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In the past 5–10 years, Venezuela has faced a severe economic crisis, precipitated by political instability and declining oil revenue. Public health provision has been affected particularly. In this Review, we assess the impact of Venezuela's health-care crisis on vector-borne diseases, and the spillover into neighbouring countries. Between 2000 and 2015, Venezuela witnessed a 359% increase in malaria cases, followed by a 71% increase in 2017 (411 586 cases) compared with 2016 (240 613). Neighbouring countries, such as Brazil, have reported an escalating trend of imported malaria cases from Venezuela, from 1538 in 2014 to 3129 in 2017. In Venezuela, active Chagas disease transmission has been reported, with seroprevalence in children (<10 years), estimated to be as high as 12·5% in one community tested (n=64). Dengue incidence increased by more than four times between 1990 and 2016. The estimated incidence of chikungunya during its epidemic peak is 6975 cases per 100 000 people and that of Zika virus is 2057 cases per 100 000 people. The re-emergence of many vector-borne diseases represents a public health crisis in Venezuela and has the possibility of severely undermining regional disease elimination efforts. National, regional, and global authorities must take action to address these worsening epidemics and prevent their expansion beyond Venezuelan borders.

Climate change is already affecting vector-borne disease transmission and spread, and its impacts are likely to worsen. In the face of ongoing climate change, we must intensify efforts to prevent and control vector-borne diseases.

Over half the world’s population is at risk for viruses transmitted by Aedes mosquitoes, such as dengue and Zika. The primary vector, Aedes aegypti, thrives in urban environments. Despite decades of effort, cases and geographic range of Aedes-borne viruses (ABVs) continue to expand. Rigorously proven vector control interventions that measure protective efficacy against ABV diseases are limited to Wolbachia in a single trial in Indonesia and do not include any chemical intervention. Spatial repellents, a new option for efficient deployment, are designed to decrease human exposure to ABVs by releasing active ingredients into the air that disrupt mosquito–human contact. A parallel, cluster-randomized controlled trial was conducted in Iquitos, Peru, to quantify the impact of a transfluthrin-based spatial repellent on human ABV infection. From 2,907 households across 26 clusters (13 per arm), 1,578 participants were assessed for seroconversion (primary endpoint) by survival analysis. Incidence of acute disease was calculated among 16,683 participants (secondary endpoint). Adult mosquito collections were conducted to compare Ae. aegypti abundance, blood-fed rate, and parity status through mixed-effect difference-in-difference analyses. The spatial repellent significantly reduced ABV infection by 34.1% (one-sided 95% CI lower limit, 6.9%; onesided P value = 0.0236, z = 1.98). Aedes aegypti abundance and blood-fed rates were significantly reduced by 28.6 (95% CI 24.1%, ∞); z = 29.11) and 12.4% (95% CI 4.2%, ∞); z = 22.43), respectively. Our trial provides conclusive statistical evidence from an appropriately powered, preplanned cluster-randomized controlled clinical trial of the impact of a chemical intervention, in this case a spatial repellent, to reduce the risk of ABV transmission compared to a placebo.

Vector-borne diseases (VBDs) such as malaria, dengue, and leishmaniasis exert a huge burden of morbidity and mortality worldwide, particularly affecting the poorest of the poor. The principal method by which these diseases are controlled is through vector control, which has a long and distinguished history. Vector control, to a greater extent than drugs or vaccines, has been responsible for shrinking the map of many VBDs. Here, we describe the history of vector control programmes worldwide from the late 1800s to date. Pre 1940, vector control relied on a thorough understanding of vector ecology and epidemiology, and implementation of environmental management tailored to the ecology and behaviour of local vector species. This complex understanding was replaced by a simplified dependency on a handful of insecticide-based tools, particularly for malaria control, without an adequate understanding of entomology and epidemiology and without proper monitoring and evaluation. With the rising threat from insecticide-resistant vectors, global environmental change, and the need to incorporate more vector control interventions to eliminate these diseases, we advocate for continued investment in evidence-based vector control. There is a need to return to vector control approaches based on a thorough knowledge of the determinants of pathogen transmission, which utilise a range of insecticide and non-insecticide-based approaches in a locally tailored manner for more effective and sustainable vector control.

