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Mosquitoes play a central role in the transmission of pathogens causing important diseases to humans and other animals. The incidence of zoonotic diseases has increased in recent decades, many of them caused by pathogens transmitted by mosquitoes. Due to the relevance of these diseases in public and animal health, medical and veterinary entomologists have traditionally focused their studies on the impact of mosquitoes, among other vectors, in diseases such as malaria, West Nile fever or dengue. However, the relevance of mosquitoes in the transmission of pathogens affecting wildlife have been comparatively neglected. The current volume of Ecology and Control of Vector-Borne Diseases series highlights significant and novel aspects of the ecology of diseases transmitted by mosquitoes to wildlife, contributing to the better understanding of their epidemiology. We hope this volume will influence to improve our understanding of the dynamics of transmission of mosquito-borne diseases in the wild and provide updated information on the surveillance, control and epidemiology of mosquito-borne zoonotic diseases.

Open Access
In: Ecology of diseases transmitted by mosquitoes to wildlife

Current tools for vector control are insufficient to curb vector-borne disease transmission. Recent outbreaks of ‘new’ vector-borne diseases, such as Zika and chikungunya, and the ongoing fight against malaria underscore this. Scientists and public health authorities collaborate on a continued search for innovative strategies to address this challenge. To guide the integration of currently available and new tools in vector control programs, the World Health Organization (WHO) developed the Global Vector Control Response (GVCR).This initiative was unanimously endorsed by the World Health Assembly in 2017.

This 6th volume of the Ecology and Control of Vector-borne Diseases series reflects on the progress of GVCR by reviewing: (1) innovative strategies for vector control that are in the pipeline; (2) the role of integrated vector management (IVM) in these strategies; and (3) inclusion of social aspects of IVM, such as community engagement, in effective control programs. The introduction and concluding chapters of the book have been written in collaboration with WHO.

Open Access
In: Innovative strategies for vector control
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The benefits and logic of intersectoral collaboration have been reiterated at regular intervals and substantial experience has been gained in what works and what doesn’t. One of the iterations was the joint WHO/FAO/UNEP/UNCHS Panel of Experts on Environmental Management for Vector Control. This chapter starts by summarising that experience. We learned that successful intersectoral collaboration depends on vested interests, external pressures, strong institutional arrangements and suitable instruments. Health impact assessment (HIA) has proved one of the most successful instruments and we describe its procedures and methods in some detail. Although HIA is completely general, it includes the management of vector-borne diseases (VBD). In countries where VBD are of major public health importance, they make up a large part of the fraction of the increased disease burden attributable to development projects. HIA assists planners and decision-makers in non-health sectors, such as water resource development, energy, transport, mining or agriculture, to anticipate the health impacts and opportunities of their plans and projects. A set of recommendations can then be formulated to protect and promote health. These recommendations can be arranged in a hierarchy and this includes healthy engineering design. We identify different types of intersectoral collaboration and suggest where intervention points lie during development project planning. Reference is made to the health and safety performance standards of the lending institutions, and national planning and environmental regulations. There is still a global lack of capacity to carry out HIA to an acceptable standard and we summarise some of the causes and consequences. We provide two recent examples of intersectoral collaboration. The first example is a recently completed programme of the Asian Development Bank that focused on malaria and other communicable disease threats. The second example concerns the procedures used by multinational corporations and often referred to as environmental, social and health impact assessment (ESHIA). We conclude with a brief summary of future directions.

