Histopathological investigation of complex gill disease in sea farmed Atlantic salmon

Autoři: Mona C. Gjessing aff001;  Terje Steinum aff001;  Anne Berit Olsen aff002;  Kai Inge Lie aff001;  Saraya Tavornpanich aff001;  Duncan J. Colquhoun aff001;  Anne-Gerd Gjevre aff001
Působiště autorů: Norwegian Veterinary Institute, Oslo, Norway aff001;  Norwegian Veterinary Institute, Bergen, Norway aff002
Vyšlo v časopise: PLoS ONE 14(10)
Kategorie: Research Article
doi: https://doi.org/10.1371/journal.pone.0222926


Various agents including Ca. Piscichlamydia salmonis, Ca. Branchiomonas cysticola, Desmozoon lepeophtherii, Paramoeba perurans and salmon gill poxvirus may be associated with complex gill disease in Atlantic salmon. Co-infections involving two or more of these agents are common and histopathological interpretation of lesions is therefore challenging. In this study, we developed a semi-quantitative scoring system for examination of histopathological gill lesions in sea-farmed Atlantic salmon suffering from gill disease. Following qPCR analysis of gills sampled for Ca. P. salmonis, Ca. B. cysticola, D. lepeophtherii and P. perurans from 22 geographically spread outbreaks, five cases representing different infectious loads and combinations of agents were chosen for histopathological scoring. Twenty-eight histological features were evaluated and potential associations between individual pathological changes and the occurrence of individual agents studied. The inter-observer agreement in interpretation of histological parameters between the three pathologists involved, was calculated to validate robustness of the scoring scheme. Seventeen histological parameters met the criteria for inter-observer agreement analysis and were included in the calculation. The three most frequent findings were identification of subepithelial leukocytes, epithelial cell hyperplasia and mucus cell hyperplasia. While few findings could be specifically related to particular agents, necrosis in hyperplastic lesions, pustules and necrosis of subepithelial cells appeared to be associated with the presence of Ca. B. cysticola. Further, lesion profiles clearly support the previously identified association between P. perurans and pathological changes associated with AGD. Very few pathological changes were observed in the single case in which Ca. P. salmonis was the dominating agent. Some lesions were only very rarely observed e.g. chloride cell necrosis, epithelial cell apoptosis, lamellar deposition of melanin and haemophagocytosis. The scoring scheme developed and applied was robust and sensitive. A less extensive scheme for routine diagnostic use is proposed.

Klíčová slova:

Epithelial cells – Fish – Gills – Histology – Inflammation – Necrosis – Pathologists – Chlorides


1. Koppang EO, Kvellestad A, Fischer U. Fish mucosal immunity: gill, in Mucosal Health in Aquaculture, Beck B.H. and Peatman E., Editors. 2015, ELSEVIER. p. 385

2. Rodger HD, Mitchell SO. Marine Gill Histopathology Workshop. Bulletin of the European Association of Fish Pathologists. 2013;33(2):35–43.

3. Mitchell SO, Rodger HD. A review of infectious gill disease in marine salmonid fish. Journal of Fish Diseases. 2011;34(6):411–32. doi: 10.1111/j.1365-2761.2011.01251.x 21401646

4. Herrero A, Thompson KD, Ashby A, Rodger HD, Dagleish MP. Complex Gill Disease: an Emerging Syndrome in Farmed Atlantic Salmon (Salmo salar L.). Journal of Comparative Pathology. 2018;163:23–8. doi: 10.1016/j.jcpa.2018.07.004 30213370

5. Rodger HD, Henry L, Mitchell SO. Non-infectious gill disorders of marine salmonid fish. Reviews in Fish Biology and Fisheries. 2011;21(3):423–40.

6. Steinum T, Kvellestad A, Colguhoun DJ, Heum M, Mohammad S, Grontvedt RN, et al. Microbial and pathological findings in farmed Atlantic salmon Salmo salar with proliferative gill inflammation. Diseases of Aquatic Organisms. 2010;91(3):201–11. doi: 10.3354/dao02266 21133320

7. Steinum T, Sjastad K, Falk K, Kvellestad A, Colquhoun DJ. An RT PCR-DGGE survey of gill-associated bacteria in Norwegian seawater-reared Atlantic salmon suffering proliferative gill inflammation. Aquaculture. 2009;293(3–4):172–9.

8. Toenshoff ER, Kvellestad A, Mitchell SO, Steinum T, Falk K, Colquhoun DJ, et al. A novel betaproteobacterial agent of gill epitheliocystis in seawater farmed Atlantic salmon (Salmo salar). PloS one. 2012;7(3):e32696. doi: 10.1371/journal.pone.0032696 22427865

9. Kvellestad A, Falk K, Nygaard SM, Flesja K, Holm JA. Atlantic salmon paramyxovirus (ASPV) infection contributes to proliferative gill inflammation (PGI) in seawater-reared Salmo salar. Dis Aquat Organ. 2005;67(1–2):47–54. doi: 10.3354/dao067047 16385807

