Seasonality in Human Zoonotic Enteric Diseases: A Systematic Review

BACKGROUND: Although seasonality is a defining characteristic of many infectious diseases, few studies have described and compared seasonal patterns across diseases globally, impeding our understanding of putative mechanisms. Here, we review seasonal patterns across five enteric zoonotic diseases: campylobacteriosis, salmonellosis, vero-cytotoxigenic Escherichia coli (VTEC), cryptosporidiosis and giardiasis in the context of two primary drivers of seasonality: (i) environmental effects on pathogen occurrence and pathogen-host associations and (ii) population characteristics/behaviour. METHODOLOGY/PRINCIPAL FINDINGS: We systematically reviewed published literature from 1960-2010, resulting in the review of 86 studies across the five diseases. The Gini coefficient compared temporal variations in incidence across diseases and the monthly seasonality index characterised timing of seasonal peaks. Consistent seasonal patterns across transnational boundaries, albeit with regional variations was observed. The bacterial diseases all had a distinct summer peak, with identical Gini values for campylobacteriosis and salmonellosis (0.22) and a higher index for VTEC (Gini  0.36). Cryptosporidiosis displayed a bi-modal peak with spring and summer highs and the most marked temporal variation (Gini = 0.39). Giardiasis showed a relatively small summer increase and was the least variable (Gini = 0.18). CONCLUSIONS/SIGNIFICANCE: Seasonal variation in enteric zoonotic diseases is ubiquitous, with regional variations highlighting complex environment-pathogen-host interactions. Results suggest that proximal environmental influences and host population dynamics, together with distal, longer-term climatic variability could have important direct and indirect consequences for future enteric disease risk. Additional understanding of the concerted influence of these factors on disease patterns may improve assessment and prediction of enteric disease burden in temperate, developed countries

Toxoplasma gondii Infection Regulates the Balance of Activating and Inhibitory Receptors on Decidual Natural Killer Cells

Inhibitory receptors and activating receptor expressed on decidual natural killer (dNK) cells are generally believed to be important in abnormal pregnancy outcomes and induced adverse pregnancy. However, if Toxoplasma gondii (T. gondii) infection induced abnormal pregnancy was related to dNK cells changes is not clear. In this study, we used human dNK cells co-cultured with human extravillous cytotrophoblast (EVT) cells following YFP-Toxoplasma gondii (YFP-T. gondii) infection in vitro and established animal pregnant infection model. Levels of inhibitory receptors KIR2DL4 and ILT-2, their ligand HLA-G, and activating receptor NKG2D in human decidua, and NKG2A and its ligand Qa-1 and NKG2D in mice uterine were analyzed by real-time PCR and flow cytometry with levels of NKG2D significantly higher than those of KIR2DL4 and ILT-2 in vitro and in invo. The level of NKG2D was positively correlated with cytotoxic activity of dNK cells in vitro. Numbers of abnormal pregnancies were significantly greater in the infected group than in the control group. This result demonstrated that the increased NKG2D expression and imbalance between inhibitory receptors of dNK cells and HLA-G may contribute to abnormal pregnancy outcomes observed upon maternal infection with T. gondii

Direct scaffolding of biomimetic hydroxyapatite-gelatin nanocomposites using aminosilane cross-linker for bone regeneration

Hydroxyapatite-gelatin modified siloxane (GEMOSIL) nanocomposite was developed by coating, kneading and hardening processes to provide formable scaffolding for alloplastic graft applications. The present study aims to characterize scaffolding formability and mechanical properties of GEMOSIL, and to test the in vitro and in vivo biocompatibility of GEMOSIL. Buffer Solution initiated formable paste followed by the sol-gel reaction led to a final hardened composite. Results showed the adequate coating of aminosilane, 11–19 wt%, affected the cohesiveness of the powders and the final compressive strength (69 MPa) of the composite. TGA and TEM results showed the effective aminosilane coating that preserves hydroxyapatite-gelatin nanocrystals from damage. Both GEMOSIL with and without titania increased the mineralization of preosteoblasts in vitro. Only did titania additives revealed good in vivo bone formation in rat calvarium defects. The scaffolding formability, due to cohesive bonding among GEMOSIL particles, could be further refined to fulfill the complicated scaffold processes