Munné María S, Vladimirsky Sara, Otegui Lucio, Soto Sonia, Brajterman Leonardo, Castro Raúl, Velasco María C Cañero, Bonnano Alicia, Fernández Eduardo, Remondegui Carlos, Passeggi Carlos, Rodríguez Claudia, Pizarro Marta, Fabre Adriana, Moreiro Rita, Quarleri Jorge, González Jorge E
Lab. Nac.de Referencia Hepatitis Virales, Instituto Nacional de Enfermedades Infecciosas, ANLIS Dr. C.G. Malbrán, Ciudad Autónoma de Buenos Aires, Argentina.
J Med Virol. 2007 Jul;79(7):887-94. doi: 10.1002/jmv.20818.
Hepatitis A, a vaccine preventable disease, is now of transitional or intermediate endemicity in Argentina, as the epidemiologic pattern of the disease has shifted with improvements in living conditions in some parts of the country. Increase in the susceptibility of older children and adults has led to increasing disease incidence. Molecular epidemiology has played an important role in the understanding of HAV infection by identifying modes of spreading and by permitting the monitoring of changes in circulating virus brought about by prevention programs. South American isolates characterized are limited. Eighty-two sporadic and outbreak isolates from Argentina were sequenced in the VP1/2A region of HAV genome over a 9-year period. All the isolates belonged to subgenotype IA. All our sequences grouped into two big clusters. Apparently, at least two lineages have been co-circulating in the same place at the same time. Despite great genetic variability, few point amino acid changes could be deduced. Four sequences showed an Arg --> Lys substitution at 1-297 which characterized the genotype IB at the amino acid level. Many isolates carried a conservative amino acid substitution Leu --> Ile at position 42 of the 2A domain, previously described as a possible fingerprint of HAV sequences in Brazil. The other rare changes have been found before, except for a 1-277 Asn --> Ser substitution displayed in two isolates that has not been previously reported. Argentina recently implemented universal vaccination in 1-year-old children. Molecular tools would be useful in an active surveillance program.
甲型肝炎是一种可用疫苗预防的疾病，在阿根廷目前处于过渡性或中等地方性流行状态，因为随着该国一些地区生活条件的改善，该疾病的流行病学模式已发生转变。大龄儿童和成人易感性的增加导致了发病率的上升。分子流行病学通过识别传播模式以及监测预防计划所引起的流行病毒变化，在理解甲型肝炎病毒（HAV）感染方面发挥了重要作用。已鉴定的南美分离株数量有限。在9年时间里，对来自阿根廷的82株散发和暴发分离株的HAV基因组VP1/2A区域进行了测序。所有分离株均属于IA亚基因型。我们所有的序列分为两大簇。显然，至少有两个谱系曾在同一时间、同一地点共同传播。尽管存在很大的遗传变异性，但能推断出的氨基酸点突变很少。4个序列在1-297位点显示精氨酸（Arg）到赖氨酸（Lys）的替换，这在氨基酸水平上是IB基因型的特征。许多分离株在2A结构域的42位携带亮氨酸（Leu）到异亮氨酸（Ile）的保守氨基酸替换，这在巴西曾被描述为HAV序列的一种可能特征。除了在两个分离株中显示的1-277位点天冬酰胺（Asn）到丝氨酸（Ser）的替换此前未被报道外，其他罕见变化以前曾被发现过。阿根廷最近对1岁儿童实施了普遍接种疫苗。分子工具在主动监测计划中将很有用。
