Foodborne parasites: Outbreaks and outbreak investigations. A meeting report from the European network for foodborne parasites (Euro-FBP)

A new human opisthorchiasis outbreak in central Italy: a never-ending story

PURPOSE

Opisthorchis felineus is a trematode causing a foodborne infection transmitted by raw freshwater fish belonging to Cyprinidae family. Human outbreaks in Italy dated back to 2003-2011 and involved lakes of Central Italy. The aim of this study is to report epidemiological and clinical characteristics of the human opisthorchiasis outbreak occurred in Central Italy in 2022 comparing it with previous events.

METHODS

We report cases diagnosed from June to December 2022 in Perugia hospital thanks to serological and molecular tests and direct examination of feces.

RESULTS

Sixty-seven individuals were traced back by epidemiological investigation. Forty-seven received a diagnosis of opisthorchiasis, of which 45 were confirmed cases and two were considered as probable cases. These 47 individuals attended a Trasimeno lakeshore restaurant in May 2022. All but 20 presented symptoms, mostly fever. Sixteen (15 confirmed and 1 probable) cases required hospitalization. Feces examination revealed Opisthorchis spp. eggs in 35/45 (78%) confirmed cases. Thirty individuals underwent to serology and molecular stool test: 5 (16.7%) results positive to the former, 1 (3.3%) to the latter while 4 (13.3%) to both. Laboratory tests, available in 28 patients, showed eosinophilia in 82.1%, increase of alanine aminotransferase, gamma-glutamyl transferase and alkaline phosphatase in 64.3%, 75% and 67.9%, respectively. Because of pharmacy shortage of praziquantel, 22 patients were treated with albendazole, of which 13 failed clearing the parasite.

CONCLUSION

Opisthorchiasis still represents a challenging diagnosis, in particular for asymptomatic patients. Albendazole may lead to treatment failure. Control measures in known endemic areas should be implemented.

TRIAL REGISTRATION

number 27,498/23/ON, approved by Ethical Committee of Umbrian Region in 09.13.2023.

Efficacy of an aerosol-resistant pepsin powder used in artificial digestion for the detection of Trichinella larvae in meat

Trichinellosis is an important worldwide foodborne zoonosis. The gold standard test to detect Trichinella spp. larvae in muscle samples of animals intended for human consumption is the artificial digestion method. Handling and dispensing of conventional pepsin powder present significant safety risks for analysts. The use of pepsin powder that is resistant to aerosolization should alleviate these safety concerns. The aim of this study was to compare the efficacy of an aerosol-resistant pepsin powder to conventional pepsin powder in the artificial digestion method. Proficiency samples of pork diaphragm containing specific numbers of viable Trichinella spiralis larvae were tested in two laboratories. The results revealed that aerosol-resistant pepsin was simple, effective and convenient to use, and showed good solubility and larval recovery that met the requirements of the European Union regulation EU 2015/1375. Overall, the efficacy of the aerosol-resistant pepsin was comparable to the conventional pepsin and safer for analysts.

Trichinella britovi outbreak in Piedmont, North-West Italy, 2019-2020: Clinical and epidemiological insights in the one health perspective

BACKGROUND

Trichinellosis, a foodborne zoonosis due to nematodes of the genus Trichinella, occurs in the form of outbreaks following meat consumption. North Italy has been rarely involved. We report here the most significant wildlife derived trichinellosis outbreak ever registered in the Piedmont region.

METHOD

We retrospectively included 96 outpatients referred to our institution (December 20th, 2019-January 15th, 2020) 2020 after consuming raw sausages prepared from a single wild boar hunted in the Susa Valley, 59 km away from Torino, in November 2019.

RESULTS

We confirmed 35 cases and found additional 10 probable/suspected cases. Our cohort found that 47% of patients were symptomatic, with a median time from symptoms to presentation at clinic and serology testing of 14 days. Peripheral blood eosinophilia >500/μl and CK alterations were common. Further qualitative and quantitative analysis at the International Trichinella Reference Center c/o ISS, Rome identified T. britovi as the causative agent.

CONCLUSIONS

No autochthonous human case has ever been detected in Torino province, and a single wild boar has tested positive for Trichinella since active surveillance was implemented in 2013. This outbreak should raise attention on the preventive role of veterinary surveillance and the need to optimize sampling procedures and targeted health education.

