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Increased fry or fingerling mortality in catfish in warm weather, especially after stress, should raise suspicion of CCVD.
Increased fry or fingerling mortality in catfish in warm weather, especially after stress, should raise suspicion of CCVD.
CCV can be detected in '''water''' containing infected fish and organs of diseases fish, particularly the '''kidneys'''. All viscera should be taken from fish of 4-6cm, whole fish if smaller and kidney, spleen and encephalon if larger than 6cm. All should be transported cooled or on ice but not frozen. The virus can be '''isolated in cell culture and identified by Virus Neutralisation, [[Fluorescent Antibody Testing]] (FAT), [[ELISA testing|ELISA]] and PCR'''. FAT and ELISA are best for diagnosis of clinically infected fish while carrier fish can only be detected by Neutralisation or PCR. The formation of '''syncytia''' in ovary cell cultures is also specific for CCV.
CCV can be detected in '''water''' containing infected fish and organs of diseases fish, particularly the '''kidneys'''. All viscera should be taken from fish of 4-6cm, whole fish if smaller and kidney, spleen and encephalon if larger than 6cm. All should be transported cooled or on ice but not frozen. The virus can be '''isolated in cell culture and identified by Virus Neutralisation, [[Fluorescent antibody testing]] (FAT), [[ELISA testing|ELISA]] and PCR'''. FAT and ELISA are best for diagnosis of clinically infected fish while carrier fish can only be detected by Neutralisation or PCR. The formation of '''syncytia''' in ovary cell cultures is also specific for CCV.
At necropsy, the '''peritoneal cavity is hyperaemic and a serosanguinous fluid''' often present. The liver and kidneys may be pale and petechiated. Yellow mucoid material is found within the digestive tract.
At necropsy, the '''peritoneal cavity is hyperaemic and a serosanguinous fluid''' often present. The liver and kidneys may be pale and petechiated. Yellow mucoid material is found within the digestive tract.
Histologically, '''extensive tubular and interstitial tissue necrosis''' is evident in the kidneys of infected fish. Haematopoeitic tissues show '''lymphoid aggregation, oedema, necrosis and macrophage accumulation'''. Similar congestion, oedema, macrophage infiltration and focal haemorrhage is seen in the liver, spleen, gastrointestinal mucosa and infrequently, heart. Occasional eosinophilic inclusions may be seen in hepatocytes.
Histologically, '''extensive tubular and interstitial tissue necrosis''' is evident in the kidneys of infected fish. Haematopoeitic tissues show '''lymphoid aggregation, oedema, necrosis and macrophage accumulation'''. Similar congestion, oedema, macrophage infiltration and focal haemorrhage is seen in the liver, spleen, gastrointestinal mucosa and infrequently, heart. Occasional eosinophilic inclusions may be seen in hepatocytes.
==Treatment==
==Treatment==