10. Weli SC, Dale OB, Hansen H, Gjessing MC, Ronneberg LB, Falk K. A case study of Desmozoon lepeophtherii infection in farmed Atlantic salmon associated with gill disease, peritonitis, intestinal infection, stunted growth, and increased mortality. Parasit Vectors. 2017;10(1):370. doi: 10.1186/s13071-017-2303-5 28764744

11. Steinum T, Kvellestad A, Ronneberg LB, Nilsen H, Asheim A, Fjell K, et al. First cases of amoebic gill disease (AGD) in Norwegian seawater farmed Atlantic salmon, Salmo salar L., and phylogeny of the causative amoeba using 18S cDNA sequences. Journal of fish diseases. 2008;31(3):205–14. doi: 10.1111/j.1365-2761.2007.00893.x 18261034

12. Steinum T, Kvellestad A, Colquhoun DJ, Heum M, Mohammad S, Grontvedt RN, et al. Microbial and pathological findings in farmed Atlantic salmon Salmo salar with proliferative gill inflammation. Dis Aquat Organ. 2010;91(3):201–11 doi: 10.3354/dao02266 21133320

13. Matthews CG, Richards RH, Shinn AP, Cox DI. Gill pathology in Scottish farmed Atlantic salmon, Salmo salar L., associated with the microsporidian Desmozoon lepeophtherii Freeman et Sommerville, 2009. J Fish Dis. 2013;36(10):861–9. doi: 10.1111/jfd.12084 23444900

14. Adams MB, Nowak BF. Distribution and structure of lesions in the gills of Atlantic salmon, Salmo salar L., affected with amoebic gill disease. Journal of fish diseases. 2001;24(9):535–42.

15. Young ND, Crosbie PB, Adams MB, Nowak BF, Morrison RN. Neoparamoeba perurans n. sp., an agent of amoebic gill disease of Atlantic salmon (Salmo salar). International journal for parasitology. 2007;37(13):1469–81

16. Freeman MA, Sommerville C. Desmozoon lepeophtherii n. gen., n. sp., (Microsporidia: Enterocytozoonidae) infecting the salmon louse Lepeophtheirus salmonis (Copepoda: Caligidae). Parasit Vectors. 2009;2(1):58. doi: 10.1186/1756-3305-2-58 19943930

17. Freeman MA, Sommerville C. Original observations of Desmozoon lepeophtherii, a microsporidian hyperparasite infecting the salmon louse Lepeophtheirus salmonis, and its subsequent detection by other researchers. Parasites & vectors. 2011;4:231.

18. Draghi A 2nd, Popov VL, Kahl MM, Stanton JB, Brown CC, Tsongalis GJ, et al. Characterization of "Candidatus piscichlamydia salmonis" (order Chlamydiales), a chlamydia-like bacterium associated with epitheliocystis in farmed Atlantic salmon (Salmo salar). Journal of clinical microbiology. 2004;42(11):5286–97. doi: 10.1128/JCM.42.11.5286-5297.2004 15528727

19. Nylund S, Steigen A, Karlsbakk E, Plarre H, Andersen L, Karlsen M, et al. Characterization of ‘Candidatus Syngnamydia salmonis’ (Chlamydiales, Simkaniaceae), a bacterium associated with epitheliocystis in Atlantic salmon (Salmo salar L.). Arch Microbiol. 2015;197(1):17–25. doi: 10.1007/s00203-014-1038-3 25294188

20. Apablaza P, Frisch K, Brevik OJ, Smage SB, Vallestad C, Duesund H, et al. Primary Isolation and Characterization of Tenacibaculum maritimum from Chilean Atlantic Salmon Mortalities Associated with a Pseudochattonella spp. Algal Bloom. J Aquat Anim Health. 2017;29(3):143–9. doi: 10.1080/08997659.2017.1339643 28613984

21. Gjessing MC, Yutin N, Tengs T, Senkevich T, Koonin E, Ronning HP, et al. Salmon Gill Poxvirus, the Deepest Representative of the Chordopoxvirinae. Journal of virology. 2015;89(18):9348–67. doi: 10.1128/JVI.01174-15 26136578

22. Gjessing MC, Christensen DH, Manji F, Mohammad S, Petersen PE, Saure B, et al. Salmon gill poxvirus disease in Atlantic salmon fry as recognized by improved immunohistochemistry also demonstrates infected cells in non-respiratory epithelial cells. Journal of fish diseases. 2018;41(7):1103–10. doi: 10.1111/jfd.12802 29745427

23. Gjessing MC, Thoen E, Tengs T, Skotheim SA, Dale OB. Salmon gill poxvirus, a recently characterized infectious agent of multifactorial gill disease in freshwater- and seawater-reared Atlantic salmon. Journal of fish diseases. 2017;40(10):1253–65. doi: 10.1111/jfd.12608 28105681

24. Nylund A, Watanabe K, Nylund S, Karlsen M, Saether PA, Arnesen CE, et al. Morphogenesis of salmonid gill poxvirus associated with proliferative gill disease in farmed Atlantic salmon (Salmo salar) in Norway. Archives of virology. 2008;153(7):1299–309. doi: 10.1007/s00705-008-0117-7 18521535

25. Lovy J, Goodwin AE, Speare DJ, Wadowska DW, Wright GM. Histochemical and ultrastructural analysis of pathology and cell responses in gills of channel catfish affected with proliferative gill disease. Dis Aquat Organ. 2011;94:125–34. doi: 10.3354/dao02322 21648241

26. Gibson-Corley KN, Olivier AK, Meyerholz DK. Principles for valid histopathologic scoring in research. Vet Pathol. 2013;50(6):1007–15. doi: 10.1177/0300985813485099 23558974

27. Rutgers M, van Pelt MJ, Dhert WJ, Creemers LB, Saris DB. Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage. Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society. 2010;18(1):12–23.

