A survey of migratory waterfowl for duck plague (DP) virus was conducted in the Mississippi and Central flyways during 1982 and in the Atlantic and Pacific flyways during 1983. Cloacal and pharyngeal swabs were collected from 3,169 migratory waterfowl in these four flyways, principally mallards (Anas platyrhynchos L.), black ducks (Anas rubripes Brewster), and pintails (Anas acuta L). In addition 1,033 birds were sampled from areas of recurrent DP outbreaks among nonmigratory and captive waterfowl, and 590 from Lake Andes National Wildlife Refuge, the site of the only known major DP outbreak in migratory waterfowl. Duck plague virus was not found in any of the samples. Results support the hypothesis that DP is not established in North American migratory waterfowl as an enzootic disease.

Under spring conditions (mean daily maximum 22 C, mean daily minimum 9 C), the temperature within duck carcasses paralleled air temperature for 3 days; on days 4 and 5 the internal temperature rose above 30 C for approximately 30 hr and maximum temperatures of 40–47 C occurred. This coincided with the period of maximum blowfly maggot activity in the carcasses. Carcasses screened from blowflies did not experience this period of high internal temperature. Under autumn conditions (mean daily maximum 13 C, mean daily minimum 1 C), the internal temperature of carcasses paralleled air temperature for approximately 2 wk. Following a warm day (23.5 C), maggots appeared in the carcasses and the internal temperature rose markedly higher than air temperature. Maggots moved into the soil on cold nights and reinhabited the carcasses during the day. The microclimate within maggot-infested carcasses appeared very suitable for growth and toxin production by Clostridium botulinum and this phenomenon may help explain the occurrence of botulism outbreaks during cool weather.

Kidneys from 309 Interior Canada geese from three locations in the Mississippi Flyway were examined for renal coccidia. Oocysts and/or young zygotes of Eimeria sp. were found in 6.8% of goose kidneys sampled. Only one type of renal coccidian oocyst was observed. Significantly more immature geese were infected than adults; however, there was no significant difference observed between the prevalences of infection in male and female birds. A host cellular response to zygotes and oocysts was noted in the majority of infected adult geese. Heavily infected kidneys were hypertrophic with minute foci on the surface of the organ. Histological examinations showed large numbers of unsporulated oocysts accumulated in distended collecting tubules, resulting in pressure necrosis to adjacent tissue and urate retention. Zygotes were observed in the cytoplasm of tubule cells and extracellularly in interstitial tissue. Infected tubule cells were characterized by the peripheral location of the nuclei, cytoplasmic basophilia, and cellular hypertrophy. This is the first report of an Eimeria sp. in the kidneys of Canada geese of the Mississippi Valley population.

A survey of potential hosts of Giardia spp. was carried out during 1982 and 1983 in the Kananaskis Valley and Banff National Park, Alberta, Canada. Diagnosis was based mainly on fecal analysis but a few animals were examined at necropsy and scrapings from the small intestine analyzed. A total of 304 specimens was examined from humans (Homo sapiens L.) and a variety of animal species. Cysts and/or trophozoites of Giardia were found in 10.5% of the specimens examined. Positive samples were found from 20 of 21 red-backed voles (Clethrionomys gapperi Vigors), two of six meadow voles (Microtus pennsylvanicus Ord), one of three long-tailed voles (Microtus longicaudus Allen), five of 50 deer mice (Peromyscus maniculatus Mearns), and two of 58 beavers (Castor canadensis Kuhl). Cysts obtained from a beaver were successfully introduced to gerbils (Meriones unguiculatus Milne-Edwards) and the trophozoites obtained were cultured in vitro.

Lungs and fecal samples from nine hunter-killed Rocky Mountain bighorn sheep were examined for lungworms. All samples contained adults and/or larvae of Muellerius capillaris (Mueller, 1889). Protostrongylus spp., the lungworms commonly reported from bighorn sheep, were not present in any samples. Larvae of M. capillaris bear a spine on the dorsal side of the posterior end and are shorter than dorsal-spined larvae of other lungworms recorded from North American ungulates. Larvae similar in shape but longer than those of Muellerius were found in free-ranging bighorn sheep in Alberta and British Columbia. In addition, dorsal-spined larvae have been found in bighorn sheep in Montana, North Dakota, and Washington. The identity of the dorsal-spined larvae is known only from sheep in South Dakota. Thus, caution must be taken when diagnosing lungworm infections in Rocky Mountain bighorn sheep.

Geopetitia aspiculata was found in 12 species of Passeriformes, one species of Cor-aciiformes, and one species of Charadriiformes which died in a free-flight area in the Tropical House at the Assiniboine Park Zoo, Winnipeg, Canada. The nematodes occurred in chronic inflammatory cysts attached to the serosa of the posterior end of the esophagus, proventriculus, and the anterior part of the gizzard. Posterior ends of worms were observed to extend from the cyst into the lumen of the proventriculus. Birds hatched and raised in the Tropical House acquired infections, probably through the agency of feral crickets. Experimental studies showed that G. aspiculata developed to the infective third stage in the fat body of Acheta domesticus (L). This is the first transmission cycle of Geopetitia spp. to be elucidated and the egg, first, third, and early fifth stages of the parasite are described. The absence of spicules in males of G. aspiculata is confirmed. Geopetitia aspiculata was probably introduced to the Zoo by infected tropical birds obtained from dealers or other zoos. The wild source of the parasite is not known since G. aspiculata has never been reported in wild birds; the report of G. aspiculata in wild Piciformes in Cuba by Barus (1971) is in error.

