ORIGINAL ARTICLE First outbreak of norovirus in Albania D. Donia 1 , M. Kota 2 , L. Leno 3 , A. Ylli 4 , F. Cenko 5 and M. Divizia 1 1 Tor Vergata University, Hygiene, Rome, Italy 2 Public Health Institute, Tirane, Department Infectious Disease Control 3 Public Health Institute, Tirane, Department of Health and Environment 4 Director of Public Health Institute, Tirane 5 Professional Development System Project, Ministry of Health Introduction Noroviruses (NoVs) are nonenveloped RNA viruses belonging to the Caliciviridae family. They are considered as the leading cause of outbreaks and sporadic cases of acute nonbacterial gastroenteritis world-wide (Nayak et al. 2008). NoV’s infection may be spread through contami- nated water or food and person-to-person contacts (Hed- berg and Osterholm 1993; Koopmans et al. 2002). The RNA genome of NoVs, approximately 7Æ6 kilobases, is organized into three open-reading frames (ORFs). Based upon the phylogenetic analysis of VP1 gene (ORF 2), NoVs are classified into five distinct genogroups (GG) and further subdivided into genotypes. Usually, GGI, GGII and GGIV cause human infections, and the GGIIÆ4 is the predominant circulating genotypes identi- fied in outbreaks world-wide (Phan et al. 2007; Koop- mans 2008; Mans et al. 2010). In the absence of a reliable cell culture system, the reverse transcription–polymerase chain reaction (RT- PCR) is considered the gold standard to detect NoVs in clinical and environmental samples. However, no primer pair is able to detect all NoV genotypes because of their genetic diversity. Many RT-PCR protocols are currently available, and they involve the use of a large assortment of primer set to amplify the most of genetic variants due at the accumulation of point mutations associated with genetic recombination events. Albania is a country rich in water resources; however, the economy transformation of the country has deter- mined a significant damage to the natural resources, mainly to natural waters. At present, most of the aquatic Keywords genotyping, infection, molecular epidemiology, polymerase chain reaction, viruses. Correspondence Domenica Donia, Tor Vergata University, Via Montpellier, 1 Rome, Italy. E-mail: donia@med.uniroma2.it 2011 ⁄ 0515: received 28 March 2011, revised 7 June 2011 and accepted 8 June 2011 doi:10.1111/j.1472-765X.2011.03104.x Abstract Aims: Noroviruses (NoVs) represent the most important enteric viruses responsible for acute gastroenteritis world-wide. This study objective is to characterize the first outbreak of NoV that occurred in Ballsh, a small city in Albania. Methods and Results: Stool specimens were collected from people attending to the hospital. Samples were also collected from the aqueduct for bacteriological and virological tests. Overall 33 stools and five drinking water samples were collected, respectively, from the hospital in Ballsh and from the municipal aqueduct. No water samples were scored positive whereas ten stool samples (30Æ3%) were scored GGII NoV positive. All the GGII isolates were identified as GGIIÆ4 genotype, and no GGI was identified. The alignment and protein analysis were performed using, respectively, ClustalV and the mega 4 soft- ware. Conclusions: This is the first report of NoV GGIIÆ4 in Albania causing an out- break. The genetic analysis showed several point mutations and amino acid substitutions with respect to the international strains. Significance and Impact of Study: Over the last decades, Albania has suffered from different outbreaks as cholera, poliomyelitis, hepatitis A and now, for the first time, it has been documented an outbreak of NoV. Letters in Applied Microbiology ISSN 0266-8254 ª 2011 The Authors Letters in Applied Microbiology 53, 283–287 ª 2011 The Society for Applied Microbiology 283