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Human adenoviruses (Ad40 and Ad41) cause prolonged diarrhea in children. Despite replication challenges, these enteric adenoviruses can be detected in stool samples using various diagnostic methods.
Area of Science:
- Virology
- Pediatric Gastroenterology
Background:
- Human adenoviruses are classified into six subgenera (A-F), with subgenus F serotypes Ad40 and Ad41 specifically linked to enteric infections in children.
- Unlike most human adenoviruses, Ad40 and Ad41 exhibit distinct tropisms and are difficult to culture in standard cell lines, though they replicate in 293 cells.
Purpose of the Study:
- To investigate the characteristics and diagnostic approaches for enteric adenoviruses Ad40 and Ad41.
- To compare the clinical presentation of diarrhea caused by Ad40 and Ad41 with other causes like rotavirus.
Main Methods:
- Utilized enzyme-linked immunosorbent assay (ELISA), solid-phase immuno-electron microscopy, DNA restriction, and dot-blot analysis for direct identification of Ad40 and Ad41 in stool samples.
- Clinical data from children with diarrhea were collected and analyzed to compare symptoms and duration between adenovirus and rotavirus infections.
Main Results:
- Ad40 and Ad41 are associated with 7-17% of childhood diarrhea cases, occurring year-round.
- Diarrhea caused by Ad40 and Ad41 is characterized by watery stools, vomiting, moderate fever, infrequent respiratory symptoms, and prolonged duration (mean 8.6-12.2 days).
- Children with rotavirus diarrhea exhibited more frequent vomiting, higher temperatures, and shorter illness duration compared to those with adenovirus-induced diarrhea.
Conclusions:
- Enteric adenoviruses Ad40 and Ad41 are significant contributors to childhood diarrhea, presenting with prolonged symptoms.
- Despite in vitro replication challenges, sensitive diagnostic methods allow for their identification in clinical samples.
- Further research is needed to determine the global impact of enteric adenoviruses on childhood diarrhea etiology.
Abstract:
The 41 serotypes of human adenoviruses are classified into six subgenera (A-F) with different tropisms. Enteric infections are caused in children by serotypes Ad40 and Ad41 of subgenus F. Serotypes Ad40 and Ad41 transform embryonic cells but cannot induce tumours in newborn hamsters. They differ from all other (established) human adenoviruses by being unable to replicate in conventional cell cultures. Ad40 and Ad41 grow in 293 cells (human embryonic kidney cells immortalized by transfection with the E1A, E1B regions of Ad5). In spite of the difficulty of isolating Ad40 and Ad41 they can be directly identified in stools by enzyme-linked immunosorbent assay (ELISA) and solid-phase immuno-electron microscopy. The amount of viral DNA in stool preparations is sufficient for identification by DNA restriction or dot-blot analysis. Adenoviruses have been associated with 7-17% of cases of diarrhoea in children. Ad40 and Ad41 cause diarrhoea throughout the year. Clinical features are watery stools, vomiting and moderately elevated temperature; respiratory symptoms are infrequent. The diarrhoea is protracted (mean 8.6 and 12.2 days for Ad40 and Ad41 respectively). Children with rotavirus diarrhoea vomited more frequently and had a higher temperature and diarrhoea of shorter duration. The impact of enteric adenoviruses in the aetiology of diarrhoea world-wide is not known but is accessible to investigation.