MLB1 Astrovirus in Children with Gastroenteritis, Italy

Food Safety and Inspection Service. New performance standards for Salmonella and Campylobacter in young chicken and turkey slaughter establishments: response to comments and announcement of implementation schedule. Contamination of individual whole broiler chickens with multiple molecular subtypes of Salmonella and Campylo-bacter. To the Editor: Astroviruses are notable agents of gastroenteritis in many mammalian and avian hosts. Astroviruses are nonenveloped RNA small, round, viruses (SRVs) with a single-stranded, positive sense RNA of 6.1 to 7.9 kb (1). The genome contains 2 nonstructural genes, open reading frame (ORF) 1a and 1b, and a capsid gene, ORF2, with short 5′ and 3′ untranslated regions. Human astro-viruses, a major cause of gastroenteri-tis, are classified in the human astro-virus species, comprising 8 serotypes (1). Recently, astroviruses genetically unrelated to canonical human astro-viruses have been identified in human stools in several countries. These unusual astroviruses form 2 main genetic clades. One clade contains MLB1, MLB2, and MLB3 (2–4). The second clade contains VA1, VA2, VA3 (also known as HMO-C, HMO-A, and HMO-B, respectively) and VA4 (5,6). More recently, a VA1/HMO-C– like virus was detected in brain tissue from an immunocompromised child with encephalitis (7). The discoveries of these viruses provide novel candidate agents of human disease and raise concerns inherent of possible zoonotic implications. Here we describe the detection and genome characterization of MLB1-like astrovirus in a 4-year-old male child hospitalized with severe gastroenteritis during January 2007 at the University Hospital of Parma, Italy. Clinical signs included vomiting and severe diarrhea, with moderate dehydration. The child was treated with rehydration and maintenance therapy (balanced glucose-electrolyte solutions) and completely recovered after 3 days. Fecal samples collected at admission were subjected to routine vi-rologic (electron microscopy [EM], cell cultures, latex agglutination, and reverse transcription PCR) and bac-teriologic (culturing with selective and differential media) examinations. Fecal samples tested negative for common bacterial (Clostridium dif-were observed in the feces of the patient (Figure, panel A). Despite several efforts with additional consensus primer sets for calicivirus and entero-virus, it was not possible to identify the SRVs detected by EM, and the case was archived as undiagnosed. However, beginning in 2008, several astroviruses genetically unrelated to canonical human astroviruses have been described (2). Broadly reactive consensus primers for astrovirus (8) spanning the RNA-dependent RNA polymerase (RdRp, ORF1b), along with sets of specific primers for these novel astroviruses (2), have been designed. By using these sets of primers, astrovirus RNA was detected in …