Campitelli Laura, Di Martino Angela, Spagnolo Domenico, Smith Gavin J D, Di Trani Livia, Facchini Marzia, De Marco Maria Alessandra, Foni Emanuela, Chiapponi Chiara, Martin Ana Moreno, Chen Honglin, Guan Yi, Delogu Mauro, Donatelli Isabella
Department of Infectious, Parasitic and Immune-Mediated Diseases and Department of Food Safety and Veterinary Public Health, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
State Key Laboratory of Emerging Infectious Diseases, Department of Microbiology, The University of Hong Kong, Faculty of Medicine Building, 21 Sassoon Road, Pokfulam, Hong Kong SAR.
J Gen Virol. 2008 Jan;89(Pt 1):48-59. doi: 10.1099/vir.0.83111-0.
Avian influenza infections by high and low pathogenicity H7 influenza viruses have caused several outbreaks in European poultry in recent years, also resulting in human infections. Although in some cases the source of H7 strains from domestic poultry was shown to be the viruses circulating in the wild bird reservoir, a thorough characterization of the entire genome of H7 viruses from both wild and domestic Eurasian birds, and their evolutionary relationships, has not been conducted. In our study, we have analysed low pathogenicity H7 influenza strains isolated from wild and domestic ducks in Italy and southern China and compared them with those from reared terrestrial poultry such as chicken and turkey. Phylogenetic analysis demonstrated that the H7 haemagglutinin genes were all closely related to each other, whereas the remaining genes could be divided into two or more phylogenetic groups. Almost each year different H7 reassortant viruses were identified and in at least two different years more than one H7 genotype co-circulated. A recent precursor in wild waterfowl was identified for most of the gene segments of terrestrial poultry viruses. Our data suggest that reassortment allows avian influenza viruses, in their natural reservoir, to increase their genetic diversity. In turn this might help avian influenza viruses colonize a wider range of hosts, including domestic poultry.
近年来，高致病性和低致病性H7流感病毒引起的禽流感感染已在欧洲家禽中引发了多次疫情，还导致了人类感染。尽管在某些情况下，已证明家禽中的H7毒株来源是野生鸟类宿主中传播的病毒，但尚未对来自欧亚野生和家养鸟类的H7病毒的全基因组及其进化关系进行全面表征。在我们的研究中，我们分析了从意大利和中国南方的野生和家养鸭子中分离出的低致病性H7流感毒株，并将它们与从鸡和火鸡等饲养陆禽中分离出的毒株进行了比较。系统发育分析表明，H7血凝素基因彼此密切相关，而其余基因可分为两个或更多个系统发育组。几乎每年都会鉴定出不同的H7重配病毒，并且在至少两个不同年份中，不止一种H7基因型共同流行。已确定野生水禽是陆禽病毒大多数基因片段的近期前体。我们的数据表明，重配使禽流感病毒在其自然宿主中增加了遗传多样性。反过来，这可能有助于禽流感病毒在更广泛的宿主中定殖，包括家禽。
