Human Astrovirus Outbreak in a Daycare Center and Propagation among Household Contacts oleh Ignacio Parrón, Elsa Plasencia, Thais Cornejo-Sánchez, Mireia Jané, Cristina Pérez, Conchita Izquierdo, Susana Guix, Àngela Domínguez, on behalf of the Working Group for the Study of Acute Gastroenteritis Outbreaks in Catalonia