published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Gastroenteritis in the form of diarrhea and vomiting is common in human and is mostly caused by viral infection. As the significant proportion of gastrointestinal infections are still not diagnosed, novel viruses are suggested to be the causative agents of unknown gastroenteritis. Novel and emerging picornaviruses, including human parechovirus (HPeV), Aichi virus (AiV) and salivirus (SalV) are suggested to play an important role in acute gastroenteritis. Since little was known about the molecular and clinical epidemiology of these viruses, the present study aims to investigate the presence of HPeV, AiV and SalV in fecal samples of children with acute gastroenteritis in Hong Kong. Retrospective and prospective studies were performed using fecal samples from pediatric patients hospitalized for acute gastroenteritis from November 2004 to August 2005, August 2006 to October 2006 and September 2012 to August 2013. Among 1708 fecal samples subjected to RT-PCR using primers targeted to 5’NCR of picornaviruses, viruses were detected in 57 samples, with 47 patients (2.8%) positive for HPeVs, three patients (0.18%) positive for AiV and one patient (0.1%) positive for SalV. Phylogenetic analysis of the partial VP1 capsid gene of the 33 HPeV strains revealed the presence of genotypes of HPeV- 1, 3, 4, 5, 7, 10, among which HPeV1 was the predominant genotype circulating in our population. The peak activity of HPeV infection was in autumn. Of the three children with AiV detected in fecal samples, phylogenetic analysis of the partial VP1 and 3CD regions indicated the three AiV strains from fecal samples belonged to the AiV genotype A. Co-detection of different pathogens was noted in 6 samples (10.5%) of 57 stool samples positive for picornaviruses. Among the five samples with HPeV, co-detection with HBoV, AiV, SalV and Aeromonas were observed. In one sample with AiV, picobirnavirus was identified. In conclusion, HPeV, AiV and SalV were found to be present in fecal samples of Hong Kong children with gastroenteritis, with HPeV being the most common virus detected. Routine screening for these viruses in young children with gastroenteritis may better define their epidemiology and help prevent their transmission. / published_or_final_version / Microbiology / Master / Master of Medical Sciences

Salmonella infections remain one of the most common food borne diseases worldwide. Gastroenteritis, which can be caused by many non-typhoidal Salmonella (NTS) serovars, is relatively common in North America. One of the main risk factors of NTS gastroenteritis is travel to endemic areas in the developing world. The current treatment of NTS infections with antibiotics is reserved for severe cases. A growing concern with antibiotic use is that clinical isolates are becoming drug resistant. Although most NTS infections are self-limiting in nature, the burden on the body and recovery can take several months. Thus, it is vital to prevent NTS infections rather than solely rely on treatment. We have previously discovered two novel surface associated polysaccharides in Salmonella: O-Antigen capsule and X-factor. Not only O-Antigen Capsule is considered a common surface antigen, but its’ genes were found to be expressed during in vivo infections in mice. Such an antigen would be a suitable candidate in developing a vaccine against Salmonella induced gastroenteritis. The goal of this research was to evaluate the use of O-Antigen capsule to develop a traveler’s vaccine for NTS associated gastroenteritis. Results and Conclusions: We have developed a purification protocol and purified the capsule and X-factor from Salmonella Typhimurium, Enteritidis, and Heidelberg. Lipopolysaccharide (LPS) was co-isolated with O-Antigen capsule, but removed using Triton extraction. Salmonella LPS is strain-specific and an adaptive immune response against LPS will not provide cross-protection. We generated specific immune sera in rabbits to recognize O-Antigen capsule and X-factor produced by Salmonella Typhimurium and Enteritidis. We used a mouse model to determine the immunization dose of O-Antigen capsule and showed that conjugation is necessary to enhance the immune response in mice. To boost capsule production, we analyzed PyihUTSRQPO activity using a luciferase-based reporter system. Deletion of a putative transcriptional repressor (YihW) resulted in over 100-fold increase in PyihUTSRQPO confirming YihW as a repressor. We have also looked at the effect of growth media, temperature, and sugar precursors on PyihUTSRQPO activity, and were able to show that PyihUTSRQPO has highest activity in Tryptone broth at 30oC in the absence of any additional sugars.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

Thesis (MSc (Veterinary Tropical Diseases, Veterinary Science))--University of Pretoria, 2008. / Includes bibliographical references. Also available in print format.

