Attractive targeted sugar bait phase III trials in Kenya, Mali, and Zambia.

BACKGROUND: Long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) target night-time indoor biting mosquitoes and effectively reduce malaria transmission in rural settings across Africa, but additional vector control tools are needed to interrupt transmission. Attractive targeted sugar baits (ATSBs) attract and kill mosquitoes, including those biting outdoors. Deployment of ATSBs incorporating the insecticide dinotefuran was associated with major reductions in mosquito density and longevity in Mali. The impact of this promising intervention on malaria transmission and morbidity now needs to be determined in a range of transmission settings. METHODS/DESIGN: We will conduct three similar stand-alone, open-label, two-arm, cluster-randomized, controlled trials (cRCTs) in Mali, Kenya, and Zambia to determine the impact of ATSB + universal vector control versus universal vector control alone on clinical malaria. The trials will use a "fried-egg" design, with primary outcomes measured in the core area of each cluster to reduce spill-over effects. All household structures in the ATSB clusters will receive two ATSBs, but the impact will be measured in the core of clusters. Restricted randomization will be used. The primary outcome is clinical malaria incidence among children aged 5-14 years in Mali and 1-14 years in Kenya and Zambia. A key secondary outcome is malaria parasite prevalence across all ages. The trials will include 76 clusters (38 per arm) in Mali and 70 (35 per arm) in each of Kenya and Zambia. The trials are powered to detect a 30% reduction in clinical malaria, requiring a total of 3850 person-years of follow-up in Mali, 1260 person-years in Kenya, and 1610 person-years in Zambia. These sample sizes will be ascertained using two seasonal 8-month cohorts in Mali and two 6-month seasonal cohorts in Zambia. In Kenya, which has year-round transmission, four 6-month cohorts will be used (total 24 months of follow-up). The design allows for one interim analysis in Mali and Zambia and two in Kenya. DISCUSSION: Strengths of the design include the use of multiple study sites with different transmission patterns and a range of vectors to improve external validity, a large number of clusters within each trial site, restricted randomization, between-cluster separation to minimize contamination between study arms, and an adaptive trial design. Noted threats to internal validity include open-label design, risk of contamination between study arms, risk of imbalance of covariates across study arms, variation in durability of ATSB stations, and potential disruption resulting from the COVID-19 pandemic. TRIAL REGISTRATION: Zambia: ClinicalTrials.gov NCT04800055 . Registered on March 15, 2021 Mali: ClinicalTrials.gov NCT04149119 . Registered on November 4, 2019 Kenya: ClinicalTrials.gov NCT05219565 . Registered on February 2, 2022.

Changes and correlation of dengue fever epidemic and Aedes albopictus density in Haizhu district, Guangzhou before and after the COVID-19 pandemic

To analyze the population density, seasonal fluctuation of Aedes albopictus in Haizhu District, Guangzhou from 2017 to 2021, so as to provide a scientific basis for the monitoring and prevention and control of mosquito vector density of dengue fever. The data of dengue fever cases and Aedes surveillance data in Haizhu District, Guangzhou from 2017 to 2021 were collected, and the data of 2017-2019 and 2020-2021 were grouped to compare and analyze the characteristics of dengue epidemic and the density fluctuation of Aedes mosquitoes. A total of 517 dengue cases were reported in Haizhu District, Guangzhou from 2017 to 2021, of which only 7 cases were reported from 2020 to 2021, and the peak period of reported cases every year was August to November. Before the COVID-19 pandemic, there was a positive correlation between the number of local cases and the number of imported cases(rs=0.63, P<0.05) and BI(rs=0.73, P<0.05). The peak density of Aedes was from May to October, and the differences of mean BI(X~2=1 143.40,P<0.001), MOI(X~2=188.30,P<0.001), and SSI(X~2=4 499.43,P<0.001)before and after the COVID-19 pandemic were statistically significant. In general, before and after the COVID-19 pandemic, the density of Aedes in high-risk areas was higher than that in low-risk areas. After COVID-19 pandemic, the number of reported cases and the density of Aedes in Haizhu District decreased, but the density of Aedes in the high-risk area was still higher than that in low-risk areas, and a certain risk of outbreak still existed, so the government should continue to take more precise measures to strictly prevent dengue epidemic.

