Livestock are seasonally subjected to the nuisance of haematophagous flies, such as tabanids and stomoxyine flies. Topical application of insecticides has short term efficacy (a week or so), is expensive, and generates pesticide residues in animal products and environment. Attractive insecticide-impregnated blue fabrics are used for tsetse fly control in Africa; however, they are expensive and were never evaluated for other haematophagous flies. In previous works, we defined specifications of a white and blue screen specifically attracting haematophagous flies, particularly Stomoxys spp. In the present study, an assay was carried out in Kantchanaburi Province, Thailand, with around 30 of such screen prototypes, made of a multilayer polyethylene film incorporated with deltamethrin. Screens (also called 'targets') were deployed in 12 test farms, to evaluate the efficacy of a so-called 'multi-target method' (MTM); four control farms were also enrolled. A Vavoua trap was deployed one day/week in each farm to follow-up the density of insects. In the test-farms, during the 4 months post treatment, the mean density of haematophagous flies was significantly and consistently reduced by 63-73% compared to the control group. Laboratory tests indicated that insecticidal activity of these screen prototypes lasted around 3-4 months. However, in the field, significant reduction of fly densities was observed in all test farms up to 7 months after screen deployment, possibly as a consequence of the early impact of the screens on fly population dynamics. The significant effects obtained in test farms provided evidence for the proof of concept that MTM is effective for on-farm control of haematophagous and common flies. Durability of the screens will be increased in the next prototype generation. This innovative control method will be evaluated more extensively and in other livestock and poultry farms.
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 highrisk 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.
Great challenges to sustained malaria and arbovirus control remain, including transmission by vectors that occur outdoors or outside of sleeping hours, the enormous scale of larval breeding in urban centres and the failure of people to comply with vector control. Furthermore, developing insecticide resistance, shifts in vector dominance and behaviour emphasises the need for new integrated vector management strategies. Behavioural aspects of the mosquitoes' lifecycle, such as mating, oviposition, sugar-and host-seeking, are influenced by olfactory cues in the environment. This chapter focuses on two new technologies that are in development for targeted vector control in and around the home that require minimal compliance from users. Both technologies exploit specific olfactory mechanisms in mosquito genera that could unlock the potential for highly targeted vector control interventions. Attractive targeted sugar baits (ATSB) exploit mosquito sugar-feeding behaviour to deploy insecticides. They use an attractive scent as an olfaction stimulant and a sugar solution as a feeding stimulant mixed with an oral insecticide to induce mosquito mortality upon ingestion. ATSB methods may be deployed as a stand-alone method or integrated with other interventions. They are technologically and operationally simple, lowcost and effective across all major mosquito genera. A major benefit of ATSB is that it targets and kills male and female mosquitoes on emergence from breeding sites and multiple contact points throughout the mosquito's lifetime, increasing the likelihood of reducing the mosquito's lifespan, and thus, its probability of transmitting disease. Push-pull systems exploit mosquito host-seeking behaviour using a combination of spatial repellents and lure and kill strategies to push mosquitoes away from the home or the peridomestic space and into traps that mimic vertebrate hosts. At the moment, the greatest limitation to push-pull systems is the need for CO2 to attract mosquitoes. Most of the current trials have shown that efficacy of the push-pull strategy is primarily reliant upon the push unit, with only marginally improved efficacy with the addition of the pull unit. This finding could potentially be due to the size of these studies, because community-level protection from malaria using removal trapping has been demonstrated.
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.
In the context of increasing levels of insecticide resistance, changes in mosquito biting behaviour and drug resistant malaria parasites, mass mosquito trapping for malaria control forms a promising tool to complement long-lasting insecticide-treated nets and indoor residual spraying. Laboratory studies led to the development of synthetic odour baits to lure host-seeking mosquitoes, and these baits have been incorporated into odour-baited trapping systems which have been evaluated under semi-field and field conditions in East Africa. On Rusinga Island, western Kenya, the first ever field evaluation of mass mosquito trapping for malaria control took place between 2012 and 2015. The results showed that mass trapping is associated with reductions in Anopheles funestus populations of 70% corresponded with a 30% reduction in malaria cases among people living in households with the trapping systems, compared to people living in households yet to receive traps. The success of this intervention leads to questions about the next steps in trap development and the feasibility of using traps in a malaria control or elimination context. Development of next generation traps which are cheaper, more durable and require less user-maintenance would take this technology one step closer to a policy recommendation. Adaptation of odour baits and traps to attract malaria vectors in other regions would be advantageous. Combining solar-powered traps with rural electrification programmes forms a promising pathway for the distribution of trapping systems, and expanding the scope of the intervention to include a spatial repellent in a push-pull set-up could increase the efficacy of traps and the degree of personal protection provided. Learning from past successes in mass trapping for vector control leads to exciting prospects.
