Control Of Vector-borne Diseases Research Articles

Exploring community participation in vectorborne disease control in Southeast Asia: a scoping review protocol

IntroductionVector borne diseases (VBDs) present significant public health challenges in Southeast Asia (SEA), and the increasing number of cases threatens vulnerable communities. Inadequate vector control and management have been linked...

Epidemiological Trends of Dengue in One of the Western Hilly Areas of Himachal Pradesh

Background: Dengue is one of the neglected tropical diseases, with a wide spectrum of diseases, ranging from acute febrile illness dengue fever to life-threatening dengue hemorrhagic fever or dengue shock syndrome. In recent years, it has become a major public health concern in many nonendemic areas as well. Materials and Methods: A secondary data analysis of records available with district Integrated Disease Surveillance Programme cell was conducted to study distribution (time, place, and person) of dengue from 2017 to 2022 in Kangra, a sub-Himalayan district of Himachal Pradesh (HP). Results: In the evaluated period (2017–2022), a total of 6008 cases suspected of dengue were tested and test positivity of 7% (441) with male gender predominance was found. Mean age of the diagnosed cases was 37.7 ± 16.8 years. A seasonal trend was observed starting from late August to November in all study years. Conclusion: Dengue is still a neglected disease, but it has shown its presence especially in this part of HP, indicating the need for better preparation and sensitization of vector-borne disease control program activities, especially in post-monsoon, to prevent future epidemics.

Modeling and stability analysis of the transmission dynamics of Monkeypox with control intervention

Monkeypox is a deadly disease from the Orthopox family. The paper explores a nonlinear trend in the dynamics of Monkeypox propagation. In this model, we include vaccination, treatment, and level of awareness as the main parameters of the propagation of Monkeypox. We also include the quarantined infected individuals with severe complications in the Monkeypox dynamics. We show the boundedness and positivity of the model and also demonstrate the stability of the model using the Banach fixed point theory and the Picard successive approximation method to ensure that it is meaningful mathematically and epidemiologically. We obtain the unique solution of the model under appropriate conditions. This work finds three equilibrium points: Monkeypox free, Rodents free, and endemic. We show the local stability of monkeypox free equilibria and rodent-free endemic equilibria through reproduction number. Furthermore, Dulac’s function technique demonstrates the global stability of endemic equilibrium. We show the transformation from endemic equilibria to Monkeypox-free equilibria via rodent-free. We also obtain the condition of transcritical bifurcation. We analyze the system’s dynamic behavior to develop efficient infection control strategies. We find that if we increase awareness, vaccination, treatment, and quarantine rates, we effectively control the transmission. The model is connected with a continuous model using an ordinary differential equation. We examine the complex dynamics of Monkeypox infection under diverse system input factors through numerical simulation of the proposed model with variable input parameters in reducing Monkeypox. We present the theory of Monkeypox disease control in humankind as an application in real-world problems. The work can be helpful in the vector-borne disease control system.

Transcriptomic Investigation of the Virus Spectrum Carried by Midges in Border Areas of Yunnan Province.

