“…They are skilled and opportunistic marine predators, feeding on a wide range of fi sh and cephalopod species. However, occasionally, northern sea lions have been observed killing and eating northern fur seal pups, ringed seals and sea otter pups (Seal Conservation Society, 2011;Canisius College). The infection status in this species has not been previously documented.…”
Section: Discussionmentioning
confidence: 99%
“…endemic area, near coastal waters of Finland. Trichinella has not been reported in marine mammals such as California sea lions (Zalophus californianus) or harbor seals (Phoca vitulina) so far (Isomursu and Kunnasranta, 2011;Seymour et al, 2014).…”
Section: Discussionmentioning
confidence: 99%
“…The presence of T. spiralis in arctic animals suggests environmental contamination and can be explained by its cosmopolitan distribution, wide host range and the ability to infect apace the surrounding fauna . T. spiralis is mainly associated with domestic pigs and its infection in marine mammal species may transpire from utilization of coastal or near shore habitats in close proximity to the agricultural areas where run-off from livestock operations occurs (Seymour et al, 2014). T. pseudospiralis is a cosmopolitan species and is typical for the Palearctic and Nearctic.…”
SummaryThe parasitic nematodes of genus Trichinella are infective to a wide range of hosts, including humans, and have global distribution from tropic to arctic areas. Muscle samples from animals, collected in two areas of the Russian Federation, Chukotka Peninsula and Arkhangelsk Oblast, were tested for the presence of Trichinella spp. larvae. Trichinella spp. larvae were recovered from tissues of eleven wild and domestic animals: 1 polar bear, 1 wolverine, 3 arctic foxes, 1 ringed seal, 1 brown bear, 1 cat, 1 sled dog, 1 domestic pig and 1 northern sea lion. Two molecular methods, multiplex PCR and inter-simple sequence repeat polymerase chain reaction (ISSR PCR), were utilized for species identifi cation. T. nativa was identifi ed in the majority of tested animals and mixed infections with two Trichinella species were detected in four animals. T. spiralis/T. pseudospiralis mixed infection was found in a domestic pig and T. spiralis/T. nativa in two arctic foxes and a northern sea lion. Here, for the fi rst time, Trichinella spp. infection in a northern sea lion and the northern sea lion as a new host for T. spiralis and T. nativa is reported. Discovery of Trichinella spp. infection in a new host, such as a northern sea lion, which is an opportunistic marine predator, mainly feeding on fi sh, indicates environmental contamination. Leaving of carcasses or waste from animals and improper management of livestock operations is important for spreading Trichinella spp. infection in free living animals. Therefore, further extensive epidemiological and environmental research and molecular studies are needed to investigate the local fauna.
“…They are skilled and opportunistic marine predators, feeding on a wide range of fi sh and cephalopod species. However, occasionally, northern sea lions have been observed killing and eating northern fur seal pups, ringed seals and sea otter pups (Seal Conservation Society, 2011;Canisius College). The infection status in this species has not been previously documented.…”
Section: Discussionmentioning
confidence: 99%
“…endemic area, near coastal waters of Finland. Trichinella has not been reported in marine mammals such as California sea lions (Zalophus californianus) or harbor seals (Phoca vitulina) so far (Isomursu and Kunnasranta, 2011;Seymour et al, 2014).…”
Section: Discussionmentioning
confidence: 99%
“…The presence of T. spiralis in arctic animals suggests environmental contamination and can be explained by its cosmopolitan distribution, wide host range and the ability to infect apace the surrounding fauna . T. spiralis is mainly associated with domestic pigs and its infection in marine mammal species may transpire from utilization of coastal or near shore habitats in close proximity to the agricultural areas where run-off from livestock operations occurs (Seymour et al, 2014). T. pseudospiralis is a cosmopolitan species and is typical for the Palearctic and Nearctic.…”
SummaryThe parasitic nematodes of genus Trichinella are infective to a wide range of hosts, including humans, and have global distribution from tropic to arctic areas. Muscle samples from animals, collected in two areas of the Russian Federation, Chukotka Peninsula and Arkhangelsk Oblast, were tested for the presence of Trichinella spp. larvae. Trichinella spp. larvae were recovered from tissues of eleven wild and domestic animals: 1 polar bear, 1 wolverine, 3 arctic foxes, 1 ringed seal, 1 brown bear, 1 cat, 1 sled dog, 1 domestic pig and 1 northern sea lion. Two molecular methods, multiplex PCR and inter-simple sequence repeat polymerase chain reaction (ISSR PCR), were utilized for species identifi cation. T. nativa was identifi ed in the majority of tested animals and mixed infections with two Trichinella species were detected in four animals. T. spiralis/T. pseudospiralis mixed infection was found in a domestic pig and T. spiralis/T. nativa in two arctic foxes and a northern sea lion. Here, for the fi rst time, Trichinella spp. infection in a northern sea lion and the northern sea lion as a new host for T. spiralis and T. nativa is reported. Discovery of Trichinella spp. infection in a new host, such as a northern sea lion, which is an opportunistic marine predator, mainly feeding on fi sh, indicates environmental contamination. Leaving of carcasses or waste from animals and improper management of livestock operations is important for spreading Trichinella spp. infection in free living animals. Therefore, further extensive epidemiological and environmental research and molecular studies are needed to investigate the local fauna.
