Janke B H
DVM, PhD, Veterinary Diagnostic Laboratory, Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA. Email:
Vet Pathol. 2014 Mar;51(2):410-26. doi: 10.1177/0300985813513043. Epub 2013 Dec 20.
Influenza has been recognized as a respiratory disease in swine since its first appearance concurrent with the 1918 "Spanish flu" human pandemic. All influenza viruses of significance in swine are type A, subtype H1N1, H1N2, or H3N2 viruses. Influenza viruses infect epithelial cells lining the surface of the respiratory tract, inducing prominent necrotizing bronchitis and bronchiolitis and variable interstitial pneumonia. Cell death is due to direct virus infection and to insult directed by leukocytes and cytokines of the innate immune system. The most virulent viruses consistently express the following characteristics of infection: (1) higher or more prolonged virus replication, (2) excessive cytokine induction, and (3) replication in the lower respiratory tract. Nearly all the viral proteins contribute to virulence. Pigs are susceptible to infection with both human and avian viruses, which often results in gene reassortment between these viruses and endemic swine viruses. The receptors on the epithelial cells lining the respiratory tract are major determinants of infection by influenza viruses from other hosts. The polymerases, especially PB2, also influence cross-species infection. Methods of diagnosis and characterization of influenza viruses that infect swine have improved over the years, driven both by the availability of new technologies and by the necessity of keeping up with changes in the virus. Testing of oral fluids from pigs for virus and antibody is a recent development that allows efficient sampling of large numbers of animals.
自1918年“西班牙流感”大流行期间首次出现以来，流感就被认为是猪的一种呼吸道疾病。在猪身上具有重要意义的所有流感病毒均为甲型，亚型为H1N1、H1N2或H3N2病毒。流感病毒感染呼吸道表面的上皮细胞，引发显著的坏死性支气管炎和细支气管炎以及不同程度的间质性肺炎。细胞死亡是由病毒直接感染以及先天性免疫系统的白细胞和细胞因子引起的损伤所致。最具毒力的病毒始终表现出以下感染特征：（1）更高或更长时间的病毒复制，（2）过度的细胞因子诱导，以及（3）在下呼吸道复制。几乎所有病毒蛋白都对毒力有影响。猪易感染人类和禽流感病毒，这通常会导致这些病毒与地方性猪病毒之间发生基因重配。呼吸道上皮细胞上的受体是其他宿主流感病毒感染的主要决定因素。聚合酶，尤其是PB2，也会影响跨物种感染。多年来，随着新技术的出现以及跟上病毒变化的必要性，用于诊断和鉴定感染猪的流感病毒的方法有所改进。检测猪口腔液中的病毒和抗体是一项新进展，可实现对大量动物的高效采样。
