Early warning and response system (EWARS) for dengue outbreaks: Recent advancements towards widespread applications in critical settings

AbstractBackgroundDuring 2017, twenty health districts (locations) in Mexico implemented a dengue outbreak early warning and response system (EWARS) that uses epidemiological, meteorological and entomological variables (alarm indicators) to predict dengue outbreaks and triggers early response activities.Eleven of these districts were analyzed as they presented reliable information. Nine districts presented outbreak alarms but without subsequent outbreaks (“non-outbreak districts”) and two presented after the alarms dengue outbreaks (“outbreak districts”). This study is concerned with i) if the alarms without outbreaks were false alarms or if the control services had established effective response activities averting an outbreak and ii) if vector control activities can mitigate or even avert dengue outbreaks.MethodsFive components of dengue outbreak response (larval control, entomological studies with water container interventions, focal spraying, indoor residual spraying, space spraying) were quantitatively analyzed across two groups (”outbreak districts” and “non-outbreak districts”).ResultsThe average coverage of vector control and responses were higher in non-outbreak districts and across all five components. In the “outbreak districts” the response activities started late and were of much lower intensity compared to “non-outbreak districts”. District vector control teams demonstrated diverse compliance with local guidlines for ‘initial’, ‘early’ and ‘late’ responses to outbreak alarms which could explain the different outcomes observed following the outbreak alarms.Conclusionfindings from this study plausibly demonstrates important operational scenarios when succeeding or failing alarms signals generated by EWARS at national level. This study presents evidence warranting for further investigation into the effectiveness and cost-effectiveness of EWARS using gold-standard designs.

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Validation of the Early Warning and Response System (EWARS) for dengue outbreaks: Evidence from the national vector control program in Mexico

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0009261 ◽

2021 ◽

Vol 15 (12) ◽

pp. e0009261

Author(s):

David Benitez-Valladares ◽

Axel Kroeger ◽

Gustavo Sánchez Tejeda ◽

Laith Hussain-Alkhateeb

Keyword(s):

Vector Control ◽

Early Warning ◽

Disease Transmission ◽

Indoor Residual Spraying ◽

Alarm Signals ◽

Dengue Outbreak ◽

Response System ◽

Adequate Response ◽

Dengue Outbreaks ◽

The Impact

Background During 2017, twenty health districts (locations) implemented a dengue outbreak Early Warning and Response System (EWARS) in Mexico, which processes epidemiological, meteorological and entomological alarm indicators to predict dengue outbreaks and triggers early response activities. Out of the 20 priority districts where more than one fifth of all national disease transmission in Mexico occur, eleven districts were purposely selected and analyzed. Nine districts presented outbreak alarms by EWARS but without subsequent outbreaks (“non-outbreak districts”) and two presented alarms with subsequent dengue outbreaks (“outbreak districts”). This evaluation study assesses and compares the impact of alarm-informed response activities and the consequences of failing a timely and adequate response across the outbreak groups. Methods Five indicators of dengue outbreak response (larval control, entomological studies with water container interventions, focal spraying and indoor residual spraying) were quantitatively analyzed across two groups (”outbreak districts” and “non-outbreak districts”). However, for quality control purposes, only qualitative concluding remarks were derived from the fifth response indicator (fogging). Results The average coverage of vector control responses was significantly higher in non-outbreak districts and across all four indicators. In the “outbreak districts” the response activities started late and were of much lower intensity compared to “non-outbreak districts”. Vector control teams at districts-level demonstrated diverse levels of compliance with local guidelines for ‘initial’, ‘early’ and ‘late’ responses to outbreak alarms, which could potentially explain the different outcomes observed following the outbreak alarms. Conclusion Failing timely and adequate response of alarm signals generated by EWARS showed to negatively impact the disease outbreak control process. On the other hand, districts with adequate and timely response guided by alarm signals demonstrated successful records of outbreak prevention. This study presents important operational scenarios when failing or successding EWARS but warrants investigating the effectiveness and cost-effectiveness of EWARS using a more robust designs.

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The Early Warning And Response System (EWARS-TDR) For Dengue Outbreaks: Can It Also Be Applied To Chikungunya And Zika Outbreak Warning?

10.21203/rs.3.rs-498936/v1 ◽

2021 ◽

Author(s):

Rocio Cardenas ◽

Laith Hussain-Alkhateeb ◽

David Benitez-Valladares ◽

Gustavo Sanchez-Tejeda ◽

Axel Kroeger

Keyword(s):

