There has been little surveillance of influenza A viruses (IAVs) circulating in swine at live animal markets, particularly in the United States. To address this gap, we conducted active surveillance of IAVs in pigs, the air, and the environment during a summer and winter season in a live animal market in St. Paul, Minnesota, that had been epidemiologically associated with swine-origin influenza cases in humans previously. High rates of IAV were detected by PCR in swine lungs and oral fluids during both summer and winter seasons. Rates of IAV detection by PCR in the air were similar during summer and winter, although rates of successful virus isolation in the air were lower during summer than in winter (26% and 67%, respectively). H3N2 was the most prevalent subtype in both seasons, followed by H1N2. Genetically diverse viruses with multiple gene constellations were isolated from both winter and summer, with a total of 19 distinct genotypes identified. Comparative phylogenetic analysis of all eight segments of 40 virus isolates from summer and 122 isolates from winter revealed that the summer and winter isolates were genetically distinct, indicating IAVs are not maintained in the market, but rather are re-introduced, likely from commercial swine. These findings highlight the extent of IAV genetic diversity circulating in swine in live animal markets, even during summer months, and the ongoing risk to humans.

中文翻译：

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在明尼苏达州的一个活体动物市场中，冬季和夏季之间在猪中传播的甲型流感病毒的遗传多样性。

在活的动物市场上，尤其是在美国，几乎没有监视过在猪中传播的甲型流感病毒（IAV）。为了弥补这一差距，我们在夏季和冬季在明尼苏达州圣保罗市的一个活体动物市场中对猪，空气和环境中的IAV进行了主动监视，该市场在流行病学上与2002年的猪源性流感病例有关。人类以前。在夏季和冬季，通过PCR在猪肺和口腔液中检出的IAV率很高。尽管夏季空气中成功分离出病毒的比率低于冬季（分别为26％和67％），但夏季和冬季通过空气中PCR的IAV检出率相似。在两个季节中，H3N2是最普遍的亚型，其次是H1N2。从冬季和夏季分离出具有多个基因星座的遗传多样性病毒，共鉴定出19种不同的基因型。对来自夏季的40个病毒分离株和来自冬季的122个分离株的所有八个片段进行的系统发育分析比较表明，夏季和冬季分离株在遗传上是不同的，这表明IAV没有在市场上出售，而是被重新引入了，很可能是从商业猪中引入的。这些发现突显了即使在夏季，IAV遗传多样性在活畜市场的猪中循环的程度以及对人类的持续危险。对来自夏季的40个病毒分离株和来自冬季的122个分离株的所有八个片段进行的系统发育分析比较表明，夏季和冬季分离株在遗传上是不同的，这表明IAV没有在市场上出售，而是被重新引入了，很可能是从商业猪中引入的。这些发现突显了即使在夏季，IAV遗传多样性在活畜市场的猪中循环的程度以及对人类的持续危险。对来自夏季的40个病毒分离株和来自冬季的122个分离株的所有八个片段进行的系统发育分析比较表明，夏季和冬季分离株在遗传上是不同的，这表明IAV没有在市场上出售，而是被重新引入了，很可能是从商业猪中引入的。这些发现突显了即使在夏季，IAV遗传多样性在活畜市场的猪中循环的程度以及对人类的持续危险。