Arctic trichinosis presenting as prolonged diarrhea

A Review of Circumpolar Arctic Marine Mammal Health-A Call to Action in a Time of Rapid Environmental Change

The impacts of climate change on the health of marine mammals are increasingly being recognised. Given the rapid rate of environmental change in the Arctic, the potential ramifications on the health of marine mammals in this region are a particular concern. There are eleven endemic Arctic marine mammal species (AMMs) comprising three cetaceans, seven pinnipeds, and the polar bear (Ursus maritimus). All of these species are dependent on sea ice for survival, particularly those requiring ice for breeding. As air and water temperatures increase, additional species previously non-resident in Arctic waters are extending their ranges northward, leading to greater species overlaps and a concomitant increased risk of disease transmission. In this study, we review the literature documenting disease presence in Arctic marine mammals to understand the current causes of morbidity and mortality in these species and forecast future disease issues. Our review highlights potential pathogen occurrence in a changing Arctic environment, discussing surveillance methods for 35 specific pathogens, identifying risk factors associated with these diseases, as well as making recommendations for future monitoring for emerging pathogens. Several of the pathogens discussed have the potential to cause unusual mortality events in AMMs. Brucella, morbillivirus, influenza A virus, and Toxoplasma gondii are all of concern, particularly with the relative naivety of the immune systems of endemic Arctic species. There is a clear need for increased surveillance to understand baseline disease levels and address the gravity of the predicted impacts of climate change on marine mammal species.

Epidemiology of Trichinella in the Arctic and subarctic: A review

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.

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Trichinella infection is common in wild animals in the Arctic and subarctic regions.

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The high prevalence of Trichinella infection in some arctic marine mammal species suggests a marine cycle.

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Outbreaks of human trichinellosis have been described, and public health importance still remains obvious.

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In this review, we had access to the large amount of Trichinella literature published in the Russian language.

Drivers and health implications of the dietary transition among Inuit in the Canadian Arctic: a scoping review

OBJECTIVE

The current study undertook a systematic scoping review on the drivers and implications of dietary changes among Inuit in the Canadian Arctic.

DESIGN

A keyword search of peer-reviewed articles was performed using PubMed, Web of Science, CINAHL, Academic Search Premier, Circumpolar Health Bibliographic Database and High North Research Documents. Eligibility criteria included all full-text articles of any design reporting on research on food consumption, nutrient intake, dietary adequacy, dietary change, food security, nutrition-related chronic diseases or traditional food harvesting and consumption among Inuit populations residing in Canada. Articles reporting on in vivo and in vitro experiments or on health impacts of environmental contaminants were excluded.

RESULTS

A total of 162 studies were included. Studies indicated declining country food (CF) consumption in favour of market food (MF). Drivers of this transition include colonial processes, poverty and socio-economic factors, changing food preferences and knowledge, and climate change. Health implications of the dietary transition are complex. Micro-nutrient deficiencies and dietary inadequacy are serious concerns and likely exacerbated by increased consumption of non-nutrient dense MF. Food insecurity, overweight, obesity and related cardiometabolic health outcomes are growing public health concerns. Meanwhile, declining CF consumption is entangled with shifting culture and traditional knowledge, with potential implications for psychological, spiritual, social and cultural health and well-being.

CONCLUSIONS

By exploring and synthesising published literature, this review provides insight into the complex factors influencing Inuit diet and health. Findings may be informative for future research, decision-making and intersectoral actions around risk assessment, food policy and innovative community programmes.

A common source for a trichinellosis outbreak reported in France and Serbia in 2017

Trichinellosis is a rare parasitic zoonosis in the European Union. Meat from backyard pigs was the common source for a trichinellosis outbreak caused by Trichinella spiralis, which occurred in France and Serbia in the beginning of 2017. An epidemiological study was conducted in France and Serbia to determine the extent of the outbreak, to identify its source and to implement control measures. Three cases were exposed in Serbia and brought back to France pork delicatessen which they shared with relatives and friends. Around 47 individuals were exposed to the parasitised meat in France and Serbia and 20 cases of trichinellosis were reported (nine in France and 11 in Serbia). Nine of them were female. The diagnosis was delayed, in part because the parasitosis was not known by most physicians, which led to complications in the French cases such as facial paralysis and pulmonary embolism. Health alerts and survey networks are indispensable at a European level to control the disease.

