The finding of Trichinella in the Arctic was foreseen because captive polar bears and arctic foxes had been found infected during the first decades of the 20th century. Human trichinellosis outbreaks were reported to have taken place in 1944 in Franz Josef Archipelago and 1947 in Greenland, and previous outbreaks in Greenland also appeared to have been trichinellosis. Now, it is known that Trichinella parasites thrive in the Arctic and subarctic and pose a risk for public health. We collated the available information, which show that infection prevalences are high in many animal host species, and that outbreaks of human trichinellosis have been described also recently. The species diversity of Trichinella in the Arctic and subarctic is relatively high, and the circulation is in non-domestic cycles with transmission by predation, scavenging and cannibalism. There are also sporadic reports on the synanthropic species Trichinella spiralis in arctic wild mammals with little known or assumed contact to potential synanthropic cycles. In this paper, we summarize the knowledge on epidemiology of Trichinella parasites in the circumpolar Arctic and subarctic regions, and discuss the challenges and solutions for their control.

One Health, a multidisciplinary approach to public health, which integrates human, animal, and environmental studies, is prudent for circumpolar Arctic health research. The objective of our bibliometric review was to identify and compare research in select infectious diseases in Arctic wildlife species with importance to human health indexed in English language databases (PubMed, Scopus) and the Russian database eLibrary.ru. Included articles (in English and Russian languages) needed to meet the following criteria: (1) data comes from the Arctic, (2) articles report original research or surveillance reports, (3) articles were published between 1990 and 2018, and (4) research relates to naturally occurring infections. Of the included articles (total n = 352), most were from Russia (n = 131, 37%), Norway (n = 58, 16%), Canada (n = 39, 11%), and Alaska (n = 39, 11%). Frequently reported infectious agents among selected mammals were Trichinella spp. (n = 39), Brucella spp. (n = 25), rabies virus (n = 11), Echinococcus spp. (n = 10), and Francisella tularensis (n = 9). There were 25 articles on anthrax in eLibrary.ru, while there were none in the other two databases. We identified future directions where opportunities for further research, collaboration, systematic reviews, or monitoring programs are possible and needed.

The Russian Arctic supports wild sympatric ruminants and their data-deficient helminths. In this study, we: (1) collected fecal samples of wild and semiwild reindeer (Rangifer tarandus), muskoxen (Ovibos moschatus), and snow sheep (Ovis nivicola) across Palearctic North territories: Arkhangelsk Oblast (including Novaya Zemlya archipelago), Karelia and Sakha Republics, Kola, Yamal, Taimyr, and Chukotka Peninsulas, Bering, Svalbard, and Wrangel Islands; (2) conducted a coprological survey (noninvasive life-time method preferable for protected animals) to obtain eggs and larvae of helminths inhabiting digestive, respiratory, nervous, and muscular systems; (3) identified helminths according to their morphology and DNA sequences; (4) estimated parasite load per host; (5) analyzed our findings. Varestrongylus eleguneniensis (in reindeer) was reported for the Palearctic for the first time, while Orthostrongylus sp. was reported both for R. tarandus and for the Palearctic for the first time. Capillarid-type eggs were reported for snow sheep for the first time. The question of the role of wild Arctic ruminants as vectors for rotifers was raised.

During a survey for helminths in reindeer (Rangifer tarandus) across the Palearctic region, eggs were found in zoo reindeer feces. These were identified as eggs of Fasciola hepatica based on their morphology, morphometrics, location, and analysis of their partial sequence of ITS rDNA region. Some of the eggs had an appendage, previously unreported. Additionally, adults of F. hepatica were studied. Eggs derived from their uteri were also appendaged. Diagnostic morphological traits of F. hepatica eggs (abopercular appendage, knob, egg shell thickening, and egg shape) are discussed in this article. Three dimensional models of F. hepatica eggs were created to demonstrate the eggs features as best as possible. Since fecal examination remains gold standard in diagnosing fasciolosis in humans and animals worldwide, our findings may contribute to improved diagnostics. This research has also shown that reindeer can be a final host for F. hepatica. We also discuss whether the Novaya Zemlya archipelago might be the northernmost site of fasciolosis.

Parasites of marine mammals are of significant interest in the fields of evolutionary biology, veterinary medicine, human health, conservation, and ecology. Therefore, every opportunity to study them should be seized. This study aimed to report on specimens of cestodes found in the small intestine of a gray whale (Eschrichtius robustus) in Chukotka, Russia, in 2024. The specimens were examined using light and scanning electron microscopy, histology, and molecular analysis. Based on their morphology and host specificity, the cestodes were identified as Priapocephalus eschrichtii. Analyses of the 18S and 28S ribosomal RNA genes confirmed a close relationship between P. eschrichtii and species of Tetrabothrius, which infect seabirds and whales. Sequences of the 18S, 28S, ITS2 rDNA, and gene CoxI mtDNA are reported here for the first time. More than 50 specimens of P. eschrichtii were detected in 1 meter of intestine of the whale with a maximum length of 50 cm. Chronic lymphoplasmacytic inflammation of the intestinal mucosa was observed in the infected whale. The eggs of the cestodes were clustered within an irregular membrane, which may contribute to multiple infestations of the host and lead to diseases that affect the whale’s health and survival. This study should be continued.