in blood vessels, but with relatively few and mild lesions in
organs. The inflammatory response is variable, depending on
the duration of the disease and temperature. A mucosal and
sub-mucosal granulomatous gastritis may found in more
chronic cases. In the compact/spongy interface of the ventricular myocardium, aggregates of the parasite may be found.
Individual parasitic cells, alone or in clusters may also be
recorded in blood vessels virtually anywhere in the body, but
frequently occur in vessels of the choroid and in coronary
branches. In the brain, vast numbers of the parasite may be
found infiltrating the meninges. Typically, the inflammatory
response is minimal.
The parasite has an alternating life cycle between trophozoite and cyst. They multiply by longitudinal binary fission.
The trophozoites are motile by 6 anterior flagella arranged in
two groups, and two posterior flagella (Fig. 8.31), with size
ranging from 6 to 35 μm. Diagnosis is assisted by light
microscopy to identify characteristic flagellates and lesions,
while accurate identification of species must be based upon
molecular analysis.
Further Reading
Adams MB, Crosbie PBB, Nowak BF (2012) Preliminary success using
hydrogen peroxide to treat Atlantic salmon, Salmo salar L., affected
with experimentally induced amoebic gill disease (AGD). J Fish Dis
35:839–848
Allen RL, Meekin TK, Pauley GB, Fujihara MP (1968) Mortality
among chinook salmon associated with the fungus Dermocystidium.
J Fish Res Board Can 25:2467–2475
Andreou D, Arkush KD, Gue ´gan J-F, Goxlan RE (2012) Introduced
pathogens and native freshwater biodiversity: a case study of
Sphaerothecum destruens. PLoS One 7(5):e36998. doi:10.1371/
journal.pone.0036998
Ardelli BF, Forward GM, Woo PTK (1994) Brook charr, Salvelinus
fontinalis (Mitchill), and cryptobiosis: a potential salmonid reservoir host for Cryptobia salmositica Katz, 1951. J Fish Dis
17:567–577
Awakura A (1974) Studies on the microsporidian infection in salmonid
fishes. Sci Rep Hokkaido Fish Hatch 29:1–95
Bower SM, Evelyn TPT (1980) Acquired and innate resistance to the
haemoflagellate Cryptobia salmositica in sockeye salmon
(Oncorhynchus nerka). Dev Comp Immunol 12:749–760
Bruno DW (1992) Ichthyobodo sp., on farmed Atlantic salmon, Salmo
salar L., reared in the marine environment. J Fish Dis 15:349–351
Bruno DW (2001) Dermocystidium sp. in Scottish Atlantic salmon,
Salmo salar: evidence for impact on fish in marine fish farms.
Bull Eur Assoc Fish Pathol 21:209–213
Bruno DW, Collins R, Morrison CM (1995) The occurrence of Loma
salmonae sp., (Protozoa: Microspora) in farmed rainbow trout,
Oncorhynchus mykiss Walbaum in Scotland. Aquaculture
133:341–344
Bruno DW, Nowak B, Elliott DG (2006) A guide to the identification of
fish protozoan and metazoan parasites in stained tissue sections. Dis
Aquat Org 70:1–36
Bustos PA, Young ND, Rozas MA, Bohle HM, Ildefonso RS, Morrison
RN, Nowak BF (2011) Amoebic gill disease (AGD) in Atlantic
salmon (Salmo salar) farmed in Chile. Aquaculture 310:281–288
Crosbie PBB, Bridle AR, Cadoret K, Nowak BF (2012) In vitro cultured
Neoparamoeba perurans causes amoebic gill disease in Atlantic
salmon and fulfils Koch’s postulates. Int J Parasitol 42:511–545
Draghi A, Bebak J, Popov VL, Noble AC, Geary S, West AB, Byrne P,
Frasca S (2007) Characterisation of a Neochlamydia-like bacterium
associated with epitheliocystis in cultured Arctic charr Salvelinus
alpinus. Dis Aquat Org 76:27–38
Ellis AE, Wootten R (1978) Costiasis of Atlantic salmon, Salmo salar
L. smolts in salt water. J Fish Dis 1:389–393
Ferguson JA, St-Hilaire S, Peterson TS, Rodnick KJ, Kent ML (2011)
Survey of parasites in threatened stocks of coho salmon
(Oncorhynchus kisutch) in Oregon by examination of wet tissues
and histology. J Parasitol 97:1085–1098
Isaksen TE, Karlsbakk E, Sundnes GA, Nylund A (2010) Patterns of
Ichthyobodo necator sensu stricto infections on hatchery-reared
Atlantic salmon Salmo salar in Norway. Dis Aquat Org 88:07–214
Jørgensen A, Sterud E (2006) The marine pathogenic genotype of
Spironucleus barkhanus from farmed salmonids redescribed as
Spironucleus salmonicida n. sp. J Eukaryot Microbiol 53:531–541
Jørgensen A, Torp K, Bjørland MA, Poppe TT (2011) Wild Arctic char
Salvelinus alpinus and trout Salmo trutta: hosts and reservoir of the
salmonid pathogen Spironucleus salmonicida (Diplomonadida;
Hexamitidae). Dis Aquat Org 97:57–63
Kent ML, Speare DJ (2005) Review of the sequential development of
Loma salmonae (Microsporidia) based on experimental infections
of rainbow trout (Oncorhynchus mykiss) and Chinook salmon (O.