Primary characterization of the immune response in pigs infected with Trichinella spiralis

Trichinellosis, which is caused by Trichinella spiralis (T. spiralis), is a serious zoonosis. Pigs play an important role in the transmission of human trichinellosis. Characterizing the immune response to T. spiralis infection is key to elucidating host–parasite interactions. However, most studies on the immune response to T. spiralis infection have employed murine models. In this study, we investigated the immune response to T. spiralis infection in pigs. The results showed that the average numbers of larvae per gram (lpg) for the 100-muscle larvae (ML), 1000-ML, and 10 000-ML groups were 1.502, 35.947, and 398.811, respectively. The percentages of CD3+ T cells, B cells, CD4+ T cells, Treg cells, and Th17 cells were elevated in the infection groups compared to the control animals. In contrast, CD8+ T cell percentages were reduced after infection in the low-dose group. The number of neutrophils was increased at 3–17 days post-infection (dpi). Th1 cytokine IL-2 levels were significantly decreased at 7 dpi, and Th2 cytokine IL-4 levels were significantly elevated at 3 dpi. Treg cytokine IL-10 levels were significantly elevated between 7 dpi and 30 dpi. Th17 cytokine IL-17A levels were significantly increased beginning at 11 dpi. These results confirmed that pigs infected with T. spiralis predominantly induced Th2 and Treg immune responses, which suppress the Th1 immune responses. This study provides novel insights into the immune response of pigs infected with T. spiralis.

Human Trichinellosis in Italy: an epidemiological review since 1989

Objectives

Trichinellosis is a worldwide zooantroponosis caused by a nematode of the genus Trichinella that can pose a risk to human health. Among the species of Trichinella, T. Spiralis is the most common represented. The main source of human infection is the consumption of raw or undercooked meat (especially from pigs, wild boars and horses). Infection with Trichinella was one of the most frequent parasitic diseases in Italy until 1959 when obligatory screening for these parasites in slaughtered swines was introduced. As the last review on this topic was performed in 1989, the aim of our study was to describe the epidemiology of Trichinellosis in Italy from 1989 to 2017.

Study design

We performed a systematic research in Pubmed (MEDLINE).

Methods

We included in our review studies that were published in the peer reviewed literature using the MESH terms “Trichinellosis” and “Italy”. The only restrictions were the language (articles should be in English, Italian, Spanish or French) and the date of publication: from 1989 to March 2017. We excluded all the articles which referred to trichinellosis in the animals or which focused only on molecular biology of trichinella or on diagnostic techniques.

Results

We found 56 studies, but only 8 were considered eligible. During the study period, 764 cases of Trichinellosis occurred in Italy: 13.7% caused by T. Britovi and 84.4% by T. spiralis; in 14 cases the identification of the parasite was not performed. The outbreaks occurred in Umbria, Piedmont, Apulia (500 cases in 1990, by T. spiralis), Basilicata, Tuscany, Abruzzo, Emilia Romagna, Sardinia. In 2001 and in 2008 two outbreaks occurred in Lazio and Veneto respectively, but imported from abroad. The most important sources of infections were: horse meat (82.2%); wild boar meat (11.9%); pig meat (5.9%).

Conclusions

Trichinellosis is still present in Italy, but often forgotten by general practitioners and infectious diseases specialists. It’s pivotal to improve awareness about this parasitic disease in Physicians and veterinarians. A strict surveillance, especially on meat products from endemic countries or from wild animals is necessary to considerably reduce the risk of acquiring the infection.

Trichinella and polar bears: a limited risk for humans

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.

Foodborne and waterborne illness among Canadian Indigenous populations: A scoping review

Background

Indigenous populations are often at higher risk for foodborne illness than the general Canadian population.

Objective

To investigate the extent of the literature on the link between food safety and the occurrence of foodborne and waterborne illness in Canadian Indigenous populations.

Methods

A scoping review was conducted using search strings in five databases and grey literature to identify all papers that studied a Canadian Indigenous population and referred to any potential associations between food safety (including consumption and preparation of traditional foods and retail foods) or water safety practices and food or waterborne illness. Two authors screened papers based on inclusion and exclusion criteria. Included documents were analyzed for emergent themes.

Results

From 1,718 unique records identified, 21 documents were selected. Foodborne illness was most common in children up to 14 years old. Walrus, seal, caribou and whale were the most common traditional foods tied to foodborne illness and were primarily associated with botulism and trichinosis. Aside from consuming the food raw, fermentation was the most common traditional preparation method linked to foodborne illness. There was concern about the safety of retail food but no clear link was identified with foodborne illness. Lastly, although there was concern about tap water, the use of alternate water sources, such as untreated brook water, and hygiene and cleaning practices in communities with boil water advisories were the most common risk behaviours associated with waterborne illness.

Conclusion

Consumption of certain game meats, as well as the use of traditional fermentation practices may lead to an increased risk of foodborne illness among Indigenous populations. Concern about tap water may lead to use of unsafe alternate water sources. Further research is needed to examine potential culturally appropriate food and water safety opportunities.

