scholarly journals Genetic Characterization of Chikungunya Virus in Field-Caught Aedes aegypti Mosquitoes Collected during the Recent Outbreaks in 2019, Thailand

Pathogens ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 121 ◽  
Author(s):  
Intayot ◽  
Phumee ◽  
Boonserm ◽  
Sor-suwan ◽  
Buathong ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
South African ◽  
Chikungunya Virus ◽  
Mosquito Control ◽  
Control Strategies ◽  
Pathogen Transmission ◽  
Sequencing Analysis ◽  
Chikv Infection ◽  
Infected Female ◽  
Health Authorities

Chikungunya virus (CHIKV) is a mosquito-borne virus belonging to the genus Alphavirus. The virus is transmitted to humans by the bite of infected female Aedes mosquitoes, primarily Aedes aegypti. CHIKV infection is spreading worldwide, and it periodically sparks new outbreaks. There are no specific drugs or effective vaccines against CHIKV. The interruption of pathogen transmission by mosquito control provides the only effective approach to the control of CHIKV infection. Many studies have shown that CHIKV can be transmitted among the Ae. aegypti through vertical transmission. The previous chikungunya fever outbreaks in Thailand during 2008–2009 were caused by CHIKV, the East/Central/South African (ECSA) genotype. Recently, there have been 3794 chikungunya cases in 27 provinces reported by the Bureau of Epidemiology of Health Ministry, Thailand during 1 January–16 June 2019; however, the cause of the re-emergence of CHIKV outbreaks is uncertain. Therefore, the aims of this study were to detect and analyze the genetic diversity of CHIKV infection in field-caught mosquitoes. Both female and male Ae. aegypti were collected from endemic areas of Thailand, and CHIKV detection was done by using E1-nested RT-PCR and sequencing analysis. A total of 1646 Ae. aegypti samples (900 females and 746 males) were tested. CHIKV was detected in 54 (3.28%) and 14 samples (0.85%) in female and male mosquitoes, respectively. Seventeen samples of female Ae. aegypti collected from the Ubon Ratchathani, Chiang Rai, Chiang Mai, Nakhon Sawan, and Songkhla provinces found mutation at E1: A226V. Interestingly, E1: K211E mutation was observed in 50 samples collected from Nong Khai, Bangkok, Prachuap Khiri Khan, and Krabi. In addition, the phylogenetic tree indicated that CHIKV in Ae. aegypti samples were from the Indian Ocean Clade and East/South African Clade. Both clades belong to the ECSA genotype. The information obtained from this study could be used for prediction, epidemiological study, prevention, and effective vector control of CHIKV. For instance, a novel CHIKV strain found in new areas has the potential to lead to a new outbreak. Health authorities could plan and apply control strategies more effectively given the tools provided by this research.

scholarly journals Current Status of Aedes aegypti Insecticide Resistance Development from Banjarmasin, Kalimantan, Indonesia

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
P. H. Hamid ◽  
V. I. Ninditya ◽  
J. Prastowo ◽  
A. Haryanto ◽  
A. Taubert ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Insecticide Resistance ◽  
Point Mutation ◽  
Mosquito Control ◽  
Control Strategies ◽  
Current Status ◽  
Resistance Development ◽  
Health Authorities ◽  
Public Health Authorities ◽  
High Level

Aedes aegypti represents the principal vector of many arthropod-borne diseases in tropical areas worldwide. Since mosquito control strategies are mainly based on use of insecticides, resistance development can be expected to occur in frequently exposed Ae. aegypti populations. Surveillance on resistance development as well as testing of insecticide susceptibility is therefore mandatory and needs further attention by national/international public health authorities. In accordance, we here conducted a study on Ae. aegypti resistance development towards several often used insecticides, i.e., malathion, deltamethrin, permethrin, λ-cyhalothrin, bendiocarb, and cyfluthrin, in the periurban area of Banjarmasin city, Kalimantan, Indonesia. Our results clearly showed resistance development of Ae. aegypti populations against tested insecticides. Mortalities of Ae. aegypti were less than 90% with the highest resistance observed against 0.75% permethrin. Collected mosquitoes from Banjarmasin also presented high level of resistance development to 0.1% bendiocarb. Molecular analysis of voltage-gated sodium channel (Vgsc) gene showed significant association of V1016G gene point mutation in resistance Ae. aegypti phenotypes against 0.75% permethrin. However, F1534C gene point mutation did not correlate to Ae. aegypti insecticide resistance to 0.75% permethrin. Irrespective of periurban areas in Kalimantan considered as less densed island of Indonesia, Ae. aegypti-derived resistance to different routinely applied insecticides occurred. Our findings evidence that Ae. aegypti insecticide resistance is most likely spreading into less populated areas and thus needs further surveillance in order to delay Ae. aegypti resistance development.

