# Commission Implementing Decision (EU) 2015/1554 of 11 September 2015 laying down rules for the application of Directive 2006/88/EC as regards requirements for surveillance and diagnostic methods (notified under document C(2015) 6188) (Text with EEA relevance), Division II.4: Histology

Extent: E+W+S+N.I.

Paraffin-embedded sections shall be cut at 5 μm and stained using haematoxylin and eosin.
Histological changes in clinically diseased Atlantic salmon are variable, but may include the following:
(a)numerous erythrocytes in the central venous sinus and lamellar capillaries of the gills, where erythrocyte thrombi also may be formed;
(b)multifocal to confluent petechiae or hepatocyte necrosis or both at some distance from larger vessels in the liver; multifocal accumulation of erythrocytes in dilated hepatic sinusoids;
(c)accumulation of erythrocytes in blood vessels of the intestinal lamina propria and eventually haemorrhage into the lamina propria;
(d)spleen stroma distended by erythrocyte accumulation;
(e)slight multifocal to extensive diffuse interstitial haemorrhage with tubular necrosis in the haemorrhagic areas, erythrocyte accumulation in the glomeruli in the kidney;
(f)erythrophagocytosis in the spleen and secondary haemorrhages in liver and kidney.

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Source: https://www.legislation.gov.uk/eudn/2015/1554/annex/II/part/3/division/II/division/II.4 (the official version)
Page: https://openlegislation.uk/eu-decision-2015-1554/annex-II/part-3/division-II/division-II.4
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.