Yunnan province in China shares its borders with three neighboring countries: Myanmar, Vietnam, and Laos. The region is characterized by a diverse climate and is known to be a suitable habitat for various arthropods, including midges which are notorious for transmitting diseases which pose significant health burdens affecting both human and animal health. A total of 431,100 midges were collected from 15 different locations in the border region of Yunnan province from 2015 to 2020. These midges were divided into 37 groups according to the collection year and sampling site. These 37 groups of midges were then homogenized to extract nucleic acid. Metatranscriptomics were used to analyze their viromes. Based on the obtained cytochrome C oxidase I gene (COI) sequences, three genera were identified, including one species of Forcipomyia, one species of Dasyhelea, and twenty-five species of Culicoides. We identified a total of 3199 viruses in five orders and 12 families, including 1305 single-stranded positive-stranded RNA viruses (+ssRNA) in two orders and seven families, 175 single-stranded negative-stranded RNA viruses (-ssRNA) in two orders and one family, and 1719 double-stranded RNA viruses in five families. Six arboviruses of economic importance were identified, namely Banna virus (BAV), Japanese encephalitis virus (JEV), Akabane virus (AKV), Bluetongue virus (BTV), Tibetan circovirus (TIBOV), and Epizootic hemorrhagic disease virus (EHDV), all of which are capable, to varying extents, of causing disease in humans and/or animals. The survey sites in this study basically covered the current distribution area of midges in Yunnan province, which helps to predict the geographic expansion of midge species. The complexity and diversity of the viral spectrum carried by midges identified in the study calls for more in-depth research, which can be utilized to monitor arthropod vectors and to predict the emergence and spread of zoonoses and animal epidemics, which is of great significance for the control of vector-borne diseases.

Perceived needs of disease vector control programs: A review and synthesis of (sub)national assessments from South Asia and the Middle East.

Systems for disease vector control should be effective, efficient, and flexible to be able to tackle contemporary challenges and threats in the control and elimination of vector-borne diseases. As a priority activity towards the strengthening of vector control systems, it has been advocated that countries conduct a vector-control needs assessment. A review was carried out of the perceived needs for disease vector control programs among eleven countries and subnational states in South Asia and the Middle East. In each country or state, independent teams conducted vector control needs assessment with engagement of stakeholders. Important weaknesses were described for malaria, dengue and leishmaniases regarding vector surveillance, insecticide susceptibility testing, monitoring and evaluation of operations, entomological capacity and laboratory infrastructure. In addition, community mobilization and intersectoral collaboration showed important gaps. Countries and states expressed concern about insecticide resistance that could reduce the continued effectiveness of interventions, which demands improved monitoring. Moreover, attainment of disease elimination necessitates enhanced vector surveillance. Vector control needs assessment provided a useful planning tool for systematic strengthening of vector control systems. A limitation in conducting the vector control needs assessment was that it is time- and resource-intensive. To increase the feasibility and utility of national assessments, an abridged version of the guidance should focus on operationally relevant topics of the assessment. Similar reviews are needed in other regions with different contextual conditions.

Chemical Exposure of Synthetic Pyrethroid on Deltamethrin Under the Selection Pressure over the Generations: A Reproductive Potential Study of Anopheles stephensi.

Biochemical synthetic pyrethroids, deltamethrin are presently used insecticides for the control of mosquito vector-borne diseases in worldwide. Mosquito re-emergence with diseases becoming a serious problem due to development of insecticide resistance. The comprehensive knowledge on the underlying mechanisms of resistance against deltamethrin is required for implementation of an efficient vector control programme. The assessment of the biological fitness of a mosquito strain exposed to insecticide pressure is extremely vital because it provides information on the development of resistance. In the present study, the adult stage of malaria vector, Anopheles stephensi, was designated for the study of deltamethrin resistance (F40 generations). The non-blood-fed, laboratory-reared females to sub-lethal doses of deltamethrin (0.004%, 0.005%, 0.007%, or 0.01%) exposed to every generation for up to F40. The adult mosquito susceptibility was performed by WHO standard method for evaluation. After 24h, mortality was recorded in both treated and control groups. Therefore, the biological fitness characteristics such as feeding, fecundity, hatchability, egg retention, immature duration, adult emergence, and adult life span were studied to assess the exposed deltamethrin under selection pressure as compared to the unexposed (control) population. The laboratory selection of An. stephensi exposed deltamethrin over the generations were diminished its biological fitness. Information on biological fitness including reproductive potential of mosquito strain under selection pressure against deltamethrin is incredibly necessary because it would facilitate in resistance management. Baseline information gives in this experiment will guide for future studies on the susceptibilities of wild malaria mosquito populations in India.

