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The arctic fox variant of the rabies virus (RABV) is enzootic in the circumpolar north. Reports of abortive RABV exposures motivated a retrospective analysis of sera from 41 arctic foxes (Vulpes lagopus) captured at Karrak Lake in Nunavut, Canada, during 2011-15. Estimated RABV antibody prevalence among foxes was 15% (95% confidence interval, 7-28%).

Transmission dynamics of Toxoplasma gondii, a parasite of importance for wildlife and human health, are enigmatic in the Arctic tundra, where free-ranging wild and domestic felid definiti...

Although the protozoan parasite Toxoplasma gondii is ubiquitous in birds and mammals worldwide, the full suite of hosts and transmission routes is not completely understood, especially in the Arctic. Toxoplasma gondii occurrence in humans and wildlife can be high in Arctic regions, despite apparently limited opportunities for transmission of oocysts shed by felid definitive hosts. Arctic foxes (Vulpes lagopus) are under increasing anthropogenic and ecologic pressure, leading to population declines in parts of their range. Our understanding of T. gondii occurrence in arctic foxes is limited to only a few regions, but mortality events caused by this parasite have been reported. We investigated the exposure of arctic foxes to T. gondii in the Karrak Lake goose colony, Queen Maud Gulf Migratory Bird Sanctuary, Nunavut, Canada. Following an occupancy-modeling framework, we performed replicated antibody testing on serum samples by direct agglutination test (DAT), indirect fluorescent antibody test (IFAT), and an indirect enzyme-linked immunosorbent assay (ELISA) that can be used in multiple mammalian host species. As a metric of test performance, we then estimated the probability of detecting T. gondii antibodies for each of the tests. Occupancy estimates for T. gondii antibodies in arctic foxes under this framework were between 0.430 and 0.758. Detection probability was highest for IFAT (0.716) and lower for DAT (0.611) and ELISA (0.464), indicating that the test of choice for antibody detection in arctic foxes might be the IFAT. We document a new geographic record of T. gondii exposure in arctic foxes and demonstrate an emerging application of ecologic modeling techniques to account for imperfect performance of diagnostic tests in wildlife species.

Arctic foxes, 620 that were trapped and 22 found dead on Svalbard, Norway (1996-2004), as well as 10 foxes trapped in Nenets, North-West Russia (1999), were tested for rabies virus antigen in brain tissue by standard direct fluorescent antibody test. Rabies antigen was found in two foxes from Svalbard and in three from Russia. Blood samples from 515 of the fox carcasses were screened for rabies antibodies with negative result. Our results, together with a previous screening (1980-1989, n=817) indicate that the prevalence of rabies in Svalbard has remained low or that the virus has not been enzootic in the arctic fox population since the first reported outbreak in 1980. Brain tissues from four arctic foxes (one from Svalbard, three from Russia) in which rabies virus antigen was detected were further analyzed by reverse-transcriptase polymerase chain reaction direct amplicon sequencing and phylogenetic analysis. Sequences were compared to corresponding sequences from rabies virus isolates from other arctic regions. The Svalbard isolate and two of the Russian isolates were identical (310 nucleotides), whereas the third Russian isolate differed in six nucleotide positions. However, when translated into amino acid sequences, none of these substitutions produced changes in the amino acid sequence. These findings suggest that the spread of rabies virus to Svalbard was likely due to migration of arctic foxes over sea ice from Russia to Svalbard. Furthermore, when compared to other Arctic rabies virus isolates, a high degree of homology was found, suggesting a high contact rate between arctic fox populations from different arctic regions. The high degree of homology also indicates that other, and more variable, regions of the genome than this part of the nucleoprotein gene should be used to distinguish Arctic rabies virus isolates for epidemiologic purposes.

We tested the Raboral V-RG® recombinant oral rabies vaccine for its response in Arctic foxes (Vulpes lagopus), the reservoir of rabies virus in the circumpolar North. The vaccine, which is currently the only licensed oral rabies vaccine in the United States, induced a strong antibody response and protected foxes against a challenge of 500,000 mouse intracerebral lethal dose 50% of an Arctic rabies virus variant. However, one unvaccinated control fox survived challenge with rabies virus, either indicating a high resistance of Arctic foxes to rabies infection or a previous exposure that induced immunity. This preliminary study suggested that Raboral V-RG vaccine may be efficacious in Arctic foxes.