Listen to the shopkeeper.

His mosquito control project heading for failure, a field entomologist recalls how a chance encounter led to a Eureka moment.

Development and user testing study of MozzHub: a bipartite network-based dengue hotspot detector.

Traditionally, dengue is controlled by fogging, and the prime location for the control measure is at the patient's residence. However, when Malaysia was hit by the first wave of the Coronavirus disease (COVID-19), and the government-imposed movement control order, dengue cases have decreased by more than 30% from the previous year. This implies that residential areas may not be the prime locations for dengue-infected mosquitoes. The existing early warning system was focused on temporal prediction wherein the lack of consideration for spatial component at the microlevel and human mobility were not considered. Thus, we developed MozzHub, which is a web-based application system based on the bipartite network-based dengue model that is focused on identifying the source of dengue infection at a small spatial level (400 m) by integrating human mobility and environmental predictors. The model was earlier developed and validated; therefore, this study presents the design and implementation of the MozzHub system and the results of a preliminary pilot test and user acceptance of MozzHub in six district health offices in Malaysia. It was found that the MozzHub system is well received by the sample of end-users as it was demonstrated as a useful (77.4%), easy-to-operate system (80.6%), and has achieved adequate client satisfaction for its use (74.2%).

What Is the Impact of Lockdowns on Dengue?

PURPOSE OF REVIEW: Societal lockdowns in response to the COVID-19 pandemic have led to unprecedented disruption to daily life across the globe. A collateral effect of these lockdowns may be a change to transmission dynamics of a wide range of infectious diseases that are all highly dependent on rates of contact between humans. With timing, duration and intensity of lockdowns varying country-to-country, the wave of lockdowns in 2020 present a unique opportunity to observe how changes in human contact rates, disease control and surveillance affect dengue virus transmission in a global natural experiment. We explore the theoretical basis for the impact of lockdowns on dengue transmission and surveillance then summarise the current evidence base from country reports. RECENT FINDINGS: We find considerable variation in the intensity of dengue epidemics reported so far in 2020 with some countries experiencing historic low levels of transmission while others are seeing record outbreaks. Despite many studies warning of the risks of lockdown for dengue transmission, few empirically quantify the impact and issues such as the specific timing of the lockdowns and multi-annual cycles of dengue are not accounted for. In the few studies where such issues have been accounted for, the impact of lockdowns on dengue appears to be limited. SUMMARY: Studying the impact of lockdowns on dengue transmission is important both in how we deal with the immediate COVID-19 and dengue crisis, but also over the coming years in the post-pandemic recovery period. It is clear lockdowns have had very different impacts in different settings. Further analyses might ultimately allow this unique natural experiment to provide insights into how to better control dengue that will ultimately lead to better long-term control.

Rapid Appraisals of the Transformation Strategy Required to Sustain Dengue Vector Control During and After the COVID-19 Pandemic in Indonesia.

Purpose: This research aimed to observe the gap for improvement in dengue vector control during COVID-19, considering two stakeholders: the government and society. We formulated two research questions: 1) How is the government managing dengue vector control during the COVID-19 pandemic? 2) What is the situation of dengue disease, its vectors, and vector control in the community? Methods: This study uses multiple approaches: policy review, social listening using Twitter analysis, and interviews. A policy review was employed to capture the journey of dengue vector control in Indonesia from dengue found in Indonesia until the COVID-19 pandemic. Twitter data captured public opinions through social media about dengue and vector control. Interviews involved program implementers that consider knowing the situation in the field of dengue and its vector control. The informant was selected through purposive sampling. Results: To control dengue disease, the Indonesian government has released regulations about dengue vector control that adjusts the COVID-19 situation, but vector control is still not running optimally, resulting in the data supply for policy not running well. Conclusion: Dengue cases continued during the COVID-19 pandemic, even in some places stated an outbreak occurred. Vector control does not work correctly during the COVID-19 pandemic due to social restrictions. It is recommended to encourage the implementation of community empowerment through one house, one jumantik, which is equipped with self-reporting to mitigate and respond to similar situations as the pandemic.

