Supplementation With Fish Oil in Pregnancy Reduces Gastroenteritis in Early Childhood.

BACKGROUND: We hypothesized that insufficient intake of fish oil-derived omega-3 long-chain polyunsaturated fatty acids (n-3 LCPUFAs) during pregnancy is a contributing factor to gastroenteritis in early childhood. We examined the effect of n-3 LCPUFA supplementation on gastroenteritis symptoms in the offspring's first 3 years of life. METHODS: This was a double-blinded, randomized controlled trial whereby 736 mothers were administered n-3 LCPUFA or control from pregnancy week 24 until 1 week after birth. We measured the number of days with gastroenteritis, number of episodes with gastroenteritis, and the risk of having a gastroenteritis episode in the first 3 years of life. RESULTS: A median reduction of 2.5 days with gastroenteritis (P = .018) was shown, corresponding to a 14% reduction in the n-3 LCPUFA group compared with controls in the first 3 years of life (P = .037). A reduction in the number of gastroenteritis episodes (P = .027) and a reduced risk of having an episode (hazard ratio, 0.80 [95% confidence interval, .66-.97]; P = .023) were also shown. CONCLUSIONS: Fish oil supplementation from the 24th week of pregnancy led to a reduction in the number of days and episodes with gastroenteritis symptoms in the first 3 years of life. The findings suggest n-3 LCPUFA supplementation as a preventive measure against gastrointestinal infections in early childhood. CLINICAL TRIALS REGISTRATION: NCT00798226.

Rotavirus Vaccine Impact Within an Integrated Healthcare Delivery System in the United States.

We assessed rotavirus vaccine impact using data on acute gastroenteritis (AGE) encounters within an integrated healthcare delivery system during 2000-2018. Following rotavirus vaccine introduction, all-cause AGE rates among children <5 years declined by 36% (95% confidence interval [CI]: 32%-40%) for outpatient and 54% (95% CI: 46%-60%) for inpatient encounters.

Effect of Lactobacillus acidophilus Fermented Broths Enriched with Eruca sativa Seed Extracts on Intestinal Barrier and Inflammation in a Co-Culture System of an Enterohemorrhagic Escherichia coli and Human Intestinal Cells.

Lactic acid bacteria (LAB) "fermentates" confer a beneficial effect on intestinal function. However, the ability of new fermentations to improve LAB broth activity in preventing pathogen-induced intestinal inflammation and barrier dysfunction has not yet been studied. The objective of this study was to determine if broths of LAB fermented with Eruca sativa or Barbarea verna seed extracts prevent gut barrier dysfunction and interleukin-8 (CXCL8) release in vitro in human intestinal Caco-2 cells infected with enterohemorrhagic Escherichia coli (EHEC) O157:H7. LAB broths were assayed for their effects on EHEC growth and on Caco-2 viability; thereafter, their biological properties were analysed in a co-culture system consisting of EHEC and Caco-2 cells. Caco-2 cells infected with EHEC significantly increased CXCL8 release, and decreased Trans-Epithelial Electrical Resistance (TEER), a barrier-integrity marker. Notably, when Caco-2 cells were treated with LAB broth enriched with E. sativa seed extract and thereafter infected, both CXCL8 expression and epithelial dysfunction reduced compared to in untreated cells. These results underline the beneficial effect of broths from LAB fermented with E. sativa seed extracts in gut barrier and inflammation after EHEC infection and reveal that these LAB broths can be used as functional bioactive compounds to regulate intestinal function.

Does Caesarean Section or Preterm Delivery Influence TGF-ß2 Concentrations in Human Colostrum?

