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Carp edema virus disease (CEVD), also known as koi sleepy disease, is caused by a poxvirus associated with outbreaks of clinical disease in koi and common carp Cyprinus carpio. Originally characterised in Japan in the 1970s, international trade in koi has led to the spread of CEV, although the first recognised outbreak of the disease outside of Japan was not reported until 1996 in the USA. In Europe, the disease was first recognised in 2009 and, as detection and diagnosis have improved, more EU member states have reported CEV associated with disease outbreaks. Although the structure of the CEV genome is not yet elucidated, molecular epidemiology studies have suggested distinct geographical populations of CEV infecting both koi and common carp. Detection and identification of cases of CEVD in common carp were unreliable using the original PCR primers. New primers for conventional and quantitative PCR (qPCR) have been designed that improve detection, and their sequences are provided in this paper. The qPCR primers have successfully detected CEV DNA in archive material from investigations of unexplained carp mortalities conducted > 15 yr ago. Improvement in disease management and control is possible, and the principles of biosecurity, good health management and disease surveillance, applied to koi herpesvirus disease, can be equally applied to CEVD. However, further research studies are needed to fill the knowledge gaps in the disease pathogenesis and epidemiology that, currently, prevent an accurate assessment of the likely impact of CEVD on European koi and common carp aquaculture and on wild carp stocks.

According to the European Council Directive 2006/88/EC, additional legislation should be implemented describing sampling and diagnostic procedures for the diseases listed in Annex IV Part 2 of the Directive. The sampling plans and the diagnostic methods for the detection and confirmation of VHS and IHN diseases and for ISA disease are described in commission decisions from 2001 and 2003, respectively. However, KHV was only included as a non-exotic disease at the implementation of the Council Directive and no descriptions of procedures were available for this disease. A preliminary version, describing sampling and diagnostic procedures, was later provided on the EURL Fish web page. This version was based on recommendations from the report of a KHV expert working group under the EPIZONE network “KHV PCR diagnosis and surveillance” convened at the Central Veterinary Institute, Lelystad, The Netherlands, in 2009. However, significant new knowledge based on new research on KHV has appeared in recent years. So, the EURL asked the Commission for permission to organize an expert meeting in order to discuss and agree common new recommendations for sampling and diagnosis of KHV for implementation in a new Commission Decision. The two day meeting was held at the premises of the EURL at Frederiksberg, Denmark and three of the top experts in the field of KHV from Germany, Netherlands and UK, respectively, were invited to participate. The meeting was very successful and produced final drafts of two documents: 1) The Commission decision Part 2 on surveillance and diagnostic methods for KHV 2) Diagnostic procedures for the surveillance and confirmation of KHV disease. Significant changes from the former versions were accepted and recommended for inclusion in the commission decision. Among the changes are: - The splitting of sampling and diagnostic tests for diagnostic and surveillance purposes respectively. - Inclusion of real-time PCR as the method of choice for sur

De koi sector is bekend met verschillende ziekten van koi, zoals koi herpesvirus (KHV) en columnaris disease door Flavobacterium columnare. Dit najaar is echter een in Nederland nog niet eerder aangetoonde ziekte aangetroffen in koi: het koi sleepy disease (KSD). We gaan in dit artikel in op deze ziekte

De koi sector is bekend met verschillende ziekten van koi, zoals koi herpesvirus (KHV) en columnaris disease door Flavobacterium columnare. Dit najaar is echter een in Nederland nog niet eerder aangetoonde ziekte aangetroffen in koi: het koi sleepy disease (KSD).

Koi herpesvirus (KHV), which is also known as Cyprinid herpesvirus 3 (CyHV-3) infection, is an OIE(international des epizootis) listed disease that caused high losses in common and koi carp in Indonesiaand Japan in 2002 and 2003. Since the mid of 2006, the polymerase chain reaction (PCR) has been usedin Malaysia for surveillance of koi fingerlings to detect virus nucleic acid, but it has been found to produceunreliable results. Following this, an alternative enzyme-link immunosorbent assay (ELISA) technique forthe detection of antibody against KHV was used to find evidence of KHV infection in koi carp stocks on farmsthat had been sampled for the PCR. For this purpose, a total of 245 serum samples from koi carp stocks werecollected and tested for the antibody to KHV by the ELISA at the Centre for Environment, Fisheries andAquaculture Science (CEFAS) laboratory, Weymouth, UK. Two hundred and eight samples were found to benegative but 37 others were either definitely positive or close to borderline positive and all were retested. Thefinal results showed that 222 (90%) samples were confirmed as negative and 19 (8%) others were definitelypositive. Meanwhile, four samples (1.6%) were positive at dilutions of 1:400 or 1:200, but cross reactionswith CyHV-1 (causing herpesviral epidermal hyperplasia) could have occurred at those dilutions. Three of thesamples were the only positive fish at two sites, but the fourth sample came from a site at which there were 4definite positive samples (from 20 fish sampled). Thus this study confirmed that Malaysian koi stocks havepreviously been exposed to KHV. With the lack of bio-security measures and awareness, there was a highprobability that the koi carp had been exposed to KHV, leading to subclinical infections and some fish mightpossibly have become carriers of the virus. Hence, further surveillance needs to be conducted to determinethe true situation of the KHV infection in Malaysia.

Koi herpesvirus (KHV), which is also known as Cyprinid herpesvirus 3 (CyHV-3) infection, is an OIE(international des epizootis) listed disease that caused high losses in common and koi carp in Indonesiaand Japan in 2002 and 2003. Since the mid of 2006, the polymerase chain reaction (PCR) has been usedin Malaysia for surveillance of koi fingerlings to detect virus nucleic acid, but it has been found to produceunreliable results. Following this, an alternative enzyme-link immunosorbent assay (ELISA) technique forthe detection of antibody against KHV was used to find evidence of KHV infection in koi carp stocks on farmsthat had been sampled for the PCR. For this purpose, a total of 245 serum samples from koi carp stocks werecollected and tested for the antibody to KHV by the ELISA at the Centre for Environment, Fisheries andAquaculture Science (CEFAS) laboratory, Weymouth, UK. Two hundred and eight samples were found to benegative but 37 others were either definitely positive or close to borderline positive and all were retested. Thefinal results showed that 222 (90%) samples were confirmed as negative and 19 (8%) others were definitelypositive. Meanwhile, four samples (1.6%) were positive at dilutions of 1:400 or 1:200, but cross reactionswith CyHV-1 (causing herpesviral epidermal hyperplasia) could have occurred at those dilutions. Three of thesamples were the only positive fish at two sites, but the fourth sample came from a site at which there were 4definite positive samples (from 20 fish sampled). Thus this study confirmed that Malaysian koi stocks havepreviously been exposed to KHV. With the lack of bio-security measures and awareness, there was a highprobability that the koi carp had been exposed to KHV, leading to subclinical infections and some fish mightpossibly have become carriers of the virus. Hence, further surveillance needs to be conducted to determinethe true situation of the KHV infection in Malaysia.

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