Vector control at a crossroad: Grappling with multiple challenges

Ashwani Kumar; Dharani Govindasamy

doi:10.25259/IJMR_1953_2025

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Editorial

162 (

2

); 131-134

doi:

10.25259/IJMR_1953_2025

Vector control at a crossroad: Grappling with multiple challenges

Ashwani Kumar^,*, Dharani Govindasamy

Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai 602 105, Tamil Nadu, India

*For correspondence: ashwani07@gmail.com

Received: 2025-07-24, Accepted: 2025-07-29, Epub ahead of print: 2025-09-18, Published: 2025-10-10

Licence

This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.

Vector control has historically been a cornerstone of public health, contributing to significant reductions in the burden of vector-borne diseases, such as malaria, dengue, and lymphatic filariasis. However, this success is under threat due to a confluence of existing and emerging challenges. These include a thinning pipeline of novel tools, increasing insecticide and drug resistance, ongoing climate disruption, reduced investment in technical capacity building and strengthening, and the waning human resource expertise. This editorial focuses on these intersecting challenges, assesses their implications, and proposes strategic directions to revitalise and strengthen vector control initiatives.

Vector control strategies have played a vital role in global health, substantially reducing transmission of diseases spread by mosquitoes, sandflies, ticks, and other vectors. Major vector control tools, viz., insecticide-treated nets (ITNs), indoor residual spraying (IRS), larval source management (LSM) and their integration have achieved impressive gains¹. However, in recent years, these gains have stagnated or reversed in many endemic regions². The future of vector control stands at a precarious crossroads, facing challenges that are scientific, operational, environmental, and systemic.

Thin pipeline of novel vector control products

Innovation in vector control tools has not kept pace with evolving challenges. Most frontline interventions today still rely on pyrethroid-based insecticides developed decades ago³. While new products like dual-active ingredient nets (e.g., Interceptor G2), spatial repellents, Wolbachia and gene-drive mosquitoes are in the pipeline, the pace of their development and deployment remains slow⁴.

Barriers include high costs of research and development, complex regulatory pathways, limited market incentives, and insufficient global coordination. Furthermore, few private-sector players are engaged in vector control R&D compared to other health sectors, resulting in a fragile innovation ecosystem. Fortunately, in India, several recent initiatives of the government of India, such as ‘Make in India’, Start-up ecosystem push and the creation of ‘Anusandhan National Research Foundation (ANRF)’ chaired by the Prime Minister, promise to transform the innovation and product development landscape of the country, fostering synergy between academia, research and industry⁵.

Mounting insecticide and drug resistance

A universal phenomenon, insecticide resistance is one of the most pressing threats to vector control, which blunts an effective vector control product in less than a decade. Widespread resistance to pyrethroids, a cornerstone of IRS and ITNs, has been documented in Anopheles and Aedes populations across Asia, Africa, and Latin America⁶. The underlying resistance mechanisms are multifaceted, including metabolic detoxification (elevated cytochrome P450s), target site mutations such as knockdown resistance (kdr), cuticular thickening, and behavioural avoidance.

The efficacy of IRS and ITNs, the two tools most relied upon, are compromised in areas with high resistance levels, and alternative classes, such as organophosphates or neonicotinoids, are not always sustainable due to cost or environmental concerns. Compounding the issue, resistance monitoring systems are patchy and aim at select vectors, limiting early detection and timely responses. Although a promising monitoring and evaluation tool, Xenomonitoring has been scantily deployed in vector-borne disease control programmes⁷. Taking advantage of the nationwide laboratory infrastructure created during the COVID-19 pandemic, the RT-PCR facilities can be leveraged for xenomonitoring of vector-borne infections in India and elsewhere.

Climate change and environmental disruption

Climate change is altering the ecological dynamics of vector populations and their phenology. Rising temperatures accelerate mosquito development and shorten the extrinsic incubation period of arboviruses, thereby enhancing the transmission potential of diseases like dengue and Zika^8,9. In combination with rapid urbanisation, climate change is also driving the geographic expansion of Anopheles stephensi into urban areas of Africa, raising new concerns about urban malaria transmission¹⁰. Moreover, changes in precipitation patterns and extreme weather events provide favourable conditions for Culex quinquefasciatus to breed in organically polluted water bodies, sustaining the risk of filariasis¹¹.

Urban heat islands, deforestation, and land-use changes further contribute to the proliferation of vector breeding habitats. Vector habitat fragmentation brings sylvatic vector species and reservoirs of zoonotic infections closer to human habitations, increasing the likelihood of spillover events. These ecological shifts demand adaptive and climate-resilient vector surveillance and control strategies. Moreover, climate-induced migration and urbanisation may increase opportunities for human-vector contact, thereby amplifying the risk of vector-borne disease transmission. Addressing these complex challenges underscores the importance of an integrated ‘One Health Approach.’

Diminishing technical skills and human resources

Over the past decades, many vector control programmes have suffered from a steady erosion of technical expertise. The retirement of experienced entomologists, lack of fresh recruitment, inadequate training infrastructure, and limited career incentives have created a vacuum in human capital¹². This is a global phenomenon, and India is not an exception in dealing with the inadequacies of skilled personnel. Field-level operations continue to rely heavily on contractual multipurpose workers with inadequate entomological training, leading to poor execution of source reduction, insecticide spraying and larval surveillance.

Moreover, poor resistance management is compounded by a lack of trained bioassay technicians and limited laboratory infrastructure¹³. Absence of refresher training programmes and limited engagement of trained vector biologists further exacerbate the operational challenges¹⁴. This loss is particularly acute in decentralised health systems, where operational staff often lack focused and rigorous entomological training and motivation. Programmatic weaknesses are compounded by limited institutional capacity for innovation, monitoring, data analysis, and evidence-based decision-making. Without revitalising technical skillsets, even the best tools may fail to deliver the intended impact.

Operational and programmatic concerns

Implementation gaps are a critical barrier. Many endemic countries and their regions report inconsistent coverage of core interventions, weak supply chains, delayed procurement, and inadequate quality assurance. Community engagement is often superficial and lacks sustainability, resulting in suboptimal compliance.

India has brought all vector-borne diseases under a single umbrella of the National Centre for Vector Borne Diseases Control (NCVBDC), which is a welcome step. However, vertical fragmentation among disease control programmes (e.g., malaria vs. dengue or LF vs. Leishmaniasis) undermines efficiency. Although scrub typhus has emerged as a major vector-borne zoonotic disease in recent years, no formal control programme exists for this disease, let alone its vector control. Integrated Vector Management (IVM) principles remain underutilised, despite being endorsed nationally and globally. Addressing these gaps requires better governance, a strategic shift, stronger partnerships, and robust data systems for guiding decisions on vector control.

Financing and policy constraints

Globally, financial support for vector control remains volatile and donor-dependent, especially in several endemic countries in Africa. There is, however, no dearth of financial resources in India currently in dealing with vector-borne diseases, particularly for those under elimination like malaria, lymphatic filariasis and leishmaniasis. Historically, as malaria burden stabilises or declines in some regions, funding is redirected, programme structure is dismantled, risking resurgence, for example, the resurgence of malaria in the 1960s in India. Moreover, the existing and new vector-borne disease threats, such as Dengue, which is the fastest-growing among infectious diseases, Zika or chikungunya, receive episodic attention, without sustained investments for the control of their common vector Aedes aegypti and its allied species Aedes albopictus. The vector control component, considered vital for disease risk reduction, is conspicuously absent from the elimination efforts of lymphatic filariasis, the chronic and stigmatised disease. The LF elimination largely depends upon annual mass drug administration with a combination of double (Albendazole+DEC) or triple drugs, Ivermectin, Albendazole and DEC. In the absence of vector control, the LF programme is limping instead of running towards its goal of elimination by 2030.

Policy frameworks often lag behind scientific evidence. Regulatory bottlenecks delay the adoption of innovative tools. A lack of national ownership and multisectoral engagement impedes the mainstreaming of vector control into urban planning, agriculture, and climate resilience strategies. Unless policy and planning structures are aligned with GVCR principles, vector control efforts will remain reactive and siloed, unable to sustainably address the rising burden of vector-borne diseases in the face of rapid urbanisation and climate change.

The way forward

Addressing the multifaceted challenges in vector control requires systemic, long-term strategies. Some of these are investing in product development partnerships and regulatory streamlining, fostering local manufacturing and public-private collaborations and promoting gene-based and ecological vector control tools for risk management. There is a need to reinforce resistance management by scaling up resistance monitoring and adaptive deployment strategies, developing and rotating insecticides with novel modes of action, and exploring biological controls (e.g., Wolbachia, larvivorous fish) and introducing comprehensive vector monitoring¹⁵. Making vector control climate-resilient would require integrating vector risk mapping with climate models, designing flexible/situation-specific interventions for climate-vulnerable settings and embedding vector control into disaster preparedness and urban planning. Over the top of this, there is a dire need to build human capacities by establishing regional entomology training hubs (e.g., ICMR-Vector Control Research Centre at Puducherry, ICMR-National Institute of Malaria Research and various ICMR Regional Centres), creating career pathways for vector biologists and operational staff and promoting collaborations and knowledge exchange between the States, sharing the best practices and experiences. The critical reforms needed are transitioning from vertical to integrated vector control programme, increasing domestic financing, particularly to high-risk and high-burden States, encouraging industry as part of multisectoral ownership and modernizing data systems for real-time decision-making.

In conclusion, vector control stands at a critical intersection. Without urgent action to address the thinning innovation pipeline, escalating resistance, environmental disruptions, and erosion of technical capacity, the hard-won gains in disease control would disappear over time. A coordinated, well-financed, and forward-looking approach is essential for bolstering vector control and sustaining its impact and meeting the Sustainable Development Goals (SDG) targets. The challenges are formidable, but not insurmountable. With sustained political commitment, scientific innovation, and community partnership, vector control can be revitalised to meet both current and future threats of vector-borne diseases in India and elsewhere.

Financial support & sponsorship

None.

Conflicts of Interest

None.

Use of Artificial Intelligence (AI)-Assisted Technology for manuscript preparation

The authors confirm that there was no use of AI-assisted technology for assisting in the writing of the manuscript and no images were manipulated using AI.

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