Urban Landscape Features Influence the Movement and Distribution of the Australian Container-Inhabiting Mosquito Vectors Aedes aegypti (Diptera: Culicidae) and Aedes notoscriptus (Diptera: Culicidae)

2019 ◽  
Author(s):  
Brendan J Trewin ◽  
Daniel E Pagendam ◽  
Myron P Zalucki ◽  
Jonathan M Darbro ◽  
Gregor J Devine ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Urban Landscape ◽  
Mosquito Control ◽  
Control Strategies ◽  
Oviposition Behavior ◽  
Gaussian Kernel ◽  
Mosquito Vectors ◽  
Landscape Features ◽  
Rainwater Tanks

Abstract Urban landscape features play an important role in the distribution and population spread of mosquito vectors. Furthermore, current insecticide and novel rear-and-release strategies for urban mosquito management rarely consider the spatial structure of the landscape when applying control practices. Here, we undertake a mark-recapture experiment to examine how urban features influence the movement and distribution of Australian container-inhabiting Aedes vectors. We pay attention to the role of semipermanent water storage containers, called rainwater tanks, and the influence of movement barriers, such as roads, on the spread and distribution of vector populations. Results suggest that Aedes aegypti (Linnaeus) (Diptera: Culicidae) were more likely to be captured around rainwater tanks, and that released males travel throughout residential blocks but do not cross roads. Conversely, female Aedes notoscriptus (Skuse) (Diptera: Culicidae) movement was uninhibited by roads and rainwater tanks did not influence female distribution or oviposition behavior. Using an isotropic Gaussian kernel framework, we show that vector movement is likely to be greater when applying a temporal effect, than when estimated by traditional methods. We conclude that a greater understanding on the role of urban features on vector movement will be important in the new age of rear-and-release mosquito control strategies, particularly those where estimations of movement are important for ensuring efficacy of application.

scholarly journals The juvenile hormone receptor Methoprene-tolerant is involved in the sterilizing effect of pyriproxyfen on adult Aedes aegypti mosquitoes

2020 ◽  
Author(s):  
Tahmina Hossain Ahmed ◽  
T. Randolph Saunders ◽  
Donald Mullins ◽  
Mohammad Zillur Rahman ◽  
Jinsong Zhu
Keyword(s):  
Aedes Aegypti ◽  
Juvenile Hormone ◽  
Mosquito Control ◽  
Fat Body ◽  
Control Strategies ◽  
Follicular Development ◽  
Blood Feeding ◽  
Oocyte Development ◽  
Hormonal Responses ◽  
Before And After

