versifying food crop production to reduce labor demands can be helpful, the nutritional quality of the total diet must be considered.
6.7.3.2 Research and technological options beyond the farm
Resource poor farmers have limited resources to mitigate the spread of diseases. Controlling emerging infectious diseases requires early detection, through surveillance at national, regional, and international levels, and rapid intervention. For animal diseases, traceability, animal identification, and labeling also are needed. The main control methods for human and animal diseases include diagnostic tools, disease investigation facilities, and safe and effective treatments and/or vaccines. AKST under development can facilitate rapid detection of infectious pathogens, e.g., genetic tools were used in recent HPAI outbreaks to identify the viruses involved and to inform development of appropriate control programs (FAO/OIE/WHO, 2005). Syndromic surveillance of farm animals coupled with notification using internet-accessible devices is being used in some high-income countries to detect emerging diseases (Vourc'h et al., 2006).
The increasing importance of zoonotic diseases requires better integration of human and veterinary public health approaches for their detection, identification, monitoring, and control. Decreased funding in recent decades has eroded the required infrastructure and training underlying veterinary services and surveillance activities (Vallat and Mallet, 2006). Incentives to report cases of disease at the local and national levels and pay for culling of animals when appropriate could facilitate early identification of outbreaks. There is an urgent need to replenish basic capacity in many high-income countries and to increase capacity in middle-and low-income countries. Linkage of regional and international organizations and agencies is critical. Improved understanding is needed of disease transmission dynamics in order to develop more effective and efficient diagnostic systems and interventions. Diagnostic systems should be designed to process large numbers of samples and identify multiple infectious agents.
Although vaccines are a cornerstone of primary prevention, vaccine effectiveness is severely limited in remote rural areas with high infectious disease burdens, particularly Africa, South America, and Asia, due to the lack of vaccines, the lack of resources to afford vaccines, or the logistical problems of trying to use temperature-sensitive vaccines. Marker vaccines are needed so that vaccinated/treated animals can be distinguished from subclinically infected or convalescent animals in real time during epidemics (Laddomada, 2003).
The emergence and dissemination of bacteria resistant to antimicrobial agents is the result of complex interactions among antimicrobial agents (e.g., antibiotics), microorganisms, disease transmission dynamics, and the environment (Heinemann, 1999; Heinemann et al., 2000). The increasing incidence of antimicrobial resistant bacterial pathogens will limit future options for prevention and treatment of infectious diseases in animals and humans (McDermott et al., 2002). The World Health Organization has called for human and veterinary antimicrobial agents to be sold only under prescription, and for the rapid phaseout of antimi- |
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crobial agents used as growth promotants (WHO 2003). They also recommend that all countries establish monitoring programs for tracking antimicrobial use and resistance. Research on the use of other treatments, such as probiot-ics and vaccines, holds promise (Gilchrist et al., 2007). The ongoing costs of research and development, and challenges to delivery will prevent acute drug treatments from ever becoming a stand-alone solution.
6.7.4 Tackling persistent chemicals to protect human health and the environment
Persistent chemicals include potentially toxic elements like heavy metals and organic pollutants that are normally present at relatively low concentrations in soils, plants, or natural waters, and which may or may not be essential for the growth and development of plants, animals, or humans (Pierzynski et al., 2000).
6.7.4.1 On-farm options
More effective and less costly in situ management strategies are available to mitigate the effects of persistent chemicals and to restore soil quality. The load of persistent chemicals such as fertilizer and pesticide residues, to ground and surface waters can be significantly reduced by available technologies, such as precision agriculture. Restorative technologies like bioremediation and phytoremediation (plant based remediation) are costly and still in development. Basic research is needed on the factors affecting biotransforma-tion processes (Adriano et al., 1999; Khan, 2005).
Intrinsic remediation using indigenous organisms can degrade industrial solvents (e.g., PCBs) and many pesticides on affected sites (Sadowski and Turco, 1999). In situ bioremediation can potentially treat organic and inorganic pollutants, clean soil without excavation and it is more cost effective than excavating and treating the soil on site bioremediation techniques. Such treatments remove the mobile and easily available fractions but cannot complete removal of all the contaminants (Doelman and Breedveld, 1999).
Phytoremediation refers to the extraction of contaminants via root uptake to shoot biomass and has wide application in the remediation of surface-polluted soils. Further analysis and discovery of genes for phytoremediation may benefit from recent developments in biotechnology (Krämer, 2005). Phytoremediation has potential risks, such as those associated to the use of transgenic techniques, release of nonindigenous species (potential weed) and transfer of toxic compounds to the other environmental compartments (Wenzel et al., 1999; Alkorta and Garbisu, 2001).
6.7.4.2 Off-farm technology
More effective and sensitive technologies for identifying early effects of pollution on ecosystems can also be developed. Damage could be prevented if the source of the pollution and the presence of the pollutants could be identified at minimal concentrations. Preventing or limiting the flow of chemical pollutants into the environment should be more effective than limiting damage by remediation.
New technologies that significantly increase awareness of biological impacts include biosensors and chemical approaches (Water Science and Technology Board, 2001; Heinemann et al., 2006). These approaches can also use |