Surveillance of Shiga toxin-producing Escherichia coli and Campylobacter spp. in wild Japanese deer (Cervus nippon) and boar (Sus scrofa)

Detection and Characterization of Zoonotic Pathogens in Game Meat Hunted in Northwestern Italy

Wildlife can represent a reservoir of zoonotic pathogens and a public health problem. In the present study, we investigated the spread of zoonotic pathogens (Salmonella spp., Yersinia enterocolitica, Listeria monocytogenes, Shiga-toxin-producing Escherichia coli (STEC), and hepatitis E virus (HEV)) considering the presence of virulence and antibiotic resistance genes in game meat from animals hunted in northwest Italy. During two hunting seasons (2020 to 2022), samples of liver and/or muscle tissue were collected from chamois (n = 48), roe deer (n = 26), deer (n = 39), and wild boar (n = 35). Conventional microbiology and biomolecular methods were used for the detection, isolation, and characterization of the investigated pathogens. Two L. monocytogenes serotype IIa strains were isolated from wild boar liver; both presented fosfomycin resistance gene and a total of 22 virulence genes were detected and specified in the text. Eight Y. enterocolitica biotype 1A strains were isolated from chamois (2), wild boar (5), and deer (1) liver samples; all showed streptogramin and beta-lactam resistance genes; the virulence genes found were myfA (8/8 strains), ymoA (8/8), invA (8/8), ystB (8/8), and ail (4/8). Our data underscore the potential role of wildlife as a carrier of zoonotic and antibiotic-resistant pathogens in northwest Italy and a food safety risk for game meat consumers.

Presence of Foodborne Bacteria in Wild Boar and Wild Boar Meat-A Literature Survey for the Period 2012-2022

The wild boar is an abundant game species with high reproduction rates. The management of the wild boar population by hunting contributes to the meat supply and can help to avoid a spillover of transmissible animal diseases to domestic pigs, thus compromising food security. By the same token, wild boar can carry foodborne zoonotic pathogens, impacting food safety. We reviewed literature from 2012-2022 on biological hazards, which are considered in European Union legislation and in international standards on animal health. We identified 15 viral, 10 bacterial, and 5 parasitic agents and selected those nine bacteria that are zoonotic and can be transmitted to humans via food. The prevalence of Campylobacter, Listeria monocytogenes, Salmonella, Shiga toxin-producing E. coli, and Yersinia enterocolitica on muscle surfaces or in muscle tissues of wild boar varied from 0 to ca. 70%. One experimental study reported the transmission and survival of Mycobacterium on wild boar meat. Brucella, Coxiella burnetii, Listeria monocytogenes, and Mycobacteria have been isolated from the liver and spleen. For Brucella, studies stressed the occupational exposure risk, but no indication of meat-borne transmission was evident. Furthermore, the transmission of C. burnetii is most likely via vectors (i.e., ticks). In the absence of more detailed data for the European Union, it is advisable to focus on the efficacy of current game meat inspection and food safety management systems.

Occurrence of Campylobacter in Faeces, Livers and Carcasses of Wild Boars Hunted in Tuscany (Italy) and Evaluation of MALDI-TOF MS for the Identification of Campylobacter Species

A total of 193 wild boars hunted in Tuscany, an Italian region with a high presence of wild ungulates, were examined to assess the occurrence of Campylobacter species in faeces, bile, liver and carcasses, with the aim of clarifying their contribution to human infection through the food chain. Campylobacter spp. were found in 44.56% of the animals, 42.62% of the faecal samples, 18.18% of the carcass samples, 4.81% of the liver tissues and 1.97% of the bile samples. The Campylobacter species genotypically identified were C. coli, C. lanienae, C. jejuni and C. hyointestinalis. The prevalent species transpired to be C. coli and C. lanienae, which were isolated from all the matrices; C. jejuni was present in faeces and liver, while C. hyointestinalis only in faeces. Identification was carried out by matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) on 66 out of 100 isolates identified genotypically, and the technique yielded unsatisfactory results in the case of C. lanienae, which is responsible for sporadic human disease cases. The level of Campylobacter spp. contamination of meat and liver underlines the need to provide appropriate food safety information to hunters and consumers.

Guidelines on the hygienic management of wild meat in Japan

The density and distribution of wild ungulates, especially sika deer (Cervus nippon) and wild boar (Sus scrofa), have increased across the Japanese archipelago in the last two decades. The tradition of consuming wild game meat has been inherited in limited areas in Japan, but recently, the use of wild animals for food has increased. Game meat has become popular at local restaurants and retail meat shops. However, fundamental knowledge of game meat hygiene and health risks has not been fully established among hunters, meat processors, restaurant operators, and consumers. Moreover, game meat-borne illnesses have been reported occasionally. Unlike domesticated livestock, wild animals are not inspected for diseases when being butchered for food, and the meat obtained is at a high risk of being unhygienic. The Guidelines on the hygienic management of wild meat were established in 2014 to ensure the safety of wild meat in Japan. This study describes the situation regarding wild animals and game meat in Japan.