Insecticide Susceptibility and KDR Mutations in Aedes Albopictus Collected from Seven Districts of Guangyuan city, Northern Sichuan, China.

The Asian tiger mosquito, Aedes albopictus, is an important vector of chikungunya, dengue, yellow fever, and Zika viruses. Vector control remains an important means for the prevention and control of vector-borne diseases. The development of insecticide resistance has become a serious threat to the efficacy of insecticide-based control programs. To understand the resistance status and the underlying genetic mechanism in mosquitoes in Guangyuan City of Sichuan Province, China, we investigated the susceptibility of Ae. albopictus to four commonly used insecticides. We found that all the examined populations were susceptible to malathion and propoxur. However, Ae. albopictus populations in Guangyuan showed a possible resistance to the two tested pyrethroids (beta-cypermethrin and deltamethrin). Notably, phenotypic resistance to deltamethrin was detected in 2 of the 7 populations. The potential of resistance to pyrethroids was confirmed by the presence of knockdown resistance (kdr) related mutations in the voltage-gated sodium channel. Four kdr mutations (V1016G, I1532T, F1534L, and F1534S) were identified to be present alone or in combination, and their distribution displayed significant spatial heterogeneity. These findings are helpful for making evidence-based mosquito control strategies and highlight the need to regularly monitor the dynamics of pyrethroid resistance in this city.

A randomised controlled trial to compare the efficacy, safety, and tolerability of low dose, short course primaquine in adults with uncomplicated P. vivax malaria in two hospitals in India

BackgroundPlasmodium vivax remains a major challenge for malaria control and elimination due to its ability to cause relapsing illness. To prevent relapses the Indian National Center for Vector Borne Diseases Control (NCVBDC) recommends treatment with primaquine at a dose of 0.25 mg/kg/day provided over 14 days. Shorter treatment courses may improve adherence and treatment effectiveness.MethodsThis is a hospital-based, randomised, controlled, open-label trial in two centres in India. Patients above the age of 16 years, with uncomplicated vivax malaria, G6PD activity of ≥ 30% of the adjusted male median (AMM) and haemoglobin levels ≥ 8 g/dL will be recruited into the study and randomised in a 1:1 ratio to receive standard schizonticidal treatment plus 7-day primaquine at 0.50 mg/kg/day or standard care with schizonticidal treatment plus 14-day primaquine at 0.25 mg/kg/day. Patients will be followed up for 6 months. The primary endpoint is the incidence risk of any P. vivax parasitaemia at 6 months. Safety outcomes include the incidence risk of severe anaemia (haemoglobin < 8 g/dL), the risk of blood transfusion, a > 25% fall in haemoglobin and an acute drop in haemoglobin of > 5 g/dL during primaquine treatment.DiscussionThis study will evaluate the efficacy and safety of a 7-day primaquine regimen compared to the standard 14-day regimen in India. Results from this trial are likely to directly inform national treatment guidelines.Trial registrationTrial is registered on CTRI portal, Registration No: CTRI/2022/12/048283.

A Qualitative Analysis of the Perceptions of Stakeholders Involved in Vector Control and Vector-Borne Disease Research and Surveillance in Orinoquia, Colombia.

Colombia has a tropical climate and environmental conditions that favour the circulation of most of the known vector-borne diseases (VBDs). Protocols have been established and implemented to address the threats of these diseases, but they are for country-wide use and do not take into consideration the nuances of the different environments of the country. Almost the entire population is vulnerable to infection with one or more VBD. This study aims to characterise the perceptions and experiences of stakeholders involved in vector control and VBDs in the Orinoquia region in Colombia. Two panel discussions, and 12 semi-structured interviews, were conducted. Experts from the Colombian National Health Institute (INS), health secretaries from Meta, Guaviare and Vichada Departments, academic researchers, and individuals from private vector control companies participated. All sessions were recorded, transcribed, and translated, and then subject to thematic analysis. Three major themes emerged: involvement, limitations, and recommendations. Results showed that participants are engaged in vector surveillance activities, education, and vector control research. Participants focused on problems of disjointed efforts towards VBD control between health secretaries and the health ministry, as well as societal issues, such as socioeconomic, cultural, and political issues, which became the rationale for the lack of vector control resources. Responses in the panel discussions and interviews overlapped in opinions, and suggested that vector control could be improved through better communication between vector control bodies, strengthened engagement with vulnerable communities, more collaborative actions, and a more balanced distribution of resources.

