Influenza A viruses (IAVs) infect humans and a variety of other animal species. Infections with some subtypes of IAV were also reported in domestic cats and dogs. In addition to animal health implications, close contact between companion animals and humans also poses a potential risk of zoonotic IAV infections. In this study, serum samples from different cat and dog cohorts were analyzed for IAV antibodies against seven IAV subtypes, using three distinctive IAV-specific assays differing in IAV subtype-specific discriminatory power and sensitivity. Enzyme-linked immunosorbent assays against the complete hemagglutinin (HA) ectodomain or the HA1 domain were used, as well as a novel nanoparticle-based, virus-free hemagglutination inhibition assay. Using these three assays, we found cat and dog sera from different cohorts to be positive for antibodies against one or more IAV subtypes and/or strains. Cat and dog serum samples collected after the 2009 pandemic H1N1 outbreak exhibit much higher seropositivity against H1 compared to samples from before 2009. Cat sera, furthermore, displayed higher reactivity for avian IAVs than dog sera. Our findings show the added value of using complementary serological assays, which are based on reactivity with different numbers of HA epitopes, to study IAV antibody responses and for improved serosurveillance of IAV infections. We conclude that infection of cats and dogs with both human and avian IAVs of different subtypes is prevalent. These observations highlight the role of cats and dogs in IAV ecology and indicate the potential of these companion animals to give rise to novel (reassorted) viruses with increased zoonotic potential.

中文翻译：

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猫和狗的甲型流感病毒抗体血清学筛查表明不同亚型的频繁感染。


甲型流感病毒 (IAV) 感染人类和多种其他动物物种。在家猫和狗中也有报告感染 IAV 的某些亚型。除了对动物健康的影响外，伴侣动物与人类之间的密切接触也构成人畜共患 IAV 感染的潜在风险。在这项研究中，使用三种不同的 IAV 特异性检测方法，分析了来自不同猫和狗群体的血清样本中针对 7 种 IAV 亚型的 IAV 抗体，这三种方法在 IAV 亚型特异性辨别能力和敏感性方面有所不同。使用针对完整血凝素 (HA) 胞外域或 HA1 结构域的酶联免疫吸附测定，以及基于纳米颗粒的新型无病毒血凝抑制测定。通过这三种检测，我们发现来自不同群体的猫和狗血清对一种或多种 IAV 亚型和/或毒株的抗体呈阳性。与 2009 年之前的样本相比，2009 年 H1N1 流感爆发后收集的猫和狗血清样本表现出更高的 H1 血清阳性率。此外，猫血清对禽 IAV 的反应性比狗血清更高。我们的研究结果表明，使用基于与不同数量的 HA 表位的反应性的互补血清学检测来研究 IAV 抗体反应和改善 IAV 感染的血清监测具有附加值。我们得出的结论是，不同亚型的人类和禽类 IAV 感染猫和狗的情况很普遍。这些观察结果强调了猫和狗在 IAV 生态中的作用，并表明这些伴侣动物有可能产生具有增加人畜共患潜力的新型（重配）病毒。