Kegg Pathway: Cholera - Diarrhea

Foodborne Pathog Dis. 2009 Nov 17;
Becker PM, Widjaja-Greefkes HC, van Wikselaar PG

Abstract Cholera, travelers' Diarrhea, or colibacillosis in pigs can possibly be prevented or attenuated by dietary provision of competitive inhibitors that react with the GM1-binding sites of the enterotoxins Cholera toxin (CT), human Escherichia coli heat-labile enterotoxin of serogroup I (LTh-I), and porcine LT-I (LTp-I). The interfering efficiency of natural substances with binding of the toxins to the gangliosid receptor GM1 was tested using a specially adapted GM1-coated-microtiter-well enzyme-linked immunosorbent assay. The substances tested for their GM1 displacing capacity were galactose-containing or -related saccharides from bovine milk, skim milk powder, galactan from gum arabic, food stabilizers as well as ground fenugreek seed and soy bean constituents that contain galactomannans, the galactopolysaccharides agar and agarose, and larch wood and other plant materials that contain arabinogalactans. Skim milk powder, compared with the pure milk saccharides tested, interfered to a higher extent with LTh-I (65-66% inhibition at 5 mg test substance/mL) and CT binding (63-67% inhibition at 5 mg test substance/mL) when supplied before or simultaneously with the toxins in the GM1-enzyme-linked immunosorbent assay. Ground fenugreek seed counteracted GM1 binding of 5 ng LTh-I/mL as well as 5 ng and 1 mug LTp-I/mL (43-65% inhibition at 5 mg test substance/mL), and 4 ng CT/mL (61-92% inhibition at 5 mg test substance/mL) very efficiently when supplied before the toxin-GM1 complex had formed. With 50 mg/mL fenugreek seed, inhibition percentages of even 92-99% were reached for LTh-I and CT binding. Efforts to resolve already bound toxin from GM1 with the test substances were less effective than preincubations and concurrent incubations.

Am J Physiol Gastrointest Liver Physiol. 2009 Nov 12;
Singla A, Dwivedi A, Saksena S, Gill RK, Alrefai WA, Ramaswamy K, Dudeja PK

Lysophosphatidic acid (LPA), a potent bioactive phospholipid, is a natural component of food products like soy and egg yolk. LPA modulates a number of epithelial functions and has been shown to inhibit Cholera toxin induced Diarrhea. Anti-Diarrheal effects of LPA are known to be mediated by inhibiting chloride secretion. However, the effects of LPA on chloride absorption in the mammalian intestine are not known. The present studies examined the effects of LPA on apical Cl(-)/OH(-) exchangers known to be involved in chloride absorption in intestinal epithelial cells. Caco-2 cells were treated with LPA and Cl(-)/OH(-) exchange activity was measured as DIDS-sensitive (36)Cl(-) uptake. Cell surface biotinylation studies were performed to evaluate the effect of LPA on cell surface levels of apical Cl(-)/OH(-) exchangers, DRA (SLC26A3) and PAT1 (SLC26A6). Treatment of Caco-2 cells with LPA (100 muM) significantly stimulated Cl(-)/OH(-) exchange activity. Specific agonist for LPA2 receptor mimicked the effects of LPA. LPA mediated stimulation of Cl(-)/OH(-) exchange activity was dependent on activation of PI3 kinase/AKT signaling pathway. Consistent with the functional activity, LPA treatment resulted in increased levels of DRA on the apical membrane. Our results demonstrate that LPA stimulates apical Cl(-)/OH(-) exchange activity and surface levels of DRA in intestinal epithelial cells. This increase in Cl(-)/OH(-) exchange may contribute to the anti-Diarrheal effects of LPA.

J Health Popul Nutr. 2009 Oct; 27(5): 646-51
Das A, Manickam P, Hutin Y, Pal BB, Chhotray GP, Kar SK, Gupte MD

In November 2003, an outbreak (41 cases; attack rate-4.3%; no deaths) of severe diarrhoea was reported from a village in Orissa, eastern India. Thirteen of these cases were hospitalized. A matched case-control study was conducted to identify the possible exposure variables. Since all wells were heavily chlorinated immediately after the outbreak, water samples were not tested. The cases were managed symptomatically. Descriptive epidemiology suggested clustering of cases around one public well. Vibrio Cholerae El Tor O1, serotype Ogawa was isolated from four of six rectal swabs. The water from the public well was associated with the outbreak (matched odds ratio: 12; 95% confidence interval 1.2-44.1). On the basis of these conclusions, access to the well was barred immediately, and it was protected. This investigation highlighted the broader use of field epidemiology methods to implement public-health actions guided by epidemiologic data to control a Cholera epidemic.