Assess the Level of Knowledge Regarding Prevention and Control of Vector Borne Diseases among Farmers

Assess the Level of Knowledge Regarding Prevention and Control of Vector Borne Diseases among Farmers

MBORS: Mosquito vector Biocontrol Ontology and Recommendation System

Background &amp; objectives: Mosquito vectors are disease-causing insects, responsible for various life-threatening vector-borne diseases such as dengue, Zika, malaria, chikungunya, and lymphatic filariasis. In practice, synthetic insecticides are used to control the mosquito vector, but, the continuous usage of synthetic insecticides is toxic to human health resulting in communicable diseases. Non-toxic biocontrol agents such as bacteria, fungus, plants, and mosquito densoviruses play a vital role in controlling mosquitoes. Community awareness of mosquito biocontrol agents is required to control vector-borne diseases. Mosquito vector-based ontology facilitates mosquito biocontrol by providing information such as species names, pathogen-associated diseases, and biological controlling agents. It helps to explore the associations among the mosquitoes and their biocontrol agents in the form of rules. The Mosquito vector-based Biocontrol Ontology Recommendation System (MBORS) provides the knowledge on mosquito-associated biocontrol agents to control the vector at the early stage of the mosquitoes such as eggs, larvae, pupae, and adults. This paper proposes MBORS for the prevention and effective control of vector-borne diseases. The Mosquito Vector Association ontology (MVAont) suggests the appropriate mosquito vector biocontrol agents (MosqVecRS) for related diseases. Methods: Natural Language Processing and Data mining are employed to develop the MBORS. While Tokenization, Part-of-speech Tagging (POS), Named Entity Recognition (NER), and rule-based text mining techniques are used to identify the mosquito ontology concepts, the data mining apriori algorithm is used to predict the associations among them. Results: The outcome of the MBORS results in MVAont as Web Ontology Language (OWL) representation and MosqVecRS as an Android application. The developed ontology and recommendation system are freely available on the web portal. Interpretation &amp; conclusion: The MVAont predicts harmless biocontrol agents which help to diminish the rate of vector-borne diseases. On the other hand, the MosqVecRS system raises awareness of vectors and vector-borne diseases by recommending suitable biocontrol agents to the vector control community and researchers.

An update and review of arthropod vector sensory systems: Potential targets for behavioural manipulation by parasites and other disease agents.

For over a century, vector ecology has been a mainstay of vector-borne disease control. Much of this research has focused on the sensory ecology of blood-feeding arthropods (black flies, mosquitoes, ticks, etc.) with terrestrial vertebrate hosts. Of particular interest are the cues and sensory systems that drive host seeking and host feeding behaviours as they are critical for a vector to locate and feed from a host. An important yet overlooked component of arthropod vector ecology are the phenotypic changes observed in infected vectors that increase disease transmission. While our fundamental understanding of sensory mechanisms in disease vectors has drastically increased due to recent advances in genome engineering, for example, the advent of CRISPR-Cas9, and high-throughput "big data" approaches (genomics, proteomics, transcriptomics, etc.), we still do not know if and how parasites manipulate vector behaviour. Here, we review the latest research on arthropod vector sensory systems and propose key mechanisms that disease agents may alter to increase transmission.

