The abundance of the intestinal helminth Trichostrongylus retortaeformis in adult mountain hares (Lepus timidus) from a moor in northeastern Scotland was assessed monthly. Weight and fatness of each hare was measured and the reproductive output of females was estimated by sectioning ovaries. Abundance of the parasite was lower in December and January than at other times of year, and there was no difference in abundance between male and female hares. There was no correlation between intensity of infection with T. retortaeformis and weight or fatness of hares either at the onset of the reproductive period (February and March) or at its termination (August and September). We found no relationship between fecundity of female hares and parasite abundance.

As part of a larger epidemiological study examining the transmission of Trichinella spiralis in an agricultural ecosystem, resident wild and feral animals were trapped to determine the extent of their involvement in the natural, on-farm cycling of the parasite among swine. During a 21-mo-study, seven of 15 skunks (Mephitis mephitis), one of three opossums (Didelphis virginiana), two of two feral domestic cats and a raccoon (Procyon lotor) were found to be infected, while five shrews (Blarina brevicauda) and 18 deer mice (Peromyscus spp.) were uninfected. Most of the former hosts probably became infected by scavenging dead infected swine or rats (Rattus norvegicus). However, infections obtained through predation of living rats, particularly with regard to the cats, cannot be excluded. Our observations do not suggest that there was transmission of T. spiralis from the wild animals to swine. Therefore, transmission of T. spiralis appeared to occur only from the farm's swine and rats to the associated wild and feral animals.

Avian malaria (Plasmodium relictum) caused significant mortality in wild-caught Magellanic penguins (Spheniscus magellanicus) in 1986 at the Blank Park Zoo in Des Moines, Iowa (USA). In early winter, wild birds were captured off the southern coast of Chile and flown to Detroit, Michigan for a 38 day quarantine. After quarantine, 18 birds were dispersed to Lansing, Michigan, six to a facility in Maine, and 46 to Des Moines, Iowa. Upon arrival in Des Moines, several penguins became weak and inactive, had to be force-fed, and died after 2 days. Gross lesions at postmortem included splenomegaly, hepatomegaly, and pulmonary edema. Histopathological examination revealed numerous intraendothelial schizonts in spleen, lung, liver, heart and kidney. Schizonts were generally 16 to 28 μm by 11 to 16 μm and contained merozoites of two distinct sizes (macromerozoites, nuclei 1.0 μm micromerozoites, nuclei 0.5 μm). Based on the morphology of the abundant exoerythrocytic forms, a tentative diagnosis of avian malaria (Plasmodium sp.) was made. Subsequent transmission electron microscopic examination of schizonts in formalized tissue revealed merozoites with tear-shaped rhoptries. Antimalarial therapy was initiated early but deaths continued for 5 mo. Mortality, which eventually totaled 83%, occurred in three distinct waves, each separated by a hiatus of approximately 1 mo. Despite examinations of repeated blood smears, intraerythrocytic Plasmodium relictum was not detected until late in the outbreak. Diagnosis was based on morphologic characteristics including schizonts with eight to 12 merozoites/segmenter and round gametocytes that displaced and turned the infected erythrocyte nucleus. In addition to malaria, penguins showed evidence of aspergillosis, bacterial enteritis (Escherichia coli; Proteus sp.; and Edwardsiella sp.), and helminthiasis (Contracaecum sp. and Tetrabothrius sp). Based on gross and histological lesions, disease prevalence in this group of penguins was malaria 58%, aspergillosis 61%, enteritis 60%, helminthiasis 26%. Epidemiologic investigation including group transport history, disease prevalence in co-quarantined birds not sent to Des Moines and climatological data implicated Des Moines as the likely site for initial exposure, although information is not conclusive. Stress and concurrent disease certainly contributed to the severe mortality in this group of penguins infected with P. relictum.

