scholarly journals Entomological Surveillance for Zika and Dengue Virus in Aedes Mosquitoes: Implications for Vector Control in Thailand

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 442
Author(s):  
Nathamon Kosoltanapiwat ◽  
Jarinee Tongshoob ◽  
Preeraya Singkhaimuk ◽  
Chanyapat Nitatsukprasert ◽  
Silas A. Davidson ◽  
...  

Entomological surveillance for arthropod-borne viruses is vital for monitoring vector-borne diseases and informing vector control programs. In this study, we conducted entomological surveillance in Zika virus endemic areas. In Thailand, it is standard protocol to perform mosquito control within 24 h of a reported dengue case. Aedes females were collected within 72 h of case reports from villages with recent Zika–human cases in Kamphaeng Phet Province, Thailand in 2017 and 2018. Mosquitoes were bisected into head-thorax and abdomen and then screened for Zika (ZIKV) and dengue (DENV) viruses using real-time RT-PCR. ZIKV RNA was detected in three samples from two female Ae. aegypti (1.4%). A partial envelope sequence analysis revealed that the ZIKV sequences were the Asian lineage identical to sequences from ZIKV-infected cases reported in Thailand during 2016 and 2017. Dengue virus-1 (DENV-1) and dengue virus-4 (DENV-4) were found in four Ae. aegypti females (2.8%), and partial capsid sequences were nearly identical with DENV-1 and DENV-4 from Thai human cases reported in 2017. Findings in the current study demonstrate the importance of entomological surveillance programs to public health mosquito-borne disease prevention measures and control.

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1234
Author(s):  
Thanyalak Fansiri ◽  
Darunee Buddhari ◽  
Nattaphol Pathawong ◽  
Arissara Pongsiri ◽  
Chonticha Klungthong ◽  
...  

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.


2020 ◽  
Vol 14 (11) ◽  
pp. e0008868
Author(s):  
Clinton B. Leach ◽  
Jennifer A. Hoeting ◽  
Kim M. Pepin ◽  
Alvaro E. Eiras ◽  
Mevin B. Hooten ◽  
...  

Our ability to effectively prevent the transmission of the dengue virus through targeted control of its vector, Aedes aegypti, depends critically on our understanding of the link between mosquito abundance and human disease risk. Mosquito and clinical surveillance data are widely collected, but linking them requires a modeling framework that accounts for the complex non-linear mechanisms involved in transmission. Most critical are the bottleneck in transmission imposed by mosquito lifespan relative to the virus’ extrinsic incubation period, and the dynamics of human immunity. We developed a differential equation model of dengue transmission and embedded it in a Bayesian hierarchical framework that allowed us to estimate latent time series of mosquito demographic rates from mosquito trap counts and dengue case reports from the city of Vitória, Brazil. We used the fitted model to explore how the timing of a pulse of adult mosquito control influences its effect on the human disease burden in the following year. We found that control was generally more effective when implemented in periods of relatively low mosquito mortality (when mosquito abundance was also generally low). In particular, control implemented in early September (week 34 of the year) produced the largest reduction in predicted human case reports over the following year. This highlights the potential long-term utility of broad, off-peak-season mosquito control in addition to existing, locally targeted within-season efforts. Further, uncertainty in the effectiveness of control interventions was driven largely by posterior variation in the average mosquito mortality rate (closely tied to total mosquito abundance) with lower mosquito mortality generating systems more vulnerable to control. Broadly, these correlations suggest that mosquito control is most effective in situations in which transmission is already limited by mosquito abundance.


2016 ◽  
Author(s):  
Samuel S.C. Rund ◽  
Micaela Elvira Martinez

AbstractAccording to the World Health Organization, every year more than a billion people are infected with vector-borne diseases worldwide. There are no vaccines for most vector-borne diseases. Vector control, therefore, is often the only way to prevent outbreaks. Despite the major impact of vectors on human health, knowledge gaps exist regarding their natural population dynamics. Even the most basic information—such as spatiotemporal abundance— is not available. Mosquitoes transmit malaria and the viruses causing Yellow Fever, West Nile, Dengue, Chikungunya, and Zika in the Americas. The Americas have a long history of mosquito control efforts, including the unsustained but successful Aedes aegypti eradication initiative. In the US, municipalities have independently created agencies for mosquito control and monitoring. We propose that the ensemble of US mosquito control agencies can, and should, be used to develop a national—and potentially international—system for Cross-Scale Vector Monitoring and Control (CSVMaC), in which local level monitoring and control efforts are cross-linked by unified real-time data streaming to build the data capital needed to gain a mechanistic understanding of vector population dynamics. Vectors, and the pathogens they transmit, know no jurisdictions. The vision of CSVMaC is, therefore, to provide data for (i) the general study of mosquito ecology and (ii) to inform vector control during epidemics/outbreaks that impact multiple jurisdictions (i.e., counties, states, etc.). We reveal >1000 mosquito control agencies in the US with enormous troves of data that are hidden among many data silos. For CSVMaC, we propose the creation of a nationally-coordinated open-access database to collate mosquito data. The database would provide scientific and public health communities with highly resolved spatiotemporal data on arboviral disease vectors, empowering new interventions and insights while leveraging pre-existing human efforts, operational infrastructure, and investments already funded by taxpayers.


