Investigating the global epidemiological patterns of Trichinella in pigs is required for accurate recognition and to establishing proper control programmes and preventive measures, as well as to decrease human exposure.
To obtain a better understanding of the global prevalence of Trichinella in domestic pigs and factors that might influence the prevalence, a systematic review and meta-analysis was performed.
The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Multiple databases were used to identify literature published between January 2000 and December 2021, representing studies from 1985 to 2021, on Trichinella prevalence in domestic pigs. Prevalence was calculated on a global and country level, by country Human Development Index (HDI), climate, pig management system, and diagnostic test.
The global pooled prevalence based on 60 manuscripts representing 32 countries and 65 pig populations was 2.02% (95% confidence interval [CI]: 0.88-3.62) and the estimated pooled prevalence in different continents ranged from 0.00% to 11.8%. Trichinella was highest in low HDI countries (21.6%; 95% CI: 4.3-47.2), tropical wet climates (20.9%; 95% CI: 10.3-34.1), and non-intensive pig farming systems (6.1%; 95% CI: 1.0-15.5).
While there were regional differences in Trichinella prevalence in domestic pigs, these were likely driven by country HDI and pig farming systems versus climatic factors. Increased biosecurity in outdoor pig production systems, focused meat inspections and promoting awareness could potentially decrease risk of infection.

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.

The genus Trichinella has a worldwide distribution, infecting people, domestic animals, and wildlife. It includes 13 genotypes, which are geographically delimited; Trichinella is transmitted to people through the ingestion of undercooked meat. Historically, it has been associated with pigs, but most Trichinella species affect wildlife, and cases of trichinellosis due to the consumption of game meat have been emerging. Therefore, it is important to monitor the sources of transmission to domestic animals and humans. The objective of this work was to analyse reports of Trichinella spp. in wild/feral animals around the world to identify the needs of future research in the epidemiology of the sylvatic cycle. A search of studies published until 2021 was conducted using Web of Science and SciELO. In the Palearctic, the most commonly studied hosts were wild boars and red foxes, and hosts with the highest prevalence rates were polar bears and martens. In the Nearctic, red foxes and black bears were the most frequently studied hosts, and the highest prevalence was found for wolverines and brown bears. In the Neotropics, positive reports were only identified in two countries, with wild boars being the most commonly studied species, and armadillos featuring the highest prevalence. In the Afrotropics, Trichinella limits its presence to Sub-Saharan Africa, where lions are the most studied hosts, and spotted hyenas have the highest prevalence. In the Indo-Malaya and Australasia ecozones, information on wildlife is scarce; the Norwegian rat is the most frequently studied host, and the Tasmanian devil has the highest prevalence of infection. In the last decade, research on world wildlife has increased which is associated with more frequent trichinellosis outbreaks caused by the consumption of wild meat. The results suggest the need to increase research in developing countries, particularly where more diverse sources of meat are available for human consumption.

While global cases of trichinellosis have fallen since pork regulation began, the disease remains a danger to pork and animal game consumers as well as a liability to producers. Managing food safety risk and supporting agricultural trade requires cost-effective and sensitive diagnostic methods. Several means exist to inspect pork for parasitic infections. Here, we review literature concerning the sensitivity, specificity, and cost of these methods. We found that artificial digestion coupled with optical microscopy to be the best method for verification of Trichinella larva free pork due to its cost efficiency, high specificity, and reliability. Serological techniques such as ELISA are useful for epidemiological surveillance of swine. While current PCR techniques are quick and useful for diagnosing species-specific infections, they are not cost efficient for large-scale testing. However, as PCR techniques, including Lateral Flow- Recombinase Polymerase Amplification (LF-RPA), improve and continue to reduce cost, such methods may ultimately succeed artificial digestion.

