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Astrovirus in Italy, emergence of a novel 2c lineage

Abstract number: P1859

Platia M.A., Rotolo V., Colomba C., Cascio A., Martella V., Giammanco G.M., De Grazia S.

Objectives: Human astroviruses (HAstVs) are enteric viruses associated with gastroenteritis in young children in both developed and developing countries. The pathogenic role of HAstVs is still disputed since they are frequently found in mixed infection. In the present study we investigated on the prevalence of HAstVs in Palermo, Italy, in 2002–2005. Genetic diversity of HAstVs was determined by sequence analysis of ORF2 which allows to predict serotypes (1 to 8).

Methods: 708 faecal samples were obtained from children, less than five years, hospitalised in Palermo from January 2002 to December 2005. The samples were screened for the presence of HAstVs by EIA and positive specimens were analysed by RT-PCR to obtain ORF2 amplicons for genotyping through sequence and phylogenetic analysis. All stool specimens were also tested for presence of rotaviruses and noroviruses by RT-PCR.

Results: HAstVs were found in 28 (3.95%) patients. Mixed infections were found in 50% of the HAstV-positive samples. Coinfections with rotavirus were the most frequent. There were no significant differences in symptoms between patients with HAstV single infection and mixed infections. Fourteen HAstVs were genotyped by sequence analysis and HAstV types-1, -2, and -4 were detected. In particular, HAstVs-1 were identified in 2003–2005, HAstV-2 and -4 circulated only in 2002. In the phylogenetic tree, all Italian HAstVs-1 belonged to lineage 1d and HAstVs-4 to lineage 4b. The two Italian HAstVs-2 segregated in a well defined genetic cluster that differed from the presently described lineages and was designated 2c. Conserved nt polymorphisms allowing to differentiate the novel 2c lineage were observed.

Conclusion: The data obtained in this study confirm the role of HAstVs as agents of acute gastroenteritis in children and indicate HAstV-1d as the predominant type. This lineage, already circulating in Palermo in 1999, re-emerged in 2003 and continued to circulate until 2005. In 2002, HAstV-2c first appeared in Italy after occasional detection in other geographic areas. The emergence and re-emergence of different genotypes and lineages of astrovirus may depend on population immunity pressure. Nation-wide investigations concerted at an international level could be useful to gather more information on the impact of HAstV on enteric disease in children. Knowledge of the viral types circulating worldwide is required to plan prevention and control strategies.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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