Distribution of inorganic and methylmercury among tissues in mink (Mustela vison) and otter (Lutra canadensis)

Total mercury and methylmercury concentrations were measured in brain, kidney, liver, and fur from several mink and otter collected in south-central Ontario. There was a large range in concentrations of both total and methylmercury. The percentage of the total mercury present as methylmercury varied among the various tissues; however, the percentage mercury found as the methyl form was relatively constant within a given tissue for all tissues in mink but highly variable in otter. For both species the highest percentage of methylmercury was found in the brain, whereas the lowest percentage was found in the kidneys for the otter and in the fur for the mink. Comparison of mercury concentrations in otter reveals that animals with higher body fat have higher mercury concentrations. Measurements of mercury in fur can be used as a general indicator of internal tissue concentrations.

An examination of spatial variation in mercury concentrations in otter (Lutra canadensis) in south-central Ontario

Hair samples were collected from otter (Lutra canadensis) trapped in several parts of south-central Ontario, Canada. The concentrations of total Hg in hair were compared with methyl mercury concentrations in liver tissues from the same individuals to determine if hair is a suitable monitoring tissue. Hg in the two tissues was significantly correlated. Hair was used to monitor Hg in 51 individuals from four townships. The concentrations of total Hg in hair ranged from 4 to 20 micrograms/g. No significant variation among the four sample regions existed. Generally the highest concentrations were found in the youngest members of the population. Some possible explanations for the observations are presented.

Survival and development of the different life stages of Ixodes scapularis (Acari: Ixodidae) held within four habitats on Long Point, Ontario, Canada

From November 1989 to April 1993, blood-fed females and unfed adults and nymphs of lxodes scapularis Say were maintained in housings within 4 different habitats on Long Point, Ontario, Canada, to evaluate the effects of habitat on tick development. More fed females survived the winter within the maple forest (75.6%) than the cottonwood dune (36.1%), whereas 52.8-62.0% survived the winter within the 2 remaining habitats. The proportions of females that laid eggs within the maple forest (90.3%), oak savannah (83.9%), and white pine habitats (78.4%) were similar and greater than in the cottonwood dune (53.8%). In each habitat and all years, females began laying eggs during late April or early May. The time of egg deposition was consistent whether females fed in November and overwintered, or fed during April of the subsequent year. Significantly more eggs hatched within the maple forest (96.4%) and white pine (79.3%) than in the oak savannah (3.8%) or cottonwood dune habitats (0.0%). Hatch occurred in mid- to late July each year. The proportion of unfed I. scapularis adults that survived the winter was not significantly different among the 4 habitats. Unfed adults held in the oak savannah and cottonwood dune habitats died by early June, whereas ticks survived until late June or early July within the maple forest and white pine habitats. Unfed nymphs survived an average of 3.4 mo (range, 0.5-5.5) longer than unfed adults. Fed larvae placed in the field from 22 April to 3 July 1992 molted or died that year. In contrast, 66.7 and 100% of fed larvae placed in the field between 15 and 28 July, and after 28 July, respectively, overwintered before molting. More larvae successfully molted before overwintering (46.9%) than did those that overwintered (17.9%). The proportion of larvae that successfully molted was greatest within the maple forest and least within the cottonwood dune. Fed nymphs placed in the field from 22 April to 4 June molted or died in 1992, whereas 53.6 and 99.2% of fed nymphs placed in the field between 17 June and 28 July, and later than 28 July, respectively, overwintered before molting. Over all habitats, the proportion of nymphs that molted successfully was similar for those that overwintered (43.5%) and those that did not (36.0%). The proportion of nymphs that molted successfully was greatest in the maple forest (60.6%) and least within the cottonwood dune (13.3%). Differences in seasonal extremes of vapor pressure deficits among habitat types were likely responsible for habitat-specific differences in survival of I. scapularis. Based on observations on captive I. scapularis, the life cycle of this tick on Long Point is completed in 3 or 4 yr.

Nongastrointestinal helminths in marten (Martes americana) from Ontario, Canada

Six species of nongastrointestinal nematodes were recovered from 405 marten, (Martes americana), examined from six areas in Ontario, Canada in 1992 to 1993. Three species (Crenosoma petrowi, Eucoleus aerophilus, Filaroides martis) were found in the respiratory tract, one in the urinary bladder (Pearsonema plica), one in the kidney (Dioctophyme renale), and one in the musculature (Trichinella sp. larvae). This is the first report of F. martis and P. plica from this host. In addition a specimen of Dracunculus insignis collected from a marten pelt was received. Based on our results, martens are primary definitive hosts for few nongastrointestinal nematodes. Animals in more southern areas had greater species richness than those from higher latitudes.