“…the proportion of the host population infected). Specifically, we consider a case study of polar bears and the parasitic nematode Trichinella nativa (Rausch et al 1956, Fay 1960, Rah et al 2005, Seymour et al 2014a). Trichinella nativa is trophically transmitted, with larvae being reliant on carnivory to establish in a host (Dau and Barrett 1981, Kapel et al 2003).…”
Parasites exhibit a diverse range of life history strategies. Transmission to a host is a key component of each life cycle but the difficulty of observing host–parasite contacts has often led to confusion surrounding transmission pathways. Given limited data on most host–parasite systems, flexible approaches are needed for disentangling the obscure transmission dynamics of these systems. Here, we develop a modelling framework for formally testing long‐standing hypotheses regarding how the parasitic nematode Trichinella nativa is maintained at high prevalences in polar bear populations. We evaluated transmission from marine prey, from scavenging terrestrial carrion, from cannibalism and from scavenging on dead infected bears as possible pathways, and assessed their respective importance by comparing model‐projected prevalences for each mechanism against observed total and age‐specific population prevalences in the Southern Beaufort Sea polar bear subpopulation. Cannibalism and the scavenging on conspecifics have previously been assumed to be critical transmission pathways, but despite data scarcity, our model exposes these mechanisms as ineffective across a wide range of plausible parameter values. Instead, our analyses suggest that transmission from the consumption of infected marine prey, and in particular seals, can explain observed prevalence levels by itself, with other transmission pathways likely playing varying small contributing roles. Furthermore, our model suggests that transmission declines with bear age, perhaps due to age‐dependent changes in diet or immunity. By formalising multiple transmission mechanisms in a unified, mathematical framework, we distilled several hypotheses to a likely main mode of T. nativa transmission to polar bears. The specifics of our model are tailored towards the T. nativa‐polar bear system, but the approach is easily generalized; it provides a powerful, quantitative means for ecologists to explore competing hypothesis for parasite transmission and other difficult‐to‐observe animal interactions even in data‐poor systems.
“…The global population of polar bears consists of roughly 20,000–25,000 individuals (Museum National d'Histoire Naturelle, 2016). The most prevalent species of Trichinella in the Arctic is T. nativa , with polar bear as the main reservoir (Pozio, 2007), and larvae of this species survive freezing in the muscle of carnivores for several years (Dick & Belosevic, 1978; Chadee & Dick, 1982; Kapel et al ., 1999; Seymour et al ., 2014; Pozio, 2016). Fig.…”
In this review, we identified 63 cases reported since World War II of human trichinellosis linked to the consumption of parasitized polar bear (Ursus maritimus) meat. This low number contrasts to the numerous cases of human trichinellosis related to consumption of the meat of black (U. americanus) or brown bears (U. arctos). The prevalence of Trichinella infection is high in bears, but larval muscular burden is usually lower in polar bears compared to other bear species. Polar bears, therefore, seem to play a limited role in the transmission of trichinellosis to humans, as native residents living in the Arctic traditionally consume well-cooked bear meat, and travellers and foreign hunters have only limited access to this protected species due to the declining polar bear population.
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