Simultaneous detection of the protozoan parasites Toxoplasma, Cryptosporidium and Giardia in food matrices and their persistence on basil leaves.

Toxoplasma gondii, Cryptosporidium spp. and Giardia intestinalis are emerging pathogen parasites in the food domain. However, without standardized methods for their detection in food matrices, parasitic foodborne outbreaks remain neglected. In this study, a new immunomagnetic separation assay (IMS Toxo) targeting the oocyst's wall of T. gondii was developed using a specific purified monoclonal antibody. Performance of this IMS Toxo coupled to microscopic and qPCR analyses was evaluated in terms of limit of detection (LOD) and recovery rate (RR) on: i) simple matrix (LOD = 5 oocysts; RR between 5 and 56%); ii) raspberries and basil (LOD = 33 oocysts/g; RR between 0.2 and 35%). Finally, to simultaneously extract the three protozoa from these food matrices, T. gondii oocysts were directly concentrated (without IMS Toxo) from the supernatant of the IMS of Cryptosporidium and Giardia (oo)cysts. This strategy associated to qPCR detection led to LOD <1 to 3 (oo)cysts/g and RR between 2 and 35%. This procedure was coupled to RT-qPCR analyses and showed that the three protozoa persisted on the leaves of basil and remained viable following storage at 4 °C for 8 days. These data strengthen the need to consider these protozoa in food safety.

Interaction forces drive the environmental transmission of pathogenic protozoa.

The protozoan parasites Giardia duodenalis, Cryptosporidium spp., and Toxoplasma gondii are pathogens that are resistant to a number of environmental factors and pose significant risks to public health worldwide. Their environmental transmission is closely governed by the physicochemical properties of their cysts (Giardia) and oocysts (Cryptosporidium and Toxoplasma), allowing their transport, retention, and survival for months in water, soil, vegetables, and mollusks, which are the main reservoirs for human infection. Importantly, the cyst/oocyst wall plays a key role in that regard by exhibiting a complex polymeric coverage that determines the charge and hydrophobic characteristics of parasites' surfaces. Interaction forces between parasites and other environmental particles may be, in a first approximation, evaluated following the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory of colloidal stability. However, due to the molecular topography and nano- to microstructure of the cyst/oocyst surface, non-DVLO hydrophobic forces together with additional steric attractive and/or repulsive forces may play a pivotal role in controlling the parasite behavior when the organism is subjected to various external conditions. Here, we review several parameters that enhance or hinder the adhesion of parasites to other particles and surfaces and address the role of fast-emerging techniques for mapping the cyst/oocyst surface, e.g., by measuring its topology and the generated interaction forces at the nano- to microscale. We discuss why characterizing these interactions could be a crucial step for managing the environmental matrices at risk of microbial pollution.

Impact of the Lubrizol factory fire in Rouen on coronary events: A retrospective study from the France PCI registry.

BACKGROUND: On 26 September 2019, an industrial fire occurred in the Lubrizol factory in Rouen (France), exposing the population to the inhalation of many volatile toxic agents secondary to combustion. AIM: To assess the impact of the Lubrizol factory fire on the incidence of coronary artery events. METHODS: All coronary angiograms performed in Rouen (exposed) and Le Havre (unexposed) from May 2019 to December 2019 were extracted from the prospective France Percutaneous Coronary Intervention (France PCI) registry. To study the impact of the fire on coronary events, an interrupted time series analysis was performed in Rouen, with adjustment on Le Havre in an autoregressive moving average (ARMA)(1,1) model with the precision of 1 week. The primary outcome was the incidence of acute coronary syndrome, and the secondary outcome was the incidence of ST-segment elevation myocardial infarction. RESULTS: The mean number of acute coronary syndromes per week in the exposed zone (Rouen) increased non-significantly from 37.5±9.4 before the fire to 43.2±6.2 after the fire, for an estimated effect of +5.5 (95% confidence interval -0.7 to 11.8; P=0.09) events per week. In municipalities exposed to the plume of smoke (subgroup of Rouen), the mean number of acute coronary syndromes increased non-significantly from 7.3±2.8 before the fire to 8.7±3.6 after the fire, for an estimated effect of +1.0 (95% confidence interval -2.0 to 4.0; P=0.51) events per week. The results were similar when taking into account only ST-segment elevation myocardial infarctions or all coronary events. CONCLUSIONS: Our study did not find a significant effect of the Lubrizol factory fire on the incidence of acute coronary syndrome. Further studies are needed to investigate the impact of industrial accidents on air pollution and coronary events.

Tools and methods for detecting and characterizing giardia, cryptosporidium, and toxoplasma parasites in marine mollusks.

Foodborne infections are of public health importance and deeply impact the global economy. Consumption of bivalve mollusks generates risk for humans because these filtering aquatic invertebrates often concentrate microbial pathogens from their environment. Among them, Giardia, Cryptosporidium, and Toxoplasma are major parasites of humans and animals that may retain their infectivity in raw or undercooked mollusks. This review aims to detail current and future tools and methods for ascertaining the load and potential infectivity of these parasites in marine bivalve mollusks, including sampling strategies, parasite extraction procedures, and their characterization by using microscopy and/or molecular techniques. Method standardization should lead to better risk assessment of mollusks as a source of these major environmental parasitic pathogens and to the development of safety regulations, similar to those existing for bacterial and viral pathogens encountered in the same mollusk species.