Assessing dengue transmission risk and a vector control intervention using entomological and immunological indices in Thailand: study protocol for a cluster-randomized controlled trial

Overgaard, Hans J.; Pientong, Chamsai; Thaewnongiew, Kesorn; Bangs, Michael J.; Ekalaksananan, Tipaya; Aromseree, Sirinart; Phanitchat, Thipruethai; Phanthanawiboon, Supranee; Fustec, Benedicte; Corbel, Vincent; Cerqueira, Dominique; Alexander, Neal

doi:10.1186/s13063-018-2490-1

Cited by 10 publications

(15 citation statements)

References 72 publications

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“…Most of the studies conducted relate the entomological indices with the number of cases and other related factors [44–46]. A study in Thailand investigated the relationship between sensitivity of entomological indices and immunological indicators in sites of treated and untreated areas [47]. Comprehensive research on mosquito abundance and dengue virus infection was also conducted in Peru.…”

Section: Discussionmentioning

confidence: 99%

Small-scale field assessment of efficacy of the autodissemination approach against Aedes sp. in an urban area

Ngesom¹,

Othman

Bahauddin³

et al. 2020

Preprint

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This is the first study to evaluate the efficacy of an autodissemination approach, as suggested by WHO. Therefore, the efficacy of an autodissemination approach in small-scale field trials against wild Aedes sp. population was evaluated in an urbanized setting, Malaysia. Lethal ovitraps enhanced with pyriproxyfen were used to control Aedes sp. populations at treatment sites, with the autodissemination activity was assessed using the WHO larval bioassays. Lethal ovitraps enhanced with pyriproxyfen effectively reduced of Aedes sp. population. All autodissemination stations were shown to be visited by Aedes sp. mosquitoes with 100% complete inhibition against eggs and larvae development. In the larvae bioassay, pupae mortality ranged from 14 to 40%. Statistically, a significant reduction of Aedes sp. population in the treatment sites compared to the untreated areas. The study proved for the autodissemination of pyriproxyfen to breeding habitats by wild Aedes sp. This technique is highly potentially for vector control activities. Future evaluation should focus on large-scale field trials.Author SummarySince 2012, Dataran Automobil, Seksyen 15, Shah Alam, was declared as one of the dengue hotspot areas. Major vector control activities were conducted by government, NGOs, social communities, and local authorities, but the number still rising. We conducted a new invention of autodissemination concepts in this area by an entomological study on mosquito populations reduction and dispersal abilities of the technique. We found that the technique has proven to control mosquito populations, but the other factors such as epidemiology link still unclear and need further clarification. Our finding highlighted the effectiveness of autodissemination strategies that can be considered as one of the alternative tools in vector control programme.

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Section: Discussionmentioning

confidence: 99%

Small-scale field assessment of efficacy of the autodissemination approach against Aedes sp. in an urban area

Ngesom¹,

Othman

Bahauddin³

et al. 2020

Preprint

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“…Currently, the majority of countries adhere, at least as published policy, to WHO recommendations on mosquito control including source reduction (environmental hygiene and community-based clean-up campaigns), larvicidal treatment of water storage containers, and peridomestic space spraying of insecticides around homes of recent dengue cases [44]. However, there is currently no definitive evidence that these measures have any demonstrable effect on reducing dengue transmission [11, 24, 25].…”

Section: Discussionmentioning

confidence: 99%

“…Today, the scale of continuing urban expansion abnegates such an approach. Current mosquito control techniques based on larval habitat source reduction, larviciding, and space spray are costly, laborious, and of debatable efficacy depending on the circumstances [10, 11]; therefore, there remains an urgent need for the development of intervention methods that could be reasonably implemented in the context of modern day urban environments and with some measure of possible sustainability. One of the major challenges in large, condensed urban settings is achieving sufficient coverage of aquatic habitats preferred by Ae.…”

Section: Introductionmentioning

confidence: 99%

Efficacy of the In2Care® auto-dissemination device for reducing dengue transmission: study protocol for a parallel, two-armed cluster randomised trial in the Philippines