AbstractExposure of adult mosquitoes to pyriproxyfen (PPF), an analog of insect juvenile hormone (JH), has shown promise to effectively sterilize female mosquitoes. However, the underlying mechanisms of the PPF-induced decrease in mosquito fecundity are largely unknown. We performed a comprehensive study to dissect the mode of PPF action in Aedes aegypti mosquitoes. Exposure to PPF prompted the overgrowth of primary follicles in sugar-fed Ae. aegypti females but blocked the development of primary follicles at Christopher’s Stage III after blood feeding. Secondary follicles were precociously activated in PPF-treated mosquitoes. Moreover, PPF substantially altered the expression of many genes that are essential for mosquito physiology and oocyte development in the fat body and ovary. In particular, many metabolic genes were differentially expressed in response to PPF treatment, thereby affecting the mobilization and utilization of energy reserves. Furthermore, PPF treatment on the previtellogenic female adults considerably modified mosquito responses to JH and 20-hydroxyecdysone (20E), two major hormones that govern mosquito reproduction. Krüppel homolog 1, a JH-inducible transcriptional regulator, showed consistently elevated expression after PPF exposure. Conversely, PPF upregulated the expression of several key players of the 20E regulatory cascades, including HR3 and E75A, in the previtellogenic stage. After blood-feeding, the expression of these 20E response genes was significantly weaker in PPF-treated mosquitoes than the solvent-treated control groups. RNAi-mediated knockdown of the Methoprene-tolerant (Met) protein, the JH receptor, partially rescued the impaired follicular development after PPF exposure and substantially increased the hatching of the eggs produced by PPF-treated female mosquitoes. Thus, the results suggested that PPF relied on Met to exert its sterilizing effects on female mosquitoes. In summary, this study finds that PPF exposure disturbs normal hormonal responses and metabolism in Ae. aegypti, shedding light on the molecular targets and the downstream signaling pathways activated by PPF.Author summaryAedes aegypti mosquitoes are responsible for the transmission of dengue, yellow fever, chikungunya, and Zika fever. Insecticides are widely used as the primary tool in the prevention and control of these infectious diseases. In light of the rapid increase of insecticide resistance in mosquito populations, there is an urgent need to find new classes of insecticides with a different mode of action. Here we found that pyriproxyfen, an analog of insect juvenile hormone (JH), had a large impact on the oocyte development, both before and after blood feeding, in female mosquitoes. Pyriproxyfen disturbed normal hormonal responses and caused metabolic shifting in female adults. These actions appear to collectively impair oocyte development and substantially reduce viable progenies of female mosquitoes. Besides, we demonstrated the involvement of the JH receptor Met in pyriproxyfen-induced female sterilization. This study significantly advances our understanding of mosquito reproductive biology and the molecular basis of pyriproxyfen action, which are invaluable for the development of new mosquito control strategies.

scholarly journals Transcriptomic Analysis of Aedes aegypti Innate Immune System in Response to Ingestion of Chikungunya Virus

2019 ◽  
Vol 20 (13) ◽  
pp. 3133 ◽  
Author(s):  
Liming Zhao ◽  
Barry W. Alto ◽  
Yongxing Jiang ◽  
Fahong Yu ◽  
Yanping Zhang
Keyword(s):  
Immune System ◽  
Virus Infection ◽  
Aedes Aegypti ◽  
Innate Immune System ◽  
Chikungunya Virus ◽  
Innate Immune ◽  
Transcriptomic Analysis ◽  
System Response ◽  
Sequencing Analysis ◽  
Immune System Response

Aedes aegypti (L.) is the primary vector of emergent mosquito-borne viruses, including chikungunya, dengue, yellow fever, and Zika viruses. To understand how these viruses interact with their mosquito vectors, an analysis of the innate immune system response was conducted. The innate immune system is a conserved evolutionary defense strategy and is the dominant immune system response found in invertebrates and vertebrates, as well as plants. RNA-sequencing analysis was performed to compare target transcriptomes of two Florida Ae. aegypti strains in response to chikungunya virus infection. We analyzed a strain collected from a field population in Key West, Florida, and a laboratory strain originating from Orlando. A total of 1835 transcripts were significantly expressed at different levels between the two Florida strains of Ae. aegypti. Gene Ontology analysis placed these genes into 12 categories of biological processes, including 856 transcripts (up/down regulated) with more than 1.8-fold (p-adj (p-adjust value) ≤ 0.01). Transcriptomic analysis and q-PCR data indicated that the members of the AaeCECH genes are important for chikungunya infection response in Ae. aegypti. These immune-related enzymes that the chikungunya virus infection induces may inform molecular-based strategies for interruption of arbovirus transmission by mosquitoes.

scholarly journals Workshop for priority-setting in Aedes aegypti control interventions in Latin America and the Caribbean: a policy dialogue

2019 ◽  
Vol 35 (4) ◽  
Author(s):  
Agustin Ciapponi ◽  
Ariel Bardach ◽  
Andrea Alcaraz ◽  
María Belizán ◽  
Daniel Jones ◽  
...  
Keyword(s):  
Latin America ◽  
Aedes Aegypti ◽  
Vector Control ◽  
Priority Setting ◽  
Mosquito Control ◽  
Control Strategies ◽  
Policy Dialogue ◽  
Regional Research ◽  
Deliberative Process ◽  
The Caribbean

