GCRV (Grass Carp Reovirus)
TRANSMISSION
member of the genus Aquareovirus
Average diameter 69 mm
Isohedral in shape
Found in the inclusion bodies of the nucleus or cytoplasm
Not found in red cells or granular white cells
Sensitive to either acid and alkali
Incentive to drugs of the tetracycline family
high resistance to heat
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Horizontal: (Water borne or through ectoparasites
Not zoonotic: cannot be transmitted to humans
TEMPERATURE
optimum 25-28°C
HOST RANGE
Black carp
Topmouth gudgeon
Grass carp
CLINICAL SYMPTOMS
External
Internal
🚩Body become dark and slightly red
🚩hypodermic
🚩hyperemia in juveniles
🚩hemorrhages at the base of fins, gills covers and mouth cavity
🏁 hemorrhages throughout the musculature
🏁Red intestine
🏁Hemorrhagic gills or pale gills
🏁Hemorrhages in organs such as liver, spleen, kidney and intestine
DIAGNOSIS
Virus identification
💚neutralization test
💚ELISA
💚RT-PCR
Primary diagnosis
✅internal
✅external
✅isolation of the virus from infected fish by cell culture
TREATMENTS & CONTROL
❤Destructions of pathogens
❤Destructions of fish parasites
❤Depopulation
❤Use of virus free water
❤Disinfections of tools
❤Effective vaccination
VACCINE PREPARATION
1) Organs such as liver, spleen, and kidney from infected grass carp are collected and homogenized
2)Diluted with 0.85% NaCl to a concentrationof 1:100
3)Centrifuge at 3,000 rpm for 30 min
4)0.1% formalin is added to the supernatant
5)Solution is inactivated at 32°C for 72 h
6) The vaccine can be preserved at 4-8°C for up to 14 months
DURING PREPARATION
1)0.2-0.5 ml vaccine (depending on the fish size)
2)Injected intraperitoneally or intramuscularly to each fingerling
3) At water temperature above 20°C