Field evaluation of the combination of larvicide and rice stem immersion to improve lethal ovitrap effectiveness in dengue vector control

The combination of temephos and attractants from O.sativa was effective for lethal ovitrap in laboratory testing. However, the effectiveness of the field application needs further investigation. The study’s objective was to determine the influence of ovitrap installation sites, season variation, and attractant on lethal ovitrap efficacy. The study used a quasi-experimental design. Lethal ovitraps were installed indoors and outdoors in 102 houses and observed for 14 weeks. Statistical analysis was conducted with univariate analysis, independent t-test, and Mann-Whitney Test. The statistical analysis results showed no significant difference in positive ovitraps between LOA and LONA on indoor and outdoor applications. The number of positive ovitraps and trapped eggs was not affected by the attractant applied to the LO during indoor and outdoor observations. Lethal ovitrap can be used as a vector control instrument without the addition of attractants. The application of lethal ovitrap is more effective in the dry season when the mosquito population is lower than in the rainy season

Pandemic-associated mobility restrictions could cause increases in dengue virus transmission

Background The COVID-19 pandemic has induced unprecedented reductions in human mobility and social contacts throughout the world. Because dengue virus (DENV) transmission is strongly driven by human mobility, behavioral changes associated with the pandemic have been hypothesized to impact dengue incidence. By discouraging human contact, COVID-19 control measures have also disrupted dengue vector control interventions, the most effective of which require entry into homes. We sought to investigate how and why dengue incidence could differ under a lockdown scenario with a proportion of the population sheltered at home. Methodology & principal findings We used an agent-based model with a realistic treatment of human mobility and vector control. We found that a lockdown in which 70% of the population sheltered at home and which occurred in a season when a new serotype invaded could lead to a small average increase in cumulative DENV infections of up to 10%, depending on the time of year lockdown occurred. Lockdown had a more pronounced effect on the spatial distribution of DENV infections, with higher incidence under lockdown in regions with higher mosquito abundance. Transmission was also more focused in homes following lockdown. The proportion of people infected in their own home rose from 54% under normal conditions to 66% under lockdown, and the household secondary attack rate rose from 0.109 to 0.128, a 17% increase. When we considered that lockdown measures could disrupt regular, city-wide vector control campaigns, the increase in incidence was more pronounced than with lockdown alone, especially if lockdown occurred at the optimal time for vector control. Conclusions & significance Our results indicate that an unintended outcome of lockdown measures may be to adversely alter the epidemiology of dengue. This observation has important implications for an improved understanding of dengue epidemiology and effective application of dengue vector control. When coordinating public health responses during a syndemic, it is important to monitor multiple infections and understand that an intervention against one disease may exacerbate another.

UJI EFEKTIVITAS INFUSA DAUN SIRIH MERAH Piper crocatum ruiz TERHADAP MORTALITAS LARVA Aedes aegypti

Indonesia is known as a dengue-endemic country with an increasing number of cases. Appropriate dengue vector control efforts are needed to control the transmission of this disease effectively and efficiently. Botanical larvicide is one type of dengue vector control which is expected to be an alternative as a substitute for chemical larvicides. The purpose of this study was to determine the effect of red betel (Piper crocatum)infusion on the mortality of Ae. aegypti. True experimental design with post-test only with control group was used in this study. The test was carried out by dividing the sample into two groups, including the red betel infusion group and the control group (with aquadest), the observations were carried out for 24 hours. The results of the study showed that the larvacide test of red betel leaf infusion had an effect on 12 to 24 hours, and there was an increase in mortality of Ae. egypti for 24 hours. The humidity of the test room is one of the factors that can affect the results of the study. Abstrak Indonesia dikenal sebagai negara endemis dengue dengan jumlah kasus yang terus meningkat. Appropriate dengue vector control efforts diperlukan untuk mengendalikan penularan penyakit ini secara efektif dan efisien. Larvasida botani merupakan salah satu jenis pengendalian vektor dengue yang diharapkan dapat menjadi alternatif sebagai pengganti larvasida kimia. Tujuan penelitian ini untuk mengetahui pengaruh infusa sirih merah (Piper crocatum) terhadap mortalitas larva Ae. aegypti. True eksperimen design dengan post test only with control group digunakan dalam penelitian ini. Pengujian dilakukan dengan membagi menjadi dua kelompok sampel, meliputi kelompok infusa sirih merah dan kelompok kontrol (dengan Aquadest), pengamatan dilakukan selama 24 jam. Hasil studi menunjukkan Uji larvasida infusa daun sisrih merah berpengaruh pada 12 sampai dengan 24 jam, dan terdapat peningkatan mortalitas larva Ae. egypti selama 24 jam. Kelembaban ruangan uji menjadi salah satu faktor yang dapat mempengaruhi hasil studi.