Increasing Dengue Burden and Severe Dengue Risk in Bangladesh: An Overview.

Dengue is a prevalent and rapidly spreading mosquito-borne viral disease affecting humans. The geographic range of dengue is expanding, and much like in many other tropical regions of the world, dengue has become a major public health issue in Bangladesh. Until a large epidemic dengue outbreak in 2000, sporadic outbreaks have occurred in Bangladesh since 1964. After 2000, varying intensities of dengue activity were observed each year until 2018. However, in 2019, Bangladesh experienced the largest dengue epidemic in its history, with 101,354 dengue cases and 164 dengue-related deaths. Notably, this outbreak occurred in many regions that were previously considered free of the disease. As of 10 December 2022, a total of 60,078 dengue cases and 266 dengue-related deaths were reported in Bangladesh, with the 2022 outbreak being the second largest since 2000. There is an increased genetic diversity of the dengue virus (DENV) in Bangladesh and all four DENV serotypes are prevalent and co-circulating, which increases the risk for severe dengue owing to the antibody-dependent enhancement effect. Vector control remains the mainstay of dengue outbreak prevention; however, the vector control programs adopted in Bangladesh seem inadequate, requiring improved vector control strategies. In this review, we provide an overview of the epidemiology of DENV infection and the risks for a severe dengue outbreak in Bangladesh. Additionally, we discuss different dengue vector control strategies, from which the most suitable and effective measures can be applied in the context of Bangladesh for tackling future dengue epidemics.

The normalization of COVID-19 epidemic prevention and control calls for patriotic health campaign inherit and innovation

In order to summarize the experience of COVID-19 prevention and control, review the glorious course of the 70th anniversary of China's patriotic health campaign, and realize the Healthy China. This paper summarizes the great achievements of China's patriotic health campaign in the past 70 years, and reviews the trend of sustainable vector management, especially the progress of China and Zhejiang Province in the construction of patriotic health campaign organization, vector monitoring, early warning, informatization, prevention and control and research work in the last 10 years. The results found that the patriotic health campaign has significantly improved the health level of the Chinese people. Zhejiang Province has demonstrated and led the comprehensive monitoring of vector and vector infectious diseases, and exploration of sustainable vectors management in rural area, first to carry out the "construction of eliminate four vector villages focusing on mosquito-free and fly-free", and promoted the patriotic health campaign at a high level. The paper considers that the patriotic health campaign is a successful practice of our Party's mass line to health prevention. The experience of COVID-19 prevention and control shows that, Prevention and control the communicable disease needs the concept of patriotic health campaign and the support of public health, all for the people's health, The Times call for a patriotic health campaign with Inheritance of history, rich connotation and innovative methods. We must re-understand the extreme importance of communicable disease prevention and control, pay more attention to the potential harm of vectors in the cross-species transmission of communicable diseases, give full play to the unique role of patriotic health campaign in disease prevention and control and safeguarding people's health, and accelerate the Healthy China action.

The strategies of "early detection, early report, early assessment, and early control" in vector prevention and control

Since the outbreak of coronavirus disease 2019 (COVID-19), the social prevention and control measures of "early detection, early report, early isolation, and early treatment" have been widely used in the public health field and are widely accepted by the general public. In the practice of integrated vector management, Henan province gives full play to the advantages of mobilization and coordination of the Patriotic Health Campaign, establishes a work path of "early detection, early report, early assessment, and early control", the strategies of "four early". It defines the responsibilities of government, departments, territories, and individuals, and clarifies the working concepts of integrated vector management, which helps to form societal forces and promote the development of vector control in Henan province. This article analyzes the strategies of "four early" in integrated vector management in Henan province, in order to provide a reference for vector management strategies in China.

Addressing the COVID-19 pandemic challenges for operational adaptations of a cluster randomized controlled trial on dengue vector control in Malaysia.