Human colostrum (HC) is a rich source of immune mediators that play a role in immune defences of a newly born infant. The mediators include transforming growth factor ß (TGF-ß) which exists in three isoforms that regulate cellular homeostasis and inflammation, can induce or suppress immune responses, limit T helper 1 cells (Th1) reactions and stimulate secretory immunoglobulin A (IgA) production. Human milk TGF-ß also decreases apoptosis of intestinal cells and suppresses macrophage cytokine expression. The aim of the study was to determine the concentration of TGF-ß2 in HC obtained from the mothers who delivered vaginally (VD) or by caesarean section (CS), and to compare the concentrations in HC from mothers who delivered at term (TB) or preterm (PB). In this study, 56% of preterm pregnancies were delivered via CS. The concentrations of TGF-ß2 were measured in HC from 299 women who delivered in the 1st Department of Obstetrics and Gynaecology, Medical University of Warsaw: 192 (VD), 107 (CS), 251 (TB), and 48 (PB). The colostrum samples were collected within 5 days post-partum. TGF-ß2 levels in HC were measured by the enzyme-linked immunosorbent assay (ELISA) test with the Quantikine ELISA Kit-Human TGF-ß2 (cat.no. SB250). Statistical significance between groups was calculated by the Student t-test using StatSoft Statistica 13 software. The mean TGF-ß2 concentration in patients who delivered at term or preterm were comparable. The levels of TGF-ß2 in HC were higher after preterm than term being 4648 vs. 3899 ng/mL (p = 0.1244). The delivery via CS was associated with higher HC concentrations of TGF-ß2. The levels of TGF-ß2 were significantly higher in HC after CS than VD (7429 vs. 5240 ng/mL; p = 0.0017). The data from this study suggest: caesarean section was associated with increased levels of TGF-ß2 in HC. The increased levels of TGF-ß2 in HC of women who delivered prematurely require further research. Early and exclusive breast-feeding by mothers after caesarean section and premature births with colostrum containing high TGF-ß2 levels may prevent the negative impact of pathogens which often colonize the gastrointestinal tract and may reduce the risk of chronic diseases in this group of patients.

Antiviral effects of blueberry proanthocyanidins against Aichi virus.

Blueberry polyphenols are known for their high antioxidant and antimicrobial potential. Aichi virus (AiV) is an emerging human enteric virus that causes gastroenteritis outbreaks worldwide. This study aimed to (1) determine the time- and dose-dependent effects of blueberry proanthocyanidins (B-PAC) against AiV over 24 h at 37 °C; (2) gain insights on their mode of action using pre- and post-treatment of host cells and Transmission Electron Microscopy; and (3) determine their anti-AiV effects in model foods and under simulated gastric conditions. AiV at ∼5 log PFU/ml was incubated with equal volumes of commercial blueberry juice (BJ, pH 2.8), neutralized BJ (pH 7.0), B-PAC (2, 4, and 10 mg/ml) prepared either in 10% ethanol, apple juice (AJ), 2% milk, simulated gastric fluid (SGF, pH 1.5) or simulated intestinal fluid (SIF, pH 7.5), and controls (malic acid (pH 3.0), phosphate buffered saline (pH 7.2), apple juice (pH 3.6) and 2% milk) over 24 h at 37 °C, followed by standard plaque assays. Each experiment was replicated thrice and data were statistically analyzed. Differences in AiV titers with 1 mg/ml B-PAC were 2.13 ±â€¯0.06 log PFU/ml lower after 24 h and ≥3 log PFU/ml (undetectable levels) lower with 2 and 5 mg/ml B-PAC compared to AiV titers in PBS after 24 h and 3 h, respectively. BJ at 37 °C resulted in titer differences (lower titers compared to PBS) of 0.17 ±â€¯0.06, 1.27 ±â€¯0.01, and 1.73 ±â€¯0.23 log PFU/ml after 1, 3, and 6 h and ≥3 log PFU/ml after 24 h. Pre- and post-treatment of host cells with 0.5 mg/ml B-PAC caused titer decreases of 0.62 ±â€¯0.33 and 0.30 ±â€¯0.06 log PFU/ml, respectively suggesting a moderate effect on viral-host cell binding. B-PAC at 2 mg/ml in AJ caused titer differences of ≥3 log PFU/ml after 0.5 h, while differences of 0.84 ±â€¯0.03 log PFU/ml with 5 mg/ml B-PAC in milk, and ≥3 log PFU/ml with B-PAC at 5 mg/ml in SIF after 30 min were obtained. This study shows the ability of BJ and B-PAC to decrease AiV titers to potentially prevent AiV-related illness and outbreaks.

