Trichinella Nativa Outbreak With Rare Thrombotic Complications Associated With Meat From a Black Bear Hunted in Northern Ontario.

BACKGROUND: Although trichinellosis is known to cause thrombotic disease, serious thrombotic events are rare and have not been previously associated with Trichinella nativa infection. METHODS: Patient interviews and medical chart reviews were conducted on 10 men who became ill following consumption of a common source of black bear meat. Trichinella serology on patient sera as well as polymerase chain reaction (PCR) and larval identification of the meat samples was conducted. RESULTS: All 10 exposed individuals developed an acute illness clinically compatible with trichinellosis, characterized by fever, abdominal pain, and diarrhea, along with eosinophilia ranging from 0.9 × 109/L to 6.1 × 109/L. Within 2 weeks of the diarrheal illness, systemic symptoms developed in all exposed individuals characterized by fever, myalgia, periorbital edema, and fatigue. ST-elevation myocardial infarction and sinus venous tract thrombosis occurred as a complication of trichinellosis in 2 patients. Acute serology was nonreactive in all patients, though convalescent serology was reactive in 6 of 8 (75%) patients for whom sera was available. Multiplex PCR identified T. nativa from the bear meat, and was corroborated by microscopic larval identification. CONCLUSIONS: We report a 100% attack rate of T. nativa from bear meat among those who were exposed, and demonstrate that this species can cause serious thrombotic complications of trichinellosis in humans. Education of hunters and the public regarding the importance of proper preparation of wild game prior to ingestion is warranted.

First case of Trichinella nativa infection in wild boar in Central Europe-molecular characterization of the parasite.

The examination of wild boars gained in Poland shows for the first time occurrence of Trichinella nativa, freeze-resistant species of Trichinella in this host from the central Europe region. This finding is not only one of several cases of T. nativa invasion in wild boars all over the world but also one of the very few cases of T. nativa detected so far beyond the known boundary of occurrence of this species. The molecular characterization of discovered larvae based on analysis of partial genes: 5s rDNA-ISR and CO1 confirm the findings. Moreover, the analyzed DNA sequences of both genes present new haplotypes of T. nativa in comparison to that described previously.

Early Trichinella spiralis and Trichinella nativa infections induce similar gene expression profiles in rat jejunal mucosa.

Trichinella spiralis causes a significantly higher parasite burden in rat muscle than Trichinella nativa. To assess whether the difference in infectivity is due to the early intestinal response, we analyzed gene expression changes in the rat jejunum during Trichinella infection with a whole-genome microarray. The rats were euthanized on day five of infection, and their jejunal mucosa was sampled for microarray analysis. In addition, intestinal histology and hematology were examined. Against our expectations, the gene expression changes were similar in both T.nativa- and T. spiralis-infected groups. The two groups were hence pooled, and in the combined Trichinella-infected group, 551 genes were overexpressed and 427 underexpressed when compared to controls (false discovery rate ≤ 0.001 and fold change at least 2 in either direction). Pathway analysis identified seven pathways significantly associated with Trichinella infection (p < 0.05). The microarray data suggested nonspecific damage and an inflammatory response in the jejunal mucosa. Histological findings, including hyperemia, hemorrhage and a marked infiltration of inflammatory cells, supported the microarray data. Trichinella infection caused complex gene expression changes that indicate a host response to tissue damage in the mucosa of the jejunum, but the changes were not notably dependent on the studied species of Trichinella.

Hematological, biochemical, and serological parameters of experimentally infected rabbits with Trichinella nativa and Trichinella spiralis for early identification of trichinellosis.

