Robert A. Dieterich

STAPHYLOCOCCAL INFECTION AND TOXOPLASMOSIS IN A YOUNG HARBOR SEAL

Generalized subcutaneous abscessation followed by acute systemic infection occurred in a young male harbor seal (Phoca vitulina richardii). Clinically, infection was manifested by malaise, progressive weight loss, labored respiration, intermittant vomitation, and mucohemorrhagic diarrhea. A coagulase-positive Staphylococcus aureus was isolated from the subcutaneous abscesses, and specimens of lung, liver, small intestine, and kidney. Microscopically, cysts and trophozoites of Toxoplasma gondii were found in, or adjacent to, foci of necrosis present throughout the liver parenchyma.

Body Growth in Sixteen Rodent Species and Subspecies Maintained in Laboratory Colonies

Body growth as weight change during the initial year is described for 10 microtines: Microtus pennsylvanicus tananaensis, M. oeconomus macfarlani, M. o. operarius, M. miurus, M. abbreviatus, Lemmus lemmus, L. sibiricus, Dicrostonyx stevensoni and Clethrionomys rutilus; five cricetines: Peromyscus maniculatus borealis, P. m. bairdii, Baiomys taylori, Calomys ducilla, and Calomys callosus; and one murid, Acomys cahirinus. The growth curves constituted sets of linear segments and were characterized by their respective slopes and initiation points. A rapid growth phase was sometimes preceded by a slower initial phase and always succeeded by a slower attenuation phase. A stable adult weight was achieved in some species but not others. Early and later growth were compared using times for 40% and 80% of the weight (WA) at 1 yr (t40, t80). Early growth as gram per week was relatively stable among subspecies or related species; or between animals of different size when normalized as percent of WA per week, or t40 by a common weight function. By contrast, later growth (t80) was much more variable and may be viewed as a possible adaptive factor.

Experimental infection of reindeer with bovine viral diarrhea virus.

Two 8-month reindeer ( Rangifer tarandus ) and a 1-month-old Hereford-Holstein calf ( Bos taurus ) were inoculated intranasally with the Singer (cytopathogenic) strain of bovine viral diarrhea (BVD) virus. Clinical signs in reindeer included loose stools containing blood and mucus, and transient laminitis or coronitis. Signs in the calf were limited to bloody mucus in the stool and lesions in the nasal mucosa. Antibody titers to BVD virus in the reindeer were intermittent, and titers in the calf persisted from days 14 to 63 post-inoculation (PI). Viremia was detected on PI day 4 in one reindeer, days 3-7 in the other, and days 2-7 in the calf. Bovine viral diarrhea virus was isolated from the lung of the calf at necropsy (PI day 63).

SEROLOGIC AND EXPERIMENTAL INVESTIGATIONS OF CONTAGIOUS ECTHYMA IN ALASKA

Serologic evidence of contagious ecthyma (CE) was found in domestic sheep (Ovis aries), domestic goats (Capra hircus), Dall sheep (Ovis dalli), and muskox (Ovibos moschatus) in Alaska. A moose (Alces alces) calf and a caribou (Rangifer tarandus) fawn were susceptible to experimental infection and both developed antibody titers as a result. CE virus was isolated from lesions of Dall sheep which were involved in a natural outbreak of the disease.

THE OCCURRENCE OF SETARIA IN REINDEER

Setaria yehi Desset, 1966, is reported from domestic reindeer (Rangifer tarandus Linnaeus), maintained at College and Cantwell, Alaska. Microfilariae were present in blood from reindeer harboring S. yehi. Gross and microscopic findings in the infected animals revealed a low-grade peritonitis. Caribou, moose, dairy cows, goats, and dogs examined in the local areas were negative for microfilariae.

Trypanosoma cervi from Alaskan reindeer, Rangifer tarandus.

Twenty-nine (64.4%) or 45 reindeer, Rangifer tarandus, examined over a two-year period were infected with trypanosomes. Trypomastigotes and dividing epimastigotes were found in the blood of fawns, cows, and bulls. Morphometric analysis of bloodstream trypomastigotes from reindeer and comparison of these parasites with similar stages of trypanosomes from elk, mule deer, and white-tailed deer from the continuous United States proved them conspecific; the trypanosomes from these members of the Cervidae are identified as Trypanosoma cervi Kingston & Morton, 1975. This is the first report of trypanosomes from reindeer. No pathogenic effects are known to be caused by these parasites.

Experimental Brucella suis biovar 4 infection in a moose.

A moose (Alces alces gigas) was inoculated with Brucella suis biovar 4 to better understand the effects of brucellosis in this species. Serum antibody titers increased rapidly and peaked within 21 to 56 days. Fever, leukocytosis, recumbency, anorexia and depression were observed starting 42 days post inoculation. Brucella suis biovar 4 was isolated from blood, lymph nodes, liver and spleen.

Safety, efficacy, and tissues residues of ivermectin in reindeer

Safety, efficacy, and tissue residues of ivermectin, a broad spectrum parasiticide, were determined in Alaskan reindeer ( Rangifer tarandus ). Reindeer treated at 5 times and 10 times the standard dose of 200 mcg/kg had no detectable physical or behavioral reactions to ivermectin injected subcutaneously in the mid-cervical area. Ivermectin eliminated essentially 100% of reindeer warble larvae ( Hypoderma ( Oedemagena ) tarandi ). Tissue levels of ivermectin in back fat, injection site, muscle, liver, and kidney collected 3, 10, 17, and 24 days post injection were determined. All tissues levels rapidly declined and were approaching low unmea-surable amounts at the end of the 24 day test period. Ivermectin is a safe effective parasiticide that has been used successfully to threat thousands of reindeer in Alaska.

Diet-induced cholesteremia and atherosclerosis in wild rodents☆

Abstract Five diverse species of wild rodents were fed a high-fat-high-cholesterol diet for one year. Microtus pennsylvanicus, Calomys ducilla , and Peromyscus maniculatus had an approximate 2-fold increase, Acomys cahirinus had a 4-fold increase, and Dicrostonyx groenlandicus had a 11-fold increase in serum total cholesterol above pre-diet levels. Some evidence of atherosclerosis was observed in all species but the most severe lesions were found in A. cahirinus and D. groenlandicus . The outstanding pathologic finding in those rodents not surviving one year on the diet was an advanced fatty degeneration of the liver.

AVIAN POX INFECTION IN AN AMERICAN GREEN-WINGED TEAL (Anas crecca carolinensis) IN ALASKA

Poxvirus infection was diagnosed on the basis of gross and microscopic appearance plus the presence of typical inclusion bodies in a juvenile American green-winged teal (Anas crecca carolinensis) in Alaska. This constitutes the first known report of avian pox in migratory ducks and the first report of poxvirus infection in wild birds in Alaska.