Trich-tracker - a practical tool to trace Trichinella spiralis transmission based on rapid, cost-effective sampling of genome-wide genetic variation

Molecular epidemiology using traditional sequencing has been notoriously difficult in inbred parasites due to a lack of genetic variation available for discriminating among parasites. Next generation sequencing techniques offer a solution to this problem by increasing the number of loci that can be sequenced. Here, we introduce Trich-tracker, a tool that makes efficient use of diagnostic variation distributed throughout the genome of Trichinella spiralis to more rapidly, and conclusively, resolve connections and distinctions among focal outbreaks of T. spiralis. In particular, we rapidly characterised genetic variation among a sample of parasites from Polish farms and wildlife, sampling genomic variation using double digest restriction site-associated DNA sequencing (ddRADseq). Approximately 400,000 bases of sequence were generated from each sample and shown to be distributed across the genome with single nucleotide polymorphisms occurring at a frequency of approximately one base in 10,000. Both phylogenetic and Bayesian clustering analyses indicated that ddRADseq genotypes formed distinct clusters for specific outbreaks and were quite distinct from wild boar samples. Two of the investigated outbreaks were more similar to each other than to other outbreak samples, suggesting a link between these outbreaks. Hence, the Trich-tracker procedure identified informative genomic variation which afforded unprecedented epidemiological resolution. Trich-tracker is very flexible tool, quickly and inexpensively mining genomes of even highly inbred populations of T. spiralis to support outbreak investigations. The simplicity of the entire procedure, and time and cost effectiveness of Trich-tracker support its practical application in ongoing Trichinella outbreaks. The discriminating power of this tool is tunable and scalable, allowing application in a variety of epidemiological contexts, and is easily adapted to other parasite systems.

Application of Biosensors for Detection of Pathogenic Food Bacteria: A Review

The use of biosensors is considered a novel approach for the rapid detection of foodborne pathogens in food products. Biosensors, which can convert biological, chemical, or biochemical signals into measurable electrical signals, are systems containing a biological detection material combined with a chemical or physical transducer. The objective of this review was to present the effectiveness of various forms of sensing technologies for the detection of foodborne pathogens in food products, as well as the criteria for industrial use of this technology. In this article, the principle components and requirements for an ideal biosensor, types, and their applications in the food industry are summarized. This review also focuses in detail on the application of the most widely used biosensor types in food safety.

Single and multiple detections of foodborne pathogens by gold nanoparticle assays

A late detection of pathogenic microorganisms in food and drinking water has a high potential to cause adverse health impacts in those who have ingested the pathogens. For this reason there is intense interest in developing precise, rapid and sensitive assays that can detect multiple foodborne pathogens. Such assays would be valuable components in the campaign to minimize foodborne illness. Here, we discuss the emerging types of assays based on gold nanoparticles (GNPs) for rapidly diagnosing single or multiple foodborne pathogen infections. Colorimetric and lateral flow assays based on GNPs may be read by the human eye. Refractometric sensors based on a shift in the position of a plasmon resonance absorption peak can be read by the new generation of inexpensive optical spectrometers. Surface-enhanced Raman spectroscopy and the quartz microbalance require slightly more sophisticated equipment but can be very sensitive. A wide range of electrochemical techniques are also under development. Given the range of options provided by GNPs, we confidently expect that some, or all, of these technologies will eventually enter routine use for detecting pathogens in food. This article is categorized under: Diagnostic Tools > Biosensing.

Parasites in Food: From a Neglected Position to an Emerging Issue

Foodborne parasites have long been a neglected group of pathogens, as they often have insidious, chronic effects, rather than being acute diseases, and they are often associated with impoverished or marginalized populations. In addition, due to the long incubation period for most foodborne parasites, source attribution is often difficult, if not impossible. However, global trends have enabled foodborne parasites to emerge in different populations in new locations, transmitted through different food types, and sometimes with unexpected symptoms. This emergence of foodborne parasites has brought them into focus. In this chapter, six foodborne parasites are used as examples on emergence: Echinococcus multilocularis is spreading to new locations; Cryptosporidium spp. are beginning to be associated not only with water, but also with salads; Trypanosoma cruzi is being manifest with acute disease due to foodborne transmission, particularly transmitted with juices; Trichinella spp. have become less of a burden regarding transmission via pork in many countries, but now game animals are becoming a concern; anisakiasis is becoming a global problem as the world develops a taste for sushi, and similarly for opisthorchiasis, which is increasingly being associated with cholangiocarcinoma. However, the emergence of these foodborne parasites provides an incentive for increased efforts being made toward control. In this chapter, having described how the parasites are emerging from their neglected position, the focus turns toward control. In addition to considering control measures that may be applied to the specific parasites, an overview is provided of some of the organized collaborations, projects, and consortia, as well as some of their outputs, that have in focus the control of these emerging and important pathogens.