Trichinella britovi infection in wild boar in Portugal

Gross lesions associated with Sarcocystis miescheriana in a wild boar hunted for human consumption: the importance of trained hunters to ensure animal health surveillance and food safety

Sarcocystis is a genus of protozoa with a worldwide distribution infecting a wide range of animals, including humans. Wild boars can harbor at least two species of Sarcocystis, that is, the zoonotic Sarcocystis suihominis, using humans as definitive hosts, and Sarcocystis miescheriana, for which wild and domestic canids serve as definitive hosts. In Portugal, hunting holds significant economic and social importance, and wild boars are among the most appreciated hunted species. As the consumption of wild boar meat can expose humans to several foodborne pathogens, the presence of trained hunters can make a difference in ensuring animal health surveillance and food safety. Herein, we report the detection of macroscopic cystic lesions associated with S. miescheriana in a wild boar hunted for human consumption, resulting in carcass condemnation. To the best of the authors' knowledge, the presence of S. miescheriana in wild boar tissues has never been associated with macroscopic pathological alterations before. Although S. miescheriana cannot infect humans, carcasses affected by grossly visible pathological changes must be declared unfit for consumption. Therefore, our finding points out the potential economic damage associated with carcass rejection due to the presence of gross lesions associated with generalized sarcocystosis. Nonetheless, further studies are required to investigate these alterations that currently appear to be occasional findings.

From wildlife to humans: The global distribution of Trichinella species and genotypes in wildlife and wildlife-associated human trichinellosis

Zoonotic nematodes of the genus Trichinella are foodborne parasites that have a global distribution in wild carnivores and omnivores, with spillover and spillback into domestic livestock and people, with concomitant trade and health consequences. Historically, most human cases were linked to domestic pigs infected with Trichinella spiralis, but under current high biosecurity swine production in many countries, wildlife have become a more important source of human trichinellosis. The aim of this review is to update the global distribution of Trichinella species and genotypes reported in wildlife, as well as reported human outbreaks from the consumption of wildlife. Using several online databases and by "snowballing" references, hundreds of reports of Trichinella spp. in wildlife published between January 1991 and December 2023 provide an important update to the host and geographic range for each of the recognized 13 species/genotypes, grouped by continent. Surveillance effort was highest in Europe and North America, while Africa, Asia, Oceania, Central and South America have had limited surveillance, in some instances with human cases serving as sentinels of transmission in a region. Dozens of human outbreaks are described, with wild boars (Sus scrofa) being the most frequently implicated wildlife species in human outbreaks globally. Bears are an important source of infection in North America, for wildlife tourism, and importation of bear meat has also been implicated in multicountry outbreaks. The largest study limitation was the dearth of molecular identification of larvae in both wildlife surveillance studies and human outbreaks, particulary in under-studied regions. We highlight the need for enhanced molecular epidemiological approaches to outbreaks of this important foodborne parasite, and emphasize the need for a One Health approach to manage Trichinella spp. which transmit among terrestrial and marine wildlife (including migratory birds), pigs, horses, and people, often across large geographic scales and borders.

Trichinella spiralis Infecting Wild Boars in West, Southwest, and Northwest of Romania: Evidence of an Underrated Risk

The species of the genus Trichinella are etiological agents distributed all over the world and are able to infect mammals, birds, and reptiles. Trichinella spiralis is the species most adapted to domestic and wild pigs and is also the most important etiological agent of trichinellosis. The wild boar (Sus scrofa) is a nocturnal omnivorous mammal belonging to the Suidae family. S. scrofa has a great appetite and its diet includes a variety of small prey such as mice, rats, and other rodents, as well as carcasses of larger animals. The aim of this study was the identification and the molecular characterization of Trichinella larvae isolated from the muscle tissue of S. scrofa specimens collected in different counties of Romania. The muscle samples were examined by artificial digestion and the larvae identified at the species level by multiplex PCR. T. spiralis, a species that is able to infect a considerable number of different host species including humans, was identified. In Romania, S. scrofa is an important reservoir species for T. spiralis and plays an important role in linking the domestic and the wild cycle of Trichinella, with serious repercussions for human health.