Public health surveillance data from the United States and Canada (1961 to 1982) were analyzed to determine if consistent temporal and spatial patterns in skunk rabies could be identified. Enzootic/epizootic rabies was recognized in 18 states (enzootic states) based on the criteria of ≥20 yr of reported skunk rabies and at least 1 yr with a minimum of 50 reported rabid skunks. In other wildlife species, epizootics have been demonstrated to expand along a wave-like front. We hypothesized: if skunk rabies behaved in a similar fashion, states reporting rabid skunks would change over time. No such change was noted. During epizootics the number of counties reporting increased but not the number of states. Within Illinois certain counties were demonstrated to have persistent rabies histories and likely served as enzootic foci. Enzootic states combined prevalence indicated a 6 to 8 yr cycle for epizootics. Data on monthly percent rabies positive (number rabid/total number tested) were available from six states and Canada. Mean distributions were bimodal with winter and spring peaks. The patterns identified for skunk rabies differ from those of other major wildlife vectors and have significance for potential vaccination control regimes.

In late spring of 1986, 10 of 23 Dall's sheep (Ovis dalli dalli) at the Metropolitan Toronto Zoo were moved to a new exhibit, where all developed severe respiratory signs refractory to anthelmintic and antibiotic therapy. In July, two animals died with chronic active bronchopneumonia, and a third was euthanized because of pneumonia several months later. Bacteria were not isolated from the lungs of the first, streptococci and Pasteurella hemolytica were isolated from the other two, respectively; Mycoplasma ovipneumoniae was isolated from both. Pulmonary lesions in all three sheep were consistent with Mycoplasma sp. infection. Nasal swabs of the remaining animals yielded no consistent bacterial isolates; however, four of eight sheep were positive for M. ovipneumoniae. Viral cultures yielded an as yet unidentified herpesvirus. Sheep in the original and new herds had no serologic titers to parainfluenza-3, equine viral rhinopneumonitis, or infectious bovine rhinotracheitis, and had variable titers against bovine respiratory syncytial virus. No titers against M. ovipneumoniae were present in 13 sheep still in the original exhibit, but titers varied from 1:32 to 1:256 in eight pneumonic sheep. Sera taken from three sheep before or early in the outbreak were all negative for antibody to M. ovipneumoniae. Two of the affected Dall's sheep had been in contact with domestic sheep in the winter of 1985–1986, and M. ovipneumoniae was subsequently cultured from the domestic flock. Exposure to a new pathogen, and environmental and social stress in a new exhibit may have resulted in this severe disease in Dall's sheep.

During routine pathological studies of Franklin's ground squirrels (Spermophilus franklini) collected during a predator control program, basophilic intranuclear inclusions were found in the collecting tubule epithelium of the renal papillae in seven of 13 squirrels. This was associated with marked karyomegaly in affected cells. An inflammatory response was not seen in the adjacent tissues. Electron microscopic examination of affected cells demonstrated that the enlarged nuclei contained numerous virus-like particles. Autoculture and serial passage of renal medullary cells resulted in the isolation of virus particles producing intranuclear inclusions and cytopathic effect. The virus possessed properties typical of adenoviruses, but showed no evidence of hemagglutinating activity with a range of species of erythrocytes tested under several temperature conditions. The isolates were relatively host-cell specific; they failed to grow in hamster and rabbit kidney cell lines and in ground squirrel kidney cortical cells.

Amphileptus branchiarum is a protozoan parasite of fish in North America, Europe and Asia. In North America (Arkansas) it usually occurs on the gills of cyprinids from July to October. It seldom causes disease epizootics but may be responsible for epithelial hyperplasia and cell displacement in branchial tissue.

Two hundred one American toads (Bufo americanus) from northern Michigan were examined for blood trypanosomes. Three species, Trypanosoma bufophlebotomi, T. schmidti-like sp. and T. pseudopodia, had prevalences of 27, 16 and 1%, respectively. Cross experimental inoculations showed that T. bufophlebotomi from toads is not the same as T. ranarum found in frogs of the family Ranidae of this region.

