6 results on '"Mitchell, Douglas K."'
Search Results
2. Quantitation of human astrovirus by real-time reverse-transcription-polymerase chain reaction to examine correlation with clinical illness.
- Author
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Zhang Z, Mitchell DK, Afflerbach C, Jakab F, Walter J, Zhang YJ, Staat MA, Azimi P, and Matson DO
- Subjects
- Astroviridae Infections complications, Astroviridae Infections diagnosis, Benzothiazoles, Caco-2 Cells, Child, Diamines, Humans, Mamastrovirus genetics, Mamastrovirus growth & development, Organic Chemicals, Quinolines, RNA, Viral genetics, Rotavirus Infections complications, Astroviridae Infections virology, Colony Count, Microbial methods, Mamastrovirus isolation & purification, Reverse Transcriptase Polymerase Chain Reaction methods
- Abstract
Human astroviruses (HAstVs) cause gastroenteritis. Real-time, reverse-transcription-polymerase chain reaction (RT2-PCR) was developed to quantitate HAstV RNA. An 88 bp amplicon from the conserved 3' genomic region was detected by binding of SYBR Green. RT2-PCR was reproducible, with a correlation coefficient of 0.998-1.00 and PCR efficiency of 94.4-100% (mean 97%). The coefficient of variation was 0.6-2.5%, dynamic range with RNA standard up to 5 x 10(8) RNA copies (RNACN) and sensitivity 5 RNACN. Of 54 blinded, archived stool samples from children hospitalized because of gastroenteritis tested by RT-PCR, 49 (91%) agreed by RT2-PCR for HAstV-positivity (Cohen kappa=0.81, 95%CI 0.66-0.97). HAstV RNACN in stools ranged from 7.6 x 10(1) to 3.6 x 10(14)copies/0.1g. Children coinfected with rotavirus had lower RNACN (mean log 4.22/standard deviation=2.26) than those without coinfection (7.57/3.06; p=.019). Children taking infant formula also had lower RNACN (5.96/2.98) than breast-fed or weaned children (8.73/2.92; p=.027). Higher RNACN tended to occur with longer duration of diarrhea for the episode (r=0.49, p=.064), but was not associated with change in age, gender, illness day, severity or breast-feeding. RT2-PCR quantitated HAstV RNA and RNACN in stool correlates with features of clinical illness.
- Published
- 2006
- Full Text
- View/download PDF
3. Comparison of clinical characteristics between astrovirus and rotavirus infections diagnosed in 1997 to 2002 in Hungary.
- Author
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Jakab F, Péterfai J, Meleg E, Bányai K, Mitchell DK, and Szucs G
- Subjects
- Case-Control Studies, Child, Child, Preschool, Diarrhea physiopathology, Feces virology, Humans, Hungary, Infant, Infant, Newborn, Length of Stay, Mamastrovirus isolation & purification, Retrospective Studies, Astroviridae Infections physiopathology, Rotavirus Infections physiopathology
- Abstract
Aim: To determine the severity and clinical characteristics of human astrovirus (HAstV) infections among hospitalized children and compare them with children infected by rotavirus., Methods: Retrospective, case-control study of astrovirus-infected and rotavirus-infected children. Astroviruses were detected in stool samples by enzyme immunoassay and/or reverse transcriptase-polymerase chain reaction. All stool samples were tested for rotavirus and bacterial pathogens, and all negative samples were further tested for human astrovirus. Children with astrovirus-positive stool samples and complete clinical data were included in this study., Results: Astrovirus was detected in 29 (1.8%) children, and 63 rotavirus-infected children were included as controls. Astrovirus-infected children had shorter duration of diarrhea than rotavirus-infected children (median 4 and 6 d, respectively; p<0.05), and 79% of the astrovirus infections were associated with a short duration of vomiting (median 1 and 4 d, respectively; p<0.0001). Rotavirus-infected children had longer hospitalization (p<0.050) than astrovirus-infected children., Conclusion: HAstV-infected children had similar symptoms to those occurring in rotavirus infection. However, astrovirus-infected patients had a significantly shorter duration of diarrhea and vomiting, and they required a shorter hospitalization. On the basis of the clinical data and severity scores, children with rotavirus infection had more severe illness.