Insecticide resistance in dengue vectors from hotspots in Selangor, Malaysia

Background In Malaysia, dengue remains a top priority disease and usage of insecticides is the main method for dengue vector control. Limited baseline insecticide resistance data in dengue hotspots has prompted us to conduct this study. The present study reports the use of a map on the insecticide susceptibility status of Aedes aegypti and Aedes albopictus to provide a quick visualization and overview of the distribution of insecticide resistance. Method and results The insecticide resistance status of Aedes populations collected from 24 dengue hotspot areas from the period of December 2018 until June 2019 was proactively monitored using the World Health Organization standard protocol for adult and larval susceptibility testing was conducted, together with elucidation of the mechanisms involved in observed resistance. For resistance monitoring, susceptibility to three adulticides (permethrin, deltamethrin, and malathion) was tested, as well as susceptibility to the larvicide, temephos. Data showed significant resistance to both deltamethrin and permethrin (pyrethroid insecticides), and to malathion (organophosphate insecticide) in all sampled Aedes aegypti populations, while variable resistance patterns were found in the sampled Aedes albopictus populations. Temephos resistance was observed when larvae were tested using the diagnostic dosage of 0.012mg/L but not at the operational dosage of 1mg/L for both species. Conclusion The present study highlights evidence of a potential threat to the effectiveness of insecticides currently used in dengue vector control, and the urgent requirement for insecticide resistance management to be integrated into the National Dengue Control Program.

Effect of community-based intervention on awareness of dengue and its prevention among urban poor community in India: a systematic review approach

Owing to increased epidemic activity and difficulties in controlling the insect vector, dengue has become a major public health problem globally. The prevention and control of dengue rely mainly on vector control methods. A systematic review was conducted using four databases (PubMed, Cochrane, Google Scholar and Scopus) and a manual search of the reference lists of the identified studies. Data from included studies were extracted, analyzed. Applying all inclusion and exclusion criteria 23 articles was included. Further relevant articles using this keywords Aedes dengue breeding habits housing and community intervention were selected. Eight studies combined community participation programme with dengue control tools. Findings of the published literature indicate that at baseline, almost half the respondents did not know that dengue is serious but preventable, or that it is transmitted by mosquitoes. The analysis showed that dengue vector control is carried out by vertically structured programmes of national, state, and local administrative bodies through fogging and larval control, without any involvement of community-based organizations, and that vector control efforts were conducted in an isolated and irregular way. The most productive container types for Aedes pupae were cement tanks, drums, and discarded containers. Evidence that community-based dengue control programmes alone and in combination with other control activities can enhance the effectiveness of dengue control programmes is weak. This review demonstrates a paucity of reliable evidence for the effectiveness of any dengue vector control method. Standardized studies of higher quality to evaluate and compare methods must be prioritized to optimize cost-effective dengue prevention. Clear best practice guidelines for the methodology of entomological studies should be developed.

The impacts of COVID-19 mitigation on dengue virus transmission: a modelling study

SummaryBackgroundThe COVID-19 pandemic has induced unprecedented reductions in human mobility and social contacts throughout the world. Because dengue virus (DENV) transmission is strongly driven by human mobility, behavioral changes associated with the pandemic have been hypothesized to impact dengue incidence. By discouraging human contact, COVID-19 control measures have also disrupted dengue vector control interventions, the most effective of which require entry into homes.MethodWe used an agent-based model with a realistic treatment of human mobility and vector control to investigate how and why dengue incidence could differ under a lockdown scenario with a proportion of the population sheltered at home.ResultWe found that a lockdown in which 70% of the population sheltered at home led to a small average increase in cumulative DENV infections of up to 10%, depending on the time of year lockdown occurred. Lockdown had a more pronounced effect on the spatial distribution of DENV infections, with higher incidence under lockdown in regions with high mosquito abundance. Transmission was also more focused in homes following lockdown. The proportion of people infected in their own home rose from 54% under normal conditions to 66% under lockdown, and the household secondary attack rate rose from 0.109 to 0.128, a 17% increase. When we considered that lockdown measures could disrupt regular, city-wide vector control campaigns, the increase in incidence was more pronounced than with lockdown alone, especially if lockdown occurred at the optimal time for vector control.DiscussionOur results indicate that an unintended outcome of COVID-19 control measures may be to adversely alter the epidemiology of dengue. This observation has important implications for an improved understanding of dengue epidemiology and effective application of dengue vector control. When coordinating public health responses during a syndemic, it is important to monitor multiple infections and understand that an intervention against one disease may exacerbate another.

The effectiveness of the One Health SMART approach on dengue vector control in Majalengka, Indonesia

PurposeThe purpose of this study was to apply the OH-SMART approach on dengue vector control and assess the influence on knowledge, attitude, practice (KAP) amongst elementary students in Majalengka as well as check the dengue serotypes distribution.Design/methodology/approachThis study was designed by sequential exploration. An OH-SMART workshop involving local government institutions, schools, colleges and health professional organizations was conducted. A total of 334 elementary students, chosen by cluster sampling, participated including 171 in the intervention group and 163 in the control group. A self-administered questionnaire was used to assess the differences in the subject's KAP. Dengue serotypes were analyzed by reverse transcription–polymerase chain reaction (RT-PCR), and the distribution was measured by GPS. Descriptive statistics, paired t-test and the Wilcoxon rank test were used for data analysis.FindingsThere were eight gaps in Dengue vector control in Majalengka and three main recommendations after the OH-SMART workshop i.e. the formation of OH-teams, the preparation of module training, and training of vector control in the schools. After the program, there were statistically significant differences between the intervention and control groups (p = 0,001, CI 95%). All differences in the intervention group were higher than in the control. The most commonly found dengue serotype was DEN-1.Originality/valueOH-SMART has never been applied in Indonesia, especially in a local government setting but is recognized as an effective approach in the prevention of vector-borne disease and zoonotic.