Intrahepatic biliary lesions were observed in two of 12 lambs, seven of 12 yearlings and 10 of 25 adult impala (Aepyceros melampus) surveyed in the Kruger National Park, Republic of South Africa. Lesions were associated with the nematode Cooperioides hepaticae, a trichostrongyloid parasite that inhabits the bile ducts of impala, and ranged from a mild chronic-eosinophilic cholangitis to foci of florid hyperplastic cholangitis with duct ectasia. The latter almost always contained viable worms and, after the worms died, the lesions appeared as foreign-body granulomas. Infection was acquired early in life; severe lesions were seen most frequently in yearlings. Adults were less severely infected, which suggested an acquired immunity. Although the incidence of infection was high, cooperiiasis did not appear to be a serious herd-health problem at the time of this study.

Antler anomalies were evident in tule elk (Cervus elaphus nannodes) within 1 yr of reintroduction to Point Reyes, California (USA). These anomalies are consistent with previously described mineral deficiency-induced anomalies in cervids. The elk were judged deficient in copper. Low levels of copper in soils and vegetation at the release site, exacerbated by possible protein deficiency due to poor range conditions, are postulated as likely causes of the antler anomalies.

Two Rocky Mountain bighorn lambs (Ovis canadensis canadensis) were held in captivity for 120 days before being housed with two domestic sheep. The lambs were clinically normal and had no Pasteurella spp. on nasal swab cultures. The domestic sheep were known to carry Pasteurella haemolytica biotype A in the nasal passages. After being in close contact for 19 days, P. haemolytica biotype A was cultured from nasal swabs of one of the bighorn lambs. By 26 days, both bighorn sheep developed coughs, were anorectic and became lethargic and nasal swabs yielded P. haemolytica biotype T, serotype 10. Twenty-nine days after contact, the lambs were necropsied and found to have extensive fibrinous bronchopneumonia. From affected tissues pure cultures of beta-hemolytic P. haemolytica biotype T, serotype 10 were grown. Both domestic sheep remained clinically normal and had no gross or microscopic lesions, but they carried the same P. haemolytica serotype in their tonsils. Behavioural observations gave no indication of stress in the bighorn lambs.

The serologic response of Rio Grande wild turkeys (Meleagris gallopavo intermedia) to Mycoplasma gallisepticum (MG) was determined. Free-ranging turkeys were caught in southern Texas, shipped to the University of Wisconsin, Madison, and housed in isolation facilities. Fourteen birds were exposed to MG, by intratracheal and intranasal inoculation. Eight birds received sterile broth only. Two wk prior to the end of the experiment, MG exposed turkeys were stressed by challenge with a serologically unrelated mycoplasma. Serum from all exposed birds reacted positively for MG antibody by the rapid plate agglutination (RPA) procedure within 2 mo postexposure (PE) and all but one remained positive for 14 mo PE. Less than one half of the exposed birds developed positive MG antibody titers detectable by the hemagglutination inhibition (HI) test within 2 mo PE, and by 10 mo PE, none had positive titers. Antibody was detected by the HI test in two of 11 infected turkeys, 14 mo PE, and titers increased significantly within 2 wk. MG was isolated from tracheal swabs from two infected birds 2 mo PE, but attempts thereafter failed. However, at the termination of the experiment 15 mo later, MG was isolated from lung tissue of three of 11 exposed turkeys and from a blood clot found in the lower trachea of one bird.

Coomassie Brilliant Blue Agar was used to quantify the frequency of the A-layer phenotype in different isolates of Aeromonas salmonicida. Hydrophilic, non-clumping isolates of A. salmonicida consisted predominantly of the A-layer minus phenotype. These bacteria were avirulent by intraperitoneal injection into susceptible brook trout (Salvelinus fontinalis) and could not be reisolated from infected fish. By contrast, hydrophobic, clumping isolates were predominantly of the A-layer positive phenotype, highly virulent in brook trout, and easily recovered from dead or moribund fish. A-layer positive and negative clones of A. salmonicida were derived by plating bacteria on Coomassie Blue Agar. The plating showed clearly that Coomassie Blue Agar could be used as a highly selective in vitro screening method to reclaim the virulence of certain isolates of A. salmonicida having a relatively low percentage of A-layer positive phenotypes.