A cluster of three cases of trichinellosis linked to bear meat consumption in the Arctic

We report here three cases of trichinellosis due to polar bear meat consumption in East Greenland. In the past 20 years, 31 cases of trichinellosis have been reported in French travellers to the Arctic (North Quebec, Nunavut and Greenland) who consumed undercooked meat from black, brown, or polar bears. If local communities are increasingly becoming aware of the risk of trichinellosis, travellers visiting regions where bear meat is consumed should be informed of the risk of eating raw or non-heat-processed meats.

Human pathogens in marine mammal meat – a northern perspective

Only a few countries worldwide hunt seals and whales commercially. In Norway, hooded and harp seals and minke whales are commercially harvested, and coastal seals (harbour and grey seals) are hunted as game. Marine mammal meat is sold to the public and thus included in general microbiological meat control regulations. Slaughtering and dressing of marine mammals are performed in the open air on deck, and many factors on board sealing or whaling vessels may affect meat quality, such as the ice used for cooling whale meat and the seawater used for cleaning, storage of whale meat in the open air until ambient temperature is reached, and the hygienic conditions of equipment, decks, and other surfaces. Based on existing reports, it appears that meat of seal and whale does not usually represent a microbiological hazard to consumers in Norway, because human disease has not been associated with consumption of such foods. However, as hygienic control on marine mammal meat is ad hoc, mainly based on spot-testing, and addresses very few human pathogens, this conclusion may be premature. Additionally, few data from surveys or systematic quality control screenings have been published. This review examines the occurrence of potential human pathogens in marine mammals, as well as critical points for contamination of meat during the slaughter, dressing, cooling, storage and processing of meat. Some zoonotic agents are of particular relevance as foodborne pathogens, such as Trichinella spp., Toxoplasma gondii, Salmonella and Leptospira spp. In addition, Mycoplasma spp. parapoxvirus and Mycobacterium spp. constitute occupational risks during handling of marine mammals and marine mammal products. Adequate training in hygienic procedures is necessary to minimize the risk of contamination on board, and acquiring further data is essential for obtaining a realistic assessment of the microbiological risk to humans from consuming marine mammal meat.

Single Dose Treatments in Tropical Infectious Diarrhoea: The Place of Secnidazole

Single dose treatments have the important advantages of simple administration, excellent compliance, short-lived side effects (if any) and short period of drug pressure. However, drugs used for single dose treatments must possess important characteristics, namely, long half-life, effective concentration in tissues over a long period, and low toxicity. In tropical medicine, such drugs are an important advance in the treatment of malaria (mefloquine and halofantrine), schistosomiasis (praziquantel and metrifonate), filariasis (ivermectin), and genitourinary tract and intestinal infections.

Intestinal infections are one of the most frequent problems in tropical medicine. While a large number of cases of diarrhoea are of viral (rotavirus) or bacterial (Salmonella, Escherichia coli) origin, necessitating only oral rehydration, some are of parasitological origin (Giardia, Entamoeba histolytica, Strongyloides, Trichuris, Schistosoma) and can be cured by a single dose treatment (tinidazole, secnidazole, ivermectin, albendazole, praziquantel). Secnidazole is the nitroimidazole with the longest half-life and is, therefore, used in single dose treatments for Giardia, acute intestinal amoebiasis and E. histolytica cyst carriers. Single dose treatments of most intestinal parasites will be a major advance in the management of tropical infectious diarrhoea. In the next decade, opportunistic intestinal infections (Cryptosporidium, Isospora, Enterocytozoon) in AIDS patients that are refractory to treatment could be the major problem.

Clinical aspects, diagnosis and treatment of trichinellosis

Trichinellosis, the human disease induced by worms of the genus Trichinella, is caused by the consumption of raw or undercooked meat of various types of animals and has a worldwide prevalence of approximately eleven million. Since there are no pathognomonic signs or symptoms, clinical diagnosis is difficult and the only reliable diagnostic methods are serodiagnosis and muscle biopsy. Treatment consists of benzimidazoles and glucocorticosteroids, yet in order for these drugs to be effective, they must be administered before the end of the acute stage; thus early diagnosis is fundamental. To aid in the recognition and treatment of trichinellosis, an overall description of its clinical aspects, diagnosis and treatment has been prepared.

