Microbial Risk Analysis最新文献

Campylobacteriosis is an emerging foodborne illness which is frequently linked to the consumption of inadequately prepared poultry. The purpose of this study was to assess the risk associated with thermotolerant Campylobacter spp. in chicken döner kebab and to estimate the number of campylobacteriosis cases due to its consumption in Tlemcen city (Algeria). In order to estimate the human exposure to Campylobacter from a döner kebab meal and the number of human cases associated to this exposure, a stochastic risk model was developed, covering the whole food pathway. The model details the spread and transfer of Campylobacter in döner kebab from slaughter to consumption and the relationship between ingested dose and the probability of developing campylobacteriosis. Information and data for the development of the risk model were obtained in this study and when not available they were obtained from other research. Whenever possible, the data were represented by probability distributions rather than single point estimates, as they were to be integrated in a probabilistic estimation of the risk using Monte Carlo simulation. We found that 86.2% of chicken meat samples were contaminated, 17% higher than 4.0 Log cfu/g. 37.5% of döner kebab samples were contaminated. It is estimated that 5 infections will occur for every 100 döner kebab consumptions and that one person in sixty-six can get a campylobacteriosis by eating a döner kebab meal. The QMRA approach allows for an overall scenario analysis. It was found that intervention during slaughter and at the cooking process of döner kebab is probably most efficient to reduce Campylobacter health risks. Furthermore, important data gaps could be identified.

The probability of cysticercus bovis (CB) infection of cattle (cysticerci from Taenia saginata) in a country where T. saginata is not endemic (i.e. Australia) was assessed using a Quantitative Microbial Risk Assessment (QMRA) approach. Two important features of the QMRA were (i) a dose-response curve to describe ingestion of eggs of the helminth T. saginata (HE) by cattle and the development of cysticerci due to the infection, and (ii) characterisation of HE concentrations. Data limitations relating to HE quantification are described, and several other key variables provided the basis for a probabilistic QMRA model.

Data from over 554 sewage samples from 11 wastewater treatment plants (WWTPs) in Southern Australia indicated the background concentration of T. saginata eggs was low (<0.1 HE L^-1 measured, 0.003 HE L^-1 as an estimated baseline modelled on a ratio of Taenia:Ascaris determined from the literature). Such a low sewage concentration was estimated to require only a 2.2 log₁₀ reduction value (LRV) via sewage treatment to maintain the baseline risk of CB equivalent to background levels in Australia. However, to protect against potential future detectable outbreaks of Taeniasis in the human population and all potential exposure scenarios considered, a 3.5 LRV for WWTP was considered appropriate with confirmation by appropriate sewage monitoring. In addition, analysis of several specific exposure scenarios using the QMRA indicated that LRV credits (0.5 to 2.0 LRV) could decrease the required LRV for wastewater treatment based on the size of the WWTP and on-site management strategies (e.g. restriction of recycled water use for livestock drinking water, the years of exposure for cattle to sites irrigated with recycled water, and the use of fodder off-site). Without such measures, a HE LRV of 4.0 is recommend for WWTPs to ensure adequate protection of systems with no on-site controls.

As a response to the pandemic caused by SARS-Cov-2 virus, on 15 March 2020, the Republic of Serbia introduced comprehensive anti-epidemic measures to curb COVID-19. After a slowdown in the epidemic, on 6 May 2020, the regulatory authorities decided to relax the implemented measures. However, the epidemiological situation soon worsened again. As of 7 February 2021, a total of 406,352 cases of SARSCov-2 infection have been reported in Serbia, 4,112 deaths caused by COVID-19. In order to better understand the epidemic dynamics and predict possible outcomes, we have developed an adaptive mathematical model SEAIHRDS (S-susceptible, E-exposed, A-asymptomatic, I-infected, H-hospitalized, R-recovered, d-dead due to COVID-19 infection, S-susceptible). The model can be used to simulate various scenarios of the implemented intervention measures and calculate possible epidemic outcomes, including the necessary hospital capacities. Considering promising results regarding the development of a vaccine against COVID-19, the model is extended to simulate vaccination among different population strata. The findings from various simulation scenarios have shown that, with implementation of strict measures of contact reduction, it is possible to control COVID-19 and reduce number of deaths. The findings also show that limiting effective contacts within the most susceptible population strata merits a special attention. However, the findings also show that the disease has a potential to remain in the population for a long time, likely with a seasonal pattern. If a vaccine, with efficacy equal or higher than 65%, becomes available it could help to significantly slow down or completely stop circulation of the virus in human population.