Although the protozoan parasite Toxoplasma gondii is ubiquitous in birds and mammals worldwide, the full suite of hosts and transmission routes is not completely understood, especially in the Arctic. Toxoplasma gondii occurrence in humans and wildlife can be high in Arctic regions, despite apparently limited opportunities for transmission of oocysts shed by felid definitive hosts. Arctic foxes (Vulpes lagopus) are under increasing anthropogenic and ecologic pressure, leading to population declines in parts of their range. Our understanding of T. gondii occurrence in arctic foxes is limited to only a few regions, but mortality events caused by this parasite have been reported. We investigated the exposure of arctic foxes to T. gondii in the Karrak Lake goose colony, Queen Maud Gulf Migratory Bird Sanctuary, Nunavut, Canada. Following an occupancy-modeling framework, we performed replicated antibody analyses on serum samples by direct agglutination test (DAT), indirect fluorescent antibody test (I...

Wild arctic foxes (Alopex lagopus) from Greenland were tested for antibodies to Encephalitozoon cuniculi with an enzyme-linked immunosorbent assay and a carbon immunoassay. Of 230 tested foxes none was seropositive. This finding contrasts with observations from other arctic areas and absence of rodents in the diet of these arctic foxes is the most likely explanation for absence of E. cuniculi.

Two oil field workers were attacked by a rabid arctic fox (Alopex lagopus) in the Prudhoe Bay oil field (Alaska, USA) prompting officials to reduce the local fox population. Ninety-nine foxes were killed during winter 1994. We tested foxes for prevalence of rabies and canine distemper. Exposure to rabies was detected in five of 99 foxes. Of the five, only one fox had rabies virus in neural tissue as determined by the direct fluorescent antibody test. The other four foxes had been exposed to rabies, but had apparently produced antibodies and did not have an active infection. No evidence of canine distemper was detected as determined by the absence of distemper antibodies in serum and distemper virus in neural tissue.

The prevalence of Trichinella sp. in arctic foxes (Alopex lagopus) from Svalbard was studied from 1983 to 1989. Diaphragms of 697 foxes were examined for larvae; 59 foxes (8.5%) were infected. The prevalence of Trichinella sp. increased from 4% in juveniles to 36% in foxes aged more than 6 years of age. There were no significant correlations when condition and body weight each were correlated to the occurrence and number of larvae of Trichinella sp. More foxes were infected in the northern than in the central part of Svalbard. There were only minor differences in prevalence among years.

Three hundred forty five adult arctic foxes (Alopex lagopus) from all counties in Iceland were examined for excess cerumen and ear canker mites (Otodectes cynotis). Only 13 foxes (4%) from a single county in northwestern Iceland were infested, where the prevalence of otodectiasis was 38%. Whether or not this parasite is new to the arctic fox in Iceland is unknown. If it is recently introduced, possible sources of infestation are farmed silver foxes (Vulpes vulpes), domestic dogs, domestic or feral cats, and arctic foxes from Greenland. It appears that the rate of transmission between adult foxes is low; a more common route of transmission is probably from the mother to her offspring or between vixens breeding in the same dens in subsequent years by contamination of the dens. No correlation was found between the prevalence of mites in foxes and Samson character.

After being free of rabies of terrestrial mammals since 1988, an outbreak of rabies occurred on the Island of Newfoundland in December 2002 and continued into the middle of 2003. Twenty-one cases, all due to the arctic fox strain of rabies virus, were reported. To explore the immediate origins of this outbreak, viruses from the Newfoundland epizootic were genetically compared to two other rabies viruses recovered in mid-2002 from Cartwright, a mainland coastal community near the Island. While all Island isolates from the 2002-03 outbreak were genetically very similar, consistent with a single introduction from the mainland, they were phylogenetically quite distant from the two samples from Cartwright. A broader-based study examined the relationships between the Island viruses and arctic fox strain viruses originating from across Canada over a period of 14 yr. This analysis indicated that the Newfoundland outbreak viruses were most similar to a variant identified in Labrador in 2004 but also widely distributed in northern Quebec both before and after the Newfoundland incursion. The eastern coastline of mainland Labrador has harbored a particularly large number of variants during the study period, some of which have not been detected elsewhere. A small number of Greenland isolates included in this study were dispersed within the clades of the Canadian samples rather than forming a discrete cluster, an observation that may underline the relative ease of movement of the rabies arctic lineage between these two countries as a result of animal movements over pack ice.

