Approaches to the Surveillance of Foodborne Disease: A Review of the Evidence

Systematic review of knowledge, attitudes, and practices of dairy farmers and consumers towards bovine tuberculosis in low- and middle-income countries

Bovine Tuberculosis (bTB), caused by Mycobacterium bovis, is a neglected zoonotic disease primarily associated with cattle. The incidence of bTB is highest in low-income settings with high cattle density and unpasteurised dairy consumption. Smallholder dairy farming has steadily grown in low- and middle-income countries (LMICs) with limited professional support for adequate bTB surveillance and risk mitigation. Several studies have explored the knowledge, attitudes, and practices (KAP) of milk value chain stakeholders towards bTB in LMICs, but this evidence has not been collated and synthesised. We conducted a systematic review to determine what is known, believed, and done in relation to bTB among dairy producers and consumers in LMICs. We performed a systematic search of studies in OVID Medline, Scopus and CABI on 11 September 2023. KAP data were summarised using narrative synthesis and forest plots. We retrieved 2763 articles, retaining 51 for the review. Only studies from Africa (n = 38) and Asia (n = 13) met the eligibility criteria. Most populations reported awareness of human tuberculosis and knew it could be treated, but there was limited awareness of bTB and its zoonotic potential. Knowledge of bTB transmission routes and bTB mitigation varied across populations, and risky practices were also variable. Inconsistencies in study design and survey tools suggest some results may have a mid- to high-risk of bias. Awareness of bTB is surprisingly low among African and Asian populations with high bTB exposure risk, possibly due to the long-standing divide between animal and human health messages that has obscured the One Health implications of bTB. Addressing bTB in LMICs requires a structural One Health approach and standard KAP survey tools to adequately explore the socio-cultural, political, and economic processes and drivers favouring bTB spread and persistence.

Salmonella Infection in Pigs: Disease, Prevalence, and a Link between Swine and Human Health

Salmonella is one of the most spread foodborne pathogens worldwide, and Salmonella infections in humans still represent a global health burden. The main source of Salmonella infections in humans is represented by contaminated animal-derived foodstuffs, with pork products being one of the most important players. Salmonella infection in swine is critical not only because it is one of the main causes of economic losses in the pork industry, but also because pigs can be infected by several Salmonella serovars, potentially contaminating the pig meat production chain and thus posing a significant threat to public health globally. As of now, in Europe and in the United States, swine-related Salmonella serovars, e.g., Salmonella Typhimurium and its monophasic variant Salmonella enterica subsp. enterica 1,4,[5],12:i:-, are also frequently associated with human salmonellosis cases. Moreover, multiple outbreaks have been reported in the last few decades which were triggered by the consumption of Salmonella-contaminated pig meat. Throughout the years, changes and evolution across the pork industry may have acted as triggers for new issues and obstacles hindering Salmonella control along the food chain. Gathered evidence reinforces the importance of coordinating control measures and harmonizing monitoring programs for the efficient control of Salmonella in swine. This is necessary in order to manage outbreaks of clinical disease in pigs and also to protect pork consumers by controlling Salmonella subclinical carriage and shedding. This review provides an update on Salmonella infection in pigs, with insights on Salmonella ecology, focusing mainly on Salmonella Choleraesuis, S. Typhimurium, and S. 1,4,[5],12:i:-, and their correlation to human salmonellosis cases. An update on surveillance methods for epidemiological purposes of Salmonella infection in pigs and humans, in a "One Health" approach, will also be reported.

Epidemiology of foodborne diseases caused by Salmonella in Zhejiang Province, China, between 2010 and 2021

Objective

Salmonella infection is a common cause of bacterial foodborne diseases (FBDs) globally. In this study, we aimed to explore the epidemiological and etiological characteristics of Salmonella infection from 2012-2021 in Zhejiang Province, China.

Methods

Descriptive statistical methods were used to analyze the data reported by the Centers for Disease Control and Prevention at all levels in Zhejiang Province through the China National Foodborne Diseases Surveillance Network from 2012-2021.

Results

A total of 11,269 Salmonella cases were reported, with an average positive rate of 3.65%, including 1,614 hospitalizations. A significant seasonal trend was observed for Salmonella cases, with the highest rate over the summer period, peaking from May to October, accounting for 77.96%. The results indicated a higher positive rate among respondents aged 0-4 years, especially for the scattered children (P < 0.05). The highest number of Salmonella infections were caused due to contaminated fruit and fruit products. Households (54.69%) had the most common exposure settings. Serotypes analysis revealed that Salmonella typhimurium (36.07%), Salmonella enteritidis (15.17%), and Salmonella london (6.05%) were the dominant strains among the 173 serotypes. Diarrhea, abdominal pain, fever, nausea, and vomiting were the main symptoms of these serotypes.