京都大学 / 新制・論文博士 / 博士(社会健康医学) / 乙第13455号 / 論社医博第17号 / 新制||社医||11(附属図書館) / 京都大学大学院医学研究科社会健康医学系専攻 / (主査)教授 長尾 美紀, 教授 近藤 尚己, 教授 中川 一路 / 学位規則第4条第2項該当 / Doctor of Public Health / Kyoto University / DFAM

Norovirus Gastroenteritis Leading to Partial Small Bowel Obstruction David Berry DO, Arthur Cecchini DO, Koushik Sanku MD, Bhavesh Gajjar MD Berrydw@etsu.edu, Cecchini@etsu.edu, Sankuk@etsu.edu, Gajjarb@etsu.edu Department of Internal Medicine, Quillen College of Medicine, East Tennessee State University BACKGROUND Acute gastroenteritis (AGE) is a common problem in both inpatient and outpatient settings. Most cases are viral in origin, with norovirus being the most cited. Typical symptoms include low-grade fever, chills, nausea, vomiting, and abdominal discomfort. The physical examination is usually unremarkable, but abdominal tenderness or signs of volume depletion may be present in severe disease. Most patients have spontaneous remission within a few days and do not require hospitalization or diagnostic evaluation. Laboratory evaluation is often helpful in severe disease, immunocompromised patients, or when bloody or mucoid diarrhea is present. Polymerase chain reaction (PCR) gastrointestinal multiplex testing is often the preferred evaluation as it has a high sensitivity, specificity, and turnaround time when compared to traditional stool studies of enzyme-immunoassay studies. Treatment is often supportive, but specific bacterial and parasitic pathogens should prompt treatment with antimicrobial therapy. CASE PRESENTATION This case presents a 47-year-old male with no known previous medical history or history of intraabdominal surgeries. He presented with four days of progressive nausea, vomiting, diarrhea, and abdominal discomfort. The physical examination revealed a distended and tender abdomen. The metabolic panel did not show any electrolyte derangements. Computed tomography with intravenous contrast revealed partial small bowel obstruction versus less likely ileus. Gastrointestinal pathogen PCR returned positive for norovirus. The patient was given intravenous fluid, nausea control, and pain control, his diet was advanced, and his symptoms subsequently resolved. We believe this case to be unusual, as most cases of viral gastroenteritis are uncomplicated, and this patient presented with radiographic evidence of ileus versus partial small bowel obstruction. PCR testing revealed positivity for norovirus. He had no previous abdominal surgeries or family history of early intestinal malignancies, and the symptoms spontaneously resolved with several days of conservative management, making another etiology much less likely. CONCLUSION AGE is a common diagnosis seen in the primary care clinic, and most patients have an uneventful recovery. However, suspicion of partial obstruction or intestinal ileus should arise when severe abdominal pain and prolonged vomiting are present.

No description available.