Scand J Infect Dis. 2009 Nov 2;
Khan AI, Chowdhury F, Harris JB, Larocque RC, Faruque AS, Ryan ET, Calderwood SB, Qadri F

Abstract Vibrio Cholerae O1, Ogawa and Inaba serotypes, both cause severe Cholera. We compared clinical and immunological features in patients in Bangladesh infected with these 2 serotypes. Blood was collected from hospitalized Ogawa (N=146) or Inaba (N=191) patients at the acute stage (day 2) and 5 and 19 days later. Ogawa patients were younger than Inaba, presented with shorter duration of diarrhoea, and had more frequent abdominal pain, vomiting and need for intravenous fluids (p<0.05). Inaba patients more frequently had dark-field positive stools (p<0.01). Inaba strains were more susceptible to tetracycline and erythromycin than Ogawa strains (p<0.001). Ogawa infection produced higher plasma vibriocidal as well as IgG responses to Cholera toxin B subunit, toxin-coregulated pilus subunit and lipopolysaccharide (LPS); higher IgA responses to LPS in 'antibody in lymphocyte supernatant' (ALS) specimens were also seen. These results suggest that a Cholera vaccine based on the Ogawa serotype needs to be further investigated.

Infect Immun. 2009 Oct 26;
Zhang W, Zhang C, Francis DH, Fang Y, Knudsen D, Nataro JP, Robertson DC

Enterotoxigenic Escherichia coli (ETEC) strains are a major cause of Diarrhea disease in humans and farm animals. E. coli fimbriae or colonization factor antigens (CFAs) and enterotoxins including heat-labile (LT) and heat-stable (ST) are the key virulence factors in ETEC Diarrhea. Unlike fimbriae or LT, STa has not been much included as an antigen in vaccine development against ETEC Diarrhea because of its poor immunogenicity. STa becomes immunogenic only after being coupled with a strongly immunogenic carrier protein. However, native or shorter STa antigens either had to retain toxic activity in order to become antigenic or elicited anti-STa antibodies that were not sufficiently protective. In this study, we genetically mutated porcine LT (pLT) gene for a pLT192(R-->G) toxoid and STa (pSTa) gene for three full-length pSTatoxoids [STa11(N-->K), STa12(P-->F), and STa13(A-->Q)], and used the full-length pLT192 as an adjuvant to carry the pSTatoxoid for 'pLT192:pSTa-toxoid' fusion antigens. Rabbits immunized with 'pLT192:pSTa12' or 'pLT192:pSTa13' fusion protein developed high titers of anti-LT and anti-STa antibodies. Furthermore, rabbit antiserum and antifecal antibodies were able to neutralize purified Cholera toxin (CT) and STa toxin. In addition, preliminary data suggested that suckling piglets born from a sow immunized with the 'pLT192:pSTa13' fusion antigen were protected when challenged with a STa-positive ETEC. This study demonstrated that pSTa toxoids are antigenic when fused with a pLT toxoid, and elicited anti-LT and anti-STa antibodies were protective. This fusion strategy could provide instructive information to develop effective toxoid vaccines against ETEC associated Diarrhea in animals and humans.

Infect Immun. 2009 Oct 26;
Kendall EA, Tarique AA, Hossain A, Alam MM, Arifuzzaman M, Akhtar N, Chowdhury F, Khan AI, Larocque RC, Harris JB, Ryan ET, Qadri F, Calderwood SB

Vibrio Cholerae O1 can cause severe watery Diarrhea that can be life-threatening without treatment. Infection results in long-lasting protection against subsequent disease. Development of memory B cells of the IgG and IgA isotypes to V. Cholerae O1 antigens including serotype-specific lipopolysaccharide (LPS) and the B subunit of Cholera toxin (CTB) has been demonstrated following Cholera. Memory B cells of the IgM isotype may play a role in long-term protection, particularly against T cell-independent antigens, but IgM memory has not been studied in V. Cholerae O1 infection. Therefore, we assayed acute and convalescent blood samples from 32 Cholera patients for the presence of memory B cells that produce Cholera-antigen-specific IgM antibody upon polyclonal stimulation in in vitro culture. We also examined the development of serological and antibody-secreting-cell responses following infection. Subjects developed significant IgM memory responses by day 30 after infection, both to the T-cell-independent antigen LPS and to the T-cell-dependent antigen CTB. No significant corresponding elevations in plasma IgM antibodies or circulating IgM antibody-secreting cells to CTB were detected. In 17 subjects followed to day 90 after infection, significant persistence of elevated IgM memory responses was not observed. The IgM memory response to CTB was negatively correlated with the IgG plasma antibody response to CTB, and there was a trend toward negative correlation between the IgM memory and IgA plasma antibody responses to LPS. We did not observe an association between the IgM memory response to LPS and the vibriocidal titer.