Role of homoeopathy of Ayush in dengue fever

In 21st century, dengue came to the limelight. Earlier, it was taught that this is one of the eruptive fevers in human beings where in dengue, the eruption appears typically on the 6th day of the fever. Knowledge and approaches to dengue took a paradigm shift in 21st century. It came to be clubbed under the National Vector Borne Disease Control Program. A mosquito borne single stranded RNA virus is the leading cause of arthropod borne viral diseases like dengue globally. All the types of dengue virus are capable of inducing severe diseases like dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). No one wants to be in DHF or DSS stage as these are mortal stages while other stages are morbid. A vector borne disease (VBD) transmitted by mosquito has no specific cure in modern medicine. To add to that, the issue of platelet transfusion that is made universal because of the inherent panic does more harm than good. It is here that homoeopathy has a role to play therapeutically. The article discusses the disease and the related physiology as well as pathology that goes inside the body during an episode of dengue fever. Along with the diagnosis and management approaches, the article elicits the role of homoeopathy through a suggested treatment protocol. Through the inherent properties of homoeopathy such as cost effectiveness, clinical effectiveness and zero side effects, the article proposes large scale application of homoeopathy at all levels.

Population genetics of Aedes albopictus in the port cities of Hainan Island and Leizhou Peninsula, China

BackgroundAedes albopictus is an important vector of arboviral diseases, transmitting yellow fever, dengue fever, chikungunya and Zika. Monitoring its population genetic diversity and genetic differentiation has become essential for the control of infectious disease epidemics, especially in the functional areas of ports of entry. Population genetic monitoring of Ae. albopictus in the port area can help in the monitoring of port mosquito invasions and establishing port sanitary and quarantine measures to prevent the introduction and transmission of vector-borne diseases. MethodsSeventeen populations of Ae. albopictus were collected from five port cities on Hainan Island and the Leizhou Peninsula, 8 populations were collected from port areas, 4 from urban areas and 5 from rural areas. Nine microsatellite loci and the mitochondrial COI gene were used to study the population genetic diversity, population genetic structure and interpopulation gene flow of Ae. albopictus. ResultsThe nine microsatellite loci used were highly polymorphic, with an average PIC value of 0.768. The UPGMA genetic tree, STRUCTURE barplot and PCoA analyses showed that the 17 Ae. albopictus populations could be divided into three genetic groups. All 17 populations showed high haplotype diversity (Hd = 0.8069–0.9678) and formed 133 distinct haplotypes. These haplotypes can be divided into four genetic clades, but they are not associated with the geographical distribution of Ae. albopictus. Fst and Nm showed strong gene flow and little differentiation among populations. ConclusionAe. albopictus in port areas are not significantly different from urban and rural populations due to strong gene flow, which prevents differentiation and increases the genetic diversity of the populations. High genetic diversity facilitates mosquito adaptation to complex environmental changes, which is a challenge for vector-borne disease control in port areas.

Influence of dengue virus serotypes on the abundance of Aedes aegypti insect-specific viruses (ISVs).

