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

Thesis (MSc (Med)(Virology))--University of Limpopo (Medunsa Campus), 2009. / Background: The most important causes of viral gastroenteritis include rotaviruses, caliciviruses, adenoviruses and astroviruses. Globaly, rotavirus infection has been estimated to result in 527 000 deaths of young children annually. In South Africa rotaviruses were found to be responsible for 20 – 30% of diarrhoeal diseases in children younger than 5 years of age. Noroviruses are the leading cause of non-bacterial acute gastroenteritis outbreaks worldwide, with human noroviruses accounting for more than 86.0% of all outbreaks caused by viruses. Aim: To investigate the prevalence of rotaviruses and noroviruses and to determine the genotypes of rotaviruses circulating in children under 5 years of age attending the private health facilities in the Tshwane region of South Africa. Material and methods: A total of 1227 stool specimens and the corresponding patient‟s data were obtained from the Lancet Pathology Laboratory (Pretoria, South Africa) from children under the age of 5 years with gastroenteritis who submitted stools for testing. The MRC-DPRU detected rotaviruses using the commercially available enzyme immunoassay DAKO IDEIATM assay whereas the Lancet Pathology Laboratory detected rotaviruses using VIKIA assay. The rotavirus genome was extracted from EIA positive samples using phenol-chloroform and analyzed utilizing polyacrylamide gel electrophoresis (PAGE). Molecular characterization of the rotavirus-positive samples was done using reverse transcriptase polymerase chain reaction (RT-PCR) and genotyping assays. Samples were sequenced for further confirmation and to type the nontypeable samples. Due to lack of sufficient raw stool materials, only 673 of the specimens were screened for noroviruses using the RIDASCREEN® Norovirus testing assay. No molecular characterization of noroviruses isolates was performed. In addition, the Lancet Pathology Laboratory detected other diarrhoeal pathogens such as bacteria, parasites fungi and viruses, and the results were used to determine the relative significance of rotaviruses and noroviruses as the causes of diarrhoeal disease in comparison to other potential enteric pathogens in the Tshwane region. Results: The Lancet Laboratory reported 216 (17.6%) rotavirus positives with VIKIA assay and the MRC-DPRU reported 534 (43.5%) rotavirus positives with DAKO assay, clearly indicating that the DAKO assay has superior sensitivity. The use of a diagnostic assay which is not sensitive such as VIKIA assay could lead to misdiagnosis, under-reporting and x mismanagement of patients. Rotavirus infection was higher in children below 12 months of age (58.2% vs 41.7% for all other age groups). There was no significant difference between black and white children infected with rotaviruses [(249 or 46.6% for black versus 279 or 52.3% for white children)]. However, only 5 (0.9%) of rotavirus positives were Indians most probably due to small sample size. Rotaviruses were mostly predominant during the months of May (66.0%), June (71.0%) and July (57.4%). The prevalence of norovirus was relatively small compared to rotavirus for the same period. Only 53 (7.9%) samples were norovirus positive by ELISA. Noroviruses were detected in 11.1% of Indian children, followed by 7.9% of black children and 7.8% in white children. There was no significant difference amongst black and white children infected with noroviruses. A total of 74.2% of the EIA rotavirus positives were confirmed by PAGE. Nine PAGE patterns were obtained, displaying six long and three short electrophoretypes. A total of 319 stool specimens were genotyped for both VP4 and VP7. Of these, 289 (90.6%) were typeable for the VP4 [P] gene and 298 (93.4%) were typeable for the VP7 [G] gene. The most predominant single P genotypes were P[8] at 179 (56.1%), P[9] at 31 (9.7%) and P[4] at 25 (7.8%). Among the genotyped samples, the most predominant single G genotypes were G3 at 54 (16.9%), G8 at 48 (15.1%), G9 at 31 (9.7%) and G2 at 27 (8.5%). Mixed P and G rotavirus genotypes were detected in 12.5% and 29.5% for VP4 and VP7 respectively. Dual, triple and quadra rotavirus infections were detected for both VP4 and VP7 genotyping. The most predominant G and P genotypes found in this study were G8P[8] (8.9%), G3P[8] (8.3%) and G9P[8] (6.0%). Phylogenetic analysis indicated that of the 8 samples sequenced for VP4, all were P8 genotypes. Of these, five (DPRU1570, DPRU1754, DPRU7596, DPRU7310, and DPRU7335) clustered with Hun9-like lineage and 3 (DPRU7581, DPRU2030 and DPRU7173) clustered with Wa-like lineage on the P[8] phylogenetic tree. The only VP7 sample that was successfully sequenced (DPRU7381) clustered with lineage II of G3 on the phylogenetic tree. Children infected with rotavirus (83.0%) were also found to be co-infected with other diarrhoeal pathogens and these included Candida spp (33.2%), E. coli (19.8%), Cryptosporidium spp (8.9%), Adenoviruses types 40 and 41 (8.2%) and Giardia lamblia (7.7%). Viruses were the most predominant enteric pathogens detected in the samples at 63.0%, followed by fungi at 19.0%, bacteria at 15.0% and parasites at 3.0%. xi Conclusion: Compared to other enteric pathogens, rotaviruses are the leading cause of diarrhoea in children attending private health care facilities in Tshwane region. It was interesting to note that the most predominant G and P genotypes were G8P[8] (8.9%), G3P[8] (8.3%) and G9P[8] (6.0%). The predominance of these strains clearly indicate that the rotavirus vaccination programme that started in August 2009 in South Africa will be effective in protecting children against major circulating strains. However, more studies should be done to monitor the epidemiological trends of all enteric pathogens in South Africa, especially that rotavirus is now a vaccine-preventable disease.