Erysipelothrix rhusiopathiae, serotype 17, septicemia in moose (Alces alces) from Algonquin park, Ontario

Erysipelothrix rhusiopathiae septicemia was diagnosed in three of four moose found dead in Algonquin Provincial Park, Ontario, Canada, in the spring of 1989. Type 17 E. rhusiopathiae was isolated from liver, lung, kidney, and lymph nodes of affected animals, which were in poor body condition, and suffering hair loss associated with tick (Dermacentor albipictus) infestations. Microscopic lesions consisted of mild, multifocal, necrotizing myocarditis, sarcocystosis, and lymph node atrophy. The bacterium may have gained entry to these animals via ingestion of, or percutaneous exposure to, contaminated water, or possibly by the bites of ticks. Malnutrition and tick infestation may have predisposed the animals to infection by this opportunistic pathogen.

Postpartum immobilization of adult female moose using xylazine, ketamine and yohimbine hydrochlorides

Twenty-two free-ranging adult female moose (Alces alces) were immobilized with a 1:4 mixture of xylazine hydrochloride (XH) and ketamine hydrochloride (KH). Mean (SD) dosages/animal for XH and KH were 419 (148) and 1565 (433) mg, respectively. Mean (SD) induction time was 18.4 (9.7) minutes. Reversal with yohimbine hydrochloride using a mean dosage of 83 mg/animal resulted in a mean (SD) recovery time of 22.8 (28.5) minutes.

Cranial lesions possibly associated with Skrjabingylus (Nematoda: Metastrongyloidea) infections in martens, fishers, and otters

Skulls of 631 martens (Martes americana), 810 fishers (Martes pennanti), and 373 otters (Lutra canadensis) collected throughout Ontario were examined for frontal bone lesions possibly induced by sinus nematodes of the genus Skrjabingylus. No lesions were found in marten skulls. Lesions were present in 13.4% of otter skulls and their distribution was similar between sexes and among age-groups. Among fishers, 11.6% of skulls exhibited lesions. Frequency of lesions tended to increase with age, and adult male fishers had fewer than adult females. Lesions were characterized by discolouration, swelling, and perforation of frontal bones in descending order of frequency. Lesions were largely confined to the pars temporalis of the frontal bones with a small number also found on the pars frontalis.

Growth and development of winter tick, Dermacentor albipictus, on moose, Alces alces

Moose, Alces alces, were infested with 21,000 or 42,000 larval Dermacentor albipictus at the end of September. Larvae grew rapidly and molted to the nymphal stage 10-22 days after infestation. The nymphal stage lasted approximately 3 mo until mid-January and was characterized by a diapause. The diapause is likely an adaptation to survival in cold climates. Nymphs started engorging in January and adults were seen with increasing abundance from mid-January to March and April. The minimum parasitic period was 175 days. Growth of larvae and nymphs was similar on moose given different numbers of larvae and was generally similar between a moose infested in November and moose infested earlier. Dimensions and stages of development throughout the parasitic phase are given. Game enforcement officers are encouraged to use these data for determination of season of death of moose.

Fascioloides magna (Trematoda) and Taenia hydatigena (Cestoda) from white-tailed deer

Livers of 164 white-tailed deer (Odocoileus virginianus) from the Peterborough Crown Game Preserve in central Ontario were examined for Fascioloides magna and Taenia hydatigena. Fascioloides magna was recovered from 2.6% of fawns and 68.3% of all older deer, and mean intensity of infection increased with age. Both prevalence and intensity of unencapsulated flukes were similar among all age-groups of deer 1 year of age and older. While the majority (96%) of encapsulated flukes were within capsules containing more than one fluke, aggregation of flukes is probably not required for either encapsulation or maturation. Infection with F. magna had no detectable effect on the condition of yearling or adult male deer, where condition was measured by depth of fat on the rump and sternum. Cysticerci of T. hydatigena were most prevalent among yearlings (70%) as compared with all other age-groups (29%). Mean intensity of infection with T. hydatigena tended to increase with age.

