Puumala virus infection in Syrian hamsters (