Vector control is, and will continue to be, an essential component of dengue prevention programs, but in modern cities with highly mobile human populations and inadequate vector control infrastructure the global burden of dengue is increasing. This is in part, because effective vector control is difficult to achieve and sustain. Despite these challenges, past successes indicate that when it is carefully and thoroughly applied, mosquito control will reduce dengue, particularly when targeting Aedes aegypti in urban habitats. Herein we review insecticide-based approaches for dengue vector control. We conclude that to fight dengue it is important to use locally derived and adapted vector control tools and strategies. To achieve this, it is critical to thoroughly understand the local vector and its ecology, including its insecticide susceptibility. Available evidence indicates that most space sprays (both aerial and ground) are relatively ineffective unless they are repeatedly delivered inside homes where Ae. aegypti rests. Novel delivery methods have been developed to control Aedes vector populations using residual killing agents, including targeted indoor residual spraying, which shows promise for reducing dengue. Adulticiding for dengue prevention is most effective when it is conducted as part of an integrated vector management plan that includes source reduction and larviciding. Successful dengue prevention programs include a combination of tools and strategies (e.g. insecticides in combination with vaccines and non-insecticide-based interventions) that are applied with enhanced intersectorial and interdisciplinary cooperation and strong community engagement.
Tackling the aquatic stages of anopheline malaria vectors is a key element in integrated vector management (IVM) programmes. The first large trials with Bacillus thuringiensis var. israelensis (Bti) as a novel biological control agent demonstrated that its impact can be highly effective, but context dependent. To better understand this dependency, there is a need to answer fundamental questions on mosquito larval ecology. At the same time, new technologies enter the stage, e.g. drones for delivery of Bti and approaches with genetically modified (GM) mosquitoes, that can aid field control operations. Such developments are promising, but any larval source management (LSM) programme also needs the involvement of communities from the very start in order to implement sustainable programmes. In this chapter, progress in answering fundamental questions on larval ecology is reviewed and recent examples that specifically aimed to assess the feasibility of involving communities in IVM programs for malaria control are discussed.
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.
Complexity in the emergence of vector-borne diseases involves several components in the eco-bio-social perspective. This makes it difficult for vector-borne disease control to be based solely on one organisation working on vector reduction. Dengue in particular involves (1) ecological components, such as the increase of breeding sites through changing a landscape (from rural to urban) and expansion of the range of mosquito habitats through climate change; (2) biological components, which mainly include human-vector-virus evolution and interaction in disease transmission; and (3) socio-economic components, such as insufficient household income and inadequate public health service. It is obvious that intersectoral collaboration with all relevant sectors to address these integrated components is one of the key criteria for successful vector-borne disease control. Intersectoral collaboration related to dengue has been mostly conducted when dengue control is in action, in order to enhance interventions aimed at vector control. In this chapter, different approaches of intersectoral collaborations and actions to control dengue in Asian countries by suppressing Aedes mosquito vectors will be highlighted. A few case studies include intersectoral collaboration for integrated vector management and innovative vector birth control. Based on the Asian experience, achieving intersectoral collaboration mainly involved the following key factors: (1) financial or technical support from within and outside participating sectors; (2) a clearly defined common interest which benefit all sectors; (3) a division of workload and joint management to achieve a common goal; (4) consistent coordination and communication among partnered sectors; (5) adaptability and flexibility in management; and (6) capacity building for sustainable intersectoral partnership.