Heavy metals and metalloids in wild boars (Sus Scrofa) - a silent but serious public health hazard

Wild boars (Sus scrofa) are part of the hunting economy and are highly consumed in the Iberian Peninsula, including in the Castile and Leon regions. As zoonotic diseases, chemical pollutants in wild boars' internal tissues should be interpreted as evidence of environmental contamination and a matter of concern for animal, human and ecosystem health; in other words, a One Health concern. Twenty-eight wild boars' livers and kidneys (n = 28) from Castile and Leon were submitted to metal(loid) determination (As, Cd, Co, Cr, Cu, Ni, Pb, and Zn) with inductively coupled plasma mass spectrophotometry (ICP-MS) and histopathological exam. Cd levels, especially in the kidneys (7.063 ± 7.271 mg/kg dw), were the most concerning results, considering the calculated maximum values for consumption (EC No. 915/2023) (2.491 mg/kg dw or 1.0 mg/kg ww). Wild boars with hydropic changes in the liver presented higher concentrations of Ni. Thus, the metal(loid) contamination of wild boar carcasses seems to be a "no trace" but very relevant problem that should raise awareness of a more accurate monitoring program and other strategies to avoid public health consequences.

An Update in Knowledge of Pigs as the Source of Zoonotic Pathogens

The available data indicate that the human world population will constantly grow in the subsequent decades. This constant increase in the number of people on the Earth will lead to growth in food demand, especially in food of high nutritional value. Therefore, it is expected that the world livestock population will also increase. Such a phenomenon enhances the risk of transmitting pathogens to humans. As pig production is one of the most significant branches of the world's livestock production, zoonoses of porcine origins seem to be of particular importance. Therefore, in this review, we aim to introduce the latest data concerning, among other things, epidemiology and available preventive measures to control the most significant porcine zoonoses of viral, bacterial, and parasitic origin.

First Identification and Molecular Characterization of Trichinella britovi (Nematoda: Trichinellidae) from the Pine Marten (Martes martes Linnaeus, 1758) in Romania

Trichinella spp. are etiological zoonotic agents spread throughout the world and affect mammals, birds, and reptiles; they evolve via two cycles: domestic and sylvatic. Martes martes is a carnivorous nocturnal mammal from the family Mustelidae. In Romania, this host is widespread in all forests of the country. Martes martes has an extremely voracious appetite, feeding on fruit and also on a variety of small animals, including rodents such as mice and rats. The aim of this study was the identification and molecular characterization of Trichinella larvae isolated from the muscle tissue of Martes martes collected in different counties of Romania. The muscle samples were examined via artificial digestion, and the larvae were identified at the species level via multiplex PCR. The presence of larvae belonging to Trichinella britovi, a species frequently identified in wild carnivores in temperate zones, was observed. Although T. britovi has been already reported in several host species in Romania, this is the first time this species has been observed in a Martes martes specimen. This finding contributes to our knowledge about the host species involved in the maintenance of the Trichinella sylvatic cycle in Romania, and it confirms that this parasite is consistently present in the wild fauna of this country.

The First Identification of Trichinella britovi in the Raccoon Dog (Nyctereutes procyonoides) in Romania

Trichinella spp. are nematodes distributed throughout the world that affect an impressive number of host animals (mammals, birds, and reptiles) involved in the evolution of two cycles, the domestic and the sylvatic. The raccoon dog (Nyctereutes procyonoides) is an omnivorous mammal with great ecological plasticity. The expansion of the raccoon dog in Europe is associated with the risk of the introduction and spread of different pathogens, especially zoonotic ones (Trichinella, Echinococcus). Currently, the raccoon dog's range in Romania is limited to the Danube Delta area, the Lower Danube Meadow, and the Prut Meadow. The aim of this study was to examine the presence of Trichinella larvae isolated from the muscles of raccoon dog from six hunting funds of Giurgeni, Ialomița County, Romania. The muscle samples were examined via artificial digestion, and the obtained larvae were processed via multiplex PCR. The PCR-amplified ESV and ITS1 DNA fragments were then sequenced for species confirmation. The species Trichinella britovi, which is the most common species identified in wild carnivores in temperate zones, was confirmed. Although T. britovi has been reported in several host animals in Romania, this case report confirms its presence in the raccoon dog for the first time.

Hepatitis E Virus in the Wild Boar Population: What Is the Real Zoonotic Risk in Portugal?