A comprehensive understanding of the virome in mosquito vectors is crucial for assessing the potential transmission of viral agents, designing effective vector control strategies, and advancing our knowledge of insect-specific viruses (ISVs). In this study, we utilized Oxford Nanopore Technologies metagenomics to characterize the virome of Aedes aegypti mosquitoes collected in various regions of Colombia, a country hyperendemic for dengue virus (DENV). Analyses were conducted on groups of insects with previous natural DENV infection (DENV-1 and DENV-2 serotypes), as well as mosquito samples that tested negative for virus infection (DENV-negative). Our findings indicate that the Ae. aegypti virome exhibits a similar viral composition at the ISV family and species levels in both DENV-positive and DENV-negative samples across all study sites. However, differences were observed in the relative abundance of viral families such as Phenuiviridae, Partitiviridae, Flaviviridae, Rhabdoviridae, Picornaviridae, Bromoviridae, and Virgaviridae, depending on the serotype of DENV-1 and DENV-2. In addition, ISVs are frequently found in the core virome of Ae. aegypti, such as Phasi Charoen-like phasivirus (PCLV), which was the most prevalent and showed variable abundance in relation to the presence of specific DENV serotypes. Phylogenetic analyses of the L, M, and S segments of the PCLV genome are associated with sequences from different regions of the world but show close clustering with sequences from Brazil and Guadeloupe, indicating a shared evolutionary relationship. The profiling of the Ae. aegypti virome in Colombia presented here improves our understanding of viral diversity within mosquito vectors and provides information that opens the way to possible connections between ISVs and arboviruses. Future studies aimed at deepening our understanding of the mechanisms underlying the interactions between ISVs and DENV serotypes in Ae. aegypti could provide valuable information for the design of effective vector-borne viral disease control and prevention strategies.IMPORTANCEIn this study, we employed a metagenomic approach to characterize the virome of Aedes aegypti mosquitoes, with and without natural DENV infection, in several regions of Colombia. Our findings indicate that the mosquito virome is predominantly composed of insect-specific viruses (ISVs) and that infection with different DENV serotypes (DENV-1 and DENV-2) could lead to alterations in the relative abundance of viral families and species constituting the core virome in Aedes spp. The study also sheds light on the identification of the genome and evolutionary relationships of the Phasi Charoen-like phasivirus in Ae. aegypti in Colombia, a widespread ISV in areas with high DENV incidence.

Strength in struggle: unravelling the journey of national vector borne disease control programme India: a comprehensive SWOT analysis

India, like many other regions, faces the substantial burden of vector-borne diseases. Initially confined to tropical and sub-tropical regions, vector-borne diseases are now spreading to new geographies due to increasing unplanned urbanization, changes in land use, growing international travel, and the impact of climate and environmental dynamics. To address these challenges, India implemented the National Vector Borne Disease Control Program (NVBDCP) in 2003-04, which targets the prevention and control of the six vector-borne diseases. Over the years, numerous initiatives have been undertaken to combat the challenges posed by vector-borne diseases in India. The successes, such as streamlined resource utilization and the introduction of effective tools, have led to substantial reductions in disease burden. Nevertheless, issues like manpower shortages, logistical hurdles, and a lack of research resources remain as challenges. Moreover, the program must confront emerging threats posed by urbanization, climate change, and resistance to treatments. NVBDCP's roadmap for the future includes embracing opportunities like vaccine development, and research, as well as fostering collaborations with partners. By addressing its weaknesses and effectively managing the threats at hand, the program can continue its vital mission of combatting vector-borne diseases in India. The implementation of these strategies is essential to ensure the sustained success of disease control and prevention efforts in the country.

Novel strains of Culex flavivirus and Hubei chryso-like virus 1 from the Anopheles mosquito in western Kenya

