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Cold water strawberry disease (CWSD), or red mark syndrome (RMS), is a severe dermatitis affecting the rainbow trout Oncorynchus mykiss. The condition, which presents as multifocal, raised lesions on the flanks of affected fish, was first diagnosed in Scotland in 2003 and has since spread to England and Wales. Results of field investigations indicated the condition had an infectious aetiology, with outbreaks in England linked to movements of live fish from affected sites in Scotland. Transmission trials confirmed these results, with 11 of 149 and 106 of 159 naïve rainbow trout displaying CWSD-characteristic lesions 104 to 106 d after being cohabited with CWSD-affected fish from 2 farms (Farm B from England and Farm C from Wales, respectively). The condition apparently has a long latency, with the first characteristic lesions in the previously naïve fish not definitively observed until 65 d (650 day-degrees) post-contact with affected fish. Affected fish from both outbreak investigations and the infection trial were examined for the presence of viruses, oomycetes, parasites and bacteria using a combination of techniques and methodologies (including culture-independent cloning of PCR-amplified bacterial 16S rRNA genes from lesions), with no potentially causative infectious agent consistently identified. The majority of the cloned phylotypes from both lesion and negative control skin samples were assigned to Acidovorax-like β-Proteobacteria and Methylobacterium-like α-Proteobacteria. KEY WORDS: RFLP · 16S rRNA · Clone library · Flavobacterium psychrophilum · Red mark syndromeResale or republication not permitted without written consent of the publisher Dis Aquat Org 79: 207-218, 2008 report that the disease is prevalent at low water temperatures (<15°C), in comparison to the UK experience of WWSD, which generally occurs only when water temperatures exceed 14°C (a summer rather than winter condition). Early signs of CWSD can include severe scale loss prior to the emergence of the characteristic external lesions (Ferguson et al. 2006), and there are no signs of systemic infection (i.e. no affect on appetite, growth or mortality). However, the condition causes losses to farmers both in treatment costs and in downgrading of affected fish at harvest.The objective of the present study was to determine if the disease had an infectious aetiology by conducting a disease investigation on farms affected by the condition. Laboratory trials evaluating whether the condition could be transmitted from affected to naïve fish were also conducted. As a recent report implicated Flavobacterium psychrophilum as potentially being linked to the condition (Ferguson et al. 2006), particular effort was made to identify whether this, or a closely related organism, was associated with diseased fish. MATERIALS AND METHODS Outbreak investigationsOutbreaks of CWSD at 3 farms in England and Wales were investigated between January 2005 and January 2006. Structured interviews with the farmers asked about the chronology of the disease o...

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Summary The application of risk analysis to the spread of disease with international trade in animals and their products, that is, import risk analysis (IRA), has been largely driven by the Sanitary and Phytosanitary (SPS) agreement of the World Trade Organization (WTO). The degree to which the IRA standard established by the World Organization for Animal Health (OIE), and associated guidance, meets the needs of the SPS agreement is discussed. The use of scenario trees is the core modelling approach used to represent the steps necessary for the hazard to occur. There is scope to elaborate scenario trees for commodity IRA so that the quantity of hazard at each step is assessed, which is crucial to the likelihood of establishment. The dependence between exposure and establishment suggests that they should fall within the same subcomponent. IRA undertaken for trade reasons must include an assessment of consequences to meet SPS criteria, but guidance is sparse. The integration of epidemiological and economic modelling may open a path for better methods. Matrices have been used in qualitative IRA to combine estimates of entry and exposure, and consequences with likelihood, but this approach has flaws and better methods are needed. OIE IRA standards and guidance indicate that the volume of trade should be taken into account, but offer no detail. Some published qualitative IRAs have assumed current levels and patterns of trade without specifying the volume of trade, which constrains the use of IRA to determine mitigation measures (to reduce risk to an acceptable level) and whether the principle of equivalence, fundamental to the SPS agreement, has been observed. It is questionable whether qualitative IRA can meet all the criteria set out in the SPS agreement. Nevertheless, scope exists to elaborate the current standards and guidance, so they better serve the principle of science‐based decision‐making.