Background and Aim: Trichinellosis remains a dangerous disease for humans and animals, which can lead to a lethal outcome. The study of specific body reactions in response to invasion by different types of Trichinella can help in the early diagnosis of the disease. This study aimed to investigate the hematological, biochemical, and serological characteristics of rabbits experimentally infected with trichinellosis, as well as the possibility of using changes in these parameters at various disease stages for early hematological, biochemical, and serological diagnosis of trichinellosis. Materials and Methods: Three groups of rabbits were orally infected with Trichinella nativa and Trichinella spiralis derived from encysted T. spirtalis larvae in pork muscle samples. The first and second groups were infected with T. nativa and T. spiralis, respectively, while the third group served as control by receiving a physiological solution. An ADVIA 2120i automatic hematology analyzer with a blood smear staining module was used to determine the hematological parameters of rabbits. Antigens were used in an enzyme-linked immunosorbent assay (ELISA) to detect antibodies in the sera of infected rabbits that were supernatants containing excretory-secretory antigens (ES-Ag) and somatic antigen (S-Ag). Results: The detection of biochemical responses to the invasion of T. nativa and T. spiralis isolates was detected and hematological parameters were featured in two cases. Trichinella nativa increased the number of erythrocytes, neutrophils, eosinophils, monocytes, basophils, and thrombocytes on day 7 in rabbits. Creatine kinase (CK) is regarded as the most important indicator for the early detection of parasite invasion. Blood biochemistry showed no active response to T. spiralis infection. However, counts of erythrocytes, neutrophils, lymphocytes, and CK rose significantly. In both color indicators, the number of thrombocytes decreased. Enzyme-linked immunosorbent assay with ES-Ag and S-Ag of these isolates demonstrated the ability to detect antibodies as early as 7 days after infection, with a significant increase in the marker up to 70 days. Conclusion: On the 7th day after infection, blood tests of infected animals revealed CK-N-acetyl-cysteine (18.2%) and neutrophils (43%) when infected with T. nativa and neutrophils (26.7%) and lymphocytes (20%) when infected with T. spiralis. These indicators may serve as specific parameters for the early detection of Trichinella spp. invasion.

Towards a better understanding of the benefits and risks of country food consumption using the case of walruses in Nunavik (Northern Quebec, Canada).

Food insecurity affects Inuit communities. One solution is to consume locally harvested foods, named country foods. However, some country foods are not eaten as often as before, and pressures including contaminants and environmental changes threaten the health of Arctic fauna, thus its suitability for local consumption. By combining Inuit Knowledge with laboratory data, our study assessed the benefits and risks of walrus consumption by Inuit in Nunavik, Québec, Canada. It aimed to increase understanding of: 1) the hunt of healthy Atlantic walruses (Odobenus rosmarus rosmarus); 2) the safe preparation of walruses; 3) the nutritional benefits and risks of consuming walruses. To do so, we interviewed 34 hunters and Elders from Nunavik. Levels of mercury, omega-3 polyunsaturated fatty acids and selenium were evaluated from locally harvested walruses. Through the Nunavik Trichinellosis Prevention Program, a total of 755 Atlantic walrus samples, collected between 1994 and 2013, were tested for Trichinella nativa. Information on botulism was reviewed. While interviews informed on how to select healthy walruses and prepare them for consumption, laboratory analyses revealed that walruses had elevated levels of omega-3 fatty acids and selenium but low levels of mercury compared to some other wildlife. Only 3% of the 755 walruses were infected with T. nativa. Most walruses' infections were found within individuals from the South East Hudson Bay stock, where Inuit have thus decided to stop hunting since mid-2000s. Finally, although the number of outbreaks of trichinellosis related to the consumption of walruses has significantly reduced in Nunavik, botulism could continue to be an issue when igunaq (i.e. aged walrus) is not properly prepared. With the support of the Nunavik Trichinellosis Prevention Program and transmission of Inuit knowledge on igunaq preparation, the consumption of Atlantic walruses has the potential to help address issues related to food insecurity in Nunavik in the future.

The unique contribution of a local response group in the field investigation and management of a trichinellosis outbreak in Nunavik (Québec, Canada).