This article presents the results of a dialogue between decision-makers and experts in Latin America and the Caribbean on priority-setting for interventions and studies on Aedes aegypti control. The article is part of a project that included a systematic review of mosquito control strategies and a qualitative study with key informants from the region. Using a collective deliberative process assisted by the results of the above-mentioned projects, a list of priorities was developed by consensus for the implementation of vector control strategies and the development of key regional research lines. It was agreed that the best strategy is integrated vector management, divided into: (a) chemical control; (b) biological control; (c) environmental management; (d) community participation; and (e) integrated surveillance. The workshop highlighted the crucial role of government leadership and inter-sector coordination between government agencies and civil society stakeholders. The proposed priorities for research lines were: Ae. aegypti vector competence and associated factors; community components of interventions; incorporation of technology into vector control and monitoring; most efficient modalities of integrated surveillance; entomological indicators with the best predictive capacity; and resistance to insecticides. The policy dialogue methodology allowed validating and enriching the results of other levels of research, besides establishing priorities for regional research and control strategies.

scholarly journals Survei Entomologi, Kerentanan Aedes aegypti terhadap Insektisida Organofosfat, dan Identifikasi Gen VGSC di Dusun Malangrejo, Sleman, Yogyakarta

2019 ◽  
Vol 11 (1) ◽  
pp. 37-44
Author(s):  
Novyan Lusiyana ◽  
Siti Fitiah ◽  
Andrias Atmaja Putri ◽  
Muthia Tsabita Rahmi ◽  
Dian Maknalia Ilham
Keyword(s):  
Aedes Aegypti ◽  
Mosquito Control ◽  
Organophosphate Insecticide ◽  
Local Public Health ◽  
Health Authorities ◽  
Public Health Authorities ◽  
Control And Prevention ◽  
Pcr Method ◽  
Dengue Control ◽  
Enzyme Detection

Control and prevention effort of dengue haemorhagic fever relies on the application of insecticidesto control vector mosquito. In Indonesia, application of organophosphate insecticide (temephos andmalathion), and pyrethroid is a key part of the dengue control strategy. This study aimed to determine theentomological survey, susceptibility of Aedes aegypti against organophosphate insecticide and identificationof VGSC gene in Dusun Malangrejo, Sleman Yogyakarta. This study is an observational with a cross sectionaldesign. The entomology survey procedure used a single larvae technique, biological susceptibility test of Ae.aegypti against organophosphate insecticides using WHO (temephos), CDC (malathion), biochemistry andVGSC genes detection using PCR method. Results of this study showed that bath tub was potential breedingplace for Ae. aegypti. Susceptibility status of temephos was still tolerant (95.4%), while malathion showsresistance (13.75%). Bioassay and biochemical test shows potential resistant to insecticides due to elevatedactivity of esterase non specific enzyme. Detection of the VGSC gene shows positive for both genes (V1016G;S989P) and F1534C. Furthermore, regularly assessment of insecticide resistance status will hopefully assistthe local public health authorities to assign policy for managing mosquito control such as by rotation ofdifferent routinely used insecticide to delay Ae. aegypti resistance development.

scholarly journals Experimental Vertical Transmission of Chikungunya Virus by Brazilian and Florida Aedes Albopictus Populations

Viruses ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 353 ◽  
Author(s):  
Nildimar Alves Honório ◽  
Keenan Wiggins ◽  
Bradley Eastmond ◽  
Daniel Cardoso Portela Câmara ◽  
Barry W. Alto
Keyword(s):  
Vertical Transmission ◽  
Blood Meal ◽  
Chikungunya Virus ◽  
Viral Titer ◽  
Gonotrophic Cycle ◽  
Chikv Infection ◽  
Infected Female ◽  
Population Origin ◽  
Virus Survival ◽  
Florida Population

