Diagnostic methods Diseased fish

Mortality of fingerlings and older fish can be expected at temperatures below 18-20 C, i.e. in the spring and at the beginning of the summer, but less frequently in the autumn and winter. Clinical diagnosis is based on behavioural and external and internal signs. Haemorrhage in the skin, pale gills, ascites and protruding vent, as well as enteritis, peritonitis, oedema and varying degrees of petechial haemorrhage in the swim-bladder, muscles and other organs, warrant sampling of fish for...

Diseases

Fish ranaviruses are endotheliotropic and cause haemorrhagic diathesis, oedema and peripheral circulatory failure. Epizootic haematopoietic necrosis appeared during the spring of 1984 in a lake and caused severe mortality among juvenile redfin perch. The disease is less serious in farmed rainbow trout. Experimentally infected 35-45-day-old redfin perch develop depression, skin darkening and erratic swimming and die after 4-5 days (Langdon, 1989). Some have erythema around the brain and...

Introduction

Warm-water fin-fish which spend their entire life cycle in fresh water are considered in this chapter. They form the largest segment of the world aquaculture production and a major part of the catch-fish industry in inland waters. The harvest of farmed warm-water fish is increasing, due to investment, refinement in technologies, rapid transfer of advances and a continuous widening of the spectrum of cultivated species. Wolf (1988) in his review on fish viruses and fish viral diseases described...

Control and treatment Epizootiology

Reservoirs of virus are the overtly and the dormantly infected fish. Transmission is mostly horizontal but the claimed vertical or 'egg associated' transmission from carrier brood fish to eggs and fry seems to be important for virus survival and for perpetuation of infection in catfish culture. Horizontal transmission occurs by contact and through water, and is easily demonstrable by cohabitation of virus-free catfish with infected fish. Channel catfish virus is probably shed via faeces and...

Channel Catfish Virus Disease Introduction

Channel catfish virus disease is an acute, communicable and highly species-specific disease of young channel catfish (Ictalurus punctatus) in the USA. The causal agent is known as channel catfish virus (CCV) or ictalurid herpesvirus 1. Infection of susceptible, almost exclusively juvenile, fish results in viraemia and mortality, which occasionally reach nearly 100 . Historically, awareness of a viral disease affecting fry and fingerlings began when the channel catfish industry expanded in the...

Grass Carp Haemorrhagic Disease Introduction

Grass carp haemorrhagic disease is a severe acute disease caused by the grass carp reovirus GCRV . The disease has been known in the People's Republic of China since the 1950s Mao et al., 1988 . The GCRV was isolated during 1978-84 Mao et al., 1988 and described by Chen and Jiang 1984 . Nie and Pan 1985 , Wolf 1988 and Winton 1989 reviewed the status of knowledge on the virus and on the disease. Additional data are presented by Jiang and Ahne 1989 and Jiang et al. 1994 . Some papers written in...

The virus

Gambar Virus Channel Catfish Virus

The aetiological agent of CCVD, CCV, is herpesvirus-like Fijan et al., 1970 and was named Herpesvirus ictaluri Wolf and Darlington, 1971 . Robin and Rodrigue 1980b suggested the provisional designation ictalurid herpesvirus 1. Davison 1992 classified CCV as a sole member of a new, fourth, herpesvirus subfamily. The characterization of immediate-early genes in the CCV genome suggests that the virus is most closely related to the alpha subfamily of Herpesviridae Silverstein et al., 1995 . Fig....

Spring Viraemia Of Carp Introduction

Spring viraemia of carp is an acute, systemic, contagious disease caused by a rhabdovirus. The term SVC and the name Rhabdovirus carpio RVC for the causal agent were introduced by Fijan et al. 1971 . The virus is also known as SVCV and as RVC. It belongs to the vesiculo group vesiculovirus genus Wunner and Peters, 1991 of rhabdoviruses Lenoir and de Kinkelin, 1975 and affects primarily the common carp Cyprinus carpio . Several other cyprinids and some other species are also susceptible. Spring...

Pike Fry Rhabdovirus Disease

Pike fry rhabdovirus disease is an acute to subacute contagious disease characterized by haemorrhage, hydrops and high mortality in fry and young northern pike Esoxlucius and in a few other species. The causal agent of PFRD is closely related to SVCV. Mortality of pike fry and young fish has been a significant problem in several hatcheries in the Netherlands since 1956. Two clinical entities, 'hydrocephalus' and 'red disease', were described Bootsma, 1971 . Their viral aetiology was proved by...

Species of fish affected and geographical distribution

Natural outbreaks of CCVD occur almost exclusively in cultivated channel catfish. There is only one brief account of a natural outbreak in blue catfish Ictalurus furcatus fingerlings Plumb, 1989 . The virus has not been reported from wild channel or any other wild catfish. Experimental induction of disease by i.p. injection of virus is possible in fingerlings of blue catfish and of channel catfish x blue catfish hybrids. However, CCVD could not be induced in these fish by oral administration of...

Diagnostic methods

The diagnosis of CCVD is based on the isolation and identification of CCV or on immunological demonstration of CCV antigen in infected fish tissues. The detection of the dormant CCV infection by these methods is recommended by Fig. 5.11. Formation and contraction of syncytia in CCO cells about 14 h after inoculation with CCV and incubation at 30 C. Wright stain. x 230. Fig. 5.11. Formation and contraction of syncytia in CCO cells about 14 h after inoculation with CCV and incubation at 30 C....

The disease

Multiplication of virus in capillary endothelium, as well as in haemopoietic and excretory kidney tissues, causes an impaired salt-water balance, which is often lethal. Characteristic macroscopic lesions include oedema, haemorrhage, anaemia, enteritis and peritonitis. Mixed and secondary infections can lead to additional clinical signs and increased mortality. The disease signs outlined below are based on uncomplicated natural SVC outbreaks and experimental infections in the laboratory Fijan et...