Hepatitis E virus (HEV) is an important zoonosis in wild boar. Reported zoonotic cases are mainly associated with the consumption of raw/undercooked meat and/or liver. This study aims to determine the occurrence of HEV in the Portuguese wild boar population. During the hunting season 2021/2022, 123-matched samples (liver, faeces, and blood) were collected from hunted wild boars throughout Portugal. An RT-PCR assay tested liver and faeces samples to detect HEV-RNA. From blood samples, an ELISA test was performed. Only one liver sample was positive for HEV (0,8%) and one other from faeces. A total of 34 sera were seropositive (26.7%). At the same time, in a survey of 106 hunters, 21 consumed/ate the liver of wild boars (19.8%). Only three recognised the possibility of consuming it undercooked. Contrary to previous studies in Portugal, the prevalence of HEV in liver and faeces is low, but the seropositivity is higher. But, when analyzing in detail, it could be observed that an HEV hotspot exists in the southeast of central Portugal and that it is a zoonotic risk for hunters of this region. The data of this study reinforce the importance of including HEV in surveillance programs for wildlife diseases to expand the potential zoonotic information.

Hygiene and biosecurity conditions of initial examination on-spot in Portugal: One step toward game meat safety

Background and Aim

Due to the particularities of the first steps of the game food chain, large game species are shot, bled, and handled in collection points (spot of evisceration and initial examination in the field). These steps of the game meat chain affect the microbiological quality of this type of meat, thus posing a risk to consumers. This study aimed to characterize the collection points in terms of central hygiene and biosecurity procedures/requirements.

Materials and Methods

One survey with 16 questions was applied in 95 hunting areas throughout Portugal. It was a convenience sample obtained by direct visualization on-spot procedures. Four categories were characterized in the survey: Initial examination (performance assiduity and type of operator performing it), hygiene requirements on-spot (floor, ceiling, water, and electricity), biosecurity procedures such on initial examination (use of personal protective equipment as gloves, glasses, mask, and specific clothes), and by-products disposal (destination and packaging of by-products).

Results

Sixty percentage (n = 57) eviscerated the carcasses and performed the initial examination on-spot. Moreover, most of the time (n = 71), the initial examination was carried out by veterinarians. However, the category that showed the best results was those related to the biosecurity procedures on initial examination, mainly with the use of the individual protective material (e.g., regular use of disposal clothes and specific clothes). Concerning the questions about the disposal of by-products, 66 game managers say that this was done correctly (69%), being the majority destination of the inspected carcasses was the burial (64%; n = 47).

Conclusion

This survey demonstrates an immediate need in all this problematic of the standardization of hygiene and biosecurity requirements of the collection points, which requires uniform application of rules. There is a lot of resistance and limitations to the inclusion of these requirements in collection points, due to lack of structural and financial conditions. However, training all those involved in the hunting area (hunters, game managers, authorities, etc.) creating rules that promote hunting food security and setting limits on the microbiological criteria of game meat are hot points to consider in the future.

Trichinella britovi in wild boar meat from Italy, 2015-2021: A citizen science approach to surveillance

As a result of the increase of game meat intended for human consumption through Europe, a plethora of food-borne diseases, including trichinellosis, may occur in consumers, posing a relevant public health threat. Thus, this study aims to a citizen science approach to monitor the occurrence of Trichinella spp. in wild boar meat intended for human consumption, evaluating the risk of infection for consumers. Following the European Regulation 2015/1375 (laying down specific rules on official controls for Trichinella in meat), from 2015 to 2021, hunters (n = 478) were involved to collect diaphragm pillar samples of wild boars from mainland southern Italy, which were tested for Trichinella spp. L₁ larvae via HCl-pepsin digestion and Multiplex PCR. Overall, 139,160 animals were collected (average of 19,880 per year), being 14 (i.e., 0.01%) tested positive to Trichinella britovi by the combined biochemical and molecular approach. An average larval burden of 28.4 L₁ per gram of meat was found (minimum 3.2 - maximum 132.6). A statistically significant difference was found in the prevalence according to hunting seasons (p < 0.01, with higher values in 2016 and 2021) and regions of the study area (p < 0.01). No statistically significant decrease in the prevalence of T. britovi throughout the study period was found (p = 0.51), except in Apulia region (p < 0.01). These findings revealed a stable prevalence of T. britovi in wild boar meat intended for human consumption, suggesting a risk of infection for consumers, especially hunters and local markets users. Citizen science surveillance models could be promoted to improve trichinellosis control and prevention in a One Health perspective.

