College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, China.
Key Laboratory of Animal Vaccine Development, Ministry of Agriculture, Guangzhou 510642, China.
Viruses. 2022 May 19;14(5):1097. doi: 10.3390/v14051097.
Wild birds play an important role in the emergence, evolution, and spread of zoonotic avian influenza viruses (AIVs). However, there are few studies on the cross-species transmission of the H3N8 AIV originating from wild birds. In this study, we investigated the transmissibility and pathogenicity of two H3N8 low pathogenic avian influenza viruses (LPAIVs) isolated from wild birds, GZA1 and XJ47, to mammals. The genes of both strains belonged to Eurasian isolates, while the other genes were derived from a variety of other subtypes of AIVs. Both strains can infect specific-pathogen-free (SPF) chickens, BALB/c mice, and guinea pigs. The XJ47 strain spread horizontally in SPF chickens and guinea pigs. The GZA1 strain did not spread horizontally but caused higher weight loss and mild lung inflammation in mice. P12-GZA1- and P12-XJ47-adapted strains obtained after 12 passages in the lung of mice showed enhanced pathogenicity in mice, which led to obvious clinical symptoms, lung inflammation, and 100% death. Both adapted strains have the reported mutation T97I in the PA, and the reported mutation D701N in PB2 has been found in the P12-GZA1-adapted strain. This study provides an important scientific basis for the continuous monitoring of wild AIVs and the mechanism underlying AIV cross-species transmission.
野生鸟类在人畜共患的禽流感病毒（AIVs）的出现、进化和传播中发挥着重要作用。然而，关于源自野生鸟类的 H3N8 AIV 的跨物种传播的研究很少。在本研究中，我们研究了两种从野生鸟类中分离出的 H3N8 低致病性禽流感病毒（LPAIV），即 GZA1 和 XJ47，对哺乳动物的传染性和致病性。这两种菌株的基因都属于欧亚分离株，而其他基因则来自多种其他亚型的 AIV。两种菌株都可以感染特定病原体的鸡、BALB/c 小鼠和豚鼠。XJ47 株在 SPF 鸡和豚鼠中水平传播。GZA1 株不水平传播，但导致小鼠体重减轻和肺部炎症更严重。在小鼠肺部传代 12 次后获得的 P12-GZA1-和 P12-XJ47-适应株在小鼠中表现出更强的致病性，导致明显的临床症状、肺部炎症和 100%的死亡率。这两种适应株在 PA 中都具有报道的 T97I 突变，而在 P12-GZA1 适应株中发现了 PB2 中报道的 D701N 突变。本研究为持续监测野生 AIV 和 AIV 跨物种传播的机制提供了重要的科学依据。