Surveillance of mosquito vectors is critical for early detection, prevention and control of vector borne diseases. In this study we used advanced molecular tools, such as DNA barcoding in combination with novel sequencing technologies to discover new and already known viruses in genetically identified mosquito species. Mosquitoes were captured using BG sentinel traps in Western Kenya during May and July 2019, and homogenized individually before pooled into groups of ten mosquitoes. The pools and individual samples were then used for molecular analysis and to infect cell cultures. Of a total of fifty-four (54) 10-pools, thirteen (13) showed cytopathic effect (CPE) on VeroB4 cells, eighteen (18) showed CPE on C6/36 cells. Eight (8) 10-pools out of the 31 CPE positive pools showed CPE on both VeroB4 and C6/36 cells. When using reverse transcriptase polymerase chain reaction (RT-PCR), Sanger sequencing and Twist Comprehensive Viral Research Panel (CVRP) (Twist Biosciences), all pools were found negative by RT-PCR when using genus specific primers targeting alphaviruses, orthobunyaviruses and virus specific primers towards o'nyong-nyong virus, chikungunya virus and Sindbis virus (previously reported to circulate in the region). Interestingly, five pools were RT-PCR positive for flavivirus. Two of the RT-PCR positive pools showed CPE on both VeroB4 and C6/36 cells, two pools showed CPE on C6/36 cells alone and one pool on VeroB4 cells only. Fifty individual mosquito homogenates from the five RT-PCR positive 10-pools were analyzed further for flavivirus RNA. Of these, 19 out of the 50 individual mosquito homogenates indicated the presence of flavivirus RNA. Barcoding of the flavivirus positive mosquitoes revealed the mosquito species as Aedes aegypti (1), Mansonia uniformis (6), Anopheles spp (3), Culex pipiens (5), Culex spp (1), Coquilletidia metallica (2) and Culex quinquefasciatus (1). Of the 19 flavivirus positive individual mosquitoes, five (5) virus positive homogenates were sequenced. Genome sequences of two viruses were completed. One was identified as the single-stranded RNA Culex flavivirus and the other as the double-stranded RNA Hubei chryso-like virus 1. Both viruses were found in the same Anopheles spp. homogenate extracted from a sample that showed CPE on both VeroB4 and C6/36 cells. The detection of both viruses in a single mosquito homogenate indicated coinfection. Phylogenetic analyses suggested that the Culex flavivirus sequence detected was closely related to a Culex flavivirus isolated from Uganda in 2008. All four Hubei chryso-like virus 1 segments clusters closely to Hubei chryso-like virus 1 strains isolated in Australia, China and USA. Two novel strains of insect-specific viruses in Anopheles mosquitoes were detected and characterized.

Molecular surveillance of insecticide resistance in Phlebotomus argentipes targeted by indoor residual spraying for visceral leishmaniasis elimination in India.

Molecular surveillance of resistance is an increasingly important part of vector borne disease control programmes that utilise insecticides. The visceral leishmaniasis (VL) elimination programme in India uses indoor residual spraying (IRS) with the pyrethroid, alpha-cypermethrin to control Phlebotomus argentipes the vector of Leishmania donovani, the causative agent of VL. Prior long-term use of DDT may have selected for knockdown resistance (kdr) mutants (1014F and S) at the shared DDT and pyrethroid target site, which are common in India and can also cause pyrethroid cross-resistance. We monitored the frequency of these marker mutations over five years from 2017-2021 in sentinel sites in eight districts of north-eastern India covered by IRS. Frequencies varied markedly among the districts, though finer scale variation, among villages within districts, was limited. A pronounced and highly significant increase in resistance-associated genotypes occurred between 2017 and 2018, but with relative stability thereafter, and some reversion toward more susceptible genotypes in 2021. Analyses linked IRS with mutant frequencies suggesting an advantage to more resistant genotypes, especially when pyrethroid was under-sprayed in IRS. However, this advantage did not translate into sustained allele frequency changes over the study period, potentially because of a relatively greater net advantage under field conditions for a wild-type/mutant genotype than projected from laboratory studies and/or high costs of the most resistant genotype. Further work is required to improve calibration of each 1014 genotype with resistance, preferably using operationally relevant measures. The lack of change in resistance mechanism over the span of the study period, coupled with available bioassay data suggesting susceptibility, suggests that resistance has yet to emerge despite intensive IRS. Nevertheless, the advantage of resistance-associated genotypes with IRS and under spraying, suggest that measures to continue monitoring and improvement of spray quality are vital, and consideration of future alternatives to pyrethroids for IRS would be advisable.

