Hepatic carcinoma in rainbow trout
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Archives of Pathology↗
Geology topics
E. M. Wood
Publications and source records attributed to E. M. Wood.
Chemical and histological studies of wild and hatchery salmon in fresh water
In a study of coho salmon ( Oncorhynchus kisutch ), the gross chemical and histological changes occurring over a 14-month period spent in fresh water were determined. The determinations were made at 3-month intervals on: 1) hatchery-reared fish, 2) fish hatchery-reared for 3, 6, 9, and 12 months and then planted in a controlled stream for the remainder of the period; and 3) an indigenous group of wild fish in this stream. Wild fish showed high incidence of tissue damage from spinose hairs of the moth larva, Halisidota argentata. Hatchery fish were similarly affected with the severity and incidence of lesions varying directly with the time of exposure of the larvae in the wild environment. Both groups of fish were heavily parasitized by sporozoan organisms in the kidney and spinal cord. Kidney disease appeared in both wild and planted hatchery fish. The gross chemical composition of hatchery fish transformed rapidly after planting to that of the wild fish. Although the initial rate of fat loss is essentially constant for all hatchery groups after planting, fish that were hatchery reared for 9 to 12 months did not complete the transformation to the wild-type body composition by the time of downstream migration at 14 months.
Transactions of the American Fisheries Society↗
The nutrition of salmonid fishes. I. Chemical and histological studies of wild and domestic fish
Salmonids reared under artificial conditions show marked consistent differences in body composition in comparison with wild salmonids. Protein and mineral levels are lower and lipid values are higher in hatchery fish than in wild fish. As the period of artificial rearing is increased, these differences become more extreme. In hatchery fish, there is generally more microscopically visible fat in the liver and viscera than in these organs in wild fish although extremes are seen in both groups. In young hatchery fish and in wild fish, there is no correlation between fat deposition in the liver and in the pancreas, but in older hatchery fish, both of these organs are fatty and there is a simultaneous increase in total body lipid. In wild fish, ceroid deposition is greater, suggesting that the fatty acids are more highly unsaturated. There is little difference in disease incidence between the two groups, but parasitism is more pronounced in wild fish. The significant variables between wild and artificially produced fish appear to be limited to diet and environment. From the factors discussed above, diet alone is probably the most important single factor in producing the changes observed in body composition.
Alaska, British Columbia, California, Oregon, Wash↗
The nutrition of salmonid fishes. II. Studies on production diets
In 69 production diets fed to hatchery salmonids, there was a wide variation in the ingredients of the diets and in their content of protein, fat, carbohydrate and ash. There was a close correlation between the body composition of hatchery-raised fish and the composition of the diets fed. The data indicated, however, that differences in hatchery management, such as level of feeding, were also important contributing factors in producing the observed body composition of hatchery fish. Wild fish had a markedly different body composition characterized by a much lower level of fat and relatively higher protein and mineral content The effect on survival of differences in body composition between wild and hatchery fish is discussed. There is a clearly defined need for additional research on the nutritional requirements of salmonids, the relationship between body composition and ability to survive, and for quality control in hatchery nutrition.
Journal of Nutrition↗
Acute sulfamethazine toxicity in young salmon
Adverse effects from the medication of fish diseases with sulfonamides have been reported by several workers. A decreased growth rate (Gutsell and Snieszko 1949, Snieszko and Wood 1955), the production of drug resistant strains of pathogens (Snieszko 1952), sterility and kidney damage (Wood et al., 1955), and mortalities (Johnson and Brice 1953) have been described. Recently, increased mortalities and tissue damage were observed in young silver salmon after a single day's treatment with sulfamethazine. Subsequently an attempt to reproduce the conditions experimentally was made. The purpose of this paper is to describe the pathology of acute sulfamethazine toxicity and to discuss certain factors of possible importance in the etiology of losses among fish treated with sulfonamides.