Zoonotic Campylobacter spp. and Salmonella spp. carried by wild boars in a metropolitan area: occurrence, antimicrobial susceptibility and public health relevance

Campylobacter spp. and Salmonella spp. are the most reported zoonotic agents in Europe. They can be transmitted from wildlife to humans, and wild boars (Sus scrofa) can harbour them. In the Metropolitan Area of Barcelona (MAB, NE Spain) wild boars are found in urbanized areas. To assess the potential public health risk of this increasing wild boar population, we collected stool samples from 130 wild boars from the MAB (June 2015 - February 2016), to determine the Campylobacter and Salmonella occurrence and the antimicrobial susceptibility of the isolates. We also investigated the genetic diversity and virulence potential of Campylobacter. Campylobacter prevalence in wild boars was 61%. Forty six percent of wild boars carried Campylobacter lanienae, 16% carried Campylobacter coli, and 1% carried Campylobacter hyointestinalis; 4% carried both C. lanienae and C. coli, and 1% carried both C. lanienae and C. hyointestinalis. This is the first report of C. hyointestinalis in wildlife in Spain. Using pulse-field gel electrophoresis and multilocus sequence typing, we observed a high genetic diversity of Campylobacter and identified new sequence types. Thirty-three percent of C. coli and 14% of C. lanienae isolates showed a high virulence potential. All of the Campylobacter isolates analysed were resistant to at least one antimicrobial agent. Multidrug resistance was only detected in C. coli (67%). Salmonella enterica subsp. enterica was detected in four wild boars (3%) and included a S. Enteritidis serovar (1/4 wild boars) and a multidrug-resistant (ASSuT) monophasic S. Typhimurium serovar (1/4 wild boars) which is associated with human infections and pig meat in Europe. The characteristics of some of the Campylobacter and Salmonella isolates recovered suggest an anthropogenic origin. Wild boars are a reservoir of Campylobacter and have the potential to spread antimicrobial resistant Campylobacter and Salmonella in urbanized areas in the MAB.

Prevalence of Shiga toxin-producing Escherichia coli in Yezo sika deer (Cervus nippon yesoensis) in the Tokachi sub-prefecture of Hokkaido, Japan

In food hygiene, the surveillance of foodborne pathogens in wild animals is indispensable because we cannot control hygienic status of them. Yezo sika deer (Cervus nippon yesoensis), which are found only on the island of Hokkaido, Japan, are the most common game animal in the country. In this study, we analyzed the incidence of Shiga toxin-producing Escherichia coli (STEC) in Yezo sika deer hunted in the Tokachi sub-prefecture, which is one of the densest zones for the sub-species. Real-time polymerase chain reaction testing detected STEC in 18.3% of fecal samples (59/323) collected from deer hunted between 2016 and 2017, whereas no Shigella and Salmonella markers were detected. No correlation was found between STEC detection from fecal samples and characteristics of carcasses, such as hunting area, age, and fascioliasis. From 59 STEC-positive fecal samples, we isolated 37 STEC strains, including 34 O- and H-genotyped strains, in which 16 different serogroups were detected. Genetic analysis revealed that our isolates included various stx gene types (stx1⁺/stx2^-, stx1⁺/stx2⁺, and stx1^-/stx2⁺) and carried eae. This study demonstrated that STEC strains with various features colonized the Yezo sika deer, similar to other subspecies of sika deer. We conclude that continuous surveillance activity is important to monitor the suitability of game animals as a food source and to assess the validity of the food safety management system for game meat production.

Prevalence and whole-genome sequence analysis of Campylobacter spp. strains isolated from wild deer and boar in Japan

As a part of risk analysis for consumption of meat from wild animals, the prevalence of Campylobacter spp. in wild deer and boar in Japan was investigated. C. hyointestinalis subsp. hyointestinalis (C. hyointestinalis) was isolated from 2.8% (7/253) of the wild deer and 22.1% (71/321) of the wild boar examined. All 23 wild deer isolates and 141 (72.7%) wild boar isolates carried both chcdt-I and chcdt-II genes. The remaining 53 (27.3%) wild boar isolates had only the chcdt-II gene. By whole-genome sequence analysis, we detected 38-40 virulence- and survival-associated genes (motility, chemotactic, adhesion, invasion, toxin, glycosylation, iron uptake, drug resistance, and stress response), which had been identified in C. jejuni and C. coli. In conclusion, our study highlights C. hyointestinalis as a possible cause of food-borne disease in humans and emphasizes the importance of food hygiene in the processing of wild meats for human consumption.

Whole-genome sequence analysis of Shiga toxin-producing Escherichia coli O157 strains isolated from wild deer and boar in Japan

The prevalence of Shiga toxin-producing Escherichia coli O157 (STEC O157) strains in wild deer and boar in Japan was investigated. STEC O157 strains were isolated from 1.9% (9/474) of the wild deer and 0.7% (3/426) of the wild boar examined. Pulsed-field gel electrophoresis (PFGE) analysis classified the wild deer and boar strains into four and three PFGE patterns, respectively. The PFGE pattern of one wild boar strain was similar to that of a cattle strain that had been isolated from a farm in the same area the wild boar was caught, suggesting that a STEC O157 strain may have been transmitted between wild boar and cattle. Clade analysis indicated that, although most of the strains were classified in clade 12, two strains were classified in clade 7. Whole-genome sequence (WGS) analysis indicated that all the strains carried mdfA, a drug resistance gene for macrolide antibiotics, and also pathogenicity-related genes similar to those in the Sakai strain. In conclusion, our study emphasized the importance of food hygiene in processing meat from Japanese wild animals for human consumption.