Parasites of moose (Alces alces) from an agricultural area of eastern Ontario

Viscera of 16 moose and hide samples of 24 moose (Alces alces) shot in eastern Ontario in 1985 were examined for parasites. Two species of trematodes, one species of cestode, five species of nematodes and one species of tick were recovered. One nematode species, Trichuris discolor, is reported for the first time from moose. Our results suggest that the parasite fauna of the moose may have been influenced by the absence or scarcity of other species of wild cervids or carnivores and by the presence of domestic livestock.

Tick (Dermacentor albipictus)-induced winter hair-loss in captive moose (Alces alces)

Five captive moose calves each infested with 42,000 larval Dermacentor albipictus, six calves each infested with 19,000-21,000, and five control moose were observed for changes in hair-loss, body condition and number, stages, and distribution of the tick. Winter hair-loss was observed only in moose infested with ticks and was correlated positively with the total number of adult ticks. Hair-loss associated with ticks was minimal from October to January, but rapidly increased from February to April when up to 44% of hair had been removed. The pattern of hair-loss was similar in all moose with the neck, shoulders, withers, and perianal areas losing the most hair. Moose with extensive premature hair-loss had less pericardial and abdominal visceral fat than moose with little or no hair-loss.

Helminth parasites of Canada lynx (Felis canadensis) from northern Ontario

Six helminths were common in lynx (Felis canadensis) throughout northern Ontario: Troglostrongylus wilsoni (Stough, 1953) Sarmiento &Stough, 1956 in the lung (54% of 127 infected), Cylicospirura felineus (Chandler, 1925) Sandground, 1932 in the stomach (91% of 360), Toxascaris leonina (von Linstow, 1902) and Toxocara cati (Schrank, 1788) in the stomach and intestine(97% and 22% of 274, respectively), and Taenia laticollis Rudolphi, 1819, and Taenia rileyi Loewen, 1929 in the intestine (94% and 47% of 275, respectively). Only Toxascaris leonina is transmitted by both lynx and canids in northern Ontario. Lynx is the only definitive host of the other common parasites. Seven helminths usually found in canids occurred infrequently in lynx: Alaria marcianae (LaRue, 1917) Walton, 1949 and immature Taenia pisiformis (Bloch, 1780) Gmelin, 1790 in 4% of those examined; and Capillaria aerophila (Creplin, 1839) Travassos, 1915, Physaloptera rara Hall &Wigdor, 1918, Ancylostoma caninum (Ercolani, 1859), Uncinaria stenocephalia (Railliet, 1884), and Taenia serialis (Gervais, 1847) Baillet, 1863 in one to three lynx each. Abundances of the common parasites varied only slightly among five forest regions, and did not differ between male and female lynx or among lynx older than kits. Cylicospirura felineus and Taenia rileyi were less abundant in kits, and Taenia laticollis and Toxocara cati tended to be more abundant in kits than in older lynx. Host condition and numbers of many of the common helminths tended to be positively correlated, but the inclusion of kits affected the result. The few helminth species established in lynx and their apparent uniform distribution in the host population may reflect the dominance of snowshoe hare in the diet.

Metacestodes of moose, Alces alces, of the Chapleau Crown Game Preserve, Ontario

Lungs, liver, spleen, heart, and kidneys of moose, Alces alces, collected from 1963 to 1965 in the Chapleau Crown Game Preserve of northeastern Ontario were examined for parasites. Thirty-eight of 51 moose (75%) were infected with metacestodes of Taenia hydatigena Pallas, 1766; 40 of 54 (74%) with Taenia krabbei Moniez, 1879; and 36 of 54 (67%) with Echinococcus granulosus (Batsch, 1786). Twenty-two of 51 (43%) moose harboured all three species. Each species was more prevalent in older moose than in young moose and intensity of infections increased with the age of moose. Occurrence of small hydatid cysts decreased and large cysts increased with increasing age of moose. Of 1154 hydatid cysts, 95.3% were in lung tissue, 3.6% in liver, 0.9% in spleen, and 1 cyst (0.1%) was recovered from each of heart and kidney. Degenerate cysticerci of T. hydatigena and T. krabbei were observed in all age groups of moose. There was no apparent relationship between intensity of infection with metacestodes and physical condition of moose.