Conclusions

FBDs caused by Salmonella are important issues for public health in Zhejiang Province, and there is a need to focus on the epidemiological and etiological characteristics to control Salmonella infections.

Mapping food surveillance chains through different sectors

European countries are investing in strengthening disease surveillance from a One Health (OH) perspective. During the MATRIX project, in the context of the One Health European Joint Programme, existing surveillance chains across the sectors of animal health, food safety, and public health have been investigated through questionnaires. Provided information has then been selected to be displayed in a single slide using an implemented mapping template. Two real-life scenarios are presented as case studies: the surveillance activities in place in France for Salmonella in the pork meat food chain, and in Norway for Listeria monocytogenes in the dairy food chain. The results collected through the questionnaires and the lessons learnt during the mapping process are reported, to share the advantages and drawbacks of the methodology. Moreover, the presented template could be adjusted and applied to different contexts. Mapping the components of existing disease surveillance systems is a fundamental step in understanding the relationships between its components, and subsequently facilitating their collaboration and integration under a OH approach.

The surveillance and prediction of food contamination using intelligent systems: a bibliometric analysis

Purpose

This paper aims to report on the bibliometric research trends on the application of machine learning/intelligent systems in the prediction of food contamination and the surveillance of foodborne diseases.

Design/methodology/approach

In this study, Web of Science (WoS) core collection database was used to retrieve publications from the year 1996–2021. Document types were classified according to country of origin, journals, citation and key research areas. The bibliometric parameters were analyzed using VOSviewer version 1.6.15 to visualize the international collaboration networks, citation density and link strength.

Findings

A total of 516 articles across 6 document types were extracted with an average h-index of 51 from 10,570 citations. The leading journal in publications was Science of the Total Environment (3.6%) by Elsevier and the International Journal of Food Microbiology (2.5%). The United States of America (USA) (24%) followed by the People's Republic of China (17.2%) were the most influential countries in terms of publications. The top-cited articles in this study focused on themes such as contamination from packaging materials and on the strategies for preventing chemical contaminants in the food chain.

Originality/value

This report is significant because the public health field requires innovative strategies in forecasting foodborne disease outbreaks to advance effective interventions. Therefore, more collaboration need to be fostered, especially in developing nations regarding food safety research.

In silico characteristics for re-emerging possibility of Vibrio cholerae genotypes in Iran

Epidemic cholera has been registered several times within recent years in Iran. The dominant genotype was Ogawa until 2011, but this gradually changed to Inaba. However, in 2015, the re-appearance of a previous Ogawa genotype was detected by the Iranian CDC. This raised worries because no evidence was found for its origin abroad. The aim of the present study was to identify clearly the source of this outbreak. Pulsed field gel electrophoresis (PFGE) was used to compare the recently detected Vibrio cholerae strains with those isolated from 2011 to 2015. We selected one strain per PFGE pattern, and compared the distinct patterns. BioNumerics software was applied, which enables interpretation of phenotypic and genotypic differences. In total, we studied 33 V. cholerae Ogawa strains. Analysis showed that strains could be discriminated on the basis of annual clusters but with a similarity of more than 80%. The highest homology was observed among those isolated each year from 2011 to 2014. In contrast, strains isolated in 2015 also exhibited close correlation with each other but were located in distinct clusters. The analysis also proved genetic variations among some strains. All 2015 strains showed differences with regard to previous genotypes despite some similarities. The new genotypes were probably imported into Iran from neighbouring countries such as Iraq by travellers or contaminated food sources since 2015. However, more investigations are required to identify the exact source of the 2015 outbreak.

Whole Genome Sequencing: Bridging One-Health Surveillance of Foodborne Diseases

Infections caused by pathogens commonly acquired from consumption of food are not always transmitted by that route. They may also be transmitted through contact to animals, other humans or the environment. Additionally, many outbreaks are associated with food contaminated from these non-food sources. For this reason, such presumed foodborne outbreaks are best investigated through a One Health approach working across human, animal and environmental sectors and disciplines. Outbreak strains or clones that have propagated and continue to evolve in non-human sources and environments often show more sequence variation than observed in typical monoclonal point-source outbreaks. This represents a challenge when using whole genome sequencing (WGS), the new gold standard for molecular surveillance of foodborne pathogens, for outbreak detection and investigation. In this review, using recent examples from outbreaks investigated in the United States (US) some aspects of One Health approaches that have been used successfully to solve such outbreaks are presented. These include using different combinations of flexible WGS based case definition, efficient epidemiological follow-up, traceback, surveillance, and testing of potential food and environmental sources and animal hosts.

