Enteric Virus Laboratory, Department of Microbiology and Institute of Nutrition and Food Safety, University of Barcelona, Barcelona, Spain.
J Clin Virol. 2011 Oct;52(2):98-102. doi: 10.1016/j.jcv.2011.06.011. Epub 2011 Jul 27.
In spite of annual vaccination campaigns, hepatitis A cases increased in Catalonia (North-East Spain) in the period 2002-2005 calling for the elucidation of the underlying mechanisms associated to the epidemiological shifts.
The molecular characterization of the circulating strains to trace their origin and the study of the effects of vaccination on the incidence of sporadic and outbreak-associated cases.
Forty-eight different hepatitis A virus (HAV) strains isolated from sporadic and outbreaks cases during 2005-2009 in Catalonia were molecularly characterized.
Seventeen out of 48 strains were imported from endemic areas through traveling, immigration and food trade, 12 were endemic strains circulating in the men having sex with men (MSM) group and 1 was from a Roman child. The remaining 18 could not be associated to any specific origin and thus were considered autochthonous. Forty-eight percent of the strains belonged to subgenotype IA, 40% to subgenotype IB and 2% to subgenotype IIIA. The remaining 10% belonged to an undetermined subgenotype equidistant from IA and IB.
During the period 2005-2009, the annual attack rates remained around 3.5 and even increased up to 6.5 in the first half of 2009. This increase with respect to the period 1999-2001, in which vaccination campaigns started to be implemented, is explained by an increase in the number of outbreaks. The predominant subgenotypes were IA and IB. However a considerable amount of strains imported from Peru through consumption of contaminated shellfish belonged to an undeterminded subgenotype that may constitute a new candidate subgenotype IC.
尽管每年都进行疫苗接种活动，但 2002-2005 年间加泰罗尼亚（西班牙东北部）的甲型肝炎病例仍有所增加，这促使人们对与流行病学转变相关的潜在机制进行了研究。
对循环毒株进行分子特征分析，以追溯其来源，并研究疫苗接种对散发和暴发相关病例发病率的影响。
对 2005-2009 年间加泰罗尼亚地区散发和暴发的甲型肝炎病毒（HAV）48 株分离株进行了分子特征分析。
17 株分离株为旅行、移民和食品贸易导致的输入性流行地区来源，12 株为男男性接触者（MSM）群体中流行的地方性株，1 株为罗马儿童来源。其余 18 株不能与任何特定来源相关联，因此被认为是地方性的。48%的分离株属于亚基因型 IA，40%属于亚基因型 IB，2%属于亚基因型 IIIA。其余 10%属于无法确定来源的亚基因型，与 IA 和 IB 等距。
2005-2009 年期间，年发病率保持在 3.5 左右，2009 年上半年甚至上升至 6.5。与 1999-2001 年期间（开始实施疫苗接种活动）相比，这一增加是由于暴发数量的增加所致。主要的亚基因型为 IA 和 IB。然而，从秘鲁进口的大量通过食用受污染贝类而感染的菌株属于未确定来源的亚基因型，可能构成新的候选亚基因型 IC。