Recent decades of malaria control have been dominated by extensive commoditisation of frontline interventions. Bed nets, insecticides, drugs and diagnostics have been scaled up in endemic countries, preventing millions of malaria cases and deaths. Unfortunately after years of progress, such gains are stagnating or diminishing due to challenges, such as insecticide and drug resistance, sub-optimal user compliance and the high costs for supply and replacements of these commodities. Without any viable vaccines or approaches that effectively tackle the environmental basis of malaria transmission, current commodities, and in particular the insecticide-based interventions, are incapable of preventing reinfections and rebounds, especially in low-income communities. This paper discusses a transitional approach for malaria prevention, involving judicious use of current tools while gradually building long-term resilience to sustain control of important vectors. The idea should be to carefully transition from insecticide-based to non-insecticidal approaches, without losing the gains made so far against malaria. In the short and medium-term, countries may deploy evidence-driven suites of current tools, e.g. insecticide treated nets (ITNs) and indoor residual spraying (IRS), while gradually introducing improved versions, such as nets with multiple chemical ingredients and long-lasting IRS formulations to suppress transmission. Depending on local evidence, these may be supplemented with niche technologies, such as spatial repellents, endectocides, odour-baited traps or mosquitocidal sugar baits to address gaps such as outdoor-biting and pyrethroid resistance. Once this is in place, countries should establish programmes to build long-term resilience to sustain the accrued gains and prevent transmission rebounds. Examples may include: incentivising the private sector to supply high-quality commodities e.g. locally-manufactured mosquito nets, providing subsidies to promote mosquito-free dwellings for low-income families, expanding community engagement in disease control and strengthening health systems to more effectively detect and manage cases. To secure these developments, endemic countries should also establish multi-sectorial initiatives prioritising disease control beyond malaria. Examples may include environmental sanitation to reduce vectors, institutionalised health education and capacity-building on biology and control of disease, appropriate legislation to improve compliance and protect vulnerable sub-populations and long-term domestic financing for malaria control. These programmes should be supported by a strong in-country research culture to constantly identify gaps, monitor progress and seek transformative approaches with potential to accelerate progress. If integrated in the wider public health context, this phased approach could contain ongoing malaria transmission, reduce over-reliance on insecticide-based tools and minimise transmission rebounds even in poor communities.
Interest in biological methods for livestock and poultry pest management is largely motivated by the development of resistance to most of the available synthetic pesticides by the major pests. There also has been a marked increase in organic systems, and those that promote animal welfare by reducing animal densities and allowing greater freedom of movement. Such systems, especially organic operations, are in need of new tools and strategies to manage pest problems. This chapter reviews the status of entomopathogenic fungi, viruses, and nematodes for management of pests of livestock and poultry production. The pests covered here are limited to the research that has been conducted to date, but include biting and nuisance flies, ticks, poultry ectoparasites, and litter beetles. Many of the same pests affect horses as well, although little work has been done in this area. The fungal pathogens Beauveria bassiana and Metarhizium anisopliae s.l. have received the most attention and have been evaluated against most of the major livestock and poultry pests. These pathogens have the greatest potential for practical use, but more work is needed to identify efficacious isolates and develop formulations for both on- and off-host use. The slow kill rate of these pathogens has been considered a liability in the past, but a growing body of work has demonstrated important sublethal effects of infection that includes reduced feeding, movement, and pathogen transmission. Two pathogens of house fly, the fungus Entomophthora muscae and salivary gland hypertrophy virus, are effective under some conditions but have biological characteristics that have limited their development as practical management tools. Entomopathogenic nematodes (Steinernema and Heterorhabditis spp.) also have potential but are limited by environmental constraints, especially temperature and substrate moisture. Discovery of, or selection for, strains with wider environmental tolerance could broaden the range of situations where they can be used effectively.
A large number of state-of-the-art issues of livestock pests and diseases, and their control, has been reviewed in the current volume of the Ecology and Control of Vector-borne diseases book series. The combined reviews demonstrate a clear difference in livestock pests between northern and southern regions, where the former are more subjected to pest control and the southern areas are more confronted with infectious vector-borne diseases. It appears that arthropod pests and associated vector-borne diseases in livestock have received less attention than required, leading to a lack of novel and innovative strategies for their prevention and control. Yet, the rapid expansion of the livestock industry as a result of population growth and global change call for solutions that are essential for economic and sustainable livestock production systems. The One Health concept, by now well known in human health, still needs to be integrated into the livestock industry. This becomes more urgent given the recent emergence of novel arthropod-borne diseases and the invasion of arthropod pests in new territories. It is concluded that a multidisciplinary approach to tackle the problem of arthropod pests and associated diseases in livestock is required, which should include novel genetic and microbiological tools and strategies in order to prevent the near-unity reliance on chemical pesticides and vaccines.
In order to prevent direct contact between livestock and pest animals and thus decrease the risk of pathogen transmission, the implementation of preventive or sometimes even curative measures is required. The concept of biosecurity refers to implementation of such measures, but it is difficult to quantify the results as the situation between farms may vary substantially. In this chapter we investigate the position of biosecurity and the evolution of this concept, especially in relation to pest management. We stress the need for such a strategy not only because of the potential transmission of (zoonotic) pathogens to livestock, which can have significant consequences for livestock health and the food chain, but also because of structural damage to buildings and crops. As there are large differences in both farm conditions and between vectors, implementation of a pest management strategy can come with serious difficulties. Thus, we present a generic framework that helps to develop a more tailor-made approach for a pest management strategy on farms, which will hopefully contribute to more effective interventions.