One hundred fifty Amblyomma americanum were examined between March and September 1986 from Cookson Hills Wildlife Refuge in eastern Oklahoma (USA). Of these ticks, 11% (17 of 150) were infected with Theileria cervi. Field-collected nymphal ticks had an 8% (3 of 37) prevalence of infection averaging 1.0 infected acini/nymph. Female ticks had a 16% prevalence of infection averaging 1.6 infected acini/female; T. cervi was not observed in salivary glands of field-collected male ticks. When laboratory reared A. americanum nymphs were allowed to feed on experimental white-tailed deer (Odocoileus virginianus) with varying T. cervi parasitemias (<1, 2, 6 and >20%), only ticks which fed on deer with parasitemias >1% became infected. Although prevalence and intensity of infection varied in the infected ticks, there was no significant difference in prevalence of infection between males and females. However, females did acquire significantly greater intensities than males. The data from these studies confirm that T. cervi overwinters in A. americanum and suggests that the prevalence, intensity and abundance of infection of T. cervi in ticks is influenced by the parasitemia of the deer host. Furthermore, fawns may play a more important role in the epidemiology of T. cervi transmission than do adult deer because of the coordination between tick activity patterns and deer fawning.

The median effective dose for capture (ED50) and the median lethal dose (LD50) of alpha-chloralose given orally to domestic chickens (Gallus domesticus) were determined by probit analysis to be 45 mg/kg and 300 mg/kg, respectively. The therapeutic index (TI = LD50/ED50) was 6.7. This indicates that alpha-chloralose is only a marginally safe capture agent in domestic species and particularly in field applications involving other wild avian species in which the amount of the drug ingested by an individual bird is not controlled.

Captive gray wolves (Canis lupus) were given 2.2 mg/kg xylazine hydrochloride intramuscularly resulting in profound sedation in 9.1 ± 0.6 min (mean ± SE). Heart rate was 42.0 ±1.0 beats per minute and respiratory rate was 20.1 ± 1.6 respirations per minute during sedation. A variety of manipulations could be performed on sedated animals in relative safety. Thirty min after xylazine administration, the animals were given either 0.15 mg/kg yohimbine hydrochloride or 5% dextrose solution intravenously causing recovery in 5.3 ± 1.0 and 97.1 ± 14.0 min, respectively (P < 0.001).

Meperidine HCl was administered intramuscularly by hand-syringe to a number of individuals representing several species of cetaceans (n = 95) and pinnipeds (n = 36). Dosage administered was 0.11 mg/kg, 0.23 mg/kg or 0.45 mg/kg, with the majority of animals receiving the middle dosage. Meperidine HCl provided moderate restraint in cetaceans without obvious deleterious effects. Restraint was achieved rapidly, with maximum effect occurring 20 min after intramuscular injection and lasting for 2 to 3 hr. Analgesia appeared to last as long as 4 hr and was sometimes accompanied by a restoration of appetite in animals suffering from physical discomfort. Higher doses produced increased sedation and analgesia without noticeably depressing respiration. Meperidine HCl provided moderate restraint for phocids and walrus (Odobenus rosmarus) without apparent detriment. California sea lions (Zalophus californianus) showed little restraint, but demonstrated profound respiratory depression.

An 11-yr-old captive-raised male woodchuck (Marmota monax) presented with ataxia, poor balance, left-sided weakness, circling to the left and nystagmus with the fast-phase directed towards the left. The clinical signs were compatible with a central vestibular deficit syndrome. Necropsy and histologic findings revealed a meningotheliomatous meningioma centered over the ventrolateral left pons and medulla along with acute bronchopneumonia, chronic glomerulopathy, interstitial nephritis, and phthisis bulbi.

An adult female American alligator (Alligator mississippiensis) had diffuse, yellow, granular serosal thickening at necropsy. Light microscopic examination of affected stomach, small intestine and spleen revealed a chronic proliferative serositis associated with 3 to 15 μm eosinophilic extracellular globules identified histochemically and morphologically as egg yolk. The intracoelomic egg yolk was considered to be the cause of the serosal reaction.