EaveTubes for control of vector-borne diseases in Côte d’Ivoire: study protocol for a cluster randomized controlled trial

BackgroundVector control tools, long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS), have significantly contributed to malaria prevention efforts in sub-Saharan Africa. However, insecticide resistance has seriously hampered their efficacy in recent years and new tools are essential to further progress. In2Care® EaveTubes (ETs) are an inexpensive, new resistance-breaking vector control product under World Health Organization (WHO) evaluation informed by mosquito ecology to efficiently target malaria vectors. By installing ETs in the walls of the house at the eave level that funnel the natural airflow, mosquitoes are drawn in by the same heat and odor cues that typically attract them through open eaves. Once inside an ET, mosquitoes are exposed to insecticide-treated netting placed inside the ET. The aim of this study is to test whether ETs as stand-alone tool have an effect on the epidemiology of malaria in villages where houses have been modified with the ET intervention.MethodsA two-armed, cluster randomized controlled trial will be conducted to evaluate the effect of ETs on clinical malaria incidence in children living in Côte d’Ivoire. Thirty-four villages will be selected based on population size and the proportion of houses suitable for modification with ETs (17 treatment arms (ETs + LLINs, 17 control arms (LLINs only)). Based on the population census, 55 households per cluster with eligible children (i.e., between the ages of 6 months to 8 years old at the start of the study) will be randomly selected for recruitment into the active detection cohorts. In the treatment arm, we will enroll eligible children who reside in ET-treated houses. The intervention and control cohorts will be followed for 4 months for baseline covariate measurements and 24 months with intervention. During case detection visits, blood samples will be taken from all febrile children and tested for malaria infection with rapid diagnostic tests (RDTs). All positive clinical malaria infections will be treated. To estimate the impact of the ET on malaria vector densities, entomological measurements (indoor sampling with CDC traps) will be conducted monthly in 20 clusters (10 ET, 10 Control) in 10 randomly selected households per cluster. To estimate the infectiousness of malaria vectors, sporozoite rates will be measured in subsets of the collected mosquito samples.DiscussionFindings will serve as an efficacy trial of ETs and will be submitted to the WHO Vector Control Advisory Group (VCAG) for assessment of public health value. Entomological outcomes will also be measured as proxies of malaria transmission to help develop guidelines for the evaluation of future In2Care® ETs products.Trial registrationClinicalTrials.gov NCT05736679. Registered on 10 February 2023.

Improving vector-borne disease control in Albufeira

Abstract The Albufeira Health Centre (CSA) comprises various functional units within primary healthcare. Recognizing the limited awareness of colleagues regarding the Vector Surveillance Network (REVIVE), responsible for entomological surveillance of mosquitoes, ticks, and sandflies, the Public Health Unit (USP) initiated a project to improve coordination and knowledge sharing. Implemented in April 2023, the project involved a multidisciplinary team. Informational materials on vector surveillance and control, clinical guidance for common vector-borne diseases (VBDs), tick collection protocols, and specimen registration forms were distributed. A video highlighting entomological surveillance and strategies for prevention and control was disseminated. To date, the project has recorded 45 views of the video (51%). A questionnaire distributed among the target population revealed that only 20% had knowledge of the epidemiological importance of vectors in the Algarve region. None were familiar with REVIVE or its work. Furthermore, participants were not acquainted with the Aedes albopictus mosquito species. Regarding ticks, 20% felt confident in tick removal, but none were aware of the tick genera in the Algarve region. Only 20% were aware of notifiable vector-borne diseases through SINAVE. Training sessions on this topic were suggested. The project emphasized the significance of communication and collaboration among healthcare professionals in the prevention and control of vector-borne diseases. It highlighted the need for continuous education on VBDs, surveillance techniques, and control measures. This innovative project can serve as a model for healthcare centres and countries, contributing to global efforts to improve the response to vector-borne diseases. The project's outreach extended to the Municipal Albufeira Animal Welfare Centre. A new questionnaire will be distributed to gather additional insights and enhance the impact of the project. Key messages • The project aims to improve integration of primary healthcare services for vector-borne diseases, increasing awareness and training for healthcare professionals. • This innovative project promotes prevention culture and replicable adaptations for improved response to vector-borne diseases.