Infectious haematopoietic necrosis

The infectious hematopoietic necrosis (IHN) is a disorder salmon-like fish. In Germany it is subject to the notification requirement according to the Animal Health Act (TierGesG).

Occurrence

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

Outbreaks of this epidemic did not occur in Europe until 1987, first in France and Italy, and later in isolated cases in Germany, Belgium and Switzerland.

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

Pathogen and Symptoms

The pathogen is a rhabdovirus and is closely related to the trout VHS pathogen .

The symptoms are correspondingly similar. The fish show petechial bleeding in the muscles, fins and eyes throughout the body. They go blind and therefore reflect a dark body color. Occasionally they show goggle eyes. They appear bloated due to the accumulation of tissue fluid (ascites) in the body cavity. Because of the inflammation of the intestines, they give off feces in strings.

The histological examination reveals necrotic tissue damage in the blood-forming ( haematopoietic ) tissue of the kidneys (name of the disease).

transmission

The relatively insensitive virus is transmitted through contact with sick fish as well as waterfowl and through insufficiently disinfected fishing equipment.

The infection does not necessarily lead to immediate illness . Fish stocks can be "silently contaminated". Only in stressful situations such as transport or exposure to poor water quality can the loss-making disease break out in supposedly healthy stocks. Epidemiological studies should therefore record the antibody status, while direct virus detection may not be successful.

Web links

Information sheet from the Swiss Veterinary Administration on IHN (PDF file; 18 kB)

Individual evidence

↑ Ordinance on notifiable animal diseases in the version published on July 19, 2011 ( Federal Law Gazette I p. 1404 ), amended by Article 3 of the Ordinance of May 3, 2016 ( Federal Law Gazette I p. 1057 ) in conjunction with Section 4 of the Act for the prevention and control of animal diseases (Animal Health Act - TierGesG) of May 22, 2013 ( Federal Law Gazette I, p. 1324 ), last amended by Article 8, paragraph 12 of the law of December 3, 2015 ( Federal Law Gazette I, p. 2178 )

[1] Ordinance on notifiable animal diseases in the version published on July 19, 2011 ( Federal Law Gazette I p. 1404 ), amended by Article 3 of the Ordinance of May 3, 2016 ( Federal Law Gazette I p. 1057 ) in conjunction with Section 4 of the Act for the prevention and control of animal diseases (Animal Health Act - TierGesG) of May 22, 2013 ( Federal Law Gazette I, p. 1324 ), last amended by Article 8, paragraph 12 of the law of December 3, 2015 ( Federal Law Gazette I, p. 2178 )