PLoS One. 2009; 4(10): e7552
Tariq M, Memon M, Jafferani A, Shoukat S, Gowani SA, Nusrat R, Riaz M, Patel J, Jamil B, Smego RA

BACKGROUND: Cholera is an important infectious cause of secretory Diarrhea. The primary symptom of infection is the sudden onset of watery Diarrhea with subsequent volume depletion causing renal insufficiency. The objective of this research is to study the level of dehydration at presentation and subsequent fluid management in patients with Cholera. METHODS: This study was conducted on 191 patients of Cholera admitted at a tertiary care hospital in Karachi, Pakistan during the period of 5 years. Medical charts were evaluated retrospectively for initial hydration status, baseline lab investigations on admission and discharge and fluid therapy given to all the patients while their stay in the hospital and the data was analyzed on SPSS 15.0. RESULTS: Out of the 191 patients, 83(43%) were males and 108 (57%) were females with mean age of 42.3 years (SD+/-18.34). The average duration of symptoms was 3.75 days (SD+/-2.04). Of 191 patients, 175 (92.1%) presented with dehydration, 80 (42.3%) were given Ringer's Lactate (R/L) + Normal Saline (N/S), 45 (24%) patients were given R/L + N/S + Oral Rehydration Therapy (ORS), 27 (14.3%) of the patients were kept on R/L only and remaining were given various combinations of R/L, N/S, ORS and Dextrose Saline (D/S). On admission mean Blood Urea Nitrogen (BUN) was 24.54 (SD+/-16.6), mean creatinine was 2.47 (SD+/-2.35) and mean BUN/Creatinine ratio was 11.63 (SD+/-5.7). CONCLUSION: Aggressive fluid rehydration remains the cornerstone of management of Cholera. Instead of presenting with a classical BUN/Creatinine ratio of >20:1, patients with pre-renal failure in Cholera may present with a BUN/Creatinine ratio of <15:1.

Clin Infect Dis. 2009 Nov 15; 49(10): 1473-9
Weil AA, Khan AI, Chowdhury F, Larocque RC, Faruque AS, Ryan ET, Calderwood SB, Qadri F, Harris JB

BACKGROUND: Multiple Vibrio Cholerae infections in the same household are common. The objective of this study was to examine the incidence of V. Cholerae infection and associated clinical symptoms in household contacts of patients with Cholera and to identify risk factors for development of severe dehydration in this cohort. METHODS: Household contacts of hospitalized patients with Cholera were observed with frequent clinical assessments and collection of serum and rectal swab samples for culture for a period of 21 days after presentation of the index case. RESULTS: One-half (460 of 944) of all contacts reported Diarrhea during the study period, and symptoms most frequently began 2 days after presentation of the index case. Antibiotics were used by 199 (43%) of 460 contacts with Diarrhea. Results of rectal swab cultures for V. Cholerae were positive for 202 (21%) of 944 contacts, and 148 (73%) infected contacts experienced Diarrhea. Significant dehydration developed in 26 contacts; predictors of dehydration included vomiting, each additional day of Diarrhea, and blood group O status. CONCLUSIONS: In urban Bangladesh, the burden of Diarrheal illness among household contacts of patients with Cholera is higher than was previously estimated, and prophylactic intervention is feasible, because the majority of symptomatic cases of V. Cholerae infection in contacts begin soon after presentation of the index case. Re-evaluation of targeted chemoprophylaxis for household contacts of patients with Cholera may be warranted.

