Article
Proliferative kidney disease of salmonid fish

https://doi.org/10.1016/0959-8030(93)90039-EGet rights and content

Abstract

Proliferative kidney disease (PKD) is one of the most economically important diseases among commercially reared rainbow trout (Oncorhynchus mykiss) in Europe and causes significant losses among Pacific salmon and rainbow trout populations in western North America. The parasite that causes PKD is a poorly understood myxosporean (PKX), presumed but not yet proven to be a member of the family Sphaerosporidae, genus Sphaerospora. The disease occurs in both cultured and feral populations of salmonids that come into contact with a 20–25 μm waterborne infective stage. The disease is often seasonally dependent occurring at water temperatures above 15 °C in the summer and fall months of the year. At permissive water temperatures, the first recognizable vegetative or extrasporogonic stages appear about 10–14 days after exposure to the infective stage. They are initially prominent in the blood sinuses of the kidney, are accompanied by a mild hyperplasia of the interstitial hematopoietic cell populations, and multiply via binary fission, endogeny, and plasmotomy, provoking a strong inflammatory response. This diffuse granulomatous response occurs principally in the kidney but is also seen in the spleen and other organs. The major host cell type involved in the lesion is the macrophage, but lymphocytes are also abundant in close proximity to PKX. As the inflammation progresses (6–8 weeks postexposure to the infective stage), the gross renal swelling becomes evident as do other clinical signs including anemia. Mortality in uncomplicated cases of PKD is generally 20% or less but often secondary pathogens or unfavorable environmental conditions coincide with peak periods of PKD and mortalities can reach 95–100%. Compromised renal functions such as macromolecule adsorption and divalent cation excretion are also impaired and this may contribute to the mortality observed among fish with PKD. Generally, by 12–20 weeks postexposure, fish begin, or are in the process of, recovery and the renal hematopoietic and excretory functions return to normal. In fish that have experienced a full clinical episode of the disease, a strong acquired immunity develops. The basis of the immunity is unknown but circulating antiparasite antibodies can be detected as early as six weeks postexposure to the infective stage. A strong cellular component to the immunity is also suspected. No vaccines have yet been developed to control PKD, and only recently have experimental therapies been applied. Both fumagillin DCH, an antibiotic effective against certain microsporidia and myxosporidia, and the arylmethane dye malachite green, have shown some promise as treatments for PKD. Unfortunately, neither drug is licensed for use in the U.S. and both treatments suffer from potential difficulties with drug toxicity, tissue residues, or durg discharges in hatchery effluent waters.

References (85)

  • P. de Kinkelin et al.

    L'hépatonéphrite des salmonidés

    La Pisiculture Francaise

    (1976)
  • P. de Kinkelin et al.

    L'hépatonéphrite parasitaire de la truite arc-en-ciel

    Bull. de l'office International des Epizooties

    (1976)
  • D.J. O'Brien et al.

    A renal disease of possible protozoan aetiology resembling nephrocalcinosis in rainbow trout

    Irish Veterinary Journal

    (1977)
  • J.A. Castillo et al.

    First description of PKD in rainbow trout (Oncorhynchus mykiss) in Spain

  • C.E. Smith et al.

    Proliferative kidney disease: First outbreak in North America

    Fish Health News

    (1982)
  • C.E. Smith et al.

    Proliferative kidney disease: First reported outbreak in North America

    J. Fish Dis.

    (1984)
  • R.P. Hedrick et al.

    Proliferative kidney disease PKD in Pacific salmon and steelhead trout

    J. World. Maricult. Soc.

    (1984)
  • G.E. Hoskins et al.

    Occurrence of proliferative kidney disease in British Columbia

  • E. MacConnell et al.

    Proliferative kidney disease in feral cutthroat trout from a remote Montana reservoir: A first case

    J. Aquat. Animal Health

    (1992)
  • R.P. Hedrick et al.