Seventy-six white-tailed deer (Odocoileus virginianus (Zimmermann)) fawns captured on Crab Orchard National Wildlife Refuge in southern Illinois during June–July 1980–1983 were aged and examined for ticks. The prevalence of ticks (Amblyomma americanum (Linnaeus, 1758) and Dermacentor variabilis (Say, 1821)) was 80% intensity of infestation ranged from one to 123 ticks per fawn, averaging 21.6. Tick intensity correlated poorly with age suggesting that there were other, more important determinants of infestation rates. Packed cell volumes in blood of the fawns increased significantly with age, but were not significantly affected by existing tick intensities. Ticks were not directly or indirectly implicated in any of 16 mortalities that occurred among 61 radio-collared fawns monitored for approximately 6 mo post-partum, and were not considered a serious health problem for fawns on the study area.

Larvae of the nematode Raphidascaris acus were found free or encapsulated in the liver of yellow perch. Blood vessels were distorted or destroyed during larval migrations and larvae were eventually encapsulated in a thick-walled whitish nodule. Successful walling-off of the parasite resulted in the formation of a collagenous nodule and a complete loss of the worm. No mortality of perch was associated with larval R. acus but the introduction of susceptible fishes into a lake harboring this parasite may be important in some stocking programs.

An epizootic of myositis and death in pen-reared bobwhites occurred at a hunting club in California. The myositis was caused by myriads of elongate protozoan cysts. The cysts were in various stages of development and when mature, contained spherical zoites 1 μm in diameter. Sinuous compartments were present in all cysts. The walls of the compartments were composed of a material similar to the cyst walls. Mature cysts were filled with blood. The histologic and ultrastructural morphology of the parasite revealed the parasite to be a haemosporozoan. The parasite has numerous similarities to both Akiba caulleryi (Mathis and Leger, 1909) and organisms that cause aberrant leucocytozoonosis in other species of birds. Further studies are needed to determine if the parasite is a part of the normal parasite fauna of quail or if it represents a parasite in an aberrant host.

An all-age die-off of Rocky Mountain bighorn sheep (Ovis c. canadensis Shaw) occurred from late October 1980 through March 1981 in Waterton Canyon, Colorado, with a loss of 75 to 85% of the sheep. The cause of death was a subacute to chronic bronchopneumonia and the primary etiologic agents isolated from the respiratory system were a Pasteurella sp., P. multocida, Corynebacterium pyogenes, and Protostrongylus stilesi Dikmans, 1931. The underlying predisposing factors that initiated this die-off were believed to be related to multiple chronic environmental stressors associated with the building of a dam which included human contact, vehicular traffic, atmospheric dust, noise and harassment. The die-off was succeeded by a 100% lamb mortality the following summer and a 67% lamb mortality the next two summers. The pneumonia found in these lambs was similar to that found in adult sheep during the previous die-off, except that mature lungworms were absent.

The effect of xylazine hydrochloride on biochemical and endocrine parameters in plasma was examined in adult white-tailed deer (Odocoileus virginianus (Zimmermann)). In the first experiment, seven animals were injected intramuscularly via a blowgun dart with 0.65 mg/kg xylazine (100 mg/ml) and were bled 10, 20, 30, and 60 min post-injection. In the second experiment, eight animals were manually restrained for the first blood sampling and then injected manually and bled as before. Plasma calcium (Ca), inorganic phosphorus (P), and alkaline phosphatase (AP) were measured spectrophotometrically. Plasma parathyroid hormone (PTH), calcitonin (CT), thyroxine (T₄), triiodothyronine (T₃), and Cortisol were measured by radioimmunoassay. Plasma PTH, CT, T₄, T₃, and AP activity did not differ (P > 0.05) during the 1 hr period studied in either experiment. Plasma Ca and P decreased significantly (P < 0.05) in the second experiment, whereas Cortisol levels increased significantly (P < 0.05) 10 min post-injection in both experiments. The results may have been due to a drug effect or a combined drug and stress effect. It is suggested that xylazine may be safely used as an anesthetic in measuring PTH, CT, T₄ and T₃, and plasma AP up to 60 min post-injection in deer. Caution should be taken in using xylazine as an anesthetic to study adrenocortical function.

Baseline body temperatures (BT), heart rates (HR) and respiratory rates (RR) were obtained from Alaskan moose (Alces alces gigas Miller) at the Moose Research Center (MRC), Alaska. Excitability, seasons and drugs influenced the values to varying degrees. Excitability was the most influential factor. Safe expected ranges were: BT 38.4 to 38.9 C, HR 70 to 91 beats/min (b/min), and RR 13 to 40 respirations/min (r/min). These ranges incorporated all seasons, a central nervous system depressant drug and a paralyzing drug. Values which may be considered critical and an indication that corrective action should be taken include: BT 40.2 C, HR 102 b/min, and RR 40 r/min. It is recommended that persons trained in monitoring vital signs be on hand during moose capture and immobilization procedures.