Umingmakstrongylus pallikuukensis gen.nov. et sp.nov. is established for a protostrongylid nematode in muskoxen, Ovibos moschatus, from the Kitikmeot Region (central Arctic) of the Northwest Territories, Canada. It is distinguished from Cystocaulus and other Muelleriinae by characters that include the following: males: deeply incised, bilobed bursa, independent externodorsal rays, telamon composed of distal transverse plate, absence of falcate crurae, and spicules not distally split; females: absence of provagina; and first-stage larvae: presence of three cuticular folds on the tail. The great length of females (468 mm) and males (171 mm) is exceptional among the Protostrongylidae. Pathognomonic lesions include well-defined cysts dispersed through the lung tissue (maximum diameter 40 mm) containing adult and larval parasites in a dense matrix. Transmission involves a molluscan intermediate host, as indicated by experimental infections in the slug Deroceras reticulatum. The parasite is apparently restricted in its geographic distribution and has been found only in a population of muskoxen northwest of Coppermine, N.W.T. This may be indicative of a relictual host–parasite assemblage that has existed since the Pleistocene. The pathogenicity, high prevalence, and intensity of infection in the Coppermine herd suggest that the occurrence of U. pallikuukensis has implications for the management of muskoxen in the Holarctic region.

No abstract

Development of the muskox protostrongylid lungworm, Umingmakstrongylus pallikuukensis, in its slug intermediate host, Deroceras laeve, was investigated under field conditions in the Arctic.

During the first half of the century, the majority of anthrax outbreaks in Canada occurred in the southern portions of Ontario and Quebec and were often associated with pastures contaminated by effluent from textile industries dealing with imported animal materials. In 1952, introduction of Federal regulations requiring disinfection of these materials greatly reduced the incidence of anthrax in eastern Canada. Since 1962, domestic outbreaks of the disease have been reported almost exclusively in cattle in the western prairie provinces. Between 1962 & 1993, nine anthrax epizootics have been recorded in the bison herds of the Northwest Territories and northern Alberta resulting in the deaths of at least 1309 animals. During the nothern epizootics there has been a strong sex bias in mortalities with the majority of carcasses being sexually mature bulls. The northern epizootics occur during drought conditions in the late summer, preceded by a wet spring, and end with the arrival of coolers weather. It has been hypothesized that stress factors associated with these meteorological conditions coupled with breeding stress during the late summer rut may predispose the bulls to infection. Alternatively, the meteorological conditions may work to concentrate anthrax spores in the environment into low lying wallows preferentially utilized by the bulls. Recent genetic analyses of Bacillus anthracis isolates from Canada and the United States have identified that, while closely related to isolates from domestic outbreaks, isolates from northern bison epizootics form their own distinct strain. This suggests that the establishment of anthrax in northern Canada was a singular event that occurred prior to the first recognized epizootic in 1962. A review of the agricultural history of northern Canada has identified several situations in the first half of the century which may have provided the opportunity for the transfer of anthrax from cattle to the indigenous bison.

We document the recolonization of an indigenous large herbivore into its historic range. Eighteen wood bison (Bison bison athabascae) were reintroduced into the Mackenzie Bison Sanctuary of the Northwest Territories, Canada, in 1963. The population subsequently increased in number and range, peaking at about 2400 in 1989; numbers were estimated at about 1900 in 1998. Recolonization occurred through a series of increases in local areas followed by pulses of dispersal and range expansion. This pattern was originally described for exotic species' introductions. Differences in diet and overwinter survival of calves over the bison's range suggest that intraspecific competition for food provided the stimulus for range expansion. For a conservation strategy, the reintroduction of animals into several independent sites in their historic range would facilitate recolonization and achieve a faster spread than a reintroduction into one site followed by waiting for the population to spread as a result of its own density dependent responses.