Comparative pathological alterations caused by h1n1, h5n1, and h3n2 respiratory disease viruses in human and animal models

Influenza A viruses are animal disease pathogens that ceaselessly mutated and flow into in many hosts, as birds, pigs, and human. The spectrum of morbidity and mortality of H1N1, H5N1, and H3N2 viruses are related mainly to the pathological lesions they turn out. H1N1 and H5N1 viruses are usually associated with inflammation, congestion and necrosis of the larger airway's epithelium with extension into the alveoli producing interstitial leukocytic infiltration and oedema. High morbidity by H1N1 virus is owned to infection of the epithelium at upper and lower airways. On the other side, seasonal H3N2 virus has primarily displayed inflammation, congestion and tissue injuries of the larger airways with lesser extension into alveoli. Localization of the inflammatory reactions depends upon the presence of virus in membrane tissue cells of the airways, alveolar macrophages, and pneumocytes. Throughout this review, we tend to explain and compare the pathology of these viruses in human cases and animal models.