Encephalitis

Symptoms

Spasms - convulsions
Fish appears to be having a fit, jerking and twisting abnormally.

Loss of balance
Fish keeps falling from its attempted swimming pattern.

Respiration slow
Fish's breathing is obviously slower than normal.

Breathing at surface
Fish stays at surface usually at an inclined angle and breathes or sucks air.

Causes

Swelling of brain. Probable cause a viral infection. There are likely more than one such, that cause the condition. The nodovirus (DIEV) has been described as causing this condition in Dicenthrachus labrax (Seabass). However another virus (LcEV) has also been described as causing encephalitis in the same species. They are similar and both are closely related to the members of the Nodaviridae family.

The disease has also been reported in Tilapia larvae, and is described as a herpes-like virus. Partial analyses places this outbreak in the TLEV category. A primary morphological, biophysical and molecular characterisation of TLEV tends to confirm this assumption and places TLEV within the family of Herpesvirida.

Based on these reports above, it seems that Encephalitis in fish can be brought about by a number of viruses, and more detailed investigations will be needed.

Prognosis

Invariably fatal.

Treatment

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Prevention

DNA and RNA diagnostic references

Purification and characterization of two fish encephalitis viruses (FEV) infecting Lates calcarifer and Dicentrarchus labrax

From Aquaculture June 1994 M.Comps et al.

Encephalitis

Symptoms

Causes

Prognosis

Treatment

Prevention

Pictures

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Videos

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