tshawytscha). Folia Parasitologia 52:63–68
Kent ML, Sawyer TK, Hedrick RP (1988) Paramoeba pemaquidensis
(Sarcomastigophora: Paramoebidae) infestation of the gills of coho
salmon Oncorhynchus kisutch reared in salt water. Dis Aquat Org
5:163–169
Kent ML, Elliot DG, Groff JM, Hedrick RP (1989) Loma salmonae
(Protozoa: Microspora) infections in salt water reared coho salmon
Oncorhynchus kisutch. Aquaculture 80:211–222
Kent ML, Ellis J, Fournie JW, Dawe SC, Bagshaw JW, Whitaker DJ
(1992) Systemic hexamitid (Protozoa: Diplomonadida) infection in
salt water pen-reared chinook salmon Oncorhynchus tshawytscha.
Dis Aquat Org 14:81–89
Kocan RP, Hershberger P, Winton J (2004) Ichthyophoniasis: an
emerging disease of Chinook salmon in the Yukon river. J Aquat
Animal Health 16:58–72
Fig. 8.31 Spironucleus sp. in the gut of farmed rainbow trout. Notice
flagella. Phase contrast
120
8 Protists
organs. The inflammatory response is variable, depending on
the duration of the disease and temperature. A mucosal and
sub-mucosal granulomatous gastritis may found in more
chronic cases. In the compact/spongy interface of the ventricular myocardium, aggregates of the parasite may be found.
Individual parasitic cells, alone or in clusters may also be
recorded in blood vessels virtually anywhere in the body, but
frequently occur in vessels of the choroid and in coronary
branches. In the brain, vast numbers of the parasite may be
found infiltrating the meninges. Typically, the inflammatory
response is minimal.
The parasite has an alternating life cycle between trophozoite and cyst. They multiply by longitudinal binary fission.
The trophozoites are motile by 6 anterior flagella arranged in
two groups, and two posterior flagella (Fig. 8.31), with size
ranging from 6 to 35 μm. Diagnosis is assisted by light
microscopy to identify characteristic flagellates and lesions,
while accurate identification of species must be based upon
molecular analysis.
Further Reading
Adams MB, Crosbie PBB, Nowak BF (2012) Preliminary success using
hydrogen peroxide to treat Atlantic salmon, Salmo salar L., affected
with experimentally induced amoebic gill disease (AGD). J Fish Dis
35:839–848
Allen RL, Meekin TK, Pauley GB, Fujihara MP (1968) Mortality
among chinook salmon associated with the fungus Dermocystidium.
J Fish Res Board Can 25:2467–2475
Andreou D, Arkush KD, Gue ´gan J-F, Goxlan RE (2012) Introduced
pathogens and native freshwater biodiversity: a case study of
Sphaerothecum destruens. PLoS One 7(5):e36998. doi:10.1371/
journal.pone.0036998
Ardelli BF, Forward GM, Woo PTK (1994) Brook charr, Salvelinus
fontinalis (Mitchill), and cryptobiosis: a potential salmonid reservoir host for Cryptobia salmositica Katz, 1951. J Fish Dis
17:567–577
Awakura A (1974) Studies on the microsporidian infection in salmonid
fishes. Sci Rep Hokkaido Fish Hatch 29:1–95
Bower SM, Evelyn TPT (1980) Acquired and innate resistance to the
haemoflagellate Cryptobia salmositica in sockeye salmon
(Oncorhynchus nerka). Dev Comp Immunol 12:749–760
Bruno DW (1992) Ichthyobodo sp., on farmed Atlantic salmon, Salmo
salar L., reared in the marine environment. J Fish Dis 15:349–351
Bruno DW (2001) Dermocystidium sp. in Scottish Atlantic salmon,
Salmo salar: evidence for impact on fish in marine fish farms.