Lancet. 2009 Nov 14; 374(9702): 1694-702
Sur D, Lopez AL, Kanungo S, Paisley A, Manna B, Ali M, Niyogi SK, Park JK, Sarkar B, Puri MK, Kim DR, Deen JL, Holmgren J, Carbis R, Rao R, Nguyen TV, Donner A, Ganguly NK, Nair GB, Bhattacharya SK, Clemens JD

BACKGROUND: Oral Cholera vaccines consisting of killed whole cells have been available for many years, but they have not been used extensively in populations with endemic disease. An inexpensive, locally produced oral killed-whole-cell vaccine has been used in high-risk areas in Vietnam. To expand the use of this vaccine, it was modified to comply with WHO standards. We assessed the efficacy and safety of this modified vaccine in a population with endemic Cholera. METHODS: In this double-blind trial, 107 774 non-pregnant residents of Kolkata, India, aged 1 year or older, were cluster-randomised by dwelling to receive two doses of either modified killed-whole-cell Cholera vaccine (n=52 212; 1966 clusters) or heat-killed Escherichia coli K12 placebo (n=55 562; 1967 clusters), both delivered orally. Randomisation was done by computer-generated sequence in blocks of four. The primary endpoint was prevention of episodes of culture-confirmed Vibrio Cholerae O1 diarrhoea severe enough for the patient to seek treatment in a health-care facility. We undertook an interim, per-protocol analysis at 2 years of follow-up that included individuals who received two completely ingested doses of vaccine or placebo. We assessed first episodes of Cholera that occurred between 14 days and 730 days after receipt of the second dose. This study is registered with ClinicalTrials.gov, number NCT00289224. FINDINGS: 31 932 participants assigned to vaccine (1721 clusters) and 34 968 assigned to placebo (1757 clusters) received two doses of study treatment. There were 20 episodes of Cholera in the vaccine group and 68 episodes in the placebo group (protective efficacy 67%; one-tailed 99% CI, lower bound 35%, p<0.0001). The vaccine protected individuals in age-groups 1.0-4.9 years, 5.0-14.9 years, and 15 years and older, and protective efficacy did not differ significantly between age-groups (p=0.28). We recorded no vaccine-related serious adverse events. INTERPRETATION: This modified killed-whole-cell oral vaccine, compliant with WHO standards, is safe, provides protection against clinically significant Cholera in an endemic setting, and can be used in children aged 1.0-4.9 years, who are at highest risk of developing Cholera in endemic settings. FUNDING: Bill & Melinda Gates Foundation, Swedish International Development Cooperation Agency, Governments of South Korea, Sweden, and Kuwait.

Int J Infect Dis. 2009 Sep 23;
Pal BB, Khuntia HK, Samal SK, Kar SK, Patnaik B

BACKGROUND: We investigated the epidemic of Cholera that occurred in Kashipur and Dasmantpur blocks of Orissa, reported during July-September 2007. METHODS: Sixty-two rectal swabs and 28 water samples collected from Diarrhea patients at different hospitals and villages were bacteriologically analyzed for the identification, antibiogram, and detection of toxic genes of Vibrio Cholerae. RESULTS: The Cholera outbreaks were caused by V. Cholerae O1 Ogawa biotype El Tor in both Kashipur and Dasmantpur blocks. All the V. Cholerae isolates from the clinical and environmental samples were sensitive to tetracycline, gentamicin, azithromycin, and chloramphenicol, but were resistant to ampicillin, ciprofloxacin, norfloxacin, co-trimoxazole, nalidixic acid, neomycin, and furazolidone, except the water isolates, which were sensitive to ciprofloxacin and norfloxacin. The multiplex PCR assay revealed that all the clinical and environmental V. Cholerae isolates were positive for the ctxA and tcpA genes, showing biotype El Tor. Interestingly, 88% of the clinical and environmental isolates of V. Cholerae were El Tor biotype with mutation at the ctxB gene of the classical strain, as confirmed by mismatch amplification of mutation (MAMA)-PCR assay. CONCLUSIONS: This is the first report of the El Tor variant of V. Cholerae O1 Ogawa having the ctxB gene of the classical strain with altered antibiogram causing epidemics of Cholera in Orissa, India.