The International Trichinella Reference Centre database. Report on thirty-three years of activity and future perspectives

The International Trichinella Reference Centre (ITRC) is the official laboratory of the International Commission on Trichinellosis, of the World Organization for Animal Health and of the European Union Reference Laboratory for Parasites. The ITRC was established in 1988 as a repository of Trichinella strains and a source of reference materials and information for international scientific research. To date, more than 8000 Trichinella isolates collected throughout the world have been identified at the species or genotype level by the ITRC staff and the information has been stored in a freely accessible database providing the largest collection of data available for scientists involved in the systematics and epidemiology of this parasite. This paper presents a summary of the data collected over 33 years of activity and describes the database functionalities. It finally advocates the potential of the database to improve knowledge of the epidemiology and taxonomy of Trichinella, which in turn may help the international surveillance of Trichinella species.

Selected Livestock-Associated Zoonoses as a Growing Challenge for Public Health

The aim of this paper is to review the most significant livestock-associated zoonoses. Human and animal health are intimately connected. This idea has been known for more than a century but now it has gained special importance because of the increasing threat from zoonoses. Zoonosis is defined as any infection naturally transmissible from vertebrate animals to humans. As the frequency and prevalence of zoonotic diseases increase worldwide, they become a real threat to public health. In addition, many of the newly discovered diseases have a zoonotic origin. Due to globalization and urbanization, some of these diseases have already spread all over the world, caused by the international flow of goods, people, and animals. However, special attention should be paid to farm animals since, apart from the direct contact, humans consume their products, such as meat, eggs, and milk. Therefore, zoonoses such as salmonellosis, campylobacteriosis, tuberculosis, swine and avian influenza, Q fever, brucellosis, STEC infections, and listeriosis are crucial for both veterinary and human medicine. Consequently, in the suspicion of any zoonoses outbreak, the medical and veterinary services should closely cooperate to protect the public health.

Investigation of the Food-Transmitted Parasites Trichinella spp. and Alaria spp. in Wild Boars in Greece by Classical and Molecular Methods and Development of a Novel Real-Time PCR for Alaria spp. Detection

Simple Summary

There are many parasites that may be transmitted to humans via food, and meat is a major source of such infections. Trichinella spp. is one of the most important meat-transmitted parasites, while Alaria spp. may be considered an emerging pathogen, albeit to date rarely reported in humans. Raw and undercooked wild boar meat has been proven as a major source of human infection by both parasites. In the present study, an investigation of the presence of these parasites in wild boar meat was conducted for the first time in Greece. Classical parasitological methods and molecular techniques were implemented for the examination of samples collected from 128 hunted wild boars, and none of them were found positive for Trichinella spp. or Alaria spp. For the detection of Alaria spp., a novel molecular method was developed, offering a powerful complementary diagnostic tool that may be useful for the epizootiological surveillance of the parasite. The epizootiology/epidemiology, clinical implications, and importance of monitoring of these parasitic infections are briefly discussed.

Abstract

Foodborne parasitic diseases represent a major threat to public health. Trichinellosis, caused by the nematode parasite Trichinella spp., is one of the most important foodborne diseases, while alariosis, caused by the trematode parasite Alaria spp., is less common in humans, and rare cases have been reported only in the USA and Canada. Both parasites can infect humans via the consumption of raw or undercooked wild boar meat. In order to investigate the prevalence of these parasites in wild boar meat in Greece, samples from the diaphragm pillars and the region of the mandibular angle from 128 wild boars, hunted in Greece, were collected. The samples were examined by classical parasitological (compression, artificial digestion, and Alaria spp. migration) and by molecular (real-time PCR) methods. For Trichinella spp. an existent real-time PCR detecting all species likely to be present in Greece was applied, while for Alaria spp. a real-time PCR was developed, employing an LNA TaqMan probe targeting the large subunit ribosomal RNA gene. All examined wild boar samples from Greece resulted negative for Trichinella and Alaria species, indicating a low prevalence of infection in the examined population. The novel real-time PCR for Alaria spp. has 81.5% amplification efficiency and is able to detect 0.12 larvae per 50 g of tissue and could be utilized as a complementary to AMT diagnostic tool in surveillance.