Trichinella spp. causes human trichinellosis by means of the consumption of raw or inadequately treated meat from domestic or game animals. In the Americas, as well as in other continents, Trichinella infection is a health issue for humans and has a negative impact on the pork meat market, generated by people\'s fear of becoming infected with the parasite. The distribution of human cases and the sources of this disease in humans and animals were analysed in this report, which summarizes the information available regarding Trichinella infection in animals and humans in South America. Within South America, human infection with Trichinella was documented in Argentina and Chile during the period 2005-2019. Trichinellosis is endemic in these countries for, with human cases and foci in domestic and wild animals. In Argentina, human cases occur throughout the country, with foci found in pigs and wild animals. In Argentina, during the period 2012-2018, the number of suspected human cases reached 6,662. T. spiralis was identified in one South American sea lion (Otaria flavescens) from Patagonia, Argentina, for the first time in the region in 2018. In Chile, 258 human cases of trichinellosis were confirmed during the period 2005-2015; out of those 258 cases, most samples which tested positive for Trichinella spp. (29.5 %) were detected in the Metropolitan district (Santiago de Chile and outskirts), and 17.4 % in The Lake district. Regarding age brackets, people between 30-49 years of age showed the most cases (40.1 %). In Brazil, the infection is absent in domestic species but it has been found in wild boars (Sus scrofa) but limited to one or more region of the country. Within the animal species destined for food in South America, those that showed higher parasitical loads were pigs and wild boars, while armadillos (Chaetophractus villosus) and peccaries (Tayassu tajacu) showed very low Trichinella spp. larvae loads (0.04-0.1 larvae/g). Antibodies against Trichinella spp. have been detected in pigs from Ecuador and Bolivia. In Bolivia, antibodies were also found in humans. Peru, Colombia and Uruguay have no documented presence of Trichinella spp. in animals and humans. There is insufficient information regarding the presence of Trichinella spp. in domestic and wild animals, as well as in humans, since only a very limited number of surveys have been carried out. No papers with information on Trichinella spp. circulating in animals or humans have been published regarding the situation in Guyana, Surinam, French Guiana, Venezuela and Paraguay. Considering the growth of the guinea pig meat market in the Andean region, and the high prevalence of the disease reported in free range pigs and wild boars, as well as other game animal species, it is important to focus on the role of biosecurity and risk management, while improving meat market regulations, and detection of infection prior to consumption, in order to reduce the risk of transmission of this zoonotic disease to humans.

We reviewed the evidence on features of central nervous system (CNS) involvement in trichinellosis, systematically searching five databases (to January 2021). We categorized clinical features based on their diagnostic value as warning signs for severe CNS infection (with outcome death) or non-specific signs (outcome improvement). They were suggestive of severe infection if they substantially raised death probability. The review included 87 papers published from 1906 through 2019, with data on 168 patients. Mydriasis, paraparesis, dysphagia, psychomotor seizures, or delirium present a 30-45% increased death likelihood. The best poor prognosis predictor is mydriasis (positive likelihood ratio 9.08). Slow/absent light reflex, diminished/absent knee reflexes, globally decreased tendon reflexes present a moderate increase (20-25%) of death risk. Anisocoria, acalculia, or seizures could also indicate an increased death risk. We provided a detailed presentation of clinical and paraclinical signs that alert physicians of a possible neurotrichinellosis, emphasizing signs that might indicate a poor prognosis.

