Objective: To investigate the pathological changes and viral invasion in the main organs of rhesus macaques after experimental infection with H5N1 virus.
Methods: The rhesus macaques were infected with H5N1 virus (AF148678/ACGoose/Guangdong/11961H5N1) by nasal inoculation under anesthesia. One rhesus macaque was killed respectively at 1, 3, 6, 14 days after infection. The pathologic changes of the main organs were observed using HE staining and the characteristics of the viral invasion in the body were analyzed using viral isolation, RT-PCR andimmunohistochemistry.
Results: The influenza virus replicated only in the lung tissues characterized by diffuse alveolar damage in the infected rhesus macaques, mainly involving alveolar epithelial cells and pulmonary macrophages. The pathological changes showed 3 phases including exudative inflammation, hyperplasia and fibrosis. Extra-pulmonary organs also showed different degree of pathological changes such as degeneration and necrosis, but virus was not isolated in the corresponding organs.
Conclusions: Acute diffuse lung injury was a central part of the pathogenesis in H5N1 avian influenza virus infection. The lung was the main target organ in H5N1 viral infection, and H5N1 virus cannot replicate in other organs, which may be one of the obstacles to H5N1 viral transmission from person to person.