INTRODUCTION: The COVID-19 pandemic placed an unprecedented overload on healthcare system globally. With all medical resources being dedicated to contain the spread of the disease, the pandemic may have impacted the burden of other infectious diseases such as dengue, particularly in countries endemic for dengue fever. Indeed, the co-occurrence of COVID-19 made dengue diagnosis challenging because of some shared clinical manifestations between the two pathogens. Furthermore, the sudden emergence and novelty of this global public health crisis has forced the suspension or slow-down of several research trials due to the lack of sufficient knowledge on how to handle the continuity of research trials during the pandemic. We report on challenges we have faced during the COVID-19 pandemic and measures that were implemented to continue the iDEM project (intervention for Dengue Epidemiology in Malaysia). METHODS: This randomized controlled trial aims to assess the effectiveness of Integrated Vector Management (IVM) on the incidence of dengue in urban Malaysia by combining: targeted outdoor residual spraying (TORS), deployment of auto-dissemination devices (ADDs), and active community engagement (CE). Our operational activities started on February 10, 2020, a few weeks before the implementation of non-pharmaceutical interventions to contain the spread of COVID-19 in Malaysia. RESULTS: The three main issues affecting the continuity of the trial were: ensuring the safety of field workers during the interventions; ensuring the planned turnover of TORS application and ADD deployment and services; and maintaining the CE activities as far as possible. CONCLUSIONS: Even though the pandemic has created monumental challenges, we ensured the safety of field workers by providing complete personal protective equipment and regular COVID-19 testing. Albeit with delay, we maintained the planned interval time between TORS application and ADDs services by overlapping the intervention cycles instead of having them in a sequential scheme. CE activities continued remotely through several channels (e.g., phone calls and text messages). Sustained efforts of the management team, significant involvement of the Malaysian Ministry of Health and a quick and smart adaptation of the trial organisation according to the pandemic situation were the main factors that allowed the successful continuation of our research. TRIAL REGISTRATION: Trial registration number: ISRCTN-81915073 . Date of registration: 17/04/2020, 'Retrospectively registered'.

The Phylodynamic and Spread of the Invasive Asian Malaria Vectors, Anopheles stephensi, in Sudan.

Anopheles stephensi is an invasive Asian malaria vector that initially emerged in Africa in 2012 and was reported in Sudan in 2019. We investigated the distribution and population structure of An. stephensi throughout Sudan by using sequencing and molecular tools. We confirmed the presence of An. stephensi in eight border-states, identifying both natural and human-made breeding sites. Our analysis revealed the presence of 20 haplotypes with different distributions per state. This study revealed a countrywide spread of An. stephensi in Sudan, with confirmed presence in borders states with Chad, Egypt, Eritrea, Ethiopia, Libya, Republic of Central Africa, and South Sudan. Detection of An. stephensi at points of entry with these countries, particularly Chad, Libya, and South Sudan, indicates the rapid previously undetected spread of this invasive vector. Our phylogenetic and haplotype analysis suggested local establishment and evolutionary adaptation of the vector to different ecological and environmental conditions in Sudan. Urgent engagement of the global community is essential to control and prevent further spread into Africa.

Patterns of Kdr-L995F Allele Emergence Alongside Detoxifying Enzymes Associated with Deltamethrin Resistance in Anopheles gambiae s.l. from North Cameroon.

Understanding how multiple insecticide resistance mechanisms occur in malaria vectors is essential for efficient vector control. This study aimed at assessing the evolution of metabolic mechanisms and Kdr L995F/S resistance alleles in Anopheles gambiae s.l. from North Cameroon, following long-lasting insecticidal nets (LLINs) distribution in 2011. Female An. gambiae s.l. emerging from larvae collected in Ouro-Housso/Kanadi, Be-Centre, and Bala in 2011 and 2015, were tested for susceptibility to deltamethrin + piperonyl butoxide (PBO) or SSS-tributyl-phosphoro-thrithioate (DEF) synergists, using the World Health Organization's standard protocol. The Kdr L995F/S alleles were genotyped using Hot Ligation Oligonucleotide Assay. Tested mosquitoes identified using PCR-RFLP were composed of An. arabiensis (68.5%), An. coluzzii (25.5%) and An. gambiae (6%) species. From 2011 to 2015, metabolic resistance increased in Ouro-Housso/Kanadi (up to 89.5% mortality to deltametnrin+synergists in 2015 versus <65% in 2011; p < 0.02), while it decreased in Be-Centre and Bala (>95% mortality in 2011 versus 42-94% in 2015; p < 0.001). Conversely, the Kdr L995F allelic frequencies slightly decreased in Ouro-Housso/Kanadi (from 50% to 46%, p > 0.9), while significantly increasing in Be-Centre and Bala (from 0-13% to 18-36%, p < 0.02). These data revealed two evolutionary trends of deltamethrin resistance mechanisms; non-pyrethroid vector control tools should supplement LLINs in North Cameroon.