Trichinella spp. causes human trichinellosis by means of the consumption of raw or inadequately treated meat from domestic or game animals. In the Americas, as well as in other continents, Trichinella infection is a health issue for humans and has a negative impact on the pork meat market, generated by people\'s fear of becoming infected with the parasite. The distribution of human cases and the sources of this disease in humans and animals were analysed in this report, which summarizes the information available regarding Trichinella infection in animals and humans in South America. Within South America, human infection with Trichinella was documented in Argentina and Chile during the period 2005-2019. Trichinellosis is endemic in these countries for, with human cases and foci in domestic and wild animals. In Argentina, human cases occur throughout the country, with foci found in pigs and wild animals. In Argentina, during the period 2012-2018, the number of suspected human cases reached 6,662. T. spiralis was identified in one South American sea lion (Otaria flavescens) from Patagonia, Argentina, for the first time in the region in 2018. In Chile, 258 human cases of trichinellosis were confirmed during the period 2005-2015; out of those 258 cases, most samples which tested positive for Trichinella spp. (29.5%) were detected in the Metropolitan district (Santiago de Chile and outskirts), and 17.4% in The Lake district. Regarding age brackets, people between 30-49 years of age showed the most cases (40.1%). In Brazil, the infection is absent in domestic species but it has been found in wild boars (Sus scrofa) but limited to one or more region of the country. Within the animal species destined for food in South America, those that showed higher parasitical loads were pigs and wild boars, while armadillos (Chaetophractus villosus) and peccaries (Tayassu tajacu) showed very low Trichinella spp. larvae loads (0.04 - 0.1 larvae/g). Antibodies against Trichinella spp. have been detected in pigs from Ecuador and Bolivia. In Bolivia, antibodies were also found in humans. Peru, Colombia and Uruguay have no documented presence of Trichinella spp. in animals and humans. There is insufficient information regarding the presence of Trichinella spp. in domestic and wild animals, as well as in humans, since only a very limited number of surveys have been carried out. No papers with information on Trichinella spp. circulating in animals or humans have been published regarding the situation in Guyana, Surinam, French Guiana, Venezuela and Paraguay. Considering the growth of the guinea pig meat market in the Andean region, and the high prevalence of the disease reported in free range pigs and wild boars, as well as other game animal species, it is important to focus on the role of biosecurity and risk management, while improving meat market regulations, and detection of infection prior to consumption, in order to reduce the risk of transmission of this zoonotic disease to humans.

OBJECTIVE: Trichinella or derived antigens have been suggested to be potential therapeutic agents for inflammatory bowel disease (IBD). We aimed to conduct a systematic review and meta-analysis of the available literature to estimate the effect of Trichinella or derived antigens on chemically induced IBD.
METHODS: Studies were identified by searching the Cochrane Central Register of Controlled Trials, PubMed, Scopus, Web of Science, and Science Direct from inception to February 2020. We included articles written in English that investigated the effect of Trichinella infection and/or derived products in mouse models of IBD. Studies were pooled, and the combined standard mean difference (SMD) and 95% confidence interval (CI) were calculated using a random-effect or fixed-effect model.
RESULTS: Thirteen studies were eventually included in the meta-analysis. The results indicated significant differences in the disease activity index (DAI), myeloperoxidase (MPO) activity, macroscopic inflammation score, and microscopic inflammation score between the experimental group and the control group. The anti-inflammatory cytokines interleukin (IL)-4, transforming growth factor-beta (TGF-β), IL-10 and IL-13 were significantly increased in the experimental group compared with the control group, whereas the levels of the proinflammatory cytokines interferon (IFN)-γ, IL-6, TNF-α, and IL-17 were significantly decreased. The percentage of regulatory T (Treg) cells was also significantly increased, while the level of the M1 phenotypic macrophage marker iNOS was significantly decreased and the expression of the M2 phenotypic macrophage marker Arg-1 was significantly increased.
CONCLUSIONS: Trichinella infection or derived antigens is effective for the alleviation of IBD in mouse models.

UNASSIGNED: 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.
UNASSIGNED: We performed a systematic research in Pubmed (MEDLINE).
UNASSIGNED: 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.
UNASSIGNED: 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%).
UNASSIGNED: 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.

Trichinellosis is a cosmopolitan zoonotic parasitic disease caused by the nematodes of the genus Trichinella, through the consumption of raw or semi-raw infected meat from swine, horses and wild animals. This disease has been sporadically reported in Greece since 1946. The aim of the present study was to describe a trichinellosis case in a patient hospitalized in northern Greece, in 2017. A 47-year-old male was admitted to hospital with intense generalized myalgia, periorbital swelling, fever, exhaustion and anorexia. Biochemical and haematological profile showed eosinophilia and elevated creatine phosphokinase (CPK). Anti-Trichinella spp. IgG and IgM antibodies were detected by serology and Trichinella spp. larvae were found in two muscle biopsies by compressorium and histological examination. A larva collected from the muscle biopsy was identified as Trichinella britovi by polymerase chain reaction (PCR). Albendazole (400 mg twice per day × 10 days) was administered and the clinical condition of the patient promptly improved. This is the first identification of T. britovi in a patient in Greece.