Green tea extract prevents obesity in male mice by alleviating gut dysbiosis in association with improved intestinal barrier function that limits endotoxin translocation and adipose inflammation.

Gut-derived endotoxin translocation provokes obesity by inducing TLR4/NFκB inflammation. We hypothesized that catechin-rich green tea extract (GTE) would protect against obesity-associated TLR4/NFκB inflammation by alleviating gut dysbiosis and limiting endotoxin translocation. Male C57BL/6J mice were fed a low-fat (LF) or high-fat (HF) diet containing 0% or 2% GTE for 8 weeks. At Week 7, fluorescein isothiocyanate (FITC)-dextran was administered by oral gavage before assessing its serum concentrations as a gut permeability marker. HF-feeding increased (P<.05) adipose mass and adipose expression of genes involved in TLR4/NFκB-dependent inflammation and macrophage activation. GTE attenuated HF-induced obesity and pro-inflammatory gene expression. GTE in HF mice decreased serum FITC-dextran, and attenuated portal vein and circulating endotoxin concentrations. GTE in HF mice also prevented HF-induced decreases in the expression of intestinal tight junction proteins (TJPs) and hypoxia inducible factor-1α while preventing increases in TLR4/NFκB-dependent inflammatory genes. Gut microbial diversity was increased, and the Firmicutes:Bacteroidetes ratio was decreased, in HF mice fed GTE compared with HF controls. GTE in LF mice did not attenuate adiposity but decreased endotoxin and favorably altered several gut bacterial populations. Serum FITC-dextran was correlated with portal vein endotoxin (P<.001; rP=0.66) and inversely correlated with colonic mRNA levels of TJPs (P<.05; rP=-0.38 to -0.48). Colonic TJPs mRNA were inversely correlated with portal endotoxin (P<.05; rP=-0.33 to -0.39). These data suggest that GTE protects against diet-induced obesity consistent with a mechanism involving the gut-adipose axis that limits endotoxin translocation and consequent adipose TLR4/NFκB inflammation by improving gut barrier function.

Protective Effect of Proanthocyanidins in a Rat Model of Mild Intestinal Inflammation and Impaired Intestinal Permeability Induced by LPS.

SCOPE: Intestinal dysfunction consists of a defective barrier function, which allows the influx of luminal endotoxins, thus causing intestinal inflammation. Proanthocyanidins are natural bioactive compounds that could modulate intestinal dysfunction. This study analyzes the protective effects of proanthocyanidins in a rat model of intestinal dysfunction. METHODS AND RESULTS: To investigate the preventive effects of both high dietary (75 mg kg-1 body weight) and pharmacological (375 mg kg-1 body weight) oral doses of proanthocyanidins (GSPE), rat intestinal dysfunction is induced with LPS (i.p.). In vivo intestinal permeability (ovalbumin [OVA] assay) and systemic inflammation and endotoxemia (TNF-α and LPS plasma levels) are assessed. Intestinal inflammation and oxidative stress are determined using myeloperoxidase (MPO), cyclooxygenase-2 (COX-2) activities, and reactive oxygen species (ROS) levels, respectively. Ileal gene expression of permeability/inflammatory genes is analyzed. LPS administration induces intestinal permeability, inflammation, and oxidative stress. GSPE normalizes in vivo OVA levels. In the small intestine, the GSPE treatment decreases MPO and COX-2 activities; modulates the ileum inflammatory and permeability proteins gene expression; and in the large intestine, prevents increase of ROS levels. CONCLUSIONS: Proanthocyanidins, at nutritional and pharmacological doses, prevents endotoxin-induced-intestinal inflammation, permeability, and oxidative stress in rats differentially in each intestinal section. Proanthocyanidins are nutritional-therapeutic novel candidates for preventing intestinal dysfunction.