Update of transmission modelling and projections of gambiense human African trypanosomiasis in the Mandoul focus, Chad.

BACKGROUND: In recent years, a programme of vector control, screening and treatment of gambiense human African trypanosomiasis (gHAT) infections led to a rapid decline in cases in the Mandoul focus of Chad. To represent the biology of transmission between humans and tsetse, we previously developed a mechanistic transmission model, fitted to data between 2000 and 2013 which suggested that transmission was interrupted by 2015. The present study outlines refinements to the model to: (1) Assess whether elimination of transmission has already been achieved despite low-level case reporting; (2) quantify the role of intensified interventions in transmission reduction; and (3) predict the trajectory of gHAT in Mandoul for the next decade under different strategies. METHOD: Our previous gHAT transmission model for Mandoul was updated using human case data (2000-2019) and a series of model refinements. These include how diagnostic specificity is incorporated into the model and improvements to the fitting method (increased variance in observed case reporting and how underreporting and improvements to passive screening are captured). A side-by-side comparison of fitting to case data was performed between the models. RESULTS: We estimated that passive detection rates have increased due to improvements in diagnostic availability in fixed health facilities since 2015, by 2.1-fold for stage 1 detection, and 1.5-fold for stage 2. We find that whilst the diagnostic algorithm for active screening is estimated to be highly specific (95% credible interval (CI) 99.9-100%, Specificity = 99.9%), the high screening and low infection levels mean that some recently reported cases with no parasitological confirmation might be false positives. We also find that the focus-wide tsetse reduction estimated through model fitting (95% CI 96.1-99.6%, Reduction = 99.1%) is comparable to the reduction previously measured by the decline in tsetse catches from monitoring traps. In line with previous results, the model suggests that transmission was interrupted in 2015 due to intensified interventions. CONCLUSIONS: We recommend that additional confirmatory testing is performed in Mandoul to ensure the endgame can be carefully monitored. More specific measurement of cases, would better inform when it is safe to stop active screening and vector control, provided there is a strong passive surveillance system in place.

World malaria report 2021

The World Health Organization (WHO) World Malaria Report 2021 < https://www.who.int/publications/i/item/9789240040496 > estimates that there were 241 million malaria cases, including 627,000 deaths, worldwide in 2020, which represents around 14 million more cases, and 69,000 more deaths, than 2019. Approximately two-thirds of these additional deaths were linked to disruptions in the provision of malaria prevention, diagnosis and treatment during the COVID-19 pandemic. Sub-Saharan Africa continues to carry the heaviest malaria burden, accounting for about 95% of all cases and 96% of all deaths in 2020, with around 80% of deaths in the region among children under five years old. Since 2015, the baseline date for the WHO's global malaria strategy, registered increases in malaria deaths were reported in 24 countries. In the 11 countries that carry the highest burden of malaria worldwide, cases increased from 150 million in 2015 to 163 million cases in 2020, and malaria deaths increased from 390,000 to 444,600 over that same period. As in previous years, the report includes an up-to-date assessment on the burden of malaria at global, regional, and country levels, and tracks investment in malaria programmes and research, as well as detailing progress across the four intervention areas of prevention, diagnosis, treatment and surveillance. There are also dedicated chapters on malaria elimination and key threats, such as insecticide and drug resistance.

A practical approach for geographic prioritization and targeting of insecticide-treated net distribution campaigns during public health emergencies and in resource-limited settings.