Ticks have a tremendous impact on cattle production worldwide. Economic losses caused by tick infestation are due to direct effects like less milk production and less gain in body weight, costs for application of control measures, which in most cases is based on the application of acaricides, and the losses due to tick-borne diseases. A variety of tick-borne pathogens are responsible for significant losses due to morbidity and mortality, veterinary and diagnostic costs, vaccines and trade restrictions. In this chapter we describe tick-borne diseases of cattle caused by three different groups of pathogens in order to emphasize the challenges currently faced in their control. Antigenic and genetic heterogeneity of each of these pathogens is challenging the attempts of specifically controlling the related disease, and precise diagnostic or vaccine development is hampered. As different tick species are involved as the main transmitting vectors, the development of tick vaccines is likewise challenging. With the exception of the Bm86 gut antigen used against the two main Rhipicephalus tick species transmitting Babesia bovis and Babesia bigemina, this strategy is thus far not working with any other tick species. Currently the best protection of the cattle industry against tick-borne diseases is a combination of various measures, which have to be adapted to the particular situation and to consider all possibilities including chemical tick control, grazing management, and breeding for host resistance to ticks.
Rhipicephalus (Boophilus) microplus and Rhipicephalus annulatus are invasive tick species and vectors of microbes causing bovine babesiosis and anaplasmosis that were declared eradicated from the USA in 1943 through efforts of the Cattle Fever Tick Eradication Program. These tick disease vectors remain established and affect livestock health and production in other countries located in tropical and subtropical parts of the world. R. microplus is considered the most economically important external parasite of livestock where it is established. Synthetic acaricides are used intensely to kill R. microplus and R. annulatus, but this leads eventually to the problem of acaricide resistance and other associated undesired effects. Novel and safer technologies that can be integrated with existing control methods are required to manage R. microplus and R. annulatus populations and associated diseases sustainably. In the case of the USA, the need for a systems approach was identified to keep the national cattle herd free of bovine babesiosis through the integrated use of technologies, including anti-tick vaccines, to eliminate outbreaks of R. microplus and R. annulatus. Anti-tick vaccines containing the recombinant antigen Bm86 are veterinary biologics used together with veterinary pharmaceuticals such as acaricides to enhance livestock protection where populations of R. microplus and R. annulatus are established. But, access to Gavac™, the only anti-tick vaccine commercially available and used to control R. microplus and R. annulatus, is limited to certain national veterinary products markets, excluding the USA. Efforts of a public-private partnership that developed, and obtained an experimental use permit issued to the animal health company Zoetis for a novel Bm86-based vaccine formulation to be integrated as part of operations by the Cattle Fever Tick Eradication Program are described here. Statutes more than 100 years old governing operations of the Cattle Fever Tick Eradication Program were adapted to eliminate R. microplus and R. annulatus infestations in cattle and mitigate the risk of future tick outbreaks in the Permanent Quarantine Zone in south Texas on the border with Mexico by adding immunization with the Bm86-based vaccine as part of the operational protocol. This achievement enabled the experimental use of the Zoetis Bm-86 based vaccine to immunize beef and dairy cattle as part of the research project for integrated control of the southern cattle fever tick in Puerto Rico. Our collective work documenting anti-cattle tick vaccine discovery research is described to illustrate how international cooperation supported research on integrated management for the Cattle Fever Tick Eradication Program. Public-private partnerships may be a way to develop novel anti-tick vaccines in other parts of the world for use as part of integrated R. microplus management strategies.
Concerning the insect pest management, two different views of the world face each other: those of the partisans of the social acceptability and those of the co-conception of innovations. There is no definition of the concept of acceptability, which can appear either a grey area or polysemous, with managerial origin and inputs from political philosophy, sociology, social psychology and political sciences. In a first part, thanks to an analytic frame based on the simplified actor-network theory (ANT), we will analyse how the question of acceptability was addressed in 3 situations of vector control. The studied vectors include screwworms, tsetse, and stomoxes, and implemented control packages include innovation transfer, partial co-production and innovation by users. Thus, we will see that we need to use an accurate theory of innovation to understand innovation processes to support them. At last, we will discuss how necessary it is to go beyond acceptability to appropriation and co-production when symbolic acceptation of methods is not sufficient.
Worldwide the livestock industry, from small farmers to large industrialized farms, is affected by arthropods and arthropod-borne diseases at various scales, which cause huge losses and are a constraint to socio-economic development. Farmers make considerable efforts to prevent and control pest and disease incidence, often requiring the use of vaccines, if available, drugs and pesticides. Examples of current problems are presented, to set the stage for the detailed and state-of-the-art presentations of specific cases of livestock pests and their associated diseases and modern methods of prevention and control.
