Cross-Border Investigations on the Prevalence and Transmission Dynamics of Cryptosporidium Species in Dairy Cattle Farms in Western Mainland Europe.

Cryptosporidium is an apicomplexan parasitic protist, which infects a wide range of hosts, causing cryptosporidiosis disease. In farms, the incidence of this disease is high in animals such as cows, leading to extensive economic loss in the livestock industry. Infected cows may also act as a major reservoir of Cryptosporidium spp., in particular C. parvum, the most common cause of cryptosporidiosis in these animals. This poses a risk to the trading of livestock, to other farms via breeding centres, and to human health. This study is a part of a global project aimed at strategies to tackle cryptosporidiosis. To reach this target, it was essential to determine whether prevalence was dependent on the studied countries or if the issue was borderless. Indeed, C. parvum occurrence was assessed across dairy farms in certain regions of Belgium, France, and the Netherlands. At the same time, the animal-to-animal transmission of the circulating C. parvum subtypes was studied. To accomplish this, we analysed 1084 faecal samples, corresponding to 57 dairy farms from all three countries. To this end, 18S rRNA and gp60 genes fragments were amplified, followed by DNA sequencing, which was subsequently used for detection and subtyping C. parvum. Bioinformatic and phylogenetic methods were integrated to analyse and characterise the obtained DNA sequences. Our results show 25.7%, 24.9% and 20.8% prevalence of Cryptosporidium spp. in Belgium, France, and the Netherlands respectively. Overall, 93% of the farms were Cryptosporidium positive. The gp60 subtyping demonstrated a significant number of the C. parvum positives belonged to the IIa allelic family, which has been also identified in humans. Therefore, this study highlights how prevalent C. parvum is in dairy farms and further suggests cattle as a possible carrier of zoonotic C. parvum subtypes, which could pose a threat to human health.

Sustainability of an in situ aided phytostabilisation on highly contaminated soils using fly ashes: Effects on the vertical distribution of physicochemical parameters and trace elements.

Aided phytostabilisation using trees and fly ashes is a promising technique which has shown its effectiveness in the management of highly metal-contaminated soils. However, this success is generally established based on topsoil physicochemical analysis and short-term experiments. This paper focuses on the long-term effects of the afforestation and two fly ashes (silico-aluminous and sulfo-calcic called FA1 and FA2, respectively) by assessing the integrity of fly ashes 10 years after their incorporation into the soil as well as the vertical distribution of the physicochemical parameters and trace elements (TEs) in the amended soils (F1 and F2) in comparison with a non-amended soil (R). Ten years after the soil treatment, the particle size distribution analysis between fly ashes and their corresponding masses (fly ash + soil particles) showed a loss or an agglomeration of finer particles. This evolution matches with the appearance of gypsum (CaSO4 2H2O) in FA2m instead of anhydrite (CaSO4), which is the major compound of FA2. This finding corresponds well with the dissolution and the lixiviation of Ca, S and P included in FA2 along the F2 soil profile, generating an accumulation of these elements at 30 cm depth. However, no variation of TE contamination was found between 0 and 25 cm depth in F2 soil except for Cd. Conversely, Cd, Pb, Zn and Hg enrichment was observed at 25 cm depth in the F1 soil, whereas no enrichment was observed for As. The fly ashes studied, and notably FA2, were able to reduce Cd, Pb and Zn availability in soil and this capacity persists over the time despite their structural and chemical changes.

Combining spatial distribution with oral bioaccessibility of metals in smelter-impacted soils: implications for human health risk assessment.

Geostatistical analysis and GIS-based spatial mapping have been widely used for risk assessment of environmental pollution. The objectives of this study were to: (1) investigate the spatial variability of pseudototal concentrations of Cd, Pb, and Zn; (2) estimate the degree of contamination on the basis of pollution indexes; and (3) combine geostatistical analysis with oral bioaccessibility to better assess the population's exposure to metals in smelter-impacted soils. Implications for human health risks were assessed by considering soil as a contaminant source, a release mechanism of contaminated soil to the hands, ingestion as an exposure route, and metal bioaccessibility. The bioaccessibility data in the gastric (G) and gastrointestinal (GI) phases were integrated into the standard hazard quotient-based risk assessment method. Using pollution indices showed that the entire area studied was highly polluted in terms of soil metal concentrations. However, the spatial pattern of health risk levels did not coincide with the spatial distribution of the degree of soil contamination. Introducing the bioaccessible fraction of metals from soils into the exposure calculations resulted in a substantial decrease in calculated risk (HI, hazard index) and provided a more realistic estimate of exposure to the three metals. For the highly exposed population, 46% of the soils studied provided an HI-G > 1.0 and 15% provided an HI-GI > 1.0, suggesting probable adverse health effects in children. The present study highlights the importance of conducting studies taking into account metal bioaccessible values in risk assessment.