High levels of fecal indicator bacteria (e.g. E. coli) are the leading cause of identified surface water impairments in the United States. The US Clean Water Act of 1972 requires that jurisdictions establish priority rankings for impaired waterways and develop a Total Maximum Daily Load (TMDL) plan for each. Although past research indicates that the risk of illness to humans varies by source of fecal contamination, current watershed assessments are developed according to total concentration of indicator bacteria, with all sources weighed equally. A stochastic model using Quantitative Microbial Risk assessment (QMRA) principles to translate source-specific (e.g. human, livestock) daily average concentrations of E.coli into a daily average risk of gastroenteritis infection was developed and applied to Pigg River, an impaired watershed in southern Virginia. Exposure was calculated by multiplying a ratio of source related reference pathogens to predicted concentrations of E.coli and a series of qualifying scalars. Risk of infection was then determined using appropriate dose response relationships. Overall, human and goose sources resulted in the greatest human health risk, despite larger overall E.coli loading associated with cattle. Bacterial load reductions specified in the Pigg River TMDL were applied using Hydrological Simulation Program- FORTRAN (HSPF) to assess the effect these reductions would have on the risk of infection attributed to each modeled bacterial source. Although individual risk sources (neglecting geese) were reduced below the EPA limit of 8 illnesses per 1000 exposures, the combined risk of illness varied between 0.006 and 64 illnesses per 1000 exposures. / Master of Science

<p>Uvod: Virusni gastrointestinalni sindrom je aktuelni zdravstveni problem u celom svetu. To važi kako u razvijenim zemljama, tako i u zemljama u razvoju, a posebno u nerazvijenim zemljama, gde je drugi po redu uzrok mortaliteta. Nagli početak bolesti, praćen pojavom velikog broja tečnih stolica, mukom, povraćanjem, bolovima u stomaku, temperaturom, malaksalo&scaron;ću, ima za posledicu dehidrataciju. U svim starosnim grupama obolelih, a naročito kod sasvim male dece, starih i imunodeficitarnih osoba može da dođe do smrtnog ishoda, ukoliko se brzo ne postavi tačna etiolo&scaron;ka dijagnoza bolesti i ne pristupi se odmah nadoknadi vode i elektrolita, kao i primeni svih ostalih mera simptomatske terapije. Brzo postavljena tačna dijagnoza, &scaron;to se najbolje postiže real-time PCR testom, sprečava pojavu komplikacija, pa i fatalnog ishoda bolesti. Istovremeno, omogućava primenu odgovarajućih epidemiolo&scaron;kih mera da se spreči nastanak epidemija i njihovo &scaron;irenje. Cilj ovog istraživanja bio je da se tačno utvrdi incidenca virusnog gastrointestinalnog sindroma u Vojvodini i učestalost pojave epidemijskog i sporadičnog javljanja ove bolesti. Cilj je bio i postavljanje algoritma za primenu real-time PCR testa u dijagnostici virusnog gastrointestinalnog sindroma u budućem radu. Isto tako, cilj je bio da se molekularnom analizom, sekvenciranjem delova genoma pozitivnih uzoraka stolice, izvr&scaron;i genetska tipizacija i odredi filogenetska pripadnost virusa. Materijal i metode: Tokom petogodi&scaron;njeg istraživanja molekularnim real-time PCR testom pregledane su 1003 obolele osobe sa simptomima virusnog dijarealnog sindroma, starosti od mesec dana do preko 90 godina. Pregledani su na rota, noro, astro i enterične adenoviruse. Na osnovu podataka iz anketnih upitnika i istorija bolesti, detaljno su analizirani svi klinički pokazatelji (javljanje bolesti tokom godine, trajanje bolesti, simptomi). Procena težine kliničke slike vr&scaron;ena je prema Vesikari skali. Svi podaci su upoređivani prema vrsti virusnog uzročnika, prema starosti obolelih, godinama trajanja istraživanja i epidemijskom i sporadičnom javljanju oboljenja. Dobijeni podaci su statistički obrađeni, tabelarno i grafički prikazani. Rezultati: U petogodi&scaron;njem periodu real-time PCR testom pregledan je uzorak od 1003 obolele osobe različite starosti na 4 virusna uzročnika dijarealnog sindroma (rota, noro, astro i enterične adenoviruse). Virusni dijarealni sindrom dokazan je kod 709 obolelih (70,69%). Najče&scaron;će su dokazane rotavirusne infekcije u 28,81%. Statistički značajno najče&scaron;će rotavirusi su bili utvrđeni kod dece do 5 godina (38,90%), ali u visokom procentu i kod dece uzrasta 6 do 14 godina (24,83%). Deca mlađa od 5 godina imala su statistički značajno najtežu kliničku sliku, bila su če&scaron;će hospitalizovana i imala su statistički