesity varies by geographic remoteness. Adults from regional city urban (OR 1.53, 95% CI 1.16–2.03) and rural areas (OR 1.32, 95% CI 1.18–1.47) were more likely to be obese compared with their counterparts from major city urban areas. The results also show that adults living in major city urban areas, regional city urban areas, and regional city rural areas in Australia were 1.53 (OR 1.53, 95% CI 1.16–2.03), 1.32 (OR 1.32, 95% CI 1.18–1.47), and 1.18 (OR 1.18, 95% CI 1.08–1.29) times more likely to be overweight compared with their counterparts from major city urban areas in Australia. Substantial geographic variation in the prevalence of overweight and obesity exists among Australian adults and appears to be increasing. Public health measures should focus on contextual obesogenic factors and behavioural characteristics to curb the rising prevalence of adult obesity.

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