ENTOMON ◽  
2020 ◽  
Vol 45 (2) ◽  
pp. 135-142
Author(s):  
R. Rajendran ◽  
K. Regu ◽  
S. B. Anusree ◽  
W. Tamizharasu ◽  
Anila Rajendran

Vector-borne Diseases (VBDs) such as malaria, dengue, chikungunya, zika virus and yellow fever are reported in over 100 countries and put up to 60% of the world’s population at risk of infection; more than 500 million cases are reported each year. The International Health Regulations (IHR) emphasizes to look after international seaports/airports and surrounding areas up to 400 meters free of Aedes aegypti mosquito and other vectors of epidemiological significance. Vector surveillance and control at Port of Entry (PoE) is an essential activity for the implementation of IHR. Hence Entomological surveillance was done inside and the residential areas around Cochin International Airport during 2013 to 2019. Aedes larval indices in both inside and residential areas outside the airport were found to be below the critical level in all these years. However the study showed no Aedes positivity inside the airport during 2014, 2016, 2018 and 2019. Effectiveness of vector control measures implemented in and around the airport is deliberated.


2011 ◽  
Vol 16 (9) ◽  
Author(s):  
I Gjenero-Margan ◽  
B Aleraj ◽  
D Krajcar ◽  
V Lesnikar ◽  
A Klobučar ◽  
...  

After information about a dengue case in Germany acquired in Croatia, health professionals and the public in Croatia were alerted to assess the situation and to enhance mosquito control, resulting in the diagnosis of a second case of autochthonous dengue fever in the same area and the detection of 15 persons with evidence of recent dengue infection. Mosquito control measures were introduced. The circumstances of dengue virus introduction to Croatia remain unresolved.


Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 947
Author(s):  
Rishi Kondapaneni ◽  
Ashley N. Malcolm ◽  
Brian M. Vazquez ◽  
Eric Zeng ◽  
Tse-Yu Chen ◽  
...  

Florida lies within a subtropical region where the climate allows diverse mosquito species including invasive species to thrive year-round. As of 2021, there are currently 66 state-approved Florida Mosquito Control Districts, which are major stakeholders for Florida public universities engaged in mosquito research. Florida is one of the few states with extensive organized mosquito control programs. The Florida State Government and Florida Mosquito Control Districts have long histories of collaboration with research institutions. During fall 2020, we carried out a survey to collect baseline data on the current control priorities from Florida Mosquito Control Districts relating to (1) priority control species, (2) common adult and larval control methods, and (3) major research questions to address that will improve their control and surveillance programs. The survey data showed that a total of 17 distinct mosquito species were considered to be priority control targets, with many of these species being understudied. The most common control approaches included truck-mounted ultra-low-volume adulticiding and biopesticide-based larviciding. The districts held interest in diverse research questions, with many prioritizing studies on basic science questions to help develop evidence-based control strategies. Our data highlight the fact that mosquito control approaches and priorities differ greatly between districts and provide an important point of comparison for other regions investing in mosquito control, particularly those with similar ecological settings, and great diversity of potential mosquito vectors, such as in Florida. Our findings highlight a need for greater alignment of research priorities between mosquito control and mosquito research. In particular, we note a need to prioritize filling knowledge gaps relating to understudied mosquito species that have been implicated in arbovirus transmission.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Pandiyan Amuthavalli ◽  
Jiang-Shiou Hwang ◽  
Hans-Uwe Dahms ◽  
Lan Wang ◽  
Jagannathan Anitha ◽  
...  

AbstractMicrobes or parasites spread vector-borne diseases by mosquitoes without being affected themselves. Insecticides used in vector control produce a substantial problem for human health. This study synthesized zinc oxide nanoparticles (ZnO NPs) using Lawsonia inermis L. and were characterized by UV–vis, FT-IR, SEM with EDX, and XRD analysis. Green synthesized ZnO NPs were highly toxic against Anopheles stephensi, whose lethal concentrations values ranged from 5.494 ppm (I instar), 6.801 ppm (II instar), 9.336 ppm (III instar), 10.736 ppm (IV instar), and 12.710 ppm (pupae) in contrast to L. inermis treatment. The predation efficiency of the teleost fish Gambusia affinis and the copepod Mesocyclops aspericornis against A. stephensi was not affected by exposure at sublethal doses of ZnO NPs. The predatory potency for G. affinis was 45 (I) and 25.83% (IV), copepod M. aspericornis was 40.66 (I) and 10.8% (IV) while in an ZnO NPs contaminated environment, the predation by the fish G. affinis was boosted to 71.33 and 34.25%, and predation of the copepod M. aspericornis was 60.35 and 16.75%, respectively. ZnO NPs inhibited the growth of several microbial pathogens including the bacteria (Escherichia coli and Bacillus subtilis) and the fungi (Alternaria alternate and Aspergillus flavus), respectively. ZnO NPs decreased the cell viability of Hep-G2 with IC50 value of 21.63 µg/mL (R2 = 0.942; P < 0.001) while the concentration increased from 1.88 to 30 µg/mL. These outcomes support the use of L. inermis mediated ZnO NPs for mosquito control and drug development.


