Freeze tolerance, morphology, and RAPD-PCR identification of Trichinella nativa in naturally infected arctic foxes.

Arctic foxes (Alopex lagopus) were collected from Greenland and Svalbard (N = 319). Twenty-four were infected with Trichinella (7.5%). Molecular analysis (random-amplified polymorphic DNA polymerase chain reaction) confirmed that all animals were infected with Trichinella nativa. Motile larvae were found in muscle tissue from all foxes after carcasses had been frozen for 1 yr at -18 C. Infective larvae were found in 2 foxes after a total of 4 yr storage at -18 C, which is longer than any previous observations. Morphological examination of the cysts showed large nurse cells and significant deposition of collagen and connective tissue. It is suggested that, within the geographical distribution of T. nativa, the more freeze-resistant isolates are found at higher latitudes.

The prevalence of Trichinella sp. in Arctic foxes (Alopex lagopus) in Svalbard.

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.

Levels and congener pattern of PCBs in arctic fox, Alopex lagopus, in Svalbard.

Levels and congener pattern of polychlorinated biphenyls (PCBs) were determined in samples of subcutaneous fat and liver from 27 polar foxes, Alopex lagopus, caught in Svalbard during the winter 1983-1984. In all the samples analysed the composition of individual PCB congeners was studied by comparison with 12 individual PCB congeners (IUPAC nos. 28, 52, 101, 118, 138, 153, 170, 180, 183, 194, 206 and 209). In addition, the PCB congeners nos. 99, 105, 114, 156 and 157 were determined in the fat samples. In both liver and fat samples the sum PCB was calculated based on the concentrations of seven selected congeners, nos. 138, 153, 170, 180, 194, 206 and 209. These congeners were the same as those used in a corresponding investigation made on arctic fox from Svalbard 10 years earlier. The present study reveals that the PCB levels in arctic fox in Svalbard are high and essentially unchanged in the period from 1973-1974 to 1983-1984. The mean sum PCB levels in fat and liver were 8.3 +/- 11 and 0.4 +/- 0.4 microg g(-1), and the extractable fat was 81.2 +/- 8.4 and 4.5 +/- 1.7% for the two tissues, respectively. In fat, sum PCB ranged from 0.5 to 41.0 microg g(-1). PCB nos. 153 and 180 accounted for approximately 65% of sum PCB. The contributions of PCB nos. 138 and 153 to the sum PCB were found to increase from 1974 to 1984. The PCB congener pattern is similar to that found in polar bears, and is dominated by a few congeners (99, 138, 153, 170, 180 and 194). No significant differences in PCB levels were found between sexes or between age groups. However, significantly higher PCB levels were found in old animals (>/= 3 years) with less than 2 cm of fat on the ramp as compared with young animals (1-2 years) with more than 2 cm of fat on the rump. Effects on vital functions from the observed levels of PCBs cannot be excluded for the most contaminated foxes.

The occurrence of rabies in the Svalbard Islands of Norway.

After the first recorded outbreak of rabies in the Svalbard Islands (Norway) in 1980, brain tissue from 817 trapped arctic foxes (Alopex lagopus) was tested for rabies by a direct fluorescent antibody test. During the same period (1980 to 1990), 29 arctic foxes, 23 polar bears (Ursus maritimus), 19 reindeer (Rangifer tarandus) and five ringed seals (Phoca hispida) were also tested using the same technique. These animals had either been found dead, killed because of abnormal behavior or were apparently healthy when they were collected. Rabies virus antigen was not detected in any of the trapped foxes. Rabies was confirmed in two foxes in 1981, two foxes and one reindeer in 1987, and in one fox in 1990. The presence of rabies in the Svalbard archipelago probably resulted from immigration over the sea ice of an infected host.