Experimental Trichinella infection in seals

The susceptibility of seals to infection with Trichinella nativa and the cold tolerant characteristics of muscle larvae in seal meat were evaluated. Two grey seals, Halichoerus grypus, were inoculated with 5000 (100 larvae/kg) T. nativa larvae and two grey seals with 50000 (1000 larvae/kg). One seal from each dose group and two control seals were killed at 5 and 10 weeks post-inoculation (p.i.). At 5 weeks p.i., infection was established in both low and high dose seals with mean larval densities of 68 and 472 larvae per gram (lpg), respectively, using eight different muscles for analyses. At 10 weeks p.i., mean larval densities were 531 and 2649 lpg, respectively, suggesting an extended persistence of intestinal worms. In seals with high larval density infections, the distribution of larvae in various muscles was uniform, but in one seal with a low larval density infection, predilection sites of larvae included muscle groups with a relative high blood flow, i.e. diaphragm, intercostal and rear flipper muscles. Trichinella-specific antibody levels, as measured by ELISA, increased during the 10 week experimental period. Infected seal muscle was stored at 5, -5 and -18 degrees C for 1, 4 and 8 weeks. Muscle larvae released from stored seal muscle by artificial digestion were inoculated into mice to assess viability and infectivity. Larvae from seal muscle 10 weeks p.i. tolerated -18 degrees C for 8 weeks but larvae from seal muscle 5 weeks p.i. tolerated only 1 week at -18 degrees C, supporting the hypothesis that freeze tolerance increases with the age of the host-parasite tissue complex. The expressed susceptibility to infection, extended production of larvae, antibody response and freeze tolerance of T. nativa in seals are new findings from the first experimental Trichinella infection in any marine mammal and suggest that pinnipeds (phocids, otariiids or walrus) may acquire Trichinella infection by scavenging even small amounts of infected tissue left by hunters or predators.

Opinion on the diagnosis and treatment of human trichinellosis

The clinical diagnosis of trichinellosis is difficult because there are no pathogenic signs or symptoms and in diagnosing the infection epidemiological data are of great importance. Trichinellosis usually begins with a sensation of general discomfort and headache, increasing fever, chills and sometimes diarrhoea and/or abdominal pain. Pyrexia, eyelid or facial oedema and myalgia represent the principal syndrome of the acute stage, which can be complicated by myocarditis, thromboembolic disease and encephalitis. High eosinophilia and increased creatine phosphokinase activity are the most frequently observed laboratory features and the parasitological examination of a muscle biopsy and the detection of specific circulating antibodies will confirm the diagnosis. The medical treatment includes anthelmintics (mebendazole or albendazole) and glucocorticosteroids. Mebendazole is usually administered at a daily dose of 5 mg/kg but higher doses (up to 20 - 25 mg/kg/day) are recommended in some countries. Albendazole is used at 800 mg/day (15 mg/kg/day) administered in two doses. These drugs should be taken for 10 - 15 days. The use of mebendazole or albendazole is contraindicated during pregnancy and not recommended in children aged < 2 years. The most commonly used steroid is prednisolone, which may alleviate the general symptoms of the disease. It is administered at a dose of 30 - 60 mg/day for 10 - 15 days.

Novel prevention program for trichinellosis in inuit communities

Repeated outbreaks of trichinellosis caused by the consumption of Trichinella-infected walrus (Odobenus rosmarus) meat, which have sometimes led to serious morbidity, have stimulated Inuit communities in Nunavik (northern Quebec), Canada, to develop an innovative trichinellosis prevention program. The program involves preconsumption testing of meat samples from harvested walrus at a regional laboratory and the rapid dissemination of the results of such testing to communities. Local health authorities in Inukjuak conducted an epidemiological investigation after testing identified Trichinella-positive walrus meat in September 1997. This report describes the events that occurred before, during, and after the trichinellosis outbreak and also documents how the prevention program contributed to successful resolution of the outbreak.

New aspects of human trichinellosis: the impact of new Trichinella species

Trichinellosis is a re-emerging zoonosis and more clinical awareness is needed. In particular, the description of new Trichinella species such as T. papuae and T. murrelli and the occurrence of human cases caused by T pseudospiralis, until very recently thought to occur only in animals, requires changes in our handling of clinical trichinellosis, because existing knowledge is based mostly on cases due to classical T spiralis infection. The aim of the present review is to integrate the experiences derived from different outbreaks around the world, caused by different Trichinella species, in order to provide a more comprehensive approach to diagnosis and treatment.

A review of trichinellosis in people and wildlife in Canada

Repeated serological and parasitological analyses of commercially raised swine have shown the Canadian swine herd to be free of Trichinella in recent years in all regions of the country except for sporadic cases from one community in Nova Scotia. Nevertheless, approximately 18 cases of human trichinellosis are reported each year in Canada. Cases are generally attributed to the consumption of infected meat from wildlife. Many surveys for Trichinella in wildlife have been conducted but their results are frequently limited to a few hosts or are limited in geographic range; nonetheless, they suggest that in some regions of Canada, trichinellosis appears to be common in some wildlife species. This literature review identifies two regions of Canada where sylvatic trichinellosis is prevalent and correlates with human cases. The occurrence of Trichinella in wildlife is significant from the point of view of public health as all known biotypes of the parasite can infect people.