J Ethnopharmacol. 2009 Sep 23;
Velázquez C, Calzada F, Esquivel B, Barbosa E, Calzada S

ETHNOPHARMACOLOGICAL RELEVANCE: The flowers of Chiranthodendron pentadactylon Larreat. (Sterculiaceae) has been traditionally used as folk medicine in Mexico for the treatment of gastrointestinal disorders such as Diarrhea and dysentery. AIM OF THE STUDY: This study aimed to assess the antisecretory activity which supports the therapeutic use of Chiranthodendron pentadactylon and its flavonoids to treat Diarrhea. MATERIALS AND METHODS: The methanol extract of Chiranthodendron pentadactylon, subsequent fractions, and flavonoids were evaluated on Cholera toxin-induced intestinal secretion in rat jejunal loops model. RESULTS: Three antisecretory flavonoids were isolated by bioassay-guided purification, namely, isoquercitrin 3, (+)-catechin 4 and (-)-epicatechin 5. Among them, epicatechin exhibited the most potent antisecretory activity with ID(50) of 8.3muM/kg. Its potency was close that of to loperamide (ID(50) 6.1muM/kg), drug used as control. Isoquercitrin (ID(50) 19.2muM/kg) and catechin (ID(50) 51.7muM/kg) showed moderate and weak activity, respectively. CONCLUSION: The results of the present study lend some support to the anecdotal report for the traditional use of the flowers of Chiranthodendron pentadactylon in the control of dysentery.

Appl Environ Microbiol. 2009 Nov; 75(22): 6981-5
Huang J, Zhu Y, Wen H, Zhang J, Huang S, Niu J, Li Q

Vibrio Cholerae is a natural inhabitant of the aquatic environment. However, its toxigenic strains can cause potentially life-threatening Diarrhea. A quadruplex real-time PCR assay targeting four genes, the Cholera toxin gene (ctxA), the hemolysin gene (hlyA), O1-specific rfb, and O139-specific rfb, was developed for detection and differentiation of O1, O139, and non-O1, non-O139 strains and for prediction of their toxigenic potential. The specificity of the assay was 100% when tested against 70 strains of V. Cholerae and 31 strains of non-V. Cholerae organisms. The analytical sensitivity for detection of toxigenic V. Cholerae O1 and O139 was 2 CFU per reaction with cells from pure culture. When the assay was tested with inoculated water from bullfrog feeding ponds, 10 CFU/ml could reliably be detected after culture for 3 h. The assay was more sensitive than the immunochromatographic assay and culture method when tested against 89 bullfrog samples and 68 water samples from bullfrog feeding ponds. The applicability of this assay was confirmed in a case study involving 15 bullfrog samples, from which two mixtures of nontoxigenic O1 and toxigenic non-O1/non-O139 strains were detected and differentiated. These data indicate that the quadruplex real-time PCR assay can both rapidly and accurately detect/identify V. Cholerae and reliably predict the toxigenic potential of strains detected.

Waste Manag Res. 2009 Sep 11;
Vuai SA

The spread of municipal solid waste (MSW) in Zanzibar municipality has been associated with environmental pollution, unpleasant city conditions, contamination of water sources and coastal areas together with harbouring of malaria vectors. The contamination has a close relationship with eruption of diarrhoea, Cholera and typhoid which claim the lives of the residents. Most of the wastes are of domestic and market origin and have the potential for compost production. This study examined the possibility of composting MSW from Zanzibar municipality as an alternative way of SW management and assessed the nutrient contents of the compost for application in agricultural production. Two major classes of SW were selected for the study: municipal solid waste and rice milling by-products. The samples were composted aerobically and anaerobically. The results showed that aerobic composting reduced about 60% of the waste volume. This volume reduction suggests that composting can be a promising SW management technique by reducing the large demand of space for landfilling. Municipal solid waste composted under anaerobic conditions produced compost with relatively higher concentrations of dissolved species than that produced under aerobic conditions. The trace metal contents were higher in MSW than in rice milling by-products. It was found that the unmanaged compost collected from the dumping site had low nutrient contents and was enriched with trace metals. Generally, physico-chemical characteristics, nutrients and trace metal levels suggest that Zanzibar municipal solid waste can produce high-quality compost for application to a wide range of soil types to improve their fertility, under proper management.

J Hazard Mater. 2009 Dec 30; 172(2-3): 1229-35
Chowdhury AN, Azam MS, Aktaruzzaman M, Rahim A

Mn(3)O(4) nanoparticles with diameter ca. 10nm were synthesized by the forced hydrolysis of Mn(II) acetate at 80 degrees C. The X-ray diffraction (XRD), Fourier transform infra red (FT-IR) spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques were employed to study structural features and chemical composition of the nanoparticles. The unique oxidative activity of the Mn(3)O(4) nanoparticles was demonstrated in the polymerization and dye degradation reactions. On adding Mn(3)O(4) suspension to an acidic solution of aniline, yielded immediately green sediment of polyaniline (PANI). The organic dyes, viz., methylene blue (MB) and procion red (PR) were found to be completely decolorized from their aqueous solution on treating the dyes with Mn(3)O(4) suspension in acidic media. The Mn(3)O(4) nanoparticles also showed a clear antibacterial activity against the Vibrio Cholerae, Shigella sp., Salmonella sp., and Escherichi coli bacteria that cause Cholera, dysentery, typhoid, and Diarrhea diseases, respectively.