značajno vi&scaron;u temperaturu. Pored vi&scaron;e temperature kod obolelih od rotavirusa, klinička slika je kod ovih bolesnika bila teža i bolest je duže trajala nego kod obolelih od drugih virusa. Norovirusna infekcija je dokazana u 23,03% obolelih i to statistički značajno če&scaron;će kod odraslih osoba, starijih od 20 godina. Od kliničkih simptoma kod ovih bolesnika statistički značajno če&scaron;će su dokazani muka, povraćanje i bolovi u stomaku, nego kod obolelih od drugih virusa. Norovirusi su značajno če&scaron;će bili uzročnici epidemijskog javljanja bolesti. Astrovirus je dokazan kod znatno manjeg broja obolelih (u 2,29%) i to samo kod dece do 5 godina i dece uzrasta 6 do 14 godina. Infekcija izazvana enteričnim adenovirusima dokazana je kod 13,36% bolesnika. Njače&scaron;će je utvrđena kod dece uzrsta do 5 godina i 6 do 14 godina. Oboleli od adenovirusa imali su statistički značajno blažu kliničku sliku bolesti. Dva virusna uzročnika u uzorku stolice dokazana su u 3,19% osoba, obično u toku epidemijskog javljanja bolesti. Ovi bolesnici su imali bitno težu kliničku sliku. Najvi&scaron;e obolelih od dijarealnog sindroma bilo je u hladnim mesecima, mada su dijagnostikovani i tokom cele godine. U petogodi&scaron;njem periodu utvrđene su 22 epidemije u kolektivima i 9 porodičnih epidemija. Epidemijsko javljanje bolesti bilo je statistički značajno najče&scaron;će kod najstarijih bolesnika (starijih od 50 godina), a sporadično javljanje bilo je statističko značajno najče&scaron;će kod dece. U cilju potvrde tačnosti dijagnostike virusa u ispitivanim uzorcima real-time PCR testom, genotipizacije, kao i detaljnije molekularne analize, izabrani su reprezentativni uzorci pozitivni na rota, noro, astro ili adenoviruse. Delovi genoma ovih uzoraka su amplifikovani, a zatim sekvencirani. Sekvencirani izolati rotavirusa pripadali su grupi A i tipovima G1P[8], G2P[4], G3P[8] i G9P[8]. Sekvencirani izolati norovirusa pripadali su genogrupi I tipu 2, zatim genogrupi II tipovima 1, 2, 4 i 17. Sekvencirani izolati astrovirusa pripadali su grupi klasičnih astrovirusa i tipovima 1, 4 i 5. Sekvencirani izolati adenovirusa pripadali su grupi F i tipovima 40 i 41, kao i grupi C tipu 2. Pripadnost dobijenih sekvenci u ovom istraživanju, dodatno je potvrđena izradom filogenetskog stabla za sekvence pozitivne na rota, noro, astro ili adenoviruse. Zaključak: Incidenca virusnog dijarealnog sindroma u Vojvodini (70,69%) vrlo je visoka i vi&scaron;a je nego &scaron;to je bilo pretpostavljeno prilikom prijave teze (u hipotezi). Real-time PCR test treba da bude redovno kori&scaron;ćen u budućem dijagnostičkom radu, jer dovodi do brze dijagnostike, čak i ako su virusi prisutni u malom broju u uzorcima tečnih stolica, &scaron;to je utvrđeno tokom ovog dijagnostičkog rada. Ispitivani virusi treba da budu redovno dijagnostikovani kod obolelih od dijarealnog sindroma i to u svim starosnim grupama, tokom epidemijskog i sporadičnog javljanja oboljenja.</p> / <p>Introduction: Viral gastrointestinal syndrome is a current ongoing health problem worldwide. This is true of both developed and developing countries, especially underdeveloped ones where it is the second leading cause of mortality. Sudden onset of the disease&mdash;accompanied by the occurrence of large numbers of liquid stools, nausea, vomiting, abdominal pain, fever, and exhaustion&mdash;leads to dehydration. A fatal outcome can occur in all age groups of patients, especially very young children, the elderly, and the immuno-deficient, unless an accurate etiological diagnosis of the disease is quickly established, followed by a prompt institution of fluid and electrolyte placement, and implementation of other symptomatic therapy measures. Quick establishment of an accurate diagnosis, which is best achieved using the real-time PCR test, prevents the onset of complications, including a potentially fatal outcome of the disease. Simultaneously, it enables the implementation of appropriate epidemiological measures to prevent epidemic outbreaks and their spread. The aim of this study was to accurately determine the incidence of viral gastrointestinal syndrome in Vojvodina and the frequency of epidemic and sporadic occurrence of this disease. The aim was also to set up an algorithm for the application of the real-time PCR test in diagnostics of viral gastrointestinal syndrome in future work. Likewise, the aim was to carry out genetic typing and determine phylogenetic affiliation of the virus using molecular analysis and sequencing of parts of genomes from positive stool samples. Material and