Preventative measures

Prevention is in the first line of disease management, and the development and implementation of biosecurity strategies for fish diseases is exercised at national level and is embodied in the codes of practice of several international organisations such as the EU 2006 Directive and the OIE code of practice. Oidtmann et al. (2011) provide an overview of international and national biosecurity strategies in aquatic animal health. Preventative measures on the whole require more risk analysis and closer adherence than they currently enjoy so that they may become a higher priority. Unfortunately, the preventative measures most closely adhered to tend to be largely those most closely regulated. Some of these preventative measures as out-fined below are subjected to intensive research and are dealt with elsewhere in this book. 

Stocking a pathogen-resistant host population is the most desirable requisite for disease control, since clinical disease is prevented by the natural immune process of the fish. Resistant host populations can be achieved in a number of ways and research is advanced in some more than others. 

The most notable application so far resulting from the use of molecular techniques is the breeding of lymphocystis disease-resistant Japanese flounder (Paralichthys olivaceus) (Fuji et al. 2006,2007). This was not a selective 

Many parasite pathogens are transferred to fish stocks via indigenous fish, ubiquitous in the local natural aquatic environment, and thus farm site selection should take this into account in disease prevention. Knowledge of pathogens in the ecosystem of the culture site and their seasonal dynamics would be a valuable weapon in the armoury against epizootics of cultured fish, yet this is rarely included in the preliminary surveys. Lakes, rivers, inshore and offshore waters have characteristic faunas which, known and understood, enable the analysis of risk of transfer of parasites into farm fish and for effective methods to be put into place to minimise or prevent introductions, e.g. fallowing, filters etc. to minimise the threat of epizootics. 

Vaccination is a major tool in disease prevention and is dealt with elsewhere in this book. Multi-vaccination, together with genotype selection constitutes the major direction for the future management and control of disease for bacterial and viral pathogens. However, the future for parasite vaccines is 

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Preventive Measures. The intake uptake biokinetic model (lUBK) projects the impact of lead in the environment on blood lead. This model assumes conservatively high levels of intake and cannot account for chemical speciation, thus over-predictions of blood lead levels often occur. Nonetheless, because of the allegations of the impact of blood lead and neurobehavioral development, blood lead levels in children are being reduced adrninistratively to below 10 //g/dL. In order to do so, soil leads are being reduced to a level of between 500—1000 ppm where remediation is required. 

Medical Programs. Large chemical plants have at least one hill-time physician who is at the plant five days a week and on call at all other times. Smaller plants either have part-time physicians or take injured employees to a nearby hospital or clinic by arrangement with the company compensation-insurance carrier. When part-time physicians or outside medical services are used, there is Httle opportunity for medical personnel to become familiar with plant operations or to assist in improving the health aspects of plant work. Therefore, it is essential that chemical-ha2ards manuals and procedures, which highlight symptoms and methods of treatment, be developed. A hill-time industrial physician should devote a substantial amount of time to becoming familiar with the plant, its processes, and the materials employed. Such education enables the physician to be better prepared to treat injuries and illnesses and to advise on preventive measures. 

The understanding of these actions of aspirin started in 1971 (45) and resulted in the recommendations of the medical community that small doses of aspirin, used under the care of the doctor, may be a prevention measure for heart attack, and stroke for those considered at risk in the population. Further reported work may expand health benefits to prevention of certain kinds of cancer (46). 

Leak or spill source Characteristics Root causes Preventive measures... 

Oxychlorination reactor feed purity can also contribute to by-product formation, although the problem usually is only with low levels of acetylene which are normally present in HCl from the EDC cracking process. Since any acetylene fed to the oxychlorination reactor will be converted to highly chlorinated C2 by-products, selective hydrogenation of this acetylene to ethylene and ethane is widely used as a preventive measure (78,98—102). 

If the measures under (1) and (2), which are also known as preventive measures, cannot be used with sufficient reliability, the constructional measures (3) must be applied. 