The effects of vaccination depend primarily on: 1. Efficacy of available vaccine(s), 2. Prioritization of the population categories for vaccination, and 3. Overall vaccination coverage of the population, assuming that the vaccine(s) develop solid immunity in vaccinated individuals. With expected basic reproduction number of R_o=2.46 and vaccine efficacy of 68%, an 87% coverage would be sufficient to stop the virus circulation.

Biopreservatives such as plant-based antimicrobials and bacteriocinogenic starter cultures have been proposed as hurdles to increase microbiological safety of a variety of products, including cheese, and numerous studies have reported their pathogen inhibitory properties. For that reason, the objective of this meta-analysis was to summarise the inactivation of Listeria monocytogenes (LM), Staphylococcus aureus (SA) and Salmonella spp. (SS) in cheese attained by added lactic acid bacteria (LAB) and essential oils (EOs); and to compare the inhibitory effectiveness by application mode and specific antimicrobial. After systematic review, 1810 observations on log reduction data and study characteristics were extracted from 53 studies. Comparing among the factual methods of application of antimicrobials (in milk, cheese surface and incorporated in films), meta-regression models pointed out that addition of EOs to milk renders, as a whole, the lowest inhibitory effect against LM, SA and SS in the finished product; whereas for added LAB, incorporation in milk prompts a faster inactivation of LM than onto cheese surface. Lemon balm, sage and basil EOs showed the best inhibitory outcomes against LM and SA; whereas clove, oregano and bay EOs presented the highest bactericidal effect against SS. For a given increase in EO concentration, the application on cheese surface provides the greatest inhibitory effect against LM and SS, while EO-embedded films lead to a more rapid inactivation during maturation/storage. The experimental practice of inoculating the antimicrobial in cheese mixture should no longer be employed in challenge studies, since the meta-regression models have demonstrated that this application method biases the results, overestimating or underestimating the inhibitory effects of EOs or added LAB, respectively. This meta-analysis has also emphasised the need to further investigate the relationship between pathogen's inoculum size and their concentrations in time.

Salmonella has long presented a major problem for the food safety of broiler meat. As the popularity of alternatively produced (e.g. organic) broiler meat increases, an understanding of the food safety risks associated with these types of products is needed. The purpose of this study was to develop a retail-to-consumption quantitative microbial risk assessment model that could be used to estimate the differences in risk of salmonellosis acquired from the consumption of conventionally and alternatively produced broiler meat in the United States annually. Data were extracted and used to define distributions that could be used to estimate Salmonella growth during retail storage, transportation, and home storage, as well as concentration changes during preparation and due to cross-contamination. A Monte Carlo simulation with 100,000 iterations was performed to estimate the risk of infection per serving and total number of infections in the United States annually from both meat types. Sensitivity analyses were performed to determine the factors that were highly correlated with increased risk of salmonellosis. Conventionally produced chicken meat was estimated to have a median risk of infection per serving of 6.4 $\times$ 10⁻⁸ and cause an average of approximately 3,880,000 infections annually compared with a median risk of infection per serving of 7.7 $\times$ 10⁻⁸ and average of approximately 641,000 estimated infections for alternatively produced chicken. The sensitivity analysis identified cross-contamination of hands during meal preparation as the most important factor linked to risk. The ‘what-if’ scenario analysis estimated that using antimicrobial soap during hand washing after handling raw chicken can reduce the risk considerably. The developed risk assessment model provides information on the public health risk of conventionally and alternatively produced broiler meat. These results will be useful in determining the key intervention strategies to mitigate the food safety risks associated with the consumption of contaminated chicken products.

Risk ranking tools to prioritize the impact of exotic animal diseases in a country or area are useful to assist risk managers in optimizing the allocation of available resources for the prevention and control of infectious diseases. Although several such tools have already been developed, few focus on the probability of entry of an exotic pathogen into a territory and even fewer are able to rank multiple pathogens at the same time. We developed a semi-quantitative multi-criteria model to estimate the probability of incursion of an exotic pathogen into a European country and use Italy as a case study. We consider the import of 37 animal diseases of importance to Italy, based on OIE notification guidelines, and determine a disease status around the world based on current country-level reporting to the OIE. We identify seven possible pathways for the introduction of a pathogen and for each of them we determine a scoring system to assess for each disease the probability of introduction via each pathway. These scores, alongside the disease status, are used to calculate an overall risk score for each pathogen. The results indicate that the risk of incursion of Echinococcus multilocularis, African swine fever virus, Trichinella spp., lumpy skin disease and foot and mouth disease virus are ranked the highest. Additional analyses identified that the disease ranking is sensitive to the relative importance of the pathways of entry and also the impact of potential mitigation measures. The model is designed to be periodically updated with new data as they become available, e.g. global disease prevalence and trade volume. Therefore, it can be used by official authorities on a regular basis to obtain up-to-date results and consequentially strengthen surveillance towards those pathogens with the highest probability of entry.