Use of Ketamine hydrochloride and xylazine hydrochloride to immobilize black bears (Ursus americanus)

Ketamine hydrochloride (KH) and xylazine hydrochloride (XH) used in combination (KH-XH) were effective immobilants for captive and wild black bears (Ursus americanus). Single intramuscular injections of 1.5-17.1 mg of KH per kg body weight combined in an approximate ratio of 2:1 with 0.9-10.0 mg of XH per kg body weight immobilized bears for 1.5-197 min. Dosages most frequently used were 4.5-9 mg KH/kg with 2-4.5 mg XH kg. Supplemental administrations maintained tractability for up to 31 h. Immobilization was characterized by smooth induction, relaxed muscles, occasional groaning and vomition, no eye closure, no defecation, and a smooth recovery phase of variable length. Male and female bears responded similarly to KH-XH. Induction times for small bears (less than or equal to 25 kg) were shorter than for larger bears.

Dermacentor albipictus on moose (Alces alces) in Ontario

Fifty-five moose (Alces alces) collected from 1963 to 1965 in the Chapleau Crown Game Preserve of northern Ontario were examined for ectoparasites. Dermacentor albipictus was the only parasite recovered. D. albipictus was absent from 15 moose examined during June, July and August; first observed on 1 or 2 moose examined in September; and present on all 38 moose collected from October to May. Ticks were not evenly distributed on the body. Infestations varied from 32 to 13,490 ticks/moose for 14 individuals. Levels of infestation observed did not have an obvious adverse effect on the health of the moose.

Helminth parasites of wolverine, Gulo gulo, from the district of Mackenzie, Northwest Territories

Trematodes (Alaria sp.), cestodes (Taenia martis (Zeder 1803), Taenia twitchelli Schwartz 1924, and Diphyllobothrium sp.), and nematodes (Physaloptera sp. (?) and Baylisascaris devosi (Sprent 1952)) are reported from wolverine, Gulo gulo, from the District of Mackenzie, Northwest Territories, Canada.

Helminth and arthropod parasites of black bear, Ursus americanus, in central Ontario

One hundred and forty-eight black bears (Ursus americanus) from central Ontario, Canada, were examined for parasites between 1975and 1977. Nine species of helminths and two species of ectoparasites were recovered: Taenia krabbei Moniez, 1879 in 2 of 83 bears; Alaria americana Hall and Wigdor, 1918 in 1 of 83; Baylisascaris transfuga (Rudolphi 1819) in 20 of 83; Crenosoma spp. (C. petrowi Morozov, 1939, C. potos Buckley, 1930, and C. vulpis (Dujardin 1844)) in 21 of 64; Dirofilaria ursi Yamaguti, 1941 in 140 of 148; Physaloptera rara Hall and Wigdor, 1918 in 1 of 83; Trichinella sp. in 1 of 59; Oropsylla arctomys (Baker) on 1 of 5; and Trichodectes pinguis euarctidos Hopkins on 1 of 5 bears. The data are discussed in relation to previous records of parasites within central Ontario and previous reports of parasites of bears. Alaria americana is considered a new host record for North American ursids.

Oxyspirura turcottei n.sp. (Nematoda: Thelaziidae) from the eastern wild turkey (Meleagris gallopavo silvestris)

Oxyspirura turcottei n.sp. from beneath the nictitating membrane of Meleagris gallopavo silvestris of West Virginia is distinguished from other species of the subgenus Oxyspirura (undivided buccal capsule) by its size (males 9.8–13.8 mm long; females 9.6–17.7 mm long), the presence and morphology of the gubernaculum, the presence of three pairs of preanal papillae, no adanal papillae and three pairs of postanal papillae in most specimens, and by its long right and left spicules (215–245 μm and 495–615 μm, respectively).

Life cycle of Dipetalonema sprenti Anderson (Nematoda: Filarioidea) of beaver (Castor canadensis)

Adult Dipetalonema sprenti Anderson occur mainly in the peritoneal cavity of beaver (Castor canadensis Kuhl). Microfilariae were taken up with blood and developed to the infective stage in the fat body of the abdomen and thorax of Aedes intrudens Dyar and A. abserratus (Felt and Young). At 27C the first molt occurred 4 to 6 days and the second molt 7 to 9 days after ingestion by the mosquito. Infective larvae were first seen in the head on the eighth day. A "sausage-stage" was present during development to the first molt at 27C but not at 23C. Microfilariae appeared in the blood of six previously uninfected beaver 116–135 days after each was injected with about 125 infective larvae. Aedes intrudens and A. abserratus fed on beaver in Algonquin Park, Ontario, from the first week of June until about the middle of July during 1970 and 1971. Transmission of D. sprenti may occur principally within beaver lodges or dens.