Background Despite the growing complexity, computational power, and mapping capacity incorporated into vector-borne disease models, they still do not fully elucidate the role of environmental, demographic, socioeconomic, or other drivers, and rarely directly inform vector control efforts. To understand how we can improve the utility of vector-borne disease models for vector control activities, we interviewed vector control agents from the United States (USA) and the European Union. Methods Between July and December 2023, in-depth interviews were held using a geographically targeted convenience sample with 26 individuals from organizations involved in vector control operations: 12 in the USA and 14 in the EU. We used both deductive and inductive coding of transcribed interviews to identify themes with the goal of understanding barriers to model use and uptake. Results Despite the recognition that models could be useful, few interviewees reported that models informed surveillance and control activities, citing a mismatch in spatial and temporal scale between model outputs and operational decisions or a general lack of accessibility. Interviewees reported relying on experienced field experts and legacy protocols. Despite these critiques, there is belief that models can support operational decision-making. Conclusions The disconnect between models and users can be improved by allowing time and resources to build collaborative relationships, by acknowledging the knowledge all members bring, and by ensuring clear communication and mutual respect. Modelers must shift their focus by aligning vector-borne disease models with operational needs. Graphical abstract

Vector-borne diseases are mainly transmitted through the bites of infected arthropods. They are a major public health concern as they account for more than 700,000 deaths annually. Among many vector-borne pathogens, the neurotropic viruses have been contributing to the increased number of deaths across the globe due to severe neurological complications. Despite the advancement of vector control strategies, the prevalence and severity of neurotropic viral infections have not been alleviated till date. Anthropogenic activities cause persistent fluctuations in temperature and weather trends. This plays a major part in shaping the fate of transmission dynamics and pathogenesis of such diseases. Changes in climatic factors, such as global warming and delayed withdrawal of monsoon, have had huge impacts on stretching the window of disease transmission worldwide. The abundance, survival, feeding activity, and vectorial competence of the arthropods are expected to increase with rising temperatures. This review aims to discuss how climate change affects ecosystems, thereby influencing vectors and the associated neurotropic viruses. It also highlights the urgent need for the \"One Health\" strategy. It is a concept that recognizes that humans and animals do not exist in isolation and are part of a larger ecosystem where their activity and health are interconnected to one another. This holistic approach is essential in addressing the emerging threats posed by climate change, rising rates of infection, and epidemics across the globe.

Rapid adaptation in response to novel environments can facilitate species invasions and range expansions. Understanding how invasive disease vectors rapidly evolve to novel conditions—particularly at the edge of its non‐native range—has important implications for mitigating the prevalence and spread of disease. Here, we evaluate the role of local adaptation in overwintering capability of the Asian tiger mosquito, Aedes albopictus. This species invaded the Southern United States in the 1980s and rapidly spread northward into novel climate compared to its native range. Photoperiodically induced egg diapause is a key trait contributing to the establishment and spread of Ae. albopictus in temperate latitudes, and diapause incidence rapidly developed a cline along a latitudinal gradient in the United States shortly after its initial invasion. However, variation in overwintering survival of diapause‐induced eggs along this gradient is not known, but is critical to the fitness‐related role of diapause evolution in the establishment of Ae. albopictus in its northern US range. Using reciprocal transplants, we detected local adaptation in overwinter survival of diapausing Aedes albopictus eggs. In northern range‐edge winters, eggs produced by range‐edge individuals survived better than those produced by range‐core individuals. Diapause eggs from range‐edge and range‐core locations survived equally well in range‐core winters, and no eggs survived a winter beyond the current northern range limit in the United States. Synthesis and applications. These results demonstrate rapid (~3 decades) local adaptation of egg diapause, a key trait facilitating overwinter survival and range expansion for the invasive Asian tiger mosquito. In light of these results, control efforts could shift from targeting satellite populations to a focus on preventing dispersal into locally adapted, range‐edge locations and to aim removal efforts towards areas surrounding locally adapted populations. Adopting new approaches to target rapidly adapting populations will require large‐scale collaboration among control agencies and research institutions, and should begin in the northern US range to better control Aedes albopictus mosquito populations in the face of rapid adaptation.