Salazar

Angeles

et al. 2019

Trials

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Background Mosquito-borne viruses are imposing an ever increasing health burden worldwide. In addition to the recent Zika and chikungunya virus epidemics, dengue viruses have become the fastest growing problem with a 40-fold increase in the number of reported cases over the past five decades. Current mosquito control techniques involving larval source reduction, larviciding, and space spray of adulticides are costly, laborious, and of debatable efficacy. There remains an urgent need for the development of intervention methods that can be reasonably implemented in the context of modern day urbanisation. Auto-dissemination (AD) of insecticide by adult mosquitoes offers a potentially practical and useful tool in an integrated vector control programme. Recently, an immediately employable AD device, the In2Care® mosquito trap, has been commercialised and shows promise as an effective tool. However, there remains a lack of demonstration of epidemiological efficacy. Methods/design This trial aims to assess the extent to which implementation of In2Care® mosquito traps can reduce vector Aedes ( Stegomyia ) spp. adult mosquito densities and dengue virus transmission as measured by sequential sero-conversion rates in children 6–16 years of age in a dengue endemic location: Lipa City, Philippines. To achieve this, we will carry out a parallel, two-armed cluster randomised trial evaluating AD efficacy for reducing the incidence of dengue over a 2-year period with 4 consecutive months of vector control during peak dengue transmission each year. Discussion For decades, it has been commonly accepted that an integrated approach to mosquito control is required. The World Health Organization (WHO) Global Strategic Framework for Integrated Vector Management recommends a range of interventions, in combination, to increase control impact to reduce transmission. This efficacy trial of the first commercial product using the AD approach will be informative in assessing the general utility of AD in reducing not only adult vector densities but, more importantly, reducing the incidence of dengue. The AD technique may complement source reduction and larviciding campaigns by more efficiently targeting the most productive containers and those beyond human reach. If successful, this mosquito control strategy could prove an invaluable tool in the fight against urban mosquito vectors and a reduction in the burden of associated disease. Trial registration ISRCTN44272773 . Registered on 31 January 2019. Electronic supplementary material The online version of this article (10.1186/s13063-019-3376-6) contains supplementary material, which is available to authorized users.

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“…Furthermore, the lack of accurate entomological correlates of ABV risk [ 2 , 16 , 17 ], is affected by multiple sources of bias including the difficulty of detecting and accurately quantifying immature or adult Ae . aegypti density [ 18 ], the exposure of people to mosquitoes in residences other than their homes [ 19 , 20 ], the variable level of susceptibility in the human population against each virus [ 21 ], or the limited predictive power of entomological indices for informing vector control [ 22 ].…”

Section: Introductionmentioning

confidence: 99%

Natural arbovirus infection rate and detectability of indoor female Aedes aegypti from Mérida, Yucatán, Mexico

et al. 2021

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Arbovirus infection in Aedes aegypti has historically been quantified from a sample of the adult population by pooling collected mosquitoes to increase detectability. However, there is a significant knowledge gap about the magnitude of natural arbovirus infection within areas of active transmission, as well as the sensitivity of detection of such an approach. We used indoor Ae. aegypti sequential sampling with Prokopack aspirators to collect all mosquitoes inside 200 houses with suspected active ABV transmission from the city of Mérida, Mexico, and tested all collected specimens by RT-PCR to quantify: a) the absolute arbovirus infection rate in individually tested Ae. aegypti females; b) the sensitivity of using Prokopack aspirators in detecting ABV-infected mosquitoes; and c) the sensitivity of entomological inoculation rate (EIR) and vectorial capacity (VC), two measures ABV transmission potential, to different estimates of indoor Ae. aegypti abundance. The total number of Ae. aegypti (total catch, the sum of all Ae. aegypti across all collection intervals) as well as the number on the first 10-min of collection (sample, equivalent to a routine adult aspiration session) were calculated. We individually tested by RT-PCR 2,161 Aedes aegypti females and found that 7.7% of them were positive to any ABV. Most infections were CHIKV (77.7%), followed by DENV (11.4%) and ZIKV (9.0%). The distribution of infected Aedes aegypti was overdispersed; 33% houses contributed 81% of the infected mosquitoes. A significant association between ABV infection and Ae. aegypti total catch indoors was found (binomial GLMM, Odds Ratio > 1). A 10-min indoor Prokopack collection led to a low sensitivity of detecting ABV infection (16.3% for detecting infected mosquitoes and 23.4% for detecting infected houses). When averaged across all infested houses, mean EIR ranged between 0.04 and 0.06 infective bites per person per day, and mean VC was 0.6 infectious vectors generated from a population feeding on a single infected host per house/day. Both measures were significantly and positively associated with Ae. aegypti total catch indoors. Our findings provide evidence that the accurate estimation and quantification of arbovirus infection rate and transmission risk is a function of the sampling effort, the local abundance of Aedes aegypti and the intensity of arbovirus circulation.

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Assessing dengue transmission risk and a vector control intervention using entomological and immunological indices in Thailand: study protocol for a cluster-randomized controlled trial

Cited by 10 publications

References 72 publications

Small-scale field assessment of efficacy of the autodissemination approach against Aedes sp. in an urban area

Small-scale field assessment of efficacy of the autodissemination approach against Aedes sp. in an urban area

Efficacy of the In2Care® auto-dissemination device for reducing dengue transmission: study protocol for a parallel, two-armed cluster randomised trial in the Philippines

Natural arbovirus infection rate and detectability of indoor female Aedes aegypti from Mérida, Yucatán, Mexico

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