Food-borne and water-borne diseases under climate change in low- and middle-income countries: Further efforts needed for reducing environmental health exposure risks

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Food- and water-borne diseases (FWBD) are a major cause of mortality and morbidity.

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Africa counts 91 million people falling ill and 137,000 dying per year by FWBD.

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Climate change could increase FWBD through bad water, sanitation and hygiene (WASH).

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Floods’ vulnerability maps of drinking water systems are important for prevention.

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Appropriate WASH interventions can significantly contribute in reducing FWBD under climate change.

This paper provides a view of the major facts and figures related to infectious diseases with a focus on food-borne and water-borne diseases and their link with environmental factors and climate change. The global burden of food-borne diseases for 31 selected hazards was estimated by the World Health Organization at 33 million disability-adjusted life years (DALYs) in 2010 with 40% of this burden concentrated among children under 5 years of age. The highest burden per population of food-borne diseases is found in Africa, followed by Southeast Asia and the Eastern Mediterranean sub-regions. Unsafe water used for the cleaning and processing of food is a key risk factors contributing to food-borne diseases. The role of quality and quantity of water to the general burden of infectious diseases deserves attention, particularly in low- and middle-income countries, as its effects go beyond the food chain. Water-related infectious diseases are a major cause of mortality and morbidity worldwide, and climate change effects will exacerbate the challenges for the public health sector for both food-borne and water-borne diseases. Selected case studies from Africa and Asia show that (i) climate change extreme events, such as floods, may exacerbate the risks for infectious diseases spreading through water systems, and (ii) improvements related to drinking water, sanitation and hygiene could result in a significant reduction of intestinal parasitic infections among school-aged children. There is a need to better anticipate the impacts of climate change on infectious diseases and fostering multi-stakeholder engagement and multi-sectoral collaborations for integrated interventions at schools, community and household levels. The paper calls for giving priority to improving the environmental conditions affecting food-borne and water-borne infectious diseases under climate change.

Giardia: an under-reported foodborne parasite

Foodborne zoonotic pathogens are a serious public health issue and result in significant global economic losses. Despite their importance to public health, epidemiological data on foodborne diseases including giardiasis caused by the enteric parasite, Giardia duodenalis, are lacking. This parasite is estimated to cause ∼28.2 million cases of diarrhoea each year due to contamination of food, but very few foodborne outbreaks have been documented due to the limitations of current detection as well as surveillance methods. The current method for the recovery of Giardia cysts from food matrices using immunomagnetic separation requires further standardisation and cost reduction before it can be widely used. It also should incorporate downstream molecular procedures for genotyping, and traceback and viability analyses. Foodborne giardiasis can be potentially controlled through improvements in national disease surveillance systems and the establishment of Hazard Analysis and Critical Control Point interventions across the food chain. Studies are needed to assess the true prevalence and public health impact of foodborne giardiasis.

A large prolonged outbreak of hepatitis A associated with consumption of frozen berries, Italy, 2013-14

PURPOSE

In 2013/2014, Italy experienced one of the largest community-wide prolonged outbreaks of hepatitis A virus (HAV) throughout the country. The article provides a comprehensive description of the outbreak and the investigation carried out by a multidisciplinary National Task Force, in collaboration with regional and local public health authorities. Control strategies of food-borne HAV infection in both the human and food sectors are also described.

METHODOLOGY

Enhanced human epidemiological and microbiological surveillance together with microbiological monitoring of HAV in food and trace-back investigation were conducted.

RESULTS

A total of 1803 HAV cases were identified from 1 January 2013 to 31 August 2014, in Italy. Sequencing was possible for 368 cases (20.4 %), mostly collected between 1 January 2013 and 28 February 2014, and 246 cases (66.8 %) harboured an HAV outbreak strain. Imported frozen berries contaminated with HAV were identified as the vehicle of the outbreak which also involved many other European countries in 2013 and 2014. Epidemiological evidence obtained through a case-control study was supported by the finding of a 100 % nucleotide similarity of the VP1/2A sequences of HAVs detected in human and food samples. Trace-back investigation revealed an extremely complex supplying network with no possibility for a point source potentially explaining the vast contamination of berries found in Italy.

CONCLUSION

The investigation benefited from an excellent collaboration among different sectors who shared proactively the available information. Our findings highlight the importance of considering frozen berries among the highest risk factors for HAV.