SETTING: Consumption of raw game meats is important for Inuit health and well-being but may sometimes increase risk of exposure to parasites. In Nunavik, following trichinellosis outbreaks in the 1980s caused by raw walrus consumption, a diagnostic test was developed for the region and offered to all Inuit communities by 1997. Despite this prevention program, an important trichinellosis outbreak occurred in 2013, affecting 18 inhabitants of Inukjuak. INTERVENTION: Because the classical outbreak investigation did not rapidly converge toward a common food source or specific event, a local response group, composed of four community members appointed by the Municipal Council as well as the regional public health physician, nurse and wildlife parasitologist, was created. Their objective was to investigate potential sources of infection related to the outbreak, hence the investigation of the types of meats consumed, the movement of meats between and within the community, and the local practices of processing game meat. OUTCOMES: Though the source of infection was not fully confirmed, this local investigation identified the distribution of transformed polar bear meat as the most probable source of infection. The creation of this unique, intersectoral and intercultural local response group fostered the use of local knowledge to better understand aspects of the modern food system, and is one of the most innovative outcomes of this investigation. IMPLICATIONS: Integrating multiple ways of knowing was critical for the management of this important public health issue and contributed to community members' mobilization and empowerment with respect to local food safety issues.

Trichinella nativa and Trichinella T6 in arctic foxes (Vulpes lagopus) from northern Canada.

Parasitic zoonotic nematodes of the genus Trichinella circulate in wildlife and domestic hosts worldwide through the ingestion of infected meat. Due to their role as scavengers and predators in terrestrial and marine arctic ecosystems, Arctic foxes (Vulpes lagopus) are ideal sentinels for the detection of Trichinella spp. In this study, we determined the prevalence, larval intensity, and species of Trichinella from 91 trapped Arctic foxes collected around the northern Canadian communities of Sachs Harbour (Ikaahuk) on Banks Island (n = 23), and Ulukhaktok and Cambridge Bay (Ikaluktutiak) on Victoria Island (n = 68). Using pepsin-HCl digestion, larvae of Trichinella spp. were recovered from the left forelimb muscle (flexor carpi ulnaris) in 19 of the 91 foxes (21% prevalence, 95% CI: 14-30%). For the first time in Arctic foxes in Canada, Trichinella species were identified using multiplex PCR that was followed up with PCR-RFLP to distinguish between T. nativa and T. chanchalensis. All infected foxes harbored T. nativa, and one fox was co-infected with Trichinella T6; the latter is a new host record. Age of the fox was significantly associated with Trichinella spp. infection and the odds of being infected were three times higher in foxes ≥2 years of age (p = 0.026), indicating cumulative exposure with age. While Arctic foxes are seldom harvested for human consumption, they serve as sentinel hosts of Trichinella spp., confirming the presence of the parasite in wildlife in the region.

Tongue has higher larval burden of Trichinella spp. than diaphragm in wolverines (Gulo gulo).

Trichinella is an important zoonotic parasite found in a range of wildlife species harvested for food and fur in Canada. We compared larval intensity from tongue and diaphragm, the best predilection sites in other animal species, from naturally infected, wild wolverines (Gulo gulo) (n = 95). Muscle larvae of Trichinella spp. were recovered by the pepsin/HCl artificial digestion method (gold standard) using double separatory funnels, and species were identified using multiplex PCR. Prevalence was 83% (79/95). Of those positive for Trichinella spp. (n = 79), 76 (96.2%) were detected in both tissues, 2 (2.5%) were positive only on diaphragm, and 1 (1.3%) only on tongue. A total of 62 of 79 wolverines (78.5%) had higher larval burden in tongue than in diaphragm, whereas 17 wolverines (21.5%) had higher larval burden in diaphragm. The predilection site (higher larval burden) of Trichinella spp. larvae did not vary significantly between juvenile and adult wolverines (P = 0.2), between male and female wolverines (P = 0.9), and among wolverines classified as having low and high larval intensities overall (P = 0.2). Trichinella T6 was the predominant genotype (63 of 79; 80%), followed by T. nativa (T2) (6 of 79; 8%). Mixed infections of T2 and T6 were observed in 9 of 79 (12%) wolverines. Larval intensity of Trichinella T6 was higher in tongues than diaphragms. No statement can be made for T2 due to insufficient T2 positive samples. In conclusion, tongues are a better site for sampling than diaphragms in future surveys of Trichinella larval intensity in wolverines; however, either tissue is suitable for prevalence studies.

