Infectious hematopoietic necrosis virus

Infectious Hematopoietic Necrosis (IHN ) is a notifiable in Germany animal disease.

Occurrence

The HIM is a viral disease of salmonid fish ( salmonids ) and was previously known only in North America. Were affected preferentially the Pacific salmon species ( Oncorhynchus ).

Only since 1987, there were outbreaks of this disease in Europe, first in France and Italy, and later in some cases also in Germany, Belgium and Switzerland.

The disease is most developed at temperatures of 10 ° C and can then kill 85-100 % of a fish stock in trout farms within 1-2 weeks. No outbreaks have been recorded at temperatures above 15 ° C.

Pathogens and symptoms

Correspondingly similar are also symptoms. The fish show in the whole body petechielle bleeding into muscles, fins and eyes. You go blind and therefore take a reflex dark body color on. Mostly they show goggle eyes. Through accumulation of tissue fluid ( ascites ) in the abdominal cavity they look inflated. Because of the inflammation of the intestine them into strings from coherent feces.

On histological examination, necrotic tissue damage in the blood-forming ( hematopoietic ) tissues of the kidneys ( name of disease ) show.

Transmission

The relatively insensitive of the virus is transmitted both through contact with diseased fish as well as water birds and insufficiently disinfected fishing tackle.

The infection does not necessarily lead to immediate illness. Fish stocks can be " durchseucht dumb ". Only in stressful situations such as transport or exposure to poor water quality can cause the outbreak of the costly disease in supposedly healthy stocks. Epidemiological studies should therefore capture the antibody status, while the direct virus detection may be unsuccessful.