Field- and clinically derived estimates of Wolbachia-mediated blocking of dengue virus transmission potential in Aedes aegypti mosquitoes.

The wMel strain of Wolbachia can reduce the permissiveness of Aedes aegypti mosquitoes to disseminated arboviral infections. Here, we report that wMel-infected Ae. aegypti (Ho Chi Minh City background), when directly blood-fed on 141 viremic dengue patients, have lower dengue virus (DENV) transmission potential and have a longer extrinsic incubation period than their wild-type counterparts. The wMel-infected mosquitoes that are field-reared have even greater relative resistance to DENV infection when fed on patient-derived viremic blood meals. This is explained by an increased susceptibility of field-reared wild-type mosquitoes to infection than laboratory-reared counterparts. Collectively, these field- and clinically relevant findings support the continued careful field-testing of wMel introgression for the biocontrol of Ae. aegypti-born arboviruses.

Fate of phthalates and BPA in agricultural and non-agricultural soils of the Paris area (France).

This study (i) investigated the concentration levels of nine phthalates and bisphenol A (BPA) in sludge samples originating from a French wastewater treatment plant (WWTP), (ii) studied the distribution of target compounds according to soil depth and calculated their half-lives, and (iii) compared the contamination level of the agricultural soil with those of soils with other land uses. The sludge contamination levels varied from a few hundred nanograms per gram dry weight (dw) for diethyl phthalate (DEP), di-iso-butyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and butyl-benzyl phthalate (BBP) to a few micrograms per gram dw for diethylhexyl phthalate (DEHP), di-iso-nonyl phthalate (DiNP), and di-iso-decyl phthalate (DiDP). After sludge application, an 8-fold increase for DEHP level and a 3-fold increase for BPA level occurred in the surface horizon of the soil. The mean distribution of phthalates according to the depth showed a positive gradient for the low molecular weight compounds and inversely, a negative gradient for the highest ones. The half-lives in the 0-20-cm soil horizon were 64 days for DEHP and 36 days for BPA. A predictive environmental concentration (PEC) of 0.3 µg g(-1) dw was estimated for DEHP, while the experimental value was 0.16 µg g(-1) dw, suggesting degradation processes in soil and/or formation of non-extractable residues. Comparisons of contamination levels for soils from different origins (urban, rural, agricultural, and forest) showed that the urban soil remained the most contaminated one, prior to the agricultural soil after treatment.

BPA and phthalate fate in a sewage network and an elementary river of France. Influence of hydroclimatic conditions.

Our purpose was to characterize the fate of bisphenol A (BPA) and phthalate contamination simultaneously in a sewage network and a watercourse, in relation with hydrological and climatic conditions. An elementary catchment of the Seine basin, receiving effluents from a wastewater treatment plant (WWTP), was chosen because of its basic hydrological features. BPA and DEHP concentrations in the WWTP inputs were 4 and 33 µg L(-1) whereas in the outputs, they were only 0.4 and 2 µg L(-1), respectively. Contaminant ratios in the suspended sediment phase of the WWTP inputs ranged from 0.5% to 88%, related to their molecular properties. BPA and phthalates were effectively removed in the WWTP (>90% for both compounds), by degradation and decantation. Upstream of the discharge, river concentrations ranged from 0.002 to 0.175 µg L(-1) for BPA and from 0.16 to 0.90 µg L(-1) for DEHP. Downstream from the WWTP outputs, concentrations ranged from 0.11 to 0.79 µg L(-1) for BPA and from 0.31 µg L(-1) to 1.7 µg L(-1) for DEHP: the WWTP discharge led to contaminant increases of 3.8 and 2 times, respectively. Far downstream, concentrations were lower ranging from 0.11 to 0.19 µg L(-1) for BPA and from 0.36 µg L(-1) to 1.1 µg L(-1) for DEHP. BPA and phthalates displayed opposite seasonal variations with a decrease for the first one and an increase for the second one during summer. BPA contamination in the Charmoise river derived mainly from the WWTP, while phthalate contamination was attributed to both WWTP discharges and diffuse sources such as atmospheric bulk deposition.