The consumption of contaminated water is a major cause of acute diarrheal disease (ADD), particularly in rural areas where treatment and control are limited. The aim of this study was to characterize the epidemiological situation and microbiological risk linked to water consumption in the rural area near the capital of Colombia. A cross-sectional study was carried out using secondary data analysis about water quality records and survey information. We described the epidemiological situation of ADD in the municipality and we estimated the risk of ADD by enterotoxigenic E. coli (ETEC) from drinking water in that region using Quantitative Microbial Risk Assessment (QMRA). During the study period, 1318 cases of ADD were reported, with 33% in children under 5. For all zones evaluated the risk exceeds commonly used acceptable risk levels. Inadequate protocols for thermal treatment and subsequent storage increase the risk of illness. The study highlights the need to strengthen intersectoral work, improve water infrastructure, and implement protocols and education about the management of drinking water to reduce health risks.

Campylobacteriosis is one of the most important reported zoonosis worldwide. Besides poultry other sources of infection have been described. In the current study, the incidence of Campylobacter spp. was assessed over a five-month period in mussel samples harvested from one of the most important producing areas (Galicia, NW Spain) in Europe. Out of 91 samples screened, 8% were positive and identified as C. lari by MALDI-TOF and whole genome sequencing. All were detected during the colder months (February and March). The antimicrobial resistance and virulence genes analysis indicated that all were multi-resistant to at least 4 antimicrobials. They were negative for the presence of 5 virulence-related genes. This is the first report of this zoonotic pathogen in mussels from one of the most important shellfish producing regions in Europe. The genomes of these 7 C. lari isolates were released to the genome public database at NCBI.

Giardia duodenalis is an important source of gastroenteritis worldwide. Endemic cases have been described in developing and industrialized countries. We analyzed risk factors for sporadic giardiasis by a systematic review and a meta-analysis of the literature. From 72 studies, contact with an infected person, lack of personal hygiene, and attending a child daycare center were identified as risk factors in children and adults.

Feco-oral transmission was significantly associated with exposure to human sewage/waste water, untreated drinking water and recreational waters. Travel abroad was a risk factor in industrialized countries. No handwashing before eating or preparing food, eating unwashed vegetables, or composite food were significant risk factors. Breastfeeding was a protective factor in developing countries. Interestingly, contact with pets was found as a significant risk factor in children in this meta-analysis. This could be explored in future studies with the comparison of the Giardia assemblage isolated from humans and pets. In the future, it would be interesting to investigate more precisely the type of water, vegetable, and whenever possible the method of preparation/treatment. Environmental and epidemiological investigations of specific risk factors by assemblages and types of Giardia spp. should be further studied. Finally, host factors in relationship with the severity and sequelae of giardiasis deserve future research.

Toxoplasmosis is considered as the most prevalent parasitic zoonotic infection worldwide. The parasitic cycle is mostly known, but the relative contribution of different sources and pathways of transmission was not previously studied by a meta-analysis. A systematic review and a meta-analysis of case-control, cohort, and cross-sectional studies were performed to determine the main risk factors associated with sporadic Toxoplasma infection. Suitable scientific articles were identified through a systematic literature search and subjected to a methodological quality assessment. Mixed-effects meta-analysis models were adjusted by population type – children, mixed population, and pregnant women – to appropriate data partitions. 187 primary studies passed the quality assessment stage, investigating risk factors for sporadic infection with Toxoplasma gondii conducted between 1983 and 2016. Cases were defined by serology.

The meta-analysis of Toxoplasma sporadic infections revealed the significance of transmission by environmental factors such as contact with soil and contact with animals, in particular cats. The consumption of raw or undercooked meat and unwashed vegetables significantly increased the odds of acquiring the disease. Shellfish and raw milk were identified as significant sources of toxoplasmosis. Almost all meat categories were identified as risk factors: pork, poultry, beef, processed meat, lamb, and game meat. Contaminated drinking water may play a role in the acquisition of infection. Moreover, the lack of hygiene in preparing food was identified as a risk factor. A significant risk factor for pregnant women is traveling abroad. Lastly, blood transfusion (in pregnant women) and immunocompromised conditions were found associated with positive serology. The broad definition of exposures and the use of serology for the case definition are the main limitations for the interpretation of the results of this meta-analysis. The transmission pathways require further investigations using longitudinal studies and subtyping approaches.