Progressive Fish-Culturist↗
Some myxosporidia found in Pacific Northwest salmonids
During the histological examination of a group of wild and hatchery salmonids undescribed sporazoans were frequently observed. This was not unexpected, since Myxosporidia are typical fish parasites (Kudo, 1920). Myxidium were observed in kidney tubules, Cholromyxum in glomeruli, and Myxobous in the spinal cord and on epidermal scales. The present paper will deal with the description and indentification of these unclassified Myxosporodia.
Oregon, Washington↗
Histopathology of fish. IV. A granuloma of brook trout
In the summer of 1952, Snieszko and Griffin (1955) diagnosed kidney disease in brook trout from the Fish and Wildlife Service's station at Berlin, New Hampshire. During the examination of these fish, a peculiar lesion was observed in the vicinity of the gastric caeca. In very advanced cases, hard, glistening, white masses of tissue bearing a striking resemblance to mature testes often filled the abdominal cavity. In the initial examinations, the material was actually mistaken for normal testicular tissue. Subsequently, it was recognized as an entirely aberrant, proliferating tumor-like mass.
Progressive Fish-Culturist↗
Histopathology of fish. III. Peduncle ("cold-water") disease
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Progressive Fish-Culturist↗
Histopathologic changes of a virus-like disease of sockeye salmon
Rucker et al., (1953) described a disease of sockeye salmon ( O ncorhynchus nerka ) of possible viral etiology. First seen in Washington in 1951 with relatively minor losses, the disease recurred in 1952 killing over two million fingerling salmon with a mortality rate of 91.5 percent (Watson, 1954). In 1953, the disease was present in every sockeye salmon hatchery in the state. Rucker, Watson and their associates have demonstrated that the disease is infectious, caused by a serially-transmissible and filterable agent, and specific for one species of fish. Watson et al., (1956) have described the hematology of infected salmon. The present paper deals with the histopathology of the disease.
Transactions of the American Microscopical Society↗
Tissue damage in salmonids caused by Halisidota argentata Packard
During the histological examination of a collection of wild and hatchery salmonids, a peculiar foreign body was occasionally observed in various organs, particularly in the viscera. These objects, usually accompanied by a focal inflammation, were observed in 10 of 75 samples of wild trout and salmon collected in Oregon and Washington and were believed to represent an unknown type of parasitism. Their identity remained obscure until a massive concentration was observed in the tissues of wild coho salmon, ( Oncorhynchus kisutch ), from Minter Creek on the Olympic peninsula of Washington and in hatchery coho salmon from the Minter Creek Biological Station. The distribution of the structures suggested the intestinal tract as a point of origin. Subsequent stomach examinations revealed small, partially digested insect fragments with many long, spine-covered hairs. The insects were identified as second or third instars of the lepidopteran larvae, Halisidota argentata Packard. The spine-covered hairs penetrated the stomach wall and produced the observed lesions by working in an apparent porcupine quill-fashion throughout the body of the fish. The pathology of the Minter Creek salmon was sufficiently extensive to merit a description of the condition for the benefit of other workers who may encounter this rather unusual phenomenon and confuse it with an actual parasitic infection.
Oregon, Washington↗
Ceroid in fish
Since the original description of ceroid in rats, many papers have appeared on the etiology and characteristics of this pigment. It was first seen as a yellow, granular pigment in hematoxylin and eosin sections of the cirrhotic livers of choline deficient rats. The pigment was more fully characterized by Endicott and Lillie, and additional stainging reactions were summarized recently by Lillie. The pigment is sudanophilic in paraffin sections, acid-fast, basophilic, isotropic, iron negative, and highly resistant to solution in water, alcohol, fat solvents, and dilute aqueous acids and alkalis. It is stained by Mallory's hemofuscin stain and Weigert's myelin stain. It reduces osmium tetraoxide and diamine silver carbonate but not ferric ferricyanide. The Gmelin reactions for bile pigments is negative. It has a greenish yellow fluorescence at 3650-3660 Å. It is Schiff positive with or without antecedent diastase digestion after performic or periodic acid oxidation.
