8
CARL S . SINDERMANN
stomatitis in fishes from South American rivers (Torres and Pacheco,
1934 ; Pacheco, 1935), viral hemorrhagic septicemia of salmonids in
Europe (Jensen, 1963), and infectious pancreatic necrosis of trout,
Xalvelinus fontinalis (Mitchill) and S a l m guirdneri Richardson (Wolf
et al., 1960). Among the anadromous species, viral etiology has been
indicated for a disease of chinook salmon, Oncorhynchus tshawytscha
(Walb.), from the Sacramento River, California (Ross et al., 1960;
Parisot and Pelnar, 1962), and for a more widespread disease of sockeye
salmon, Oncorhynchus nerka (Walb.), in the Pacific Northwest (Watson
et al., 1954; Guenther et al., 1959). Transovarian transmission was
hypothesized for the chinook disease, and the feeding of fingerlings
with diets including salmon carcasses was implicated in the sockeye
disease. The discreteness of the viruses involved, and the pathological
changes in host tissue, have been summarized by Parisot et al. (1965)
and Yasutake et al. (1965).
Viruses that do not cause tumors have not yet been clearly demonstrated in marine fishes. Moewus (1963) reported studies of a ciliate
parasite, Miamiensis avidus Thompson and Moewus, which was isolated
from tumor-like nodules on seahorses, Hippocampus erectus Perry.
The organism was studied as a possible vector of virus; polio virus
was used in absence of a suitable laboratory strain of marine virus.
Results were inconclusive, but the author’s suggestion of parasites as
possible vectors of fish viruses does not seem unreasonable ; in fact it
was made previously by Thomas (1931) and Nigrelli (1948) in reference
to epidermal hyperplasias of cyprinids. Transmission of viral and
rickettsia1 agents by parasites is known for certain diseases of mammals
(swine influenza and salmon poisoning of dogs). Moewus-Kobb (1965)
also reported that virus of infectious pancreatic necrosis of fresh-water
fishes multiplied when introduced into cell cultures derived from a
marine fish, the grunt, Haemulon sciurus (Shaw). The same cell line
of grunt was found to harbor a presumed “ orphan virus ” destructive
to primary explants as well as fish cell lines (Clem et al., 1965).
B. Bacteria
Reports of bacterial epizootics in marine fishes are surprisingly
infrequent, and in fact relatively few bacterial pathogens have been
recorded from natural populations of marine fishes. This is probably
due to lack of observation or to inadequate examination rather than
lack of occurrence. Two examples support this view. Oppenheimer and
Kesteven (1953) reported underwater observations of fish schools in
which up to 10% of individuals exhibited lesions indicative of bacterial
infections later demonstrated by smears and cultures. Sindermann and
CARL S . SINDERMANN
stomatitis in fishes from South American rivers (Torres and Pacheco,
1934 ; Pacheco, 1935), viral hemorrhagic septicemia of salmonids in
Europe (Jensen, 1963), and infectious pancreatic necrosis of trout,
Xalvelinus fontinalis (Mitchill) and S a l m guirdneri Richardson (Wolf
et al., 1960). Among the anadromous species, viral etiology has been
indicated for a disease of chinook salmon, Oncorhynchus tshawytscha
(Walb.), from the Sacramento River, California (Ross et al., 1960;
Parisot and Pelnar, 1962), and for a more widespread disease of sockeye
salmon, Oncorhynchus nerka (Walb.), in the Pacific Northwest (Watson
et al., 1954; Guenther et al., 1959). Transovarian transmission was
hypothesized for the chinook disease, and the feeding of fingerlings
with diets including salmon carcasses was implicated in the sockeye
disease. The discreteness of the viruses involved, and the pathological
changes in host tissue, have been summarized by Parisot et al. (1965)
and Yasutake et al. (1965).
Viruses that do not cause tumors have not yet been clearly demonstrated in marine fishes. Moewus (1963) reported studies of a ciliate
parasite, Miamiensis avidus Thompson and Moewus, which was isolated
from tumor-like nodules on seahorses, Hippocampus erectus Perry.
The organism was studied as a possible vector of virus; polio virus
was used in absence of a suitable laboratory strain of marine virus.
Results were inconclusive, but the author’s suggestion of parasites as
possible vectors of fish viruses does not seem unreasonable ; in fact it
was made previously by Thomas (1931) and Nigrelli (1948) in reference
to epidermal hyperplasias of cyprinids. Transmission of viral and
rickettsia1 agents by parasites is known for certain diseases of mammals
(swine influenza and salmon poisoning of dogs). Moewus-Kobb (1965)
also reported that virus of infectious pancreatic necrosis of fresh-water
fishes multiplied when introduced into cell cultures derived from a
marine fish, the grunt, Haemulon sciurus (Shaw). The same cell line
of grunt was found to harbor a presumed “ orphan virus ” destructive
to primary explants as well as fish cell lines (Clem et al., 1965).
B. Bacteria
Reports of bacterial epizootics in marine fishes are surprisingly
infrequent, and in fact relatively few bacterial pathogens have been
recorded from natural populations of marine fishes. This is probably
due to lack of observation or to inadequate examination rather than
lack of occurrence. Two examples support this view. Oppenheimer and
Kesteven (1953) reported underwater observations of fish schools in
which up to 10% of individuals exhibited lesions indicative of bacterial
infections later demonstrated by smears and cultures. Sindermann and