[False beliefs about vaccines]. / Falsas creencias sobre las vacunas.

Vaccines are an essential tool for the prevention of infectious diseases. However, false ideas and rumours with no scientific foundation about their possible negative effects may dissuade people from being vaccinated, with the consequent risks for the health of the population. The objective of this article is to evaluate the origin and the arguments of some of the most frequent mistaken ideas and rumours about the possible adverse effects of vaccines. Some clearly established adverse effects are presented, as well as false beliefs about various vaccines and potential harm to health. Vaccines, like any drug, can cause adverse effects, but the possible adverse effects of vaccination programs are clearly lower than their individual (vaccinated) and collective benefits (those vaccinated and those who cannot be vaccinated for medical reasons). The possible adverse effects attributable to vaccines should be detected by powerful and well-structured pharmacovigilance systems.

A nano silicon adjuvant enhances inactivated transmissible gastroenteritis vaccine through activation the Toll-like receptors and promotes humoral and cellular immune responses.

Inactivated transmissible gastroenteritis virus (TGEV) vaccines are widely used in swine herds in China. These are limited, however, by the need to elicit both humoral and cellular immunity, as well as the efficiency of adjuvants. In this study, a 70-nm nano silicon particle was applied with inactivated TGEV vaccine in mice, and its immune-enhancing effects and mechanism of action investigated. We found that nano silicon applied with inactivated TGEV vaccine induced high antibody titers, increase IL-6, TNF-α and IFN-γ expression, and stimulate CD3+ T cell proliferation with a high CD4+/CD8+ T lymphocyte ratio. Nano silicon could quickly activate innate and adaptive immunity by stimulating Toll-like receptor signaling pathways, indicating that the nano silicon adjuvant enhanced long-term humoral and early cellular immune responses when combined with inactivated TGEV vaccine. Nano silicon could be considered for use as an antigen- carrier and adjuvant for veterinary vaccines.

Challenges to Developing a Rotavirus Vaccine.

Rotavirus is the most important cause of gastroenteritis worldwide. In developing countries, the virus is a major cause of death in infants and young children. In the United States, before the licensure of vaccines, rotavirus infections accounted for ∼2.7 million cases of gastroenteritis annually. Here are described the history and challenges surrounding the development of a rotavirus vaccine.

A fermented milk concentrate and a combination of short-chain galacto-oligosaccharides/long-chain fructo-oligosaccharides/pectin-derived acidic oligosaccharides protect suckling rats from rotavirus gastroenteritis.

Human milk contains bioactive compounds that confer a protective role against gastrointestinal infections. In order to find supplements for an infant formula able to mimic these benefits of breast-feeding, two different concepts were tested. The products consisted of the following: (1) a Bifidobacterium breve- and Streptococcus thermophilus-fermented formula and (2) a combination of short-chain galacto-oligosaccharides/long-chain fructo-oligosaccharides with pectin-derived acidic oligosaccharides. A rotavirus infection suckling rat model was used to evaluate improvements in the infectious process and in the immune response of supplemented animals. Both nutritional concepts caused amelioration of the clinical symptoms, even though this was sometimes hidden by softer stool consistency in the supplemented groups. Both products also showed certain modulation of immune response, which seemed to be enhanced earlier and was accompanied by a faster resolution of the process. The viral shedding and the in vitro blocking assay suggest that these products are able to bind the viral particles, which can result in a milder infection. In conclusion, both concepts evaluated in this study showed interesting protective properties against rotavirus infection, which deserve to be investigated further.

The impact of lactoferrin with different levels of metal saturation on the intestinal epithelial barrier function and mucosal inflammation.