Larval source management (LSM) has a long history of advocacy and successes but is rarely adopted where funds are limited. The World Health Organization (WHO) guidelines on malaria prevention recommend the use of LSM as a supplementary intervention to the core vector control methods (insecticide-treated nets and indoor residual spraying), arguing that its feasibility in many settings can be limited by larval habitats being numerous, transient, and difficult to find or treat. Another key argument is that there is insufficient high-quality evidence for its effectiveness to support wide-scale implementation. However, the stagnation of progress towards malaria elimination demands that we consider additional options to the current emphasis on insecticidal commodities targeting adult mosquitoes inside homes. This letter is the result of a global, crossdisciplinary collaboration comprising: (a) detailed online expert discussions, (b) a narrative review of countries that have eliminated local malaria transmission, and (c) a mathematical modeling exercise using two different approaches. Together, these efforts culminated in seven key recommendations for elevating larval source management as a strategy for controlling malaria and other mosquito-borne diseases in Africa (Box 1 ). LSM encompasses the use of larvicide (a commodity) as well as various environmental sanitation measures. Together, these efforts lead to the long-term reduction of mosquito populations, which benefits the entire community by controlling both disease vector and nuisance mosquitoes. In this paper, we argue that the heavy reliance on large-scale cluster-randomized controlled trials (CRTs) to generate evidence on epidemiological endpoints restricts the recommendation of approaches to only those interventions that can be measured by functional units and deliver relatively uniform impact and, therefore, are more likely to receive financial support for conducting these trials. The explicit impacts of LSM may be better captured by using alternative evaluation approaches, especially high-quality operational data and a recognition of locally distinct outcomes and tailored strategies. LSM contributions are also evidenced by the widespread use of LSM strategies in nearly all countries that have successfully achieved malaria elimination. Two modelling approaches demonstrate that a multifaceted strategy, which incorporates LSM as a central intervention alongside other vector control methods, can effectively mitigate key biological threats such as insecticide resistance and outdoor biting, leading to substantial reductions in malaria cases in representative African settings. This argument is extended to show that the available evidence is sufficient to establish the link between LSM approaches and reduced disease transmission of mosquito-borne illnesses. What is needed now is a significant boost in the financial resources and public health administration structures necessary to train, employ and deploy local-level workforces tasked with suppressing mosquito populations in scientifically driven and ecologically sensitive ways. In conclusion, having WHO guidelines that recognize LSM as a key intervention to be delivered in multiple contextualized forms would open the door to increased flexibility for funding and aid countries in implementing the strategies that they deem appropriate. Financially supporting the scale-up of LSM with high-quality operations monitoring for vector control in combination with other core tools can facilitate better health. The global health community should reconsider how evidence and funding are used to support LSM initiatives. Graphical Abstract

In this paper, a multi-patch and multi-group vector-borne disease model is proposed to study the effects of host commuting (Lagrangian approach) and/or vector migration (Eulerian approach) on disease spread. We first define the basic reproduction number of the model, R0, which completely determines the global dynamics of the model system. Namely, if R0≤1, then the disease–free equilibrium is globally asymptotically stable, and if R0>1, then there exists a unique endemic equilibrium which is globally asymptotically stable. Then, we show that the basic reproduction number has lower and upper bounds which are independent of the host residence times matrix and the vector migration matrix. In particular, nonhomogeneous mixing of hosts and vectors in a homogeneous environment generally increases disease persistence and the basic reproduction number of the model attains its minimum when the distributions of hosts and vectors are proportional. Moreover, R0 can also be estimated by the basic reproduction numbers of disconnected patches if the environment is homogeneous. The optimal vector control strategy is obtained for a special scenario. In the two-patch and two-group case, we numerically analyze the dependence of the basic reproduction number and the total number of infected people on the host residence times matrix and illustrate the optimal vector control strategy in homogeneous and heterogeneous environments.

1. Vector and host communities, as well as habitat characteristics, may have important but different impacts on the prevalence, richness and evenness of vector-borne parasites. 2. We investigated the relative importance of (1) the mosquito community composition, (2) the vertebrate community composition and (3) landscape characteristics on the prevalence, richness and evenness of avian Plasmodium. We hypothesized that parasite prevalence will be more affected by vector-related parameters, while host parameters should be also important to explain Plasmodium richness and evenness. 3. We sampled 2,588 wild house sparrows (Passer domesticus) and 340,829 mosqitoes, and we performed vertebrate censuses at 45 localities in the Southwest of Spain. These localities included urban, rural and natural landscapes that were characterized by several habitat variables. 4. Twelve Plasmodium lineages were identified in house sparrows corresponding to three major clades. Variation partitioning showed that landscape characteristics explained the highest fraction of variation in all response variables (21.0%-44.8%). Plasmodium prevalence was in addition explained by vector-related variables (5.4%) and its interaction with landscape (10.2%). Parasite richness and evenness were mostly explained by vertebrate community-related variables. 5. The structuring role of landscape characteristics in vector and host communities was a key factor in determining parasite prevalence, richness and evenness, al-though the role of each factor differed according to the parasite parameters studied. These results show that the biotic and abiotic contexts are important to explain the transmission dynamics of mosquito-borne pathogens in the wild.