Chikungunya virus (CHIKV) is a vector-borne alphavirus transmitted by the bites of mosquitoes, specifically infected, female mosquitoes of the invasive Aedes species. In nature, CHIKV can be maintained by vertical transmission, a phenomenon that relates to the transfer of CHIKV from the infected parent to their offspring within the ovary or during oviposition. In the present study, we conducted laboratory experiments to determine vertical transmission with Ae. albopictus populations from Brazil and Florida. Parental Ae. albopictus females were orally infected with the emergent Asian genotype of CHIKV in the first gonotrophic cycle (infectious blood meal) and tested for vertical transmission following the second (non-infectious blood meal) gonotrophic cycle. CHIKV infection and CHIKV viral titer in parental females were significantly related to population origin, with Brazilian Ae. albopictus showing higher viral dissemination and viral titer than the Florida population. Experimental vertical transmission of CHIKV was documented in one pool of female and four pools of male Ae. albopictus from Brazil (minimum infection rate, MIR, of 0.76% and 2.86%, respectively, for females and males). For the Florida population of Ae. albopictus, only one pool of males was positive for CHIKV infection, with an MIR of 1.06%. Our results demonstrate that Ae. albopictus populations from Brazil and Florida show heterogeneous CHIKV dissemination and vertical transmission, which may contribute to the epidemiology of CHIKV and may be particularly relevant to virus survival during inter-epidemic periods.

scholarly journals Recent outbreaks of chikungunya virus (CHIKV) in Africa and Asia are driven by a variant carrying mutations associated with increased fitness for Aedes aegypti

2018 ◽  
Author(s):  
Irina Maljkovic Berry ◽  
Fredrick Eyase ◽  
Simon Pollett ◽  
Samson Limbaso Konongoi ◽  
Katherine Figueroa ◽  
...  
Keyword(s):  
Aedes Aegypti ◽  
Chikungunya Virus ◽  
Control Strategies ◽  
Vector Competence ◽  
Virus Transmission ◽  
New Delhi ◽  
African Countries ◽  
Global Spread ◽  
Large Outbreak ◽  
The Impact

AbstractBackgroundIn 2016, a chikungunya virus (CHIKV) outbreak was reported in Mandera, Kenya. This was the first major CHIKV outbreak in the country since the global re-emergence of this virus, which arose as an initial outbreak in Kenya in 2004. Therefore, we collected samples and sequenced viral genomes from the 2016 Mandera outbreak.Methodology/Principal FindingsAll Kenyan genomes contained two mutations, E1:K211E and E2:V264A, recently reported to have an association with increased infectivity, dissemination and transmission in the Aedes aegypti (Ae. aegypti) vector. Phylogeographic inference of temporal and spatial virus relationships using Bayesian approaches showed that this Ae. aegypti adapted strain emerged within the East, Central, and South African (ECSA) lineage of CHIKV between 2005 and 2008, most probably in India. It was also in India where the first large outbreak caused by this strain appeared, in New Delhi, 2010. More importantly, our results also showed that this strain is no longer contained to India, and that it has more recently caused several major outbreaks of CHIKV, including the 2016 outbreaks in India, Pakistan and Kenya, and the 2017 outbreak in Bangladesh. In addition to its capability to cause large outbreaks in different regions of the world, this CHIKV strain has the capacity to replace less adapted wild type strains in Ae. aegypti-rich regions. Indeed, all the latest full CHIKV genomes of the ECSA Indian Ocean Lineage (IOL), from the regions of high Ae. aegypti prevalence, carry these two mutations, including samples collected in Japan, Australia, and China.Conclusions/SignificanceOur results point to the importance of continued genomic-based surveillance of this strain’s global spread, and they prompt urgent vector competence studies in Asian and African countries, in order to assess the level of vector receptiveness, virus transmission, and the impact this might have on this strain’s ability to cause major outbreaks.Author summaryChikungunya virus (CHIKV) causes a debilitating infection with high fever, intense muscle and bone pain, rash, nausea, vomiting and headaches, and persistent and/or recurrent joint pains for months or years after contracting the virus. CHIKV is spread by two mosquito vectors, Aedes albopictus and Aedes aegypti, with increased presence around the globe. In this study, we report global spread of a CHIKV strain that carries two mutations that have been suggested to increase this virus’ ability to infect the Aedes aegypti mosquito, as well as to increase CHIKV’s ability to be transmitted by this vector. We show that this strain appeared sometime between 2005 and 2008, most probably in India, and has now spread to Africa, Asia, and Australia. We show that this strain is capable of driving large outbreaks of CHIKV in the human population, causing recent major outbreaks in Kenya, Pakistan, India and Bangladesh. Thus, our results stress the importance of monitoring this strain’s global spread, as well as the need of improved vector control strategies in the areas of Aedes aegypti prevalence.