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

No description available.

Background: Rotavirus is one of the most common diarrheal diseases in children less than 5 years of age. Rotavirus vaccines have greatly reduced this burden in the United States. An examination was conducted to determine possible disparities in RV vaccination rates compared to DTaP. Methods: Children were actively enrolled during two rotavirus seasons from January-June of 2010 and 2011 in the Emergency Departments (ED) and inpatient floors from all Children's Healthcare of Atlanta (CHOA) sites (Scottish Rite, Egleston, and Hughes Spalding) with acute gastroenteritis (AGE). Data and a stool sample were collected from enrolled children and samples were tested for presence of rotavirus using an enzyme immunoassay (EIA) kit (Rotaclone). Vaccination records were abstracted from the state immunization registry and primary healthcare providers to examine complete and incomplete vaccination status. This cohort of children with vaccination records were used for this analysis. Cases were identified as children receiving a complete RV dose series and controls were identified as children with incomplete RV doses. A logistic regression model was used to determine disparities seen amongst children with incomplete vaccination status. Results: Of the 660 patients that were approached for this study, 414 participants were included in this retrospective cohort analysis. 46.9% had incomplete rotavirus vaccination status and were more likely to be positive for rotavirus AGE (OR 1.76, 95% CI 1.46-2.13). Black infants had a higher rate of incomplete RV compared to whites (p-value 0.0006). When controlling for covariates, racial differences were no longer significant (OR 1.37 95% CI 0.77-2.57); however household size (p-value 0.0343), age at onset of illness (p-value 0.0061), and DTaP vaccination status (p-value < 0.0001) were all significant in determining vaccination status for children. Conclusions: Racial disparities and socioeconomic differences are not evident in determining rotavirus vaccination rates; however, household size, a possible social determinant, has an effect on RV status. In addition, timely vaccinations are important in preventing incomplete RV vaccination status, due to RV vaccine age restrictions.

No description available.

Doctor en Ciencias con mención en Biología

Background: Rotavirus disease is the leading global cause of severe diarrhea in children under 5 years. We examined the association between different rotavirus vaccines doses and severity of diarrhea. Methods: A secondary analysis of surveillance of children with acute gastroenteritis (AGE) symptoms during two seasons (January-June) in 2010 and 2011 from three pediatric hospitals in Atlanta, Georgia was conducted. Enrolled children were tested for rotavirus, using EIA (Rotaclone) and vaccination records were collected from the state immunization registry and healthcare providers. Cases were defined as any enrolled child who tested positive for rotavirus. Each enrolled child was assigned a Vesikari score to assess AGE severity. Results: 63.9% of participants had severe AGE. Cases were more likely to have severe AGE than controls (OR 3.8, 95% CI: 2.2-6.5). Receiving a mixed vaccine regimen had similar protection against severe disease to receiving only RotaTeq® or Rotarix® (Mixed: OR 0.1, 95% CI: 0.02-0.5; RotaTeq®: OR 0.1, 95% CI: 0.02-0.5; Rotarix®: OR 0.1; 95% CI 0.01-0.3). When controlling for vaccine type and demographic covariates, three doses of vaccine offered significant protection against severe disease (OR 0.3, 95% CI: 0.2-0.6). Conclusions: Receiving a mixed regimen of rotavirus vaccine is effective in preventing severe AGE. Mixed rotavirus vaccine regimens were equally efficacious to receiving a single type of vaccine in preventing severe disease. Three doses of vaccine, regardless of type, were effective in preventing severe disease but one or two doses were not.

Thesis (Ph. D.)--Ohio State University, 2004. / Title from first page of PDF file. Document formatted into pages; contains xxii, 276 p .; also includes graphics Includes bibliographical references. Available online via OhioLINK's ETD Center

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. / Made available in DSpace on 2012-10-19T12:21:45Z (GMT). No. of bitstreams: 0Bitstream added on 2014-09-25T21:41:26Z : No. of bitstreams: 1 177653.pdf: 30024636 bytes, checksum: ea76a9fb362f44d1ea7517733b082bad (MD5) / Os rotavírus são os agentes etiológicos virais mais comuns causando diarréia severa em humanos e animais. Dentre os sete diferentes grupos de rotavírus até então descritos, os rotavírus do grupo C (RVC) são extremamente difíceis de detectar através de procedimentos de rotina. O presente trabalho teve como objetivo caracterizar o período patogênico das infecções causadas pelo rotavírus do grupo C em uma comunidade de crianças de Belém do Pará utilizando as técnicas de RT-PCR (gene 5 do RVC) e PCR-RFLP no período de março de 1983 a março de 1986. A análise estatística, feita pelo teste do Qui-quadrado, mostrou que não há diferença significativa entre as amostras diarréicas positivas e negativas para RVC. Os perfis de restrição encontrados para a linhagem Cowden (controle positivo) com as enzimas MboI, XbaI e AluI foram os mesmos encontrados em 14 amostras analisadas clínicas de pacientes distintos e 21 amostras de um mesmo paciente. Foram encontrados diferentes perfis de restrição em 3 amostras que podem sugerir variabilidade genética da espécie de RV envolvida. O presente trabalho confirmou que as técnicas de RT-PCR e de RFLP são úteis e eficazes para a detecção e caracterização de RVC em amostras de fezes e demonstrou que os RVC contribuem para a morbidade das crianças de Belém do Pará.