Open Access
In: Innovative strategies for vector control

The invasive species (IS) introduced in islands cause important impacts due to the vulnerability of their ecosystems. The invasive potential of certain mosquito species and their role as vectors of pathogens is one of the main concerns for public and animal health. The introduction of IS such as Aedes albopictus (Skuse 1895), Aedes aegypti (Linnaeus 1762) and Culex quinquefasciatus Say 1823 are also related to outbreaks of vector-borne diseases (VBD), such as yellow fever, dengue and Zika. Here, we review the surveillance activities on mosquito IS conducted in several islands of different origin (i.e. volcanic vs continental origin) located in different countries of the world. Those countries included Cabo Verde, Greece, Italy, Portugal, Spain and the USA. In regards to continental islands, Ae. albopictus was detected in the Balearic Islands (Spain) in 2012 despite monitoring at points of entry lead by national authorities since 2008. Greece comprises over 6,000 islands and islets with first record of Ae. albopictus in Corfu in 2003. In Italy, Ae. albopictus was first detected in Sicily in 2004 where several cases of filariasis by Dirofilaria repens in dogs and humans have been reported. Volcanic origin islands are characterised by having all mosquito fauna introduced from the continent. In Cabo Verde, Anopheles arabiensis is the main vector of malaria and can also transmit lymphatic filariasis. Ae. aegypti is also present in Cabo Verde since 1930 causing several outbreaks of dengue and Zika in 2009 and 2015. In Spain, Ae. aegypti was detected in Fuerteventura (Canary Islands) in 2017, but the fast intervention of local authorities reached its eradication in 2019. In Portugal, Ae. aegypti was first recorded in Madeira in 2006 with a single outbreak of dengue in 2012. In the USA, the islands of Hawaii have currently six established IS of mosquitoes including the four top vector species Ae. albopictus, Ae. aegypti, Aedes japonicus and Cx. quinquefasciatus, which have been implicated in outbreaks of dengue and transmission of Dirofilaria immitis and Plasmodium relictum.

Open Access
In: Ecology of diseases transmitted by mosquitoes to wildlife

A review of malaria vector control in Sri Lanka was conducted to understand how the country successfully transitioned from control of malaria to elimination over the past century, and how vector control is being used to prevent the reintroduction of malaria. The case study is expected to provide examples and lessons learnt to other programmes or countries. Malaria vector control in Sri Lanka has faced major challenges of sudden and unstable transmission, insecticide resistance, movements of settlers and refugees, and programme fatigue. Early on, the importance of vector ecology and environmental factors in malaria epidemics was recognised, and in response, vigilance units were set up at periphery level. After intense indoor residual spraying campaigns with DDT (1950s and 1960s) and, subsequently, malathion failed to end malaria (1970s), pesticide policy was developed in the 1980s, and a routine system of monitoring of insecticide resistance was incorporated into the malaria control programme. This system was the basis for a proactive scheme of rotation and mosaics of insecticide applications to manage resistance. Entomological and epidemiological surveillance data were used to stratify malaria incidence, identify high-risk groups or locations, and plan appropriate interventions, including larval vector control. The programme adapted to changing epidemiological circumstances. After Sri Lanka was certified malaria-free in 2016, the system of surveillance and control was reoriented, with malaria risk mapping providing the basis for decisions on proactive vector control in receptive and vulnerable locations. The vector control programme has been disease-specific, but in recent decades the entomological expertise has regularly been shared with the dengue control programme, which is an example of integrated vector management. Further coordination on vector surveillance and control between programmes will be vital to improve the efficiency, effectiveness and financial sustainability of operations.

Open Access
In: Innovative strategies for vector control

Mosquito surveillance consists in the routine monitoring of mosquito populations: to determine the presence/absence of certain mosquito species; to identify changes in the abundance and/or composition of mosquito populations; to detect the presence of invasive species; to screen for mosquito-borne pathogens; and, finally, to evaluate the effectiveness of control measures. This kind of surveillance is typically performed by means of traps, which are regularly collected and manually inspected by expert entomologists for the taxonomical identification of the samples. The main problems with traditional surveillance systems are the cost in terms of time and human resources and the lag that is created between the time the trap is placed and collected. This lag can be crucial for the accurate time monitoring of mosquito population dynamics in the field, which is determinant for the precise design and implementation of risk assessment programs. New perspectives in this field include the use of smart traps and remote monitoring systems, which generate data completely interoperable and thus available for the automatic running of prediction models; the performance of risk assessments; the issuing of warnings; and the undertaking of historical analyses of infested areas. In this way, entomological surveillance could be done automatically with unprecedented accuracy and responsiveness, overcoming the problem of manual inspection labour costs. As a result, disease vector species could be detected earlier and with greater precision, enabling an improved control of outbreaks and a greater protection from diseases, thereby saving lives and millions of Euros in health costs.