Gross lesions suggestive of severe hepatoenteropathy and myopathy were noted in a 4.5-yr-old Brazilian tapir (Tapirus terrestris) from a zoo in Michigan (USA). The major microscopic lesions were granulomatous hepatitis and hemorrhagic enteritis associated with non-operculated eggs compatible with those of the Schistosomatidae (Digenea). Skeletal muscle and tongue contained foci of severe acute myodegeneration and necrosis. The hepatic vitamin E value of 1.3 ppm dry weight was considered critically low.

The distribution of Ixodes dammini in Minnesota was studied by collecting adult ticks from hunting dogs during the grouse seasons in September and October of 1985 and 1986. The tick was most frequently found in the east-central part of the state. Borrelia spp. were observed by immunofluorescence in 10% of the ticks. The locations where ticks were found coincide with the primary endemic areas for Lyme disease in the state.

One hundred nineteen pen-raised wild turkeys (Meleagris gallopavo) from 12 locations in nine states in the United States were examined for coccidia by sugar flotation of intestinal contents and mucosa or by subinoculating the contents into uninfected domestic turkeys. Seventy-eight (66%) of the turkeys were positive for coccidia. There were no differences in the frequency of coccidia among adult, subadult or juvenile turkeys. More females (75%) were infected than males (48%). The species of coccidia from 30 of the turkeys were identified based on microscopic examination of oocysts, fresh scrapings, stained sections and inoculations of bobwhites (Colinus virginianus). The frequency of each species was Eimeria meleagrimitis (97%), E. gallopavonis (47%), E. meleagridis (27%), E. dispersa (17%), E. innocua–E. subrotunda (13%), E. adenoeides (7%) and an undescribed species (3%). Of the 30 turkeys in which the species of coccidia was determined, 30% had a single species infection, 40% had two species, 20% had three species and 10% had four species.

Septicemic pasteurellosis caused by Pasteurella multocida is believed responsible for the deaths of 48 elk (Cervus elaphus) on the National Elk Refuge near Jackson, Wyoming (USA) during 1986 and 1987. Clinical signs included depression and salivation; necropsy findings included congestion and petechial and ecchymotic hemorrhages in lymph nodes, diaphragm, lungs and endocardium. Pasteurella multocida was isolated from femur marrow of eight carcasses and a variety of tissues from eight others.

Prevalences of poxvirus in a population of California quail (Callipepla californica) at the E. E. Wilson Wildlife Area, Oregon, were determined from 1982 through 1987 and compared with previously published results on prevalences in this population from 1975 to 1979. Poxvirus was present in 19 of 89 quail collected. Prevalences ranged from 6% for immature females to 41% for immature males. Prevalences were lowest during summer and fall and highest in winter and spring. Differences in the seasonal prevalences may be related to the seasonal dispersion pattern of quail.

Heads from 78 hunter-harvested white-tailed deer (Odocoileus virginianus) were donated for study during the 1985 Wisconsin gun hunting season. The intra-cranial nervous tissue was examined for Parelaphostrongylus tenuis. Prevalences were calculated for the total sample and for the portion of the sample which had no intra-cranial trauma. The prevalences thus calculated were 58% and 75%, respectively.

During an investigation to determine the prevalence and intensity of larvae of Trichinella spiralis in raccoons (Procyon lotor), unembryonated capillariid-type eggs were found routinely in the sediment resulting from 1% pepsin-HCl acid digests of the tongue. The sediment from 36 (90%) of the 40 tongue digests examined contained these capillariid-type eggs. Mean measurements of egg width and length were 25 ± 2 μm and 62 ± 2 μm, respectively. In addition, the surface of the egg shell had a pitted appearance. Adult parasites were not found in any of the tongue digests. The egg measurements and surface topography agree with what has been described previously and are tentatively identified as Capillaria procyonis. The detection of C. procyonis eggs in the present report indicates that this parasite inhabits the epithelial lining of the raccoon tongue, in addition to the esophagus, and that eggs expelled by females are deposited in the tracts these parasites create as they migrate.