Apply heat treatment. Applying heat treatment is a remedial rather than a preventive measure. Sensitized metal may be reheated to tern-... 

Cautions. Precise determination of the cause of weld-root cracks can be difficult. Determining correct repair procedures and preventive measures may require metallographic examinations and analyses. 

The basic mechanisms involved in graphitic corrosion are familiar and easily understood. Hence, remedial and preventive measures are relatively simple to implement. Although commonly categorized as a form of dealloying, graphitic corrosion has much in common with galvanic corrosion. 

Are prevention measures being defined and used to control all identified potential health hazards adequately ... 

Product information in detail should be available and potential hazards should have been identified and occupational health preventive measures taken. Safe disposal of waste should be well under control. 

Modern management systems stress the need for continuous monitoring of defined systems and procedures for enforcement and improvement of quality systems. These should minimize immediately and eliminate ultimately the recurrence of simihir problems through preventive measures. 

From the above it is essential lo predetermine the nature, magnitude and steepness of such transients to decide the most appropriate protection or preventive measures for an FIT motor, particularly, for critical installations, such... 

Since competent manufacturers can accurately predict the susceptibility for the formation of the corrosive scale Ni3S2 for any gas analysis, it is possible to implement preventive measures. The preventive measure that is presently being used by Elliott and others is the use of a steam barrier. The principle of the steam barrier design is to inject steam into the inlet and exhaust chambers of the disc/blade area. The injection of steam into both these chambers creates a barrier of... 

Water contamination in the oil system can cause serious damage to turbomachinery, and every reasonable effort should be made to, first, prevent its entrance into the system, and second, provide suitable removal equipment if water cannot be effectively kept out. Experience indicates that designers and equipment operators can be more effective in keeping water out of the system. Since the main sources of contamination are atmospheric condensation, steam leaks, and faulty oil coolers, preventive measures should be taken. 

With a better understanding of the nature and severity of the water hammer problem, we can avoid its destructive forces. This greater understanding should also help with the introduction of more preventive measures into system designs and installations, which will help provide maximum safety for personnel, lower maintenance cost and reduce system downtime. 

Flue gas treatment (FGT) is more effective in reducing NO, emissions than are combustion controls, although at higher cost. FGT is also useful where combustion controls are not applicable. Pollution prevention measures, such as using a high-pressure process in nitric acid plants, is more cost-effective in controlling NO, emissions. FGT technologies have been primarily developed and are most widely used in Japan. The techniques can be classified as selective catalytic reduction, selective noncatalytic reduction, and adsorption. 

Implementation of cleaner production processes and pollution prevention measures can yield both economic and environmental benefits. The primary treatment technologies afforded to this manufacturing include the following ... 

Implementation of cleaner production processes and pollution prevention measures can yield both economic and environmental benefits. The following production-related targets can be achieved by measures such as those described above. The numbers relate to the production processes before the addition of pollution control measures. In sulfuric acid plants that use the double-contact, double absorption process, emissions levels of 2 to 4 kilograms of sulfur dioxide... 

A pesticide manufacturing plant should prepare a hazard assessment and operability study and also prepare and implement an emergency preparedness and response plan that takes into account neighboring land use and the potential consequences of an emergency. Measures to avoid the release of harmful substances should be incorporated in the design, operation, maintenance, and management of the plant. Implementation of cleaner production processes and pollution prevention measures can yield both economic and environmental benefits. 

Typical events that are considered are fire, explosion, ship collision, and the failure of pressurized storage vessels for which historical data established the failure frequencies. Assessment of consequences was based partly on conservative treatment of past experience. For example ilic assessment of the number of casualties from the release of a toxic material was based on past histoiy conditioned by knowledge of the toxicology and the prevailing weather conditions. An altemati. e used fault trees to estimate probabilities and identify the consequences. Credit is taken in this process for preventative measures in design, operation, and maintenance procedures. Historical data provide reliability expected from plant components and humans. 

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