- Published
- 2005
- Full Text
- View/download PDF
4. Molecular characterization and sequence analysis of human astroviruses circulating in Hungary.
- Author
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Jakab F, Walter JE, Berke T, Matson DO, Mitchell DK, and Szucs G
- Subjects
- Child, Feces virology, Genotype, Humans, Hungary epidemiology, Mamastrovirus classification, Molecular Sequence Data, Open Reading Frames, Phylogeny, Polymorphism, Genetic, RNA, Viral chemistry, RNA, Viral isolation & purification, Reverse Transcriptase Polymerase Chain Reaction methods, Sequence Analysis, DNA methods, Astroviridae Infections epidemiology, Astroviridae Infections virology, Genetic Variation, Mamastrovirus genetics, Mamastrovirus isolation & purification
- Abstract
Human astroviruses (HAstVs) are major pathogens in viral gastroenteritis worldwide. Twenty-five HAstV strains were detected from stool specimens of children hospitalized for acute gastroenteritis in Budapest, Hungary, between 1995 and 1999. Sequence analysis was performed at the 3' end of the capsid gene to determine genotypic diversity of HAstVs circulating in Hungary. Five different genotypes of HAstVs were identified: HAstV-1 was predominant, followed by types 5, 8, 3 and 4. Two different subtypes of HAstV-1 were detected, but only one at a time in the community. This is the first report on the genetic diversity of HAstVs in Hungary and Central/Eastern Europe.
- Published
- 2003
- Full Text
- View/download PDF
5. Astrovirus infection in children.
- Author
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Walter JE and Mitchell DK
- Subjects
- Age Distribution, Animal Population Groups, Animals, Astroviridae Infections diagnosis, Astroviridae Infections therapy, Astroviridae Infections transmission, Birds, Child, Gastroenteritis prevention & control, Humans, Mamastrovirus chemistry, Models, Genetic, Phylogeny, Prevalence, Seasons, Seroepidemiologic Studies, Astroviridae Infections epidemiology, Mamastrovirus isolation & purification
- Abstract
Purpose of Review: Public health concerns related to enteric viral agents, such as astroviruses and caliciviruses, include their ability to cause sporadic diarrhea, large outbreaks of gastroenteritis, and hospitalizations or deaths resulting from vomiting, diarrhea, and dehydration. Improved surveillance and application of sensitive molecular assays has increased awareness of these enteric pathogens and reduced the 'diagnostic gap' or unknown causes of non-bacterial gastroenteritis., Recent Findings: Molecular assays have been applied to further describe the epidemiology of human astroviruses from a variety of geographic areas. The burden of astrovirus infections compared with other enteric viral agents, including rotaviruses, caliciviruses, and enteric adenoviruses have been reported. New methods for detection of astroviruses such as reverse transcription-polymerase chain reaction and molecular typing methods have advanced the understanding of the epidemiology. Additional molecular studies have described the protein processing mechanisms of this single-stranded RNA virus., Summary: Astroviruses are increasingly recognized as significant gastrointestinal pathogens. The understanding of molecular epidemiology and molecular processing of the virus may lead to specific prevention strategies.
- Published
- 2003
- Full Text
- View/download PDF
6. Astrovirus gastroenteritis.
- Author
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Mitchell DK
- Subjects
- Child, Humans, Incidence, Mamastrovirus physiology, Astroviridae Infections epidemiology, Astroviridae Infections pathology, Astroviridae Infections prevention & control, Astroviridae Infections virology, Gastroenteritis epidemiology, Gastroenteritis pathology, Gastroenteritis prevention & control, Gastroenteritis virology
- Published
- 2002
- Full Text
- View/download PDF
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