2021 ◽  
Vol 6 (1) ◽  
pp. 25
Author(s):  
Cameron E. Webb ◽  
Philippe G. Porigneaux ◽  
David N. Durrheim

Exotic mosquitoes, especially container-inhabiting species such as Aedes aegypti and Aedes albopictus, pose a risk to Australia as they bring with them potentially significant pest and public health concerns. Notwithstanding the threat to public health and wellbeing, significant economic costs associated with the burden of mosquito control would fall to local authorities. Detection of these mosquitoes at airports and seaports has highlighted pathways of introduction but surveillance programs outside these first ports of entry are not routinely conducted in the majority of Australian cities. To assist local authorities to better prepare response plans for exotic mosquito incursions, an investigation was undertaken to determine the extent of habitats suitable for container-inhabiting mosquitoes in over 300 residential properties adjacent to the Port of Newcastle, Newcastle, NSW. More than 1500 water-holding containers were recorded, most commonly pot plant saucers, roof gutters, and water-holding plants (e.g., bromeliads). There were significantly more containers identified for properties classified as untidy but there was no evidence visible that property characteristics could be used to prioritise property surveys in a strategic eradication response. The results demonstrate that there is potential for local establishment of exotic mosquitoes and that considerable effort would be required to adequately survey these environments for the purpose of surveillance and eradication programs.


F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 598
Author(s):  
Gerard Ulibarri ◽  
Angel Betanzos ◽  
Mireya Betanzos ◽  
Juan Jacobo Rojas

Objective: To study the effectiveness of an integrated intervention of health worker training, a low-cost ecological mosquito ovitrap, and community engagement on Aedes spp. mosquito control over 10 months in 2015 in an urban remote community in Guatemala at risk of dengue, chikungunya and Zika virus transmission. Methods: We implemented a three-component integrated intervention consisting of: web-based training of local health personnel in vector control, cluster-randomized assignment of ecological ovillantas or standard ovitraps to capture Aedes aegypti mosquito eggs, and community engagement to promote participation of community members and health personnel in the understanding and maintenance of ovitraps for mosquito control. The intervention was implemented in local collaboration with the Ministry of Health’s Vector Control Programme, and in international collaboration with the National Institute of Public Health in Mexico. Findings: Eighty percent of the 25 local health personnel enrolled in the training programme received accreditation of their improved knowledge of vector control. Significantly more eggs were trapped by  ecological ovillantas than standard ovitraps over the 10 month (42 week) study period (t=5.2577; p<0.05). Among both community members and health workers, the levels of knowledge, interest, and participation in community mosquito control and trapping increased. Recommendations for enhancing and sustaining community mosquito control were identified. Conclusion: Our three-component integrated intervention proved beneficial to this remote community at risk of mosquito-borne diseases such as dengue, chikungunya, and Zika. The combination of training of health workers, low-cost ecological ovillanta to destroy the second generation of mosquitoes, and community engagement ensured the project met local needs and fostered collaboration and participation of the community, which can help improve sustainability. The ovillanta intervention and methodology may be modified to target other species such as Culex, should it be established that such mosquitoes carry Zika virus in addition to Aedes.


2020 ◽  
Author(s):  
Henk van den Berg ◽  
Haroldo Sergio da Silva Bezerra ◽  
Emmanuel Chanda ◽  
Samira Al-Eryani ◽  
Bhupender Nath Nagpal ◽  
...  

Abstract Background: Vector control plays a critical role in the prevention, control and elimination of vector-borne diseases, and interventions of vector control continue to depend largely on the action of chemical insecticides. A global survey was conducted on the management practices of vector control insecticides at country level to identify gaps to inform future strategies on pesticide management, seeking to improve efficacy of interventions and reduce the side effects of chemicals used on health and the environment.Methods: A survey by questionnaire on the management practices of vector control insecticides was disseminated among all WHO Member States. Data were analysed using descriptive statistics.Results: Responses were received from 94 countries, or a 48% response rate . Capacity for insecticide resistance monitoring was established in 68-80% of the countries in most regions, often with external support; however, this capacity was largely lacking from the European & Others Region. Procurement of vector control insecticides was in 50-75% of countries taking place by agencies other than the central-level procuring agency, over which the central authorities lacked control, for example, to select the product or assure product quality. Moreover, some countries experienced problems with estimating the correct amounts for procurement, especially for emergency purposes. Large fractions of countries across regions showed shortcomings in worker safety, pesticide storage practices, and pesticide waste disposal. Shortcomings were most pronounced in countries of the European & Others region, which has long been relatively free from mosquito-borne diseases but have recently faced challenges of re-emerging vector-borne diseases.Conclusions: Critical shortcomings in the management of vector control insecticides are common in countries across regions, with risks of adverse pesticide effects on health and the environment. Advocacy and resource mobilization are needed at regional and country level to address these challenges.


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