Rapidly growing populations and migration to urban areas in developing countries has resulted in a vital need for the establishment of centralized water systems to disseminate potable water to residents. Protected source water and modern, well-maintained drinking water treatment plants can provide water adequate for human consumption. However, ageing, stressed or poorly maintained distribution systems can cause the quality of piped drinking water to deteriorate below acceptable levels and pose serious health risks. This review will outline distribution system deficiencies in developing countries caused by: the failure to disinfect water or maintain a proper disinfection residual; low pipeline water pressure; intermittent service; excessive network leakages; corrosion of parts; inadequate sewage disposal; and inequitable pricing and usage of water. Through improved research, monitoring and surveillance, increased understanding of distribution system deficiencies may focus limited resources on key areas in an effort to improve public health and decrease global disease burden.

Pseudomonas aeruginosa is known to invade epithelial cells during infection and in vitro. However, little is known of bacterial or epithelial factors modulating P. aeruginosa intracellular survival or replication after invasion, except that it requires a complete lipopolysaccharide core. In this study, real-time video microscopy revealed that invasive P. aeruginosa isolates induced the formation of membrane blebs in multiple epithelial cell types and that these were then exploited for intracellular replication and rapid real-time motility. Further studies revealed that the type three secretion system (T3SS) of P. aeruginosa was required for blebbing. Mutants lacking either the entire T3SS or specific T3SS components were instead localized to intracellular perinuclear vacuoles. Most T3SS mutants that trafficked to perinuclear vacuoles gradually lost intracellular viability, and vacuoles containing those bacteria were labeled by the late endosomal marker lysosome-associated marker protein 3 (LAMP-3). Interestingly, mutants deficient only in the T3SS translocon structure survived and replicated within the vacuoles that did not label with LAMP-3. Taken together, these data suggest two novel roles of the P. aeruginosa T3SS in enabling bacterial intracellular survival: translocon-dependent formation of membrane blebs, which form a host cell niche for bacterial growth and motility, and effectordependent bacterial survival and replication within intracellular perinuclear vacuoles.

ExsA contributed to corneal virulence of only cytotoxic P. aeruginosa, with contributions made by both ExoU and ExoT to bacterial survival and disease severity. This differs from cytotoxic P. aeruginosa virulence in the lung, which is ExoU-dependent.

Uveitis, which occurs in association with systemic immunological diseases, presents a considerable medical challenge due to incomplete understanding of its pathogenesis. The signals that initiate T cells to target the eye, which may be of infectious or non-infectious origin, are poorly understood. Experimental autoimmune uveoretinitis (EAU) develops in mice immunized with the endogenous retinal protein interphotoceptor retinoid binding protein (IRBP) in the presence of the adjuvant CFA. EAU manifests as posterior ocular inflammation consisting of vasculitis, granulomas, retinal damage and invasion of self-reactive T cells, which are key clinical features of human uveitis. Our studies uncover Card9 as a critical genetic determinant for EAU. Card9 was responsible for Th17 polarization and Th17-associated antigen-specific responses, but not Th1-associated responses. Nonetheless, Card9 expression was essential for accumulation of both lineages within the eye. Consistent with its recently identified role as an intracellular signaling mediator for C-type lectin receptors (CLRs), a Card9-dependent transcriptional response in the neuroretina was observed involving genes encoding the CLRs Dectin-1, Dectin-2 and Mincle. Genetic deletion of these individual CLRs revealed an essential role for Mincle. Mincle activation was sufficient to generate the EAU phenotype, and this required activation of both Syk and Card9. In contrast, Dectin-1 contributed minimally and a possible repressive role was shown for Dectin-2. These findings extend our understanding of CLRs in autoimmune uveitis. The newly identified role of Mincle and Syk/Card9-coupled signaling axis in autoimmune uveitis could provide novel targets for treatment of patients with ocular inflammatory disease.

The 6-hour healing infection model showed a role for ExsA in early interactions with the corneal epithelium that was not detectable with the conventional (0-hour) scratch model. Comparison of the 6- and 12-hour healing models, which showed that factors additional to barrier function contribute to defense against infection, could be used to gain new insights into corneal defense mechanisms, and the methods used by bacteria to circumvent them.

Purpose. Dendritic cells (DCs) are antigen-presenting cells vital for initiating immune responses. In this study the authors examined the in vivo migratory capability of resident corneal DCs to various stimuli. Methods. The authors used mice expressing enhanced yellow fluorescent protein (eYFP) under control of the CD11c promoter to visualize corneal DCs. To assess the distribution and mobility of DCs, normal corneas were imaged in vivo and ex vivo with fluorescence microscopy. Intravital microscopy was used to examine the responses of resident central and peripheral corneal DCs to silver nitrate injury, lipopolysaccharide, microspheres, and tumor necrosis factor (TNF-alpha). In some experiments, TNF-alpha injection was used to first induce centripetal migration of DCs to the central cornea, which was subsequently reinjected with microspheres. Results. In normal corneas, DCs were sparsely distributed centrally and were denser in the periphery, with epithelial-level DCs extending into the epithelium. Videomicroscopy showed that though cell processes were in continuous movement, cells generally did not migrate. Within the first 6 hours after stimulation, neither central nor peripheral corneal DCs exhibited significant lateral migration, but central corneal DCs assumed extreme morphologic changes. An increased number of DCs in the TNF-alpha-stimulated central cornea were responsive to subsequent microsphere injection by adopting a migratory behavior, but not with increased speed. Conclusions. In vivo imaging reveals minimal lateral migration of corneal DCs after various stimuli. In contrast, DCs within the central cornea after initial TNF-alpha injection are more likely to respond to a secondary insult with lateral migration.

Differences between invasive and cytotoxic strain infections in their early response to the different therapeutic regimens did not translate to notable differences after 7 days, but the effects of antibiotics in halting disease progression were delayed for both strain types. These results suggest that successful management might be improved by addressing factors contributing to disease progression during sterilization of the cornea by antibiotics.

This review paper examines and evaluates urine-sampling methodologies in infants and young children, to determine which methods are suitable for use in large biomonitoring surveys or studies of environmental chemicals in children younger than 6 years. Methods for non-toilet-trained children include the use of urine bags, collection pads (e.g., cotton or gauze inserts), disposable diapers, cotton diapers, and the clean catch method. In toilet-trained children, collection methods include use of a commode insert pan as well as specimen collection cups. The advantages and disadvantages of these various methods need to be evaluated with respect to the target population, timing and frequency of collection, minimum sample volume required, method of urine extraction, potential for contamination of the sample, stability of the analyte of interest, and burden on participants and research team. Collection methods must not introduce contamination or affect the integrity of the sample, should be logistically practical, and should minimize discomfort experienced by the child. Although collection of urine samples from children who are not toilet-trained is more challenging than collection from older toilet-trained children, the vulnerability of younger children to the exposure to and health effects of environmental chemicals makes finding suitable methods a priority.