BACKGROUND: The use of data in targeting malaria control efforts is essential for optimal use of resources. This work provides a practical mechanism for prioritizing geographic areas for insecticide-treated net (ITN) distribution campaigns in settings with limited resources. METHODS: A GIS-based weighted approach was adopted to categorize and rank administrative units based on data that can be applied in various country contexts where Plasmodium falciparum transmission is reported. Malaria intervention and risk factors were used to rank local government areas (LGAs) in Nigeria for prioritization during mass ITN distribution campaigns. Each factor was assigned a unique weight that was obtained through application of the analytic hierarchy process (AHP). The weight was then multiplied by a value based on natural groupings inherent in the data, or the presence or absence of a given intervention. Risk scores for each factor were then summated to generate a composite unique risk score for each LGA. This risk score was translated into a prioritization map which ranks each LGA from low to high priority in terms of timing of ITN distributions. RESULTS: A case study using data from Nigeria showed that a major component that influenced the prioritization scheme was ITN access. Sensitivity analysis results indicate that changes to the methodology used to quantify ITN access did not modify outputs substantially. Some 120 LGAs were categorized as 'extremely high' or 'high' priority when a spatially interpolated ITN access layer was used. When prioritization scores were calculated using DHS-reported state level ITN access, 108 (90.0%) of the 120 LGAs were also categorized as being extremely high or high priority. The geospatial heterogeneity found among input risk factors suggests that a range of variables and covariates should be considered when using data to inform ITN distributions. CONCLUSION: The authors provide a tool for prioritizing regions in terms of timing of ITN distributions. It serves as a base upon which a wider range of vector control interventions could be targeted. Its value added can be found in its potential for application in multiple country contexts, expediated timeframe for producing outputs, and its use of systematically collected malaria indicators in informing prioritization.

Impact of climate variability and incidence on dengue hemorrhagic fever in palembang city, south sumatra, indonesia

BACKGROUND: Dengue hemorrhagic fever (DHF) is a dengue virus infection transmitted by Aedes spp. Climate has a profound influence on mosquito breeding. Palembang has the highest rate of DHF in South Sumatra. AIM: This study aimed to investigate the relationship between the components of climate factors and the incidence of DHF in Palembang. METHODS: This study was cross sectional, with an observational analytic approach. The Palembang City Health Office compiled data on DHF incidence rates from 2016 to 2020. Climatic factor data (rainfall, number of rainy days, temperature, humidity, wind speed, and sun irradiance) were collected from the Climatology Station Class I Palembang – BMKG Station and Task Force that same year. The Spearman test was used to conduct the correlation test. RESULTS: Between 2016 and 2020, there were 3398 DHF patients. From January to May, DHF increased. There was a significant correlation between rainfall (r = 0.320;p = 0.005), number of rainy days (r = 0.295;p = 0.020), temperature (r = 0.371;p = 0.040), and humidity (r = 0.221;p = 0.024), wind speed (r = 0.76;p = 0.492), and sunlight (r = 0.008;p = 0.865). CONCLUSION: Rainfall, the number of rainy days, and temperature were three climatic factors determining the increase in dengue incidence. Vector control approach must start around October, 2 months before the high DHF cases in Palembang.

The need for practical insecticide-resistance guidelines to effectively inform mosquito-borne disease control programs.

Monitoring local mosquito populations for insecticide resistance is critical for effective vector-borne disease control. However, widely used phenotypic assays, which are designed to monitor the emergence and spread of insecticide resistance (technical resistance), do not translate well to the efficacy of vector control products to suppress mosquito numbers in the field (practical resistance). This is because standard testing conditions such as environmental conditions, exposure dose, and type of substrate differ dramatically from those experienced by mosquitoes under field conditions. In addition, field mosquitoes have considerably different physiological characteristics such as age and blood-feeding status. Beyond this, indirect impacts of insecticide resistance and/or exposure on mosquito longevity, pathogen development, host-seeking behavior, and blood-feeding success impact disease transmission. Given the limited number of active ingredients currently available and the observed discordance between resistance and disease transmission, we conclude that additional testing guidelines are needed to determine practical resistance-the efficacy of vector control tools under relevant local conditions- in order to obtain programmatic impact.