Translocation of bacteria, primarily Gram-negative pathogenic flora, from the intestinal lumen into the circulatory system leads to sepsis. In newborns, and especially very low birth weight infants, sepsis is a major cause of morbidity and mortality. The results of recently conducted clinical trials suggest that lactoferrin, an iron-binding protein that is abundant in mammalian colostrum and milk, may be an effective agent in preventing sepsis in newborns. However, despite numerous basic studies on lactoferrin, very little is known about how metal saturation of this protein affects a host's health. Therefore, the main objective of this study was to elucidate how iron-depleted, iron-saturated, and manganese-saturated forms of lactoferrin regulate intestinal barrier function via interactions with epithelial cells and macrophages. For these studies, a human intestinal epithelial cell line, Caco-2, was used. In this model, none of the tested lactoferrin forms induced higher levels of apoptosis or necrosis. There was also no change in the production of tight junction proteins regardless of lactoferrin metal saturation status. None of the tested forms induced a pro-inflammatory response in Caco-2 cells or in macrophages either. However, the various lactoferrin forms did effectively inhibit the pro-inflammatory response in macrophages that were activated with lipopolysaccharide with the most potent effect observed for apolactoferrin. Lactoferrin that was not bound to its cognate receptor was able to bind and neutralize lipopolysaccharide. Lactoferrin was also able to neutralize microbial-derived antigens, thereby potentially reducing their pro-inflammatory effect. Therefore, we hypothesize that lactoferrin supplementation is a relevant strategy for preventing sepsis.

Dietary supplements and disease prevention - a global overview.

Dietary supplements are widely used and offer the potential to improve health if appropriately targeted to those in need. Inadequate nutrition and micronutrient deficiencies are prevalent conditions that adversely affect global health. Although improvements in diet quality are essential to address these issues, dietary supplements and/or food fortification could help meet requirements for individuals at risk of deficiencies. For example, supplementation with vitamin A and iron in developing countries, where women of reproductive age, infants and children often have deficiencies; with folic acid among women of reproductive age and during pregnancy; with vitamin D among infants and children; and with calcium and vitamin D to ensure bone health among adults aged ≥65 years. Intense debate surrounds the benefits of individual high-dose micronutrient supplementation among well-nourished individuals because the alleged beneficial effects on chronic diseases are not consistently supported. Daily low-dose multivitamin supplementation has been linked to reductions in the incidence of cancer and cataracts, especially among men. Baseline nutrition is an important consideration in supplementation that is likely to modify its effects. Here, we provide a detailed summary of dietary supplements and health outcomes in both developing and developed countries to help guide decisions about dietary supplement recommendations.

Engineering and expression of a human rotavirus candidate vaccine in Nicotiana benthamiana.

BACKGROUND: Human rotaviruses are the main cause of severe gastroenteritis in children and are responsible for over 500 000 deaths annually. There are two live rotavirus vaccines currently available, one based on human rotavirus serotype G1P[8], and the other a G1-G4 P[8] pentavalent vaccine. However, the recent emergence of the G9 and other novel rotavirus serotypes in Africa and Asia has prompted fears that current vaccines might not be fully effective against these new varieties. RESULTS: We report an effort to develop an affordable candidate rotavirus vaccine against the new emerging G9P[6] (RVA/Human-wt/ZAF/GR10924/1999/G9P[6]) strain. The vaccine is based on virus-like particles which are both highly immunogenic and safe. The vaccine candidate was produced in Nicotiana benthamiana by transient expression, as plants allow rapid production of antigens at lower costs, without the risk of contamination by animal pathogens. Western blot analysis of plant extracts confirmed the successful expression of two rotavirus capsid proteins, VP2 and VP6. These proteins assembled into VLPs resembling native rotavirus particles when analysed by transmission electron microscopy (TEM). Expression of the rotavirus glycoprotein VP7 and the spike protein VP4 was also tried. However, VP7 expression caused plant wilting during the course of the time trial and expression could never be detected for either protein. We therefore created three fusion proteins adding the antigenic part of VP4 (VP8*) to VP6 in an attempt to produce more appropriately immunogenic particles. Fusion protein expression in tobacco plants was detected by western blot using anti-VP6 and anti-VP4 antibodies, but no regular particles were observed by TEM, even when co-expressed with VP2. CONCLUSION: Our results suggest that the rotavirus proteins produced in N. benthamiana are candidates for a subunit vaccine specifically for the G9P[6] rotavirus strain. This could be more effective in developing countries, thereby possibly providing a higher overall efficacy for the existing vaccines. The production of rotavirus proteins in plants would probably result in lower manufacturing costs, making it more affordable for developing countries. Further investigation is required to evaluate the immunogenic potential of the VLPs and fusion proteins created in this study.

