Experimental yellow fever virus infection in the golden hamster (Mesocricetus auratus). II. Pathology

Subadult and adult hamsters were inoculated intraperitoneally with 10(6) TC ID50 of yellow fever (YF) virus (Jimenez strain). Four animals from each gr oup were subjected daily to histologic examination for 9 days. The liver sh owed spotty necrosis on day 3 after infection, which was followed by steato sis and focally confluent necrosis. In surviving hamsters, hepatocyte regen eration began on day 8, which was accompanied by decreasing steatosis. The spleen initially exhibited lymphoid hyperplasia, which was followed by lymp hoid depletion and increased phagocytosis by splenic macrophages. Focal pan creatic acinar necrosis and spotty adrenal cortical necrosis were seen tran siently between days 5 and 7. Viral antigen was detected immunohistochemica lly in the liver and the spleen. TUNEL analysis showed a dynamic change of hepatocyte necrapoptosis, with activity corresponding to the severity of di sease. The histopathologic changes were more severe in younger (subadult) a nimals. The YF-hamster model appears to be an accurate and inexpensive expe rimental system for studying the pathophysiology and treatment of YF.