Positive Predictive Value ◽

Early Warning ◽

Predictive Value ◽

Large City ◽

High Sensitivity ◽

Surveillance Systems ◽

Insect Vector ◽

Alarm Signals ◽

Response System ◽

Dengue Outbreaks

Abstract Background. In the Americas, endemic countries for Aedes-borne diseases such as dengue, chikungunya, and Zika face great challenges particularly since the recent outbreaks of CHIKV and ZIKV, all transmitted by the same insect vector Aedes aegypti and Ae. albopictus. The Special Program for Research and Training in Tropical Diseases (TDR- WHO) has developed together with partners an early warning and Response System (EWARS) for dengue outbreaks based on a variety of alarm signals with a high sensitivity and positive predictive value (PPV). The question is if this tool can also be used for the prediction of Zika and chikungunya outbreaks.Methodology. We conducted in nine districts of Mexico and one large city in Colombia a retrospective analysis of epidemiological data (for the outbreak definition) and of climate and entomological data (as potential alarm indicators) produced by the national surveillance systems for dengue, chikungunya and Zika outbreak prediction covering the following outbreak years: for dengue 2012-2016, for Zika 2015-2017, for chikungunya 2014-2016. This period was divided into a “run in period” (to establish the “historical” pattern of the disease) and an “analysis period” (to identify sensitivity and PPV of outbreak prediction). Results. In Mexico, the sensitivity of alarm signals for correctly predicting an outbreak was 92% for dengue, and 97% for Zika (chikungunya data could not be obtained in Mexico); the PPV was 68% for dengue and 100% for Zika. The time period between alarm and start of the outbreak (i.e. the time available for early response activities) was for dengue 6-8 weeks and for Zika 3-5 weeks. In Colombia the sensitivity of the outbreak prediction was 92% for dengue, 93% for chikungunya and 100% for Zika; the PPV was 68% for dengue, 92% for chikungunya and 54% for Zika; the prediction distance was for dengue 3-5 weeks, for chikungunya 10-13 weeks and for Zika 6-10 weeks. Conclusion. The implementation of an early warning and response system (EWARS) could predict outbreaks of three Aedes borne diseases with a high sensitivity and positive predictive value and with a lag time long enough for preparing an adequate outbreak response in order to reduce the magnitude or avert the occurrence of outbreaks with their elevated social and economic tolls.

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Early Warning and Response System (EWARS) for chikungunya, zika and dengue outbreaks: The innovated WHO-TDR tool.

10.21203/rs.2.18483/v1 ◽

2019 ◽

Author(s):

Rocio Cardenas ◽

Laith Hussain-Alkhateeb ◽

David Benitez-Valladares ◽

Gustavo Sanchez Tejeda ◽

Axel Kroeger

Keyword(s):

Early Warning ◽

Urban Areas ◽

High Sensitivity ◽

Early Response ◽

Surveillance Systems ◽

Insect Vector ◽

Predictive Values ◽

Alarm Signals ◽

Response System ◽

Dengue Outbreaks

Abstract Background. In the Americas, endemic cities for Aedes-borne diseases such as chikungunya, Zika and dengue face great challenges particularly since the recent outbreaks of CHIKV and ZIKV, all transmitted by the same insect vector Aedes aegypti and albopictus. Areas, such as Colombia and Mexico with the highest incidence and most frequent outbreaks of the three diseases are located in tropical environments due to their favorable eco-epidemiological conditions for vector breeding. In Colombia, the city of Cúcuta on the border with Venezuela is one of such highly endemic areas. Likewise, in Mexico a number of municipalities has very similar environmental conditions. This is why these urban areas provide the opportunity to test the Early Warning and Response System (EWARS), developed originally for dengue outbreaks, also for the other two diseases (Chikungunya and Zika). Methodology. Through the retrospective analysis of epidemiological, climate and entomological data produced by the national surveillance systems in Colombia and Mexico, we intended to predict outbreaks with a high sensitivity and positive predictive value (PPV) through alarm signals by using the EWARS tool. The registered outbreaks of DENV 2012-2016, CHIKV 2014-2016 and ZIKV 2015-2016 were analyzed for 2 years retrospectively (“run in period”) and one year of analysis (“evaluation period”). Outbreak prediction for dengue and Zika was for both countries but for Chikungunya in Colombia only due to the availability of surveillance data. Results. In Mexico, the sensitivity of different alarm signals for correctly predicting an outbreak ranged between 74-92% for dengue, 77–93% for chikungunya and 78-97% for Zika. Their Positive Predictive Values ranged between 51-68% for dengue, 48-92% for chikungunya and 11-100% for Zika. The lag time between predictions and start of the outbreak (i.e. the time available for early response activities) was for dengue 3-5 weeks, for chikungunya 10-13 weeks and for Zika 3-5 weeks. Conclusion. The implementation of an early warning and response system (EWARS) could substantially reduce the magnitude and occurrence of outbreaks and the elevated social and economic toll.

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URGENSI PENGELOLAAN KAWASAN KARST GOA PINDUL, KECAMATAN KARANGMOJO, GUNUNGKIDUL

10.31227/osf.io/xb7v8 ◽

2017 ◽

Author(s):

Ahmad Cahyadi ◽

Slamet Suprayogi ◽

Romza Fauzan Agniy

Keyword(s):

Emergency Response ◽

Early Warning ◽

Early Warning System ◽

Warning System ◽

Emergency Response System ◽

Response System

Goa Pindul adalah salah satu wisata andalan di Kabupaten Gunungkidul, Daerah Istimewa Yogyakarta. Konflik sosial yang terjadi akibat koordinasi dan peran pemerintah yang masih minim menyebabkan situasi pariwisata yang kurang kondusif dalam pengembangan wisata yang berkelanjutan. Selain itu, karakteristik unik kawasan karst yang dipengaruhi oleh perkembangan pelorongan akibat proses pelarutan dan sistem allogenik mengharuskan pengelolaan yang berwawasan bencana dengan membuat sistem pemantauan banjir, early warning system dan emergency response system untuk pengurangan risiko bencana yang mungkin terjadi di Kawasan Wisata Goa Pindul.

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