Bruni Roberto, Taffon Stefania, Equestre Michele, Chionne Paola, Madonna Elisabetta, Rizzo Caterina, Tosti Maria Elena, Alfonsi Valeria, Ricotta Lara, De Medici Dario, Di Pasquale Simona, Scavia Gaia, Pavoni Enrico, Losio Marina Nadia, Romanò Luisa, Zanetti Alessandro Remo, Morea Anna, Pacenti Monia, Palù Giorgio, Capobianchi Maria Rosaria, Chironna Maria, Pompa Maria Grazia, Ciccaglione Anna Rita
Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità (ISS), Rome, Italy.
Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità (ISS), Rome, Italy.
PLoS One. 2016 Feb 22;11(2):e0149642. doi: 10.1371/journal.pone.0149642. eCollection 2016.
Foodborne Hepatitis A Virus (HAV) outbreaks are being recognized as an emerging public health problem in industrialized countries. In 2013 three foodborne HAV outbreaks occurred in Europe and one in USA. During the largest of the three European outbreaks, most cases occurred in Italy (>1,200 cases as of March 31, 2014). A national Task Force was established at the beginning of the outbreak by the Ministry of Health. Mixed frozen berries were early demonstrated to be the source of infection by the identity of viral sequences in patients and in food. In the present study the molecular characterization of HAV isolates from 355 Italian cases is reported.
Molecular characterization was carried out by PCR/sequencing (VP1/2A region), comparison with reference strains and phylogenetic analysis.
A unique strain was responsible for most characterized cases (235/355, 66.1%). Molecular data had a key role in tracing this outbreak, allowing 110 out of the 235 outbreak cases (46.8%) to be recognized in absence of any other link. The data also showed background circulation of further unrelated strains, both autochthonous and travel related, whose sequence comparison highlighted minor outbreaks and small clusters, most of them unrecognized on the basis of epidemiological data. Phylogenetic analysis showed most isolates from travel related cases clustering with reference strains originating from the same geographical area of travel.
In conclusion, the study documents, in a real outbreak context, the crucial role of molecular analysis in investigating an old but re-emerging pathogen. Improving the molecular knowledge of HAV strains, both autochthonous and circulating in countries from which potentially contaminated foods are imported, will become increasingly important to control outbreaks by supporting trace back activities, aiming to identify the geographical source(s) of contaminated food, as well as public health interventions.
食源性甲型肝炎病毒（HAV）暴发在工业化国家正被视为一个新出现的公共卫生问题。2013年，欧洲发生了3起食源性HAV暴发，美国发生了1起。在欧洲的3起暴发中规模最大的一起中，大多数病例发生在意大利（截至2014年3月31日超过1200例）。疫情暴发初期，卫生部成立了一个国家特别工作组。通过患者和食品中病毒序列的一致性，早期证明混合冷冻浆果是感染源。在本研究中，报告了来自355例意大利病例的HAV分离株的分子特征。
通过PCR/测序（VP1/2A区域）、与参考菌株比较及系统发育分析进行分子特征分析。
一个独特的菌株导致了大多数已鉴定病例（235/355，66.1%）。分子数据在追踪此次暴发中发挥了关键作用，使得235例暴发病例中的110例（46.8%）在没有任何其他关联的情况下得以确认。数据还显示了其他不相关菌株的背景传播情况，包括本地菌株和与旅行相关的菌株，它们的序列比较突出了小规模暴发和小的聚集性病例，其中大多数根据流行病学数据未被识别。系统发育分析表明，大多数与旅行相关病例的分离株与来自相同旅行地理区域的参考菌株聚类。
总之，本研究在实际暴发背景下证明了分子分析在调查一种古老但重新出现的病原体方面的关键作用。提高对本地HAV菌株以及从可能进口受污染食品的国家流行的HAV菌株的分子认识，对于通过支持溯源活动（旨在确定受污染食品的地理来源）以及公共卫生干预措施来控制暴发将变得越来越重要。