28. Sanchez JG, Speare DJ, Johnson GJ. Morphometric and histochemical assessment of the branchial tissue response of rainbow trout, Oncorhynchus mykiss (Walbaum), associated with chloramine-T treatment. Journal of Fish Diseases. 1997;20(5):375–81.

29. Mitchell SO, Baxter EJ, Holland C, Rodger HD. Development of a novel histopathological gill scoring protocol for assessment of gill health during a longitudinal study in marine-farmed Atlantic salmon (Salmo salar). Aquacult Int. 2012;20(5):813–25.

30. Mitchell SO, Steinum TM, Toenshoff ER, Kvellestad A, Falk K, Horn M, et al. ‘Candidatus Branchiomonas cysticola’ is a common agent of epitheliocysts in seawater-farmed Atlantic salmon Salmo salar in Norway and Ireland. Diseases of aquatic organisms. 2013;103(1):35–43. doi: 10.3354/dao02563 23482383

31. Fringuelli E, Gordon AW, Rodger H, Welsh MD, Graham DA. Detection of Neoparamoeba perurans by duplex quantitative Taqman real-time PCR in formalin-fixed, paraffin-embedded Atlantic salmonid gill tissues. J Fish Dis. 2012;35(10):711–24. doi: 10.1111/j.1365-2761.2012.01395.x 22804799

32. Gisev N, Bell JS, Chen TF. Interrater agreement and interrater reliability: key concepts, approaches, and applications. Res Social Adm Pharm. 2013;9(3):330–8. doi: 10.1016/j.sapharm.2012.04.004 22695215

33. R Core Team, R: A language and environment for statistical computing. R Foundation for Statistical Computing. 2019. URL https://www.R-project.org/.

34. Cicchetti DV. Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychological Assessment. 1994;6(4):284–90.

35. Farrell AP, Stevens ED, Cech JJ, Richards JG. Encyclopedia of fish physiology: from genome to environment. London; Waltham, MA: Academic Press, an imprint of Elsevier; 2011.

36. Gjessing MC, Thoen E, Tengs T, Skotheim SA, Dale OB. Salmon gill poxvirus, a recently characterized infectious agent of multifactorial gill disease in freshwater- and seawater-reared Atlantic salmon. J Fish Dis. 2017.

37. Gunnarsson GS, Karlsbakk E, Blindheim S, Plarre H, Imsland AK, Handeland S, et al. Temporal changes in infections with some pathogens associated with gill disease in farmed Atlantic salmon (Salmo salar L). Aquaculture. 2017;468:126–34.

38. Savykoski T, Harju T, Paldanius M, Kuitunen H, Bloigu A, Wahlstrom E, et al. Chlamydia pneumoniae infection and inflammation in adults with asthma. Respiration. 2004;71(2):120–5. doi: 10.1159/000076671 15031565

39. Hou S, Yue L, Xu R, Zhu C, Shan S, Wang H, et al. Chlamydia muridarum plasmid induces mouse oviduct pathology by promoting chlamydial survival and ascending infection and triggering host inflammation. Eur J Dermatol. 2018;28(5):628–36. doi: 10.1684/ejd.2018.3399 30442635

40. Munday BL, Zilberg D, Findlay V. Gill disease of marine fish caused by infection with Neoparamoeba pemaquidensis. Journal of Fish Diseases. 2001;24(9):497–507.

41. Roubal FR, Lester RJG, Foster CK. Studies on Cultured and Gill-Attached Paramoeba Sp (Gymnamoebae, Paramoebidae) and the Cyto-Pathology of Paramebic Gill Disease in Atlantic Salmon, Salmo-Salar L, from Tasmania. Journal of Fish Diseases. 1989;12(5):481–92.

42. Kent ML, Whyte JNC, Latrace C. Gill Lesions and Mortality in Seawater Pen-Reared Atlantic Salmon Salmo-Salar Associated with a Dense Bloom of Skeletonema-Costatum and Thalassiosira Species. Diseases of aquatic organisms. 1995;22(1):77–81.

43. Aamelfot M, Dale OB, Weli SC, Koppang EO, Falk K. Expression of the infectious salmon anemia virus receptor on atlantic salmon endothelial cells correlates with the cell tropism of the virus. Journal of virology. 2012;86(19):10571–8. doi: 10.1128/JVI.00047-12 22811536

Článek vyšel v časopise


2019 Číslo 10
Nejčtenější tento týden