Llama nanoantibodies with therapeutic potential against human norovirus diarrhea.

Noroviruses are a major cause of acute gastroenteritis, but no vaccines or therapeutic drugs are available. Llama-derived single chain antibody fragments (also called VHH) are small, recombinant monoclonal antibodies of 15 kDa with several advantages over conventional antibodies. The aim of this study was to generate recombinant monoclonal VHH specific for the two major norovirus (NoV) genogroups (GI and GII) in order to investigate their potential as immunotherapy for the treatment of NoV diarrhea. To accomplish this objective, two llamas were immunized with either GI.1 (Norwalk-1968) or GII.4 (MD2004) VLPs. After immunization, peripheral blood lymphocytes were collected and used to generate two VHH libraries. Using phage display technology, 10 VHH clones specific for GI.1, and 8 specific for GII.4 were selected for further characterization. All VHH recognized conformational epitopes in the P domain of the immunizing VP1 capsid protein, with the exception of one GII.4 VHH that recognized a linear P domain epitope. The GI.1 VHHs were highly specific for the immunizing GI.1 genotype, with only one VHH cross-reacting with GI.3 genotype. The GII.4 VHHs reacted with the immunizing GII.4 strain and showed a varying reactivity profile among different GII genotypes. One VHH specific for GI.1 and three specific for GII.4 could block the binding of homologous VLPs to synthetic HBGA carbohydrates, saliva, and pig gastric mucin, and in addition, could inhibit the hemagglutination of red blood cells by homologous VLPs. The ability of Nov-specific VHHs to perform well in these surrogate neutralization assays supports their further development as immunotherapy for NoV treatment and immunoprophylaxis.

Aqueous Extracts of Hibiscus sabdariffa Calyces Decrease Hepatitis A Virus and Human Norovirus Surrogate Titers.

Hibiscus sabdariffa extract is known to have antioxidant, anti-diabetic, and antimicrobial properties. However, their effects against foodborne viruses are currently unknown. The objective of this study was to determine the antiviral effects of aqueous extracts of H. sabdariffa against human norovirus surrogates (feline calicivirus (FCV-F9) and murine norovirus (MNV-1)) and hepatitis A virus (HAV) at 37 °C over 24 h. Individual viruses (~5 log PFU/ml) were incubated with 40 or 100 mg/ml of aqueous hibiscus extract (HE; pH 3.6), protocatechuic acid (PCA; 3 or 6 mg/ml, pH 3.6), ferulic acid (FA; 0.5 or 1 mg/ml; pH 4.0), malic acid (10 mM; pH 3.0), or phosphate buffered saline (pH 7.2 as control) at 37 °C over 24 h. Each treatment was replicated thrice and plaque assayed in duplicate. FCV-F9 titers were reduced to undetectable levels after 15 min with both 40 and 100 mg/ml HE. MNV-1 was reduced by 1.77 ± 0.10 and 1.88 ± 0.12 log PFU/ml after 6 h with 40 and 100 mg/ml HE, respectively, and to undetectable levels after 24 h by both concentrations. HAV was reduced to undetectable levels by both HE concentrations after 24 h. PCA at 3 mg/ml reduced FCV-F9 titers to undetectable levels after 6 h, MNV-1 by 0.53 ± 0.01 log PFU/ml after 6 h, and caused no significant change in HAV titers. FA reduced FCV-F9 to undetectable levels after 3 h and MNV-1 and HAV after 24 h. Transmission electron microscopy showed no conclusive results. The findings suggest that H. sabdariffa extracts have potential to prevent foodborne viral transmission.