Blood samples were collected from humans and several species of free-ranging wild animals in Alaska. Sera were tested for antibody to Jamestown Canyon (JC), snowshoe hare (SSH), Northway (NOR), Klamath (KLA), Sakhalin (SAK), Great Island (GI), and Silverwater (SIL) virus. JC antibody was found in 54% of 121 human, 89% of 97 bison (Bison bison), 51% of 84 Dall sheep (Ovis dalli), 43% of 68 snowshoe hare (Lepus americanus), and 3% of 33 arctic fox (Alopex lagopus) sera. SSH antibody was found in 42% of 121 human, 89% of 97 bison, 41% of 84 Dall sheep, and 65% of 68 snowshoe hare sera. NOR antibody was found in 14% of 121 human, 94% of 97 bison, 84% of 84 Dall sheep, 43% of 69 caribou (Rangifer tarandus), 3% of 68 snowshoe hare, 48% of 64 grizzly bear (Ursus arctos), 3% of 33 arctic fox, and 78% of 27 moose (Alces alces) sera. KLA antibody was found in 5% of 121 human and 40% of 97 bison sera. SAK antibody was found in 2% of 97 bison and 3% of 33 arctic fox sera. GI antibody was found in 1% of 97 bison sera. No SIL antibody was found in any sera tested. Thus the natural host ranges of JC, SSH, NOR, and KLA viruses have been extended by inference from the occurrence of antibody.

A system to designate and define isolates of Trichinella spiralis is proposed. The designation gives the host from which the isolate was recovered, geographic origin, and year of recovery. Isolates of T. spiralis recovered from frozen muscles from four species of wild carnivores had low and different infectivity to laboratory mice. Viable larvae of T. spiralis were obtained from muscle samples of marten, wolverine, polar bear and arctic fox which had been frozen for 5, 6, 12 and 14 mo, respectively.

Arctic foxes (Alopex lagopus) were successfully immunized against rabies using an orally-administered, liquid SAD-BHK21 live virus vaccine in a sausage bait. Immunization was determined by serologic response and by resistance to challenge with an arctic rabies virus strain. Virus was not shed in saliva following oral vaccination, indicating that arctic foxes would not infect other foxes after ingesting this vaccine. High antibody levels were present in all experimental foxes 2 wk following initial vaccination. A booster vaccination at 56 wk induced a significant serologic response within 1 wk, suggesting an anamnestic response but titers began to decline within 8 wk in most foxes. Foxes were observed for 16 mo following the challenge and exhibited no symptoms of rabies. The SAD-BHK21 rabies vaccine in a sausage bait system has a strong potential for vaccinating wild populations of arctic fox.

The objectives of this study were to determine if the raccoon was a useful experimental animal for infections of Trichinella and to determine if the ability of Trichinella to survive freezing conditions, known to occur in wild animals, could be duplicated under laboratory conditions. The isolates of Trichinella used in this study were from pigs, polar bear, wolverine, arctic fox and T. spiralis var. pseudospiralis originally isolated from a raccoon in the USSR. The raccoon was found to be a useful experimental host for Trichinella as it was easily maintained under experimental conditions and was readily infected. Infectivity indices were lower in raccoons than in laboratory mice. Those isolates of Trichinella with the longest association with laboratory mice had the lowest infectivity indices. The isolate of Trichinella from an arctic fox retained its ability to survive freezing temperatures when introduced into raccoons held under experimental conditions. The type of host, method of passing the parasite and perhaps a special genetic characteristic of arctic isolates seem to be important factors influencing their ability to survive freezing temperatures.

Three of seven Arctic fox kits, Alopex lagopus, trapped on St. Paul Island, Alaska, had evidence of rickets and hyperparathyroidism. Radiographic, morphologic and histologic examination confirmed the diagnosis. The disease was presumed to be a juvenile-onset disease due to calcium-deficient intake following weaning. The possibility of insufficient exposure to sunlight could not be determined. No other abnormalities (e.g., genitourinary) were found. Skeletal involvement was quite varied. All growth plates exhibited columnar hyperplasia compatible with rickets, while the metaphyses showed decreased trabeculation and cortical thinning compatible with osteodystrophia fibrosa. One fox had bilateral metaphyseal fractures through this osteodystrophic bone.