Methods: During a five-year study, 1003 patients with symptoms of viral diarrheal syndrome, aged from one month to more than 90 years old, were examined using molecular real-time PCR test. They were screened for rota, noro, astro, and enteric adenoviruses. Based on the data from survey questionnaires and medical case history, all clinical indicators were meticulously analyzed (disease occurrence during the year, disease duration, symptoms). The assessment of the clinical severity was carried out according to the Vesikari Clinical Severity Scoring scale. All data were compared according to the type of the viral causing agent, age of the patients, duration of research in years, and epidemic and sporadic occurrence of the disease. Obtained data were statistically analyzed, tabulated, and graphically displayed. Results: In a five-year period, a sample of 1003 patients of different ages was screened for four different viral causing agents of diarrheal syndrome (rota, noro, astro, and enteric adenoviruses) using the real-time PCR test. Viral diarrheal syndrome was confirmed in 709 patients (70.69%). The most commonly found were rotavirus infections in 28.81% of the cases. Rotaviruses were statistically significantly most common in children younger than 5 years old (38.90%), but were also found in high percentage in children aged 6-14 years old (24.83%). Children under 5 years of age had statistically significantly highest clinical severity and fever, and were more frequently hospitalized. In addition to higher fever in patients with rotavirus, clinical severity in these patients was also higher, and the disease lasted longer than in patients with other viruses. Norovirus infections were reported in 23.03% of the subjects, statistically significantly more frequently in adults over 20 years of age. Regarding the clinical symptoms in these patients, nausea, vomiting, and abdominal pain were statistically significantly more common than in patients with other viruses. Noroviruses were significantly more common as causing agents of epidemic disease outbreaks. Astrovirus was found in a significantly smaller number of patients (in 2.29%), and only in children under 5 years of age and children aged 6-14 years old. Enteric adenovirus infections were reported in 13.36% of the subjects. They were most commonly found in children younger than 5, and those aged 6- 14 years old. Adenovirus sufferers had statistically significantly milder clinical disease. Two viral causing agents in the stool sample were found in 3.19% of the subjects, usually during an epidemic disease outbreak. These patients had a significantly more severe clinical disease. Highest numbers of sufferers from diarrheal syndrome occurred during the cold months, although they were diagnosed throughout the year. In a five-year period, 22epidemics in collective groups and 9 family epidemics were identified. Epidemic outbreaks of the disease were statistically significantly most frequent in the elderly patients (older than 50), while sporadic occurrences were statistically significantly most frequent in children. Representative samples positive for rota, noro, astro, or adenoviruses were selected in order to confirm the accuracy of virus diagnostics in samples tested by the real-time PCR test, and perform genotyping as well as more detailed molecular analyses. Parts of the genomes of these samples were amplified and then sequenced. Sequenced rotavirus isolates belonged to group A and types G1P[8], G2P[4], G3P[8], and G9P[8]. Sequenced norovirus isolates belonged to genogroup I type 2, and genogroup II types 1, 2, 4, and 17. Sequenced astrovirus isolates belonged to the group of classical astroviruses and types 1, 4, and 5. Sequenced adenovirus isolates belonged to group F and types 40 and 41, as well as group C type 2. The affiliation of the obtained sequences in this study was further confirmed by creating a phylogenetic tree for sequences positive for rota, noro, astro, or adenoviruses. Conclusion: The incidence of viral diarrheal syndrome in Vojvodina (70.69%) is very high&mdash;higher than what was assumed at the time of the thesis submission (in the hypothesis). The real-time PCR test should be regularly used in future diagnostic work, since it leads to rapid diagnostics even if viruses are present in small numbers in liquid stool samples, as determined in the course of this diagnostic study. The investigated viruses should be regularly tested in patients with diarrheal syndrome belonging to all age groups during both epidemic and sporadic occurrences of the disease.</p>