Foxes (Vulpes vulpes) as sentinels for parasitic zoonoses, Toxoplasma gondii and Trichinella nativa, in the northeastern Canadian Arctic.

Outbreaks of Toxoplasma gondii and Trichinella spp. have been recurring for decades among Inuit of Nunavik, northeastern Canada. Contact with wildlife has been identified as a risk factor for Inuit exposure to T. gondii, but reservoirs have yet to be confirmed based on direct detection of DNA or organism. Similarly, little is known about the occurrence of Trichinella spp. in wildlife species of Nunavik other than walrus (Odobenus rosmarus) and bears (Ursus americanus, Ursus maritimus). Foxes (Vulpes vulpes) were targeted as possible sentinels for T. gondii and Trichinella spp. because of their high trophic position within the Arctic food chain as carnivorous scavengers. A total of 39 red foxes were sampled from four communities in southern and western Nunavik between November 2015 and September 2016. For the first time in wildlife, a novel magnetic capture DNA extraction and real-time PCR technique was used to isolate and detect T. gondii DNA from the heart and brain of foxes. A double separatory funnel digestion method followed by multiplex PCR was used to recover and genotype larvae of Trichinella spp. from tongues of foxes. Seroprevalence based on detection of antibodies to T. gondii was 41% (95% CI: 27-57%) using a commercially available modified agglutination test (MAT). Detection of DNA of T. gondii and larvae of Trichinella nativa (T2) occurred in 44% (95% CI: 28-60%) and 36% (95% CI: 21-51%) of foxes, respectively. Coinfection with both T. nativa and T. gondii occurred among 23% (95%CI: 13-38%) of foxes which can be attributed to co-transmission from prey and scavenged species in their diet. There was only moderate agreement between T. gondii serology and direct detection of T. gondii DNA using the MC-PCR technique (Kappa test statistic: 0.321), suggesting that using both methods in tandem can increase the sensitivity of detection for this parasite. These findings show that foxes are good sentinels for circulation of parasitic zoonoses in terrestrial northern ecosystems since they are highly exposed, show measurable indicators of infection and do not serve as exposure sources for humans.

Trichinella spp. biomass has increased in raccoon dogs (Nyctereutes procyonoides) and red foxes (Vulpes vulpes) in Estonia.

BACKGROUND: Raccoon dogs and red foxes are well-adapted hosts for Trichinella spp. The aims of this study were to estimate Trichinella infection prevalence and biomass and to investigate which Trichinella species circulated in these indicator hosts in Estonia. METHODS: From material collected for evaluating the effectiveness of oral vaccination program for rabies eradication in wildlife, samples from 113 raccoon dogs and 87 red foxes were included in this study. From each animal, 20 g of masseter muscle tissue was tested for the presence of Trichinella larvae using an artificial digestion method. The Trichinella larvae were identified to species level by multiplex polymerase chain reaction method. RESULTS: The majority of tested animals were infected with Trichinella spp. The parasite species identified were T. nativa and T. britovi. The apparent infection prevalence was 57.5% in raccoon dogs and 69.0% in red foxes, which were higher than previous estimates. In addition, the larval burden had also increased in both hosts. We estimated that in 2011-2012, the Trichinella spp. biomass was more than 15 times higher in raccoon dogs and almost two times higher in red foxes than in 1992-2000 (based on mean larval burden), and almost 20 times higher in raccoon dogs and almost five times higher in red foxes than in 2000-2002 (based on median larval burden). CONCLUSIONS: Raccoon dogs and red foxes are relevant reservoirs for Trichinella spp. in Estonia. The biomass of Trichinella circulating in sylvatic cycles was substantial and had increased: there is substantial infection pressure in the sylvatic cycle.