    Proliferative kidney disease (PKD) among salmonid fish in California, USA: A second look

    Bull. Eur. Assoc. Fish Pathol.

    (1985)
  • B.D. Hicks et al.

    Proliferative kidney disease (PKD) in Arctic char (Salvelinus alpinus) from Newfoundland

    Am. Fish. Soc. Fish Health Sec. Newsletter

    (1986)
  • C. Seagrave et al.

    A survey of the prevalence and distribution of proliferative kidney disease (PKD) in England and Wales

    J. Fish Dis.

    (1981)
  • D. Bucke et al.

    The occurrence of proliferative kidney disease (PKD) in cultured and wild fish: Further observations

    J. Fish Dis.

    (1991)
  • R.S. Clifton-Hadley et al.

    Economic importance of proliferative kidney disease of salmonid fish in England and Wales

    Vet. Rec.

    (1986)
  • A.E. Ellis et al.

    Proliferative kidney disease in brown trout, Salmotrutta L., and Atlantic salmon, Salmo salar L. parr: Histopathological and epidemiological observations

    J. Fish Dis.

    (1985)
  • R. Wooten et al.

    Some preliminary observations on proliferative kidney disease in wild brown trout, Salmo trutta L., in a Scottish stream

    Bull. Eur. Assoc. Fish Pathol.

    (1982)
  • K. Arkush et al.

    Experimental transmission of PKX, the causative agent of proliferative kidney disease, to three species of Pacific salmon

    J. Appl. Ichythol.

    (1990)
  • R.J. Roberts et al.

    Handbook of salmon and trout diseases

  • H.W. Ferguson et al.

    Proliferative kidney disease in rainbow trout, Salmo gairdneri Richardson

    J. Fish Dis.

    (1978)
  • R.S. Clifton-Hadley et al.

    A study of the sequential clinical and pathological changes during proliferative kidney disease in rainbow trout, Salmo gairdneri Richardson

    J. Fish Dis.

    (1987)
  • M.L. Kent et al.

    Development of the PKX myxosporean in rainbow trout, Salmo gairdneri

    Dis. Aquat. Org.

    (1986)
  • E. MacConnell et al.

    Cellular inflammatory response of rainbow trout to the protozoan parasite that causes proliferative kidney disease

    J. Aquatic Animal Health

    (1989)
  • H.W. Ferguson

    Systemic pathology of fishes. A text and atlas of comparative tissue responses in diseases of teleosts

  • R. Hoffmann et al.

    Haematological studies in proliferative kidney disease of rainbow trout, Salmo gairdneri Richardson

    J. Fish Dis.

    (1984)
  • R.S. Clifton-Hadley et al.

    Further consideration of the haematology of proliferative kidney disease (PKD) in rainbow trout, Salmo gairdneri Richardson

    J. Fish Dis.

    (1987)
  • J.S. Foott et al.

    Blood parameters and immune status of rainbow trout with proliferative kidney disease

    J. Aquatic Animal Health

    (1990)
  • R.J. Roberts

    Fish pathology

  • P.W. Scott

    Changes in the serum proteins of rainbow trout (Salmo gairdneri Richardson) through an outbreak of proliferative kidney disease

    Vet. Rec.

    (1984)
  • N.J. Olesen et al.

    Quantification of serum immunoglobulin in rainbow trout, Salmo gairdneri under various environmental conditions

    Dis. Aquat. Org.

    (1986)
  • M.L. Kent et al.

    PKX, the causative agent of proliferative kidney disease (PKD) in Pacific salmonid fishes and its affinities with the Myxozoa

    J. Protozool.

    (1985)
  • H.W. Ferguson et al.

    Protozoan associated with proliferative kidney disease in rainbow trout (Salmo gairdneri)

    Vet. Rec.

    (1977)
  • R.S. Clifton-Hadley et al.

    Method for the rapid diagnosis of proliferative kidney disease in salmonids

    Vet. Rec.

    (1983)
  • Cited by (202)

    View all citing articles on Scopus
    View full text