Bull Eur Assoc Fish Pathol 21:209–213
Bruno DW, Collins R, Morrison CM (1995) The occurrence of Loma
salmonae sp., (Protozoa: Microspora) in farmed rainbow trout,
Oncorhynchus mykiss Walbaum in Scotland. Aquaculture
133:341–344
Bruno DW, Nowak B, Elliott DG (2006) A guide to the identification of
fish protozoan and metazoan parasites in stained tissue sections. Dis
Aquat Org 70:1–36
Bustos PA, Young ND, Rozas MA, Bohle HM, Ildefonso RS, Morrison
RN, Nowak BF (2011) Amoebic gill disease (AGD) in Atlantic
salmon (Salmo salar) farmed in Chile. Aquaculture 310:281–288
Crosbie PBB, Bridle AR, Cadoret K, Nowak BF (2012) In vitro cultured
Neoparamoeba perurans causes amoebic gill disease in Atlantic
salmon and fulfils Koch’s postulates. Int J Parasitol 42:511–545
Draghi A, Bebak J, Popov VL, Noble AC, Geary S, West AB, Byrne P,
Frasca S (2007) Characterisation of a Neochlamydia-like bacterium
associated with epitheliocystis in cultured Arctic charr Salvelinus
alpinus. Dis Aquat Org 76:27–38
Ellis AE, Wootten R (1978) Costiasis of Atlantic salmon, Salmo salar
L. smolts in salt water. J Fish Dis 1:389–393
Ferguson JA, St-Hilaire S, Peterson TS, Rodnick KJ, Kent ML (2011)
Survey of parasites in threatened stocks of coho salmon
(Oncorhynchus kisutch) in Oregon by examination of wet tissues
and histology. J Parasitol 97:1085–1098
Isaksen TE, Karlsbakk E, Sundnes GA, Nylund A (2010) Patterns of
Ichthyobodo necator sensu stricto infections on hatchery-reared
Atlantic salmon Salmo salar in Norway. Dis Aquat Org 88:07–214
Jørgensen A, Sterud E (2006) The marine pathogenic genotype of
Spironucleus barkhanus from farmed salmonids redescribed as
Spironucleus salmonicida n. sp. J Eukaryot Microbiol 53:531–541
Jørgensen A, Torp K, Bjørland MA, Poppe TT (2011) Wild Arctic char
Salvelinus alpinus and trout Salmo trutta: hosts and reservoir of the
salmonid pathogen Spironucleus salmonicida (Diplomonadida;
Hexamitidae). Dis Aquat Org 97:57–63
Kent ML, Speare DJ (2005) Review of the sequential development of
Loma salmonae (Microsporidia) based on experimental infections
of rainbow trout (Oncorhynchus mykiss) and Chinook salmon (O.
tshawytscha). Folia Parasitologia 52:63–68
Kent ML, Sawyer TK, Hedrick RP (1988) Paramoeba pemaquidensis
(Sarcomastigophora: Paramoebidae) infestation of the gills of coho
salmon Oncorhynchus kisutch reared in salt water. Dis Aquat Org
5:163–169
Kent ML, Elliot DG, Groff JM, Hedrick RP (1989) Loma salmonae
(Protozoa: Microspora) infections in salt water reared coho salmon
Oncorhynchus kisutch. Aquaculture 80:211–222
Kent ML, Ellis J, Fournie JW, Dawe SC, Bagshaw JW, Whitaker DJ
(1992) Systemic hexamitid (Protozoa: Diplomonadida) infection in
salt water pen-reared chinook salmon Oncorhynchus tshawytscha.
Dis Aquat Org 14:81–89
Kocan RP, Hershberger P, Winton J (2004) Ichthyophoniasis: an
emerging disease of Chinook salmon in the Yukon river. J Aquat
Animal Health 16:58–72
Fig. 8.31 Spironucleus sp. in the gut of farmed rainbow trout. Notice
flagella. Phase contrast
120
8 Protists