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health and food scares (Mazzocchi, 2006). Piggott and Marsh (2004) find that beef demand declined by 0.144% in response to 10% increase in publications with negative information. Some studies differentiate positive (reassuring the public about food safety) and negative (reporting consequences of adverse events) information. Smith, Raveswaay and Thompson (1988) find that negative media coverage dominates positive coverage, arguing that positive coverage following negative items failed to fully restore consumer confidence. In the case of deliberate outbreaks, it is even more important for the government to communicate with the public about consequences and measures undertaken (Chalk, 2004; Parker, 2005). In the absence of such communication, news and television coverage may potentially initiate chain reactions of destabilising socio-political events. 3.1.3 Strategies which can be employed both ex ante and ex post Surveillance and detection is an example of the strategies that could be used both ex ante and ex post. A functional surveillance and detection system can identify and isolate infected animals and avoid disease spread. Early detection is the difference between an easily controllable outbreak and one that escalates out of control because of rapid disease transmission. The 2001 UK FMD outbreak escalated out of control largely because of the failure to identify infected sheep for more than a week, during which time the sheep were transported and the disease spread throughout the country (NAO, 2002). Accurate surveillance and detection is also a part of response strategy. Enhanced surveillance and detection, in the case of confirmed disease presence, allows earlier culling of infected AU: References ‘Doel and Fullen (1990) and Nayga et al. (2004)’ have been cited in the text but not provided in the list. Please check. Risk assessment and management of animal disease-related biosecurity 9 herds to limit pathogen transmission and reduces unnecessary culling to reduce containment costs (Wheelis, Casagrande and Madden, 2002). We expect more frequent and extensive detection and surveillance when used as a response strategy than when used as a preventive strategy. Vaccines are sometimes used to prevent and control animal diseases. Sumner, Bervejillo and Jarvis (2005) state that Uruguay, Argentina and Paraguay maintained FMD-free status with vaccination in some periods of the 1990s. Vaccination can play an important role as a response strategy. First, it can curb disease spread and decrease total event costs. Second, it can lessen pressure on the slaughter and disposal of contaminated animals. For example, during the course of the UK 2001 FMD outbreak, at the peak more than 400,000 animals were awaiting slaughter and more than 200,000 animals were awaiting disposal (NAO, 2002). This mass backlog suggests a potential value of vaccination as a response strategy, which slows down spread of disease while depopulation is underway. However, there are several issues associated with vaccination. 1 Effectiveness. Overall, effective vaccines exist against animal disease such as FMD, Newcastle disease, classical swine fever, highly pathogenic avian influenza, provided that they are produced with the appropriate serotype of the virus (Blancou and Pearson, 2003). 2 Feasibility. The feasibility of vaccination depends upon the availability of vaccines, timely delivery of vaccines to the affected areas, and number of available veterinarians at the local and national levels. In the case of FMD vaccines, besides conventional commercial FMD vaccine that has a 12 month shelf life, the North American Vaccine Bank (NAVB) and the European Pairbright Laboratory store and manage concentrated inactivated vaccines with a 15-year predicted shelf life (Doel and Fullen, 1990). A large scale vaccination imposes great pressure on vaccine reserves and may justify vaccine stocks as well. The second dimension of feasibility is whether vaccines can be delivered in a timely fashion to the infected and contact regions. Breeze (2004) argues in the US, it will take 1–2 days for preliminary diagnosis; 2 days to determine the virus subtype; 4 days to produce the vaccine and deliver it to the outbreak location and at least 1 day to administer the vaccine in the design area designated. This implies that it will take a minimum of 8–9 days to employ vaccination even if virus subtypes are available in NAVB. Last, a large number of animals needing to be vaccinated may impose pressure on veterinarians if vaccination is adopted. 3 Trade implications. Vaccination is not viewed as desirable in some diseases because of its trade implications. As stated in Breeze (2004), based on the technology of the 1980s, blood tests for FMD cannot distinguish between vaccinated animals and infected, but recovered animals that may be still infectious for long periods. International rules restrict exports from either FMD endemic countries or countries adopting vaccination to disease-free countries (Breeze, 2004; Sumner, Bervejillo and Jarvis, 2005). The trade disadvantage was the main reason for the Farmers Union opposition to vaccination during the 2001 FMD outbreak (NAO, 2002). However, commercial tests developed by the USDA scientists in 1994 are able to distinguish between vaccinated animals and previously infected animals (Breeze, 2004). Given the technology advancement and the increasing biological threat to animals, there is a need to revisit the trade barrier associated with vaccination. 10 Y. Jin, B.A. McCarl and L. Elbakidze 3.2 Resource allocation among strategies Resource allocation between ex ante and ex post strategies as well as within each category is a complex issue as it depends on various factors such as disease type and spread rate, the probability and expected damages brought on by the event, the effectiveness, costs and co-benefits of ex ante and ex post mitigation strategies (Elbakidze and McCarl, 2006). If we have sufficient information about all relevant factors, we can determine optimal resource allocation among prevention, preparedness, response and recovery measures subject to budget and technology constraints. Unfortunately,