Vaccines for viral and bacterial pathogens causing acute gastroenteritis: Part I: Overview, vaccines for enteric viruses and Vibrio cholerae.

Efforts to develop vaccines for prevention of acute diarrhea have been going on for more than 40 y with partial success. The myriad of pathogens, more than 20, that have been identified as a cause of acute diarrhea throughout the years pose a significant challenge for selecting and further developing the most relevant vaccine candidates. Based on pathogen distribution as identified in epidemiological studies performed mostly in low-resource countries, rotavirus, Cryptosporidium, Shigella, diarrheogenic E. coli and V. cholerae are predominant, and thus the main targets for vaccine development and implementation. Vaccination against norovirus is most relevant in middle/high-income countries and possibly in resource-deprived countries, pending a more precise characterization of disease impact. Only a few licensed vaccines are currently available, of which rotavirus vaccines have been the most outstanding in demonstrating a significant impact in a short time period. This is a comprehensive review, divided into 2 articles, of nearly 50 vaccine candidates against the most relevant viral and bacterial pathogens that cause acute gastroenteritis. In order to facilitate reading, sections for each pathogen are organized as follows: i) a discussion of the main epidemiological and pathogenic features; and ii) a discussion of vaccines based on their stage of development, moving from current licensed vaccines to vaccines in advanced stage of development (in phase IIb or III trials) to vaccines in early stages of clinical development (in phase I/II) or preclinical development in animal models. In this first article we discuss rotavirus, norovirus and Vibrio cholerae. In the following article we will discuss Shigella, Salmonella (non-typhoidal), diarrheogenic E. coli (enterotoxigenic and enterohemorragic), and Campylobacter jejuni.

Vaccines for viral and bacterial pathogens causing acute gastroenteritis: Part II: Vaccines for Shigella, Salmonella, enterotoxigenic E. coli (ETEC) enterohemorragic E. coli (EHEC) and Campylobacter jejuni.

In Part II we discuss the following bacterial pathogens: Shigella, Salmonella (non-typhoidal), diarrheogenic E. coli (enterotoxigenic and enterohemorragic) and Campylobacter jejuni. In contrast to the enteric viruses and Vibrio cholerae discussed in Part I of this series, for the bacterial pathogens described here there is only one licensed vaccine, developed primarily for Vibrio cholerae and which provides moderate protection against enterotoxigenic E. coli (ETEC) (Dukoral(®)), as well as a few additional candidates in advanced stages of development for ETEC and one candidate for Shigella spp. Numerous vaccine candidates in earlier stages of development are discussed.

Inactivation of norovirus and surrogates by natural phytochemicals and bioactive substances.

Human norovirus is the leading cause of sporadic gastroenteritis, which is responsible for more than 90% of all nonbacterial gastroenteritis outbreaks. While norovirus infections typically cause mild and self-limiting symptoms lasting 24-48 h, chronic persistent infections can cause severe symptoms. Although recent advances have been made in understanding the molecular characteristics of norovirus infection, no norovirus-specific antiviral drugs, or vaccines are available. Conventional intervention methods used to inactivate norovirus, such as treatment with disinfecting agents (e.g. ethanol, hypochlorite, and quaternary ammonium formulations), have shown a lack of efficacy against human norovirus when they are applied to foods and in food preparation processes. Therefore, alternative antiviral or inactivating agents such as phytochemicals have received attention as potential norovirus inhibitors due to their relatively low toxicity and lack of side effects, which allows them to be prepared as food-safe formulations. Evidence from studies using viral surrogates suggests that numerous phytochemicals and foods containing flavonoids and polyphenols have anti-norovirus activity, and future studies will be necessary to confirm the effectiveness of such compounds against human norovirus and the molecular mechanisms through which they produce antiviral effects.