Astrovirus infection in children :

65 episodes of rotavirus diarrhoea, detected during a longitudinal follow-up of 336 infants from birth to 24-32 months of age, were analyzed for clinical symptoms. Rotavirus gastroenteritis was characterized by watery diarrhoea, vomiting (particularly in older children), fever and dehydration. A 0-20 point numerical score was devised according to the distribution of clinical features in the patients. Using this system, the mean severity score for the 65 episodes of rotavirus diarrhoea was 11.0 +/- 3.7 as compared to 5.6 +/- 3.2 for the 183 episodes of non-rotavirus diarrhoea in the same population (p less than 0.0001, t-test). The 20 point score is proposed for analysis of efficacy studies of candidate rotavirus vaccines.

As poultry becomes more important in the world economy, it is increasingly important to fully understand the mechanisms of disease and poor production that affect the industry. To more accurately and reasonably treat these diseases, a more sophisticated understanding of interrelatedness is required. This review focuses on avian astroviruses (AAstVs), in particular the recent advances in our understanding of AAstV molecular biology, and also history, diagnosis, treatment and control. The known AastVs comprise duck astrovirus 1, turkey astrovirus 1 and 2, and avian nephritis virus of chickens. Nucleotide and amino acid identities between the avian and mammalian (human, ovine, bovine) astroviruses is very low (e.g. 20 to 25% and 12 to 15%, respectively) in open reading frame (ORF) 1a. There is also variation among the avian astroviruses, including between the two known types of turkey astrovirus. The ORF 1b sequence contains a number of conserved amino acid motifs; these could be the basis of degnerate oligonucleotide primers. A nomenclature for astroviruses is also proposed, based on: host species-astrovirus-type number/country(state)/reference number/year of isolation. For example, turkey astrovirus 2/North Carolina/034/1999.

Episodes of acute gastroenteritis in prospectively followed children between 2 months and 2 years of age were examined for rotaviruses, enteric adenoviruses, astroviruses, and human caliciviruses, including both Norwalk-like viruses (NLVs) and Sapporo-like viruses (SLVs), using PCR and reverse transcription (RT)-PCR assays. A virus was identified in 60% (502/832) of all episodes and in 85% of the moderately severe or severe episodes. Human caliciviruses were as common as rotaviruses, both being detected in 29% of the cases. NLVs accounted for a 20% etiologic share of all cases; the clinical picture was a moderately severe disease with vomiting as a predominant symptom. SLVs were detected in 9% of the cases, the clinical picture being a mild diarrheal disease. Astroviruses were found in 10% and enteric adenoviruses in 6% of the cases. Diagnosis with PCR and RT-PCR methods increases the detection of all gastroenteritis viruses, particularly human caliciviruses. As a group, human caliciviruses are common causative agents of gastroenteritis in children <2 years of age in Finland, and, of these, NLVs cause more severe disease than SLVs.