The American Journal of Pathology↗
Histopathology of kidney disease in fish
Kidney disease is one of the most puzzling fish diseases known to exist in the United States. In less than Io years it has invaded the Pacific Northwest, exacting a heavy toll of hatchery salmon. Its first appearance apparently was in Massachusetts where Belding and Merrill' described a disease similar to that now seen on the Pacific Coast. In I946 it was diagnosed in Washington2 and since that time has been observed in an ever increasing number of hatcheries. There are unpublished reports of the same or similar diseases in both California and Washington in the early I93o's.3 The latest outbreaks occurred in the Federal hatcheries at Berlin, New Hampshire, and Cortland, New York, in brook, brown, and rainbow trout.4 There is evidence to indicate that the disease may be much more widely spread in New York State.5 The disease is especially dangerous since little is known of the origin or source of the causative agent. Indeed, the classification of the diplobacillus associated with kidney disease is still uncertain. Thus, with our present knowledge, it is difficult or impossible to eradicate the malady from an infected hatchery. Histopathologic studies were undertaken to clarify the pathology of the disease and to compare the eastern form with the western form.
American Journal of Pathology↗
A mycosis-like granuloma of fish
Mycoses of systemic distribution are rarely observed in fresh-water fish in this country. In a recent review of atypical cell growths in fishes, Nigrelli cited the only known instance of a mycetoma in a North American fresh-water fish which occurred in the head of fingerling landlocked salmon from an Idaho hatchery. The fungus associated with this granuloma was characterized by a branching septate mycelium. Rucker reported a streptomycete which was pathogenic to blueblack salmon. This organism produced internal nodules containing masses of hyphae but no inflammatory response. A pathogenic fungus has been observed frequently in marine fish, however, and in both marine and fresh-water fish in Europe. This organism was tentatively classified as a Phycomycete in or near the order Chytridiales and was assigned to the genus and species Ichthyophonus hoferi , later reclassified as Ichthyosporidium hoferi . The graduloma described in this report occurs in fresh-water trout and is apparently caused by a budding, yeast-like form with no hyphae which evokes a tremendous inflammatory reaction. Morphologically, the organism does not resemble the previously described Ichthyosporidium. The lesions were first seen accidentally in sections prepared from a diplobacillus infection of brook trout termed “kidney disease.” Subsequently, the granuloma was observed in three widely separated infections involving the diplobacillus in each instance. The histological material was received in a fixed condition; thus, no cultural data was available and the nomenclature and classification of the mycotic organism were not attempted. The present distribution of the disease, however, with its potential threat to domestic fish populations, seemed to warrant a description and discussion of the disease. Efforts are in progress to culture the organism.
Journal of Infectious Diseases↗
The effect of some sulfonamides on the growth of brook trout, brown trout, and rainbow trout
Sulfonamides such as sulfisoxazole (Gantrisin R ), sulfamerazine, and a mixture of sulfamerazine with sulfaguanidine were fed to apparently normal fingerlings of brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), and rainbow trout (Salmo gairdneri). None of these drugs had any growth‐affecting influence on rainbow trout. Growth of brook trout was somewhat retarded by sulfamerazine. The retardation of the growth of brown trout was greater with sulfamerazine than with the mixture of two sulfonamides. Sulfisoxazole did not retard growth of any of the three species. As soon as the medicated food was replaced with normal, brown trout resumed growth. Observations are also furnished on the tissue levels of sulfonamides and hemoglobin in the experimental trout.
Transactions of the American Fisheries Society↗
Histopathology of fish: I. Techniques and principles
The techniques of histopathology have been used for many years in the study of human and animal diseases. Until very recent times, however, histology has been applied to fish studies only very infrequently. This brief discussion is intended to acquaint the reader with the techniques and principles involved and to explain how histological studies may help to overcome fish diseases and nutritional problems.
Progressive Fish-Culturist↗