Parasitol Int. 2009 Dec; 58(4): 424-37
Corrêa G, Vilela R, Menna-Barreto RF, Midlej V, Benchimol M

Giardia lamblia is a protozoan that parasitizes the small intestine of vertebrates. It is a cause of intestinal infection and Diarrhea and infects millions of people worldwide. This protozoan presents many characteristics common to eukaryotic cells but it lacks organelles found in most eukaryotes (e.g., peroxisomes, typical Golgi complex and mitochondria). Also it presents mitosomes, a relic organelle that appears to be a mitochondrial remnant. Cell death in Giardia was induced by the drug beta-Lapachone and by starvation. Giardia behavior was followed by scanning, transmission and fluorescence microscopy, quantification of cell metabolism using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide), changes in lipid rafts, using DiIC(16) and Cholera toxin. Cell shrinkage, chromatin condensation, membrane blebbing and vacuolization provided ultrastructural evidence of apoptosis, whereas the myelinic figures in large vacuoles and LC-3 staining suggested an autophagic process. Lipids rafts were altered by drug treatment and co-localized with regions containing membrane blebbing. The treatment with beta-Lap induced encystation. A search for sequence similarities in databases and protein alignments was carried out. Although Giardia is an amitochondrial organism, it presented some autophagic-like cell death characteristics and several, but not all, apoptotic characteristics, induced by beta-Lapachone and starvation.

Indian J Gastroenterol. 2009 Mar-Apr; 28(2): 62-4
Bhunia R, Ramakrishnan R, Hutin Y, Gupte MD

Outbreaks of Cholera are common in West Bengal. In April 2006, Garulia municipality reported a cluster of Diarrhea cases. We investigated this cluster to identify the etiological agent, source of transmission and propose control measures. We defined a case of Diarrhea as occurrence of > or =3 loose/watery stools a day among the residents of Garulia since April 2006. We searched for cases of Diarrhea in health care facilities and health camp. We conducted a gender- and age-matched case-control study to identify risk factors. We inspected the sanitation and water supply system. We collected rectal swabs from Diarrhea patients and water specimens from the affected areas for laboratory investigation. Two hundred and ninety-eight cases of Diarrhea were reported to various health care facilities (attack rate: 3.5/1000, no deaths). The attack rate was highest among children (6.4/1000). Vibrio Cholerae El Tor O1 Inaba was isolated from two of 7 rectal swabs. The outbreak started on 10 April 2006, peaked on 26 April and lasted till 6 May. Cases clustered in an area distal to leaking water pipelines. Drinking municipal water exclusively was significantly associated with the illness (OR 13, 95% CI=6.5-27). Eight of the 12 water specimens from the affected area had fecal contamination and poor chlorine content. This outbreak was due to a contaminated municipal piped water supply and V. Cholera 01 Inaba was possibly the causative organism.

Clin Exp Allergy. 2009 Aug 18;
Perrier C, Thierry AC, Mercenier A, Corthésy B

Summary Background Food allergy has reached an epidemic level in westernized countries and although central mechanisms have been described, the variability associated with genetic diversity underscores the still unresolved complexity of these disorders. Objective To develop models of food allergy and oral tolerance, both strictly induced by the intestinal route, and to compare antigen-specific responses. Methods BALB/c mice were mucosally sensitized to ovalbumin (OVA) in the presence of the mucosal adjuvant Cholera toxin, or tolerized by intra-gastric administrations of OVA alone. Antibody titres and cytokines were determined by ELISA, and allergic status was determined through several physiologic parameters including decline in temperature, diarrhoea, mast cell degranulation and intestinal permeability. Results OVA-specific antibodies (IgE, IgGs and IgA in serum and feces) were produced in sensitized mice exclusively. Upon intra-gastric challenge with OVA, sensitized mice developed anaphylactic reactions associated with a decline of temperature, diarrhoea, degranulation of mast cells, which were only moderately recruited in the small intestine, and increased intestinal permeability. Cytokines produced by immune cells from sensitized mice included T-helper type 2 cytokines (IL-5, IL-13), but also IL-10, IFN-gamma and IL-17. In contrast, all markers of allergy were totally absent in tolerized animals, and yet the latter were protected from subsequent sensitization, demonstrating that oral tolerance took place efficiently. Conclusion This work allows for the first time an appropriate comparison between sensitized and tolerized BALB/c mice towards OVA. It highlights important differences from other models of allergy, and thus questions some of the generally accepted notions of allergic reactions, such as the protective role of IFN-gamma, the importance of antigen-specific secretory IgA and the role of mucosal mast cells in intestinal anaphylaxis. In addition, it suggests that IL-17 might be an effector cytokine in food allergy. Finally, it demonstrates that intestinal permeability towards the allergen is increased during challenge.