scholarly journals Favipiravir Does Not Inhibit Chikungunya Virus Replication in Mosquito Cells and Aedes aegypti Mosquitoes

2021 ◽  
Vol 9 (5) ◽  
pp. 944
Author(s):  
Sofie Jacobs ◽  
Lanjiao Wang ◽  
Ana Lucia Rosales Rosas ◽  
Ria Van Berwaer ◽  
Evelien Vanderlinden ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Aedes Aegypti ◽  
Chikungunya Virus ◽  
Active Form ◽  
Metabolic Activation ◽  
Vero Cells ◽  
Mosquito Vector ◽  
Chikv Infection ◽  
Mosquito Cells

Favipiravir (T-705) is a broad-spectrum antiviral drug that inhibits RNA viruses after intracellular conversion into its active form, T-705 ribofuranosyl 5′-triphosphate. We previously showed that T-705 is able to significantly inhibit the replication of chikungunya virus (CHIKV), an arbovirus transmitted by Aedes mosquitoes, in mammalian cells and in mouse models. In contrast, the effect of T-705 on CHIKV infection and replication in the mosquito vector is unknown. Since the antiviral activity of T-705 has been shown to be cell line-dependent, we studied here its antiviral efficacy in Aedes-derived mosquito cells and in Aedes aegypti mosquitoes. Interestingly, T-705 was devoid of anti-CHIKV activity in mosquito cells, despite being effective against CHIKV in Vero cells. By investigating the metabolic activation profile, we showed that, unlike Vero cells, mosquito cells were not able to convert T-705 into its active form. To explore whether alternative metabolization pathways might exist in vivo, Aedes aegypti mosquitoes were infected with CHIKV and administered T-705 via an artificial blood meal. Virus titrations of whole mosquitoes showed that T-705 was not able to reduce CHIKV infection in mosquitoes. Combined, these in vitro and in vivo data indicate that T-705 lacks antiviral activity in mosquitoes due to inadequate metabolic activation in this animal species.

scholarly journals Antiviral Effectors and Gene Drive Strategies for Mosquito Population Suppression or Replacement to Mitigate Arbovirus Transmission by Aedes aegypti

Insects ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 52 ◽  
Author(s):  
Adeline Williams ◽  
Alexander Franz ◽  
William Reid ◽  
Ken Olson
Keyword(s):  
Aedes Aegypti ◽  
Disease Transmission ◽  
Mosquito Control ◽  
Control Strategies ◽  
Mosquito Vector ◽  
Close Monitoring ◽  
Gene Drive ◽  
Population Replacement ◽  
Effector Genes ◽  
Population Suppression

The mosquito vector Aedes aegypti transmits arthropod-borne viruses (arboviruses) of medical importance, including Zika, dengue, and yellow fever viruses. Controlling mosquito populations remains the method of choice to prevent disease transmission. Novel mosquito control strategies based on genetically manipulating mosquitoes are being developed as additional tools to combat arbovirus transmission. Genetic control of mosquitoes includes two basic strategies: population suppression and population replacement. The former aims to eliminate mosquito populations while the latter aims to replace wild populations with engineered, pathogen-resistant mosquitoes. In this review, we outline suppression strategies being applied in the field, as well as current antiviral effector genes that have been characterized and expressed in transgenic Ae. aegypti for population replacement. We discuss cutting-edge gene drive technologies that can be used to enhance the inheritance of effector genes, while highlighting the challenges and opportunities associated with gene drives. Finally, we present currently available models that can estimate mosquito release numbers and time to transgene fixation for several gene drive systems. Based on the recent advances in genetic engineering, we anticipate that antiviral transgenic Ae. aegypti exhibiting gene drive will soon emerge; however, close monitoring in simulated field conditions will be required to demonstrate the efficacy and utility of such transgenic mosquitoes.

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