Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America.
PLoS One. 2011 Mar 31;6(3):e17643. doi: 10.1371/journal.pone.0017643.
Waterfowl and shorebirds harbor and shed all hemagglutinin and neuraminidase subtypes of influenza A viruses and interact in nature with a broad range of other avian and mammalian species to which they might transmit such viruses. Estimating the efficiency and importance of such cross-species transmission using epidemiological approaches is difficult. We therefore addressed this question by studying transmission of low pathogenic H5 and H7 viruses from infected ducks to other common animals in a quasi-natural laboratory environment designed to mimic a common barnyard. Mallards (Anas platyrhynchos) recently infected with H5N2 or H7N3 viruses were introduced into a room housing other mallards plus chickens, blackbirds, rats and pigeons, and transmission was assessed by monitoring virus shedding (ducks) or seroconversion (other species) over the following 4 weeks. Additional animals of each species were directly inoculated with virus to characterize the effect of a known exposure. In both barnyard experiments, virus accumulated to high titers in the shared water pool. The H5N2 virus was transmitted from infected ducks to other ducks and chickens in the room either directly or through environmental contamination, but not to rats or blackbirds. Ducks infected with the H7N2 virus transmitted directly or indirectly to all other species present. Chickens and blackbirds directly inoculated with these viruses shed significant amounts of virus and seroconverted; rats and pigeons developed antiviral antibodies, but, except for one pigeon, failed to shed virus.
水禽和滨鸟携带并释放所有的甲型流感病毒血凝素和神经氨酸酶亚型，并与自然界中广泛的其他禽类和哺乳动物相互作用，可能将这些病毒传播给它们。使用流行病学方法来估计这种跨物种传播的效率和重要性是困难的。因此，我们通过在一个模拟常见谷仓环境的准自然实验室中，研究从感染鸭子向其他常见动物传播低致病性 H5 和 H7 病毒，来解决这个问题。最近感染 H5N2 或 H7N3 病毒的绿头鸭被引入一个房间，里面有其他绿头鸭、鸡、乌鸫、老鼠和鸽子，并通过监测接下来 4 周的病毒排放（鸭子）或血清转化（其他物种）来评估传播情况。每种动物的其他个体都直接接种病毒，以确定已知暴露的影响。在两个谷仓实验中，病毒在共用的水池中积累到高滴度。H5N2 病毒通过直接或通过环境污染从受感染的鸭子传播到房间里的其他鸭子和鸡，但不能传播给老鼠或乌鸫。感染 H7N2 病毒的鸭子直接或间接地传播给所有其他在场的物种。直接接种这些病毒的鸡和乌鸫大量排出病毒并产生血清转化；老鼠和鸽子产生抗病毒抗体，但除了一只鸽子外，均未能排出病毒。