Trichinella nativa haplotypes in Russia show diversity in cytochrome oxidase mtDNA gene.

Partial nucleotide sequences of the two mitochondrial genes (cytB and COI) were obtained for 13 Trichinella isolates from different regions of the Russian Federation. All the cytB mtDNA sequences were identical with the sequences of T. nativa from Canada, showing no nucleotide differences between isolates. Analysis of partial COI mtDNA sequence confirmed the species identification and revealed differences between the studied isolates. Two T. nativa haplotypes, represented in the studied material by four samples, demonstrate limited geographical distribution.

High prevalence of Trichinella spp. in sylvatic carnivore mammals of Latvia.

Trichinella spp. are zoonotic parasites transmitted to humans by the consumption of raw or insufficiently cooked meat of different animal species. Carnivore mammals are important reservoir hosts of these nematodes. The aims of this work were to establish the prevalence of Trichinella spp. and infection intensity in sylvatic carnivore mammals of Latvia, to identify the etiological agents at the species level and their circulation in the Latvian regions. From 2010 to 2014, muscle samples were collected from 1286 hunted animals (2 European badgers, 137 pine martens, 24 stone martens, 4 golden jackals, 394 raccoon dogs, 668 red foxes, 23 grey wolves, and 34 Eurasian lynxes). Trichinella spp. larvae were isolated by muscle digestion. Overall, 633 animals (49.2%; 95% CI 46.5%-52.0%) belonging to all the eight investigated species, tested positive for Trichinella spp. larvae. Trichinella britovi was the most common species (94.0%; 95% CI 91.7%-95.7%). Trichinella nativa was detected in 30 animals as single (6, 1.1%; 95% CI 0.4%-2.3%) or mixed infection (24, 4.4%; 95% CI 2.9%-6.4%) with T. britovi. Trichinella spiralis was detected in only three animals as mixed infection with T. britovi. The high prevalence of Trichinella spp. infection in sylvatic carnivore mammals suggests that they are good indicators for the risk assessment of Trichinella spp. in Latvia.

Polymerase chain reaction - restriction fragment length polymorphism analysis for the differentiation of Trichinella nativa and Trichinella britovi.

Recently, Trichinella nativa was identified in foxes in Germany and Poland, indicating that the geographical distribution of T. nativa is not restricted to areas north of the isotherm -4°C in January. In the European Union, legislation requires that a regular monitoring of the occurrence of Trichinella spp. in indicator animals such as foxes or raccoon dogs be carried out. The Trichinella isolates must also be identified on a species level. The multiplex PCR recommended by the Community Reference Laboratory for Trichinella allows species identification, yet the differentiation of T. nativa and Trichinella britovi, a widespread Trichinella species in the temperate regions of Europe, is unstable. We therefore describe an easy and reliable method for the differentiation of the two species, which can be utilised to monitor a potential spread of T. nativa in Central Europe.

Trichinella nativa in red foxes (Vulpes vulpes) of Germany and Poland: possible different origins.

In Germany and Poland, the high population density of the red fox (Vulpes vulpes) is considered a public health risk since this wild canid is one of the main reservoirs of Trichinella spp. In 2010 in Poland, a program to monitor the prevalence of Trichinella spp. in the red fox population was launched. After two years, Trichinella spp. larvae were detected in 44 (2.7%) out of 1634 foxes tested. In Germany in the period 2002-2011, Trichinella spp. larvae were in 27 foxes. The Trichinella species detected were: T. spiralis in 15 foxes from Germany (one co-infection with Trichinella britovi and one with Trichinella pseudospiralis) and in 9 foxes from Poland; T. britovi in 8 and 32 foxes from Germany and Poland, respectively; and T. pseudospiralis in 1 fox from Germany. The arctic species Trichinella nativa was detected in 3 foxes from Germany (one co-infection with Trichinella spiralis) and in 1 fox from Poland. The detection of T. nativa outside its known distribution area opens new questions on the ability of this Trichinella species to colonize temperate regions.