Neurogastroenterol Motil. 2009 Aug 2;
Sarker P, Bhuiyan TR, Qadri F, Alam NH, Wretlind B, Bishop AE, Mathan M, Agerberth B, Andersson J, Raqib R

We aimed to evaluate the changes of nerve morphology and distribution of neurotransmitters and neuropeptides in the rectum of Shigella flexneri-infected patients and in the duodenum of Vibrio Cholerae O1-infected patients. Nerve morphology was observed by transmission electron microscopy. Immunoreactivity of nerve growth factor (NGF), neurotransmitters and neuropeptides in tissues were studied by immunohistochemistry. Ultrastructural analysis of intestinal biopsy revealed persisting axons degeneration throughout the study period in all patients. Regeneration was already evident at the acute stage with marked increase at late convalescence. Both acute shigellosis and Cholera were accompanied by increased expression of NGF and histamine and decreased expression of serotonin that was restored at convalescence. Immunoreactivity of vasoactive intestinal peptide (VIP) was increased during acute Cholera, whereas in shigellosis VIP- and substance P-immunoreactive nerves appeared at early convalescence. Both shigellosis and Cholera induced long-lasting degeneration of enteric neuronal axons, despite the presence of ongoing proliferation and regeneration processes. Neurotransmitters and neuropeptides may play differential roles in invasive and watery diarrhoea.

Curr Opin Infect Dis. 2009 Oct; 22(5): 471-6
Flores J, Okhuysen PC

PURPOSE OF REVIEW: This review examines recent developments in human genetic susceptibility to enteropathogens that cause infectious Diarrhea. RECENT FINDINGS: The affinity of specific norovirus genogroups to different histoblood group antigens (HBGAs) on secretor cells has been studied in different epidemiologic studies. HBGAs are also used as receptors by Vibrio Cholerae with different degrees of affinity between biotypes. Polymorphisms in the CD14, lactoferrin and osteoprotegerin promoter genes were associated to Diarrhea in travelers. Single nucleotide polymorphisms in the IL-8 genes are also associated to increased risk for enteroaggregative Escherichia coli and Clostridium difficile infection. IL-10 haplotypes were associated to enterotoxigenic E. coli associated Diarrhea in exposed individuals. A family-based study showed a significant association of the LPLUNC1 gene and Cholera. The major histocompatibility complex class II antigens are associated to different degrees of susceptibility and resistance to Salmonella, Cryptosporidium and Entamoeba infection. SUMMARY: Variants in genes that encode molecules that mediate attachment, pathogen recognition, inflammatory cytokine response, innate and acquired immunity are being identified as determinants of host genetic susceptibility to infectious Diarrhea.

Expert Rev Vaccines. 2009 Aug; 8(8): 1083-97
Yuki Y, Kiyono H

Mucosal vaccines are considered the most suitable type of vaccines to combat emerging and re-emerging infectious diseases because of their ability to induce both mucosal and systemic immunity. Considerable advances have been made toward the development of mucosal vaccines against influenza virus and rotavirus. Many additional mucosal vaccines are in development, including vaccines against Cholera, typhoid, traveler's Diarrhea and respiratory infections. In addition to oral and nasal vaccines, transcutaneous (or skin patch) and sublingual immunizations are now part of a new generation of mucosal vaccines. Furthermore, a rice-based oral vaccine (MucoRice) has been receiving global attention as a new form of cold chain-free vaccine, because it is stable at room temperature for a prolonged period. This review describes recent developments in mucosal vaccines with promising preclinical and clinical results.