Open Access
In: Ecology of diseases transmitted by mosquitoes to wildlife

Mosquitoes (Culicidae) are at the centre of worldwide entomological research and control efforts primarily because of their medical importance as vectors of diseases, like malaria, dengue, Zika, Chikungunya, West Nile or Yellow fever. They are responsible for more than half a million deaths per year. Despite their role as vectors, culicids can also cause considerable nuisance like floodwater mosquitoes frequently create as they can reproduce in a short time in enormous numbers. The consequence is that outdoor activities in parks or recreation areas are not possible and this has a detrimentrous effect on touristic activities. The most successful approach for managing nuisance or vector mosquitoes is when an integrated vector mosquito management (IVM) is implemented in which all appropriate technologies and control techniques are used, to bring about a decline of target species populations in a cost effective and environmentally safe manner. The IVM strategy can include environmental management, physical, chemical, biological or genetical components. Environmental management means physical reduction of breeding resources, water management to create conditions unfavourable for mosquito breeding. Physical control includes the use of nets and surface layers to avoid vector contact or breathing by mosquito developing stages. Chemical control by using organochlorines, organophosphates, carbamates or pyrethroids is still the most frequently practised approach to combat mosquitoes but usually these chemicals are broad-spectrum products which can have also unwanted side effects on non-target organisms and on the biodiversity when they are used in ecological sensitive areas. Therefore, biological control aiming at the reduction of target populations by the use of predators, pathogens or toxins from microorganisms are nowadays more and more in focus of control operators. Especially the use of protein toxins such as from Bacillus thuringiensis israelensis or Lysinibacillus sphaericus provide efficient control of target organisms on the one hand and environmental safety on the other hand. The increased application of biological and microbiological methods or Insect growth regulators as well as genetic methods as the Sterile Insect technique (SIT) contribute to an environmentally friendly solution of the mosquito problems. New and improved techniques like the CRISPR (clustered regularly interspaced short palindromic repeats) as a mean of editing mosquito genomes to drive desirable gene constructs into mosquito population can help in future to avoid the transmission of human pathogens. The Geographic Information System (GIS) integrated with digital mobile collection systems supported by a Global Positioning System (GPS) and modern information-technology, can significantly contribute to improving the planning, realisation and documentation of mosquito control/management operations and allow a more effective effort to reducing mosquito-borne diseases. It is out of question that all strategies should involve the public to raise the awareness of people, e.g. for the control of invasive mosquitoes by community participation.

Open Access
In: Ecology of diseases transmitted by mosquitoes to wildlife

Outbreaks of arboviruses have occurred in the last decades in many places around the world and a variety of responses have been taken in order to control them. Responses ranged from vaccination campaigns to the use of conventional vector control methods. Innovative approaches relying on biotechnological novelties, often still under development, have been considered despite the lack of solid evidence of their efficacy. While discussing these different aspects of the fight against vector-borne diseases with a focus on the context of outbreaks, this chapter considers the social and ethical aspects related to both the rhetoric and the discussion about the implementation of new and innovative approaches.

Open Access
In: Innovative strategies for vector control

Current tools for vector control are insufficient to curb vector-borne disease transmission. Recent outbreaks of ‘new’ vector-borne diseases, such as Zika and chikungunya, and the ongoing fight against malaria underscore this. Scientists and public health authorities collaborate on a continued search for innovative strategies to address this challenge. To guide the integration of currently available and new tools in vector control programs, the World Health Organization (WHO) developed the Global Vector Control Response (GVCR).This initiative was unanimously endorsed by the World Health Assembly in 2017.

This 6th volume of the Ecology and Control of Vector-borne Diseases series reflects on the progress of GVCR by reviewing: (1) innovative strategies for vector control that are in the pipeline; (2) the role of integrated vector management (IVM) in these strategies; and (3) inclusion of social aspects of IVM, such as community engagement, in effective control programs. The introduction and concluding chapters of the book have been written in collaboration with WHO.

Open Access
In: Innovative strategies for vector control

Traditionally, mosquitoes have been studied given their relevance as vectors of pathogens that affect humans. However, in recent decades, their relevance as vectors of pathogens that affect wildlife has become evident. For this reason, multidisciplinary research disciplines have been developed focusing on the ecology, epidemiology and evolution of the interactions between pathogens and their hosts, including the transmission dynamics of diseases. However, there is a gap in the knowledge of mosquito-borne pathogens that affect wildlife, being necessary to study the taxa diversity, using genomic tools and, of course, their life cycles and their vectors. However, the information on the vector competence of mosquitoes for the transmission of pathogens that affect wild animals is certainly scarce. Interspecific and intraspecific differences have been evidenced. This would determine the capacity of mosquitoes to transmit parasites that infect wild animals. Different factors such as physiological and biochemical processes, or the mosquito microbiota could determine these differential capacities of mosquitoes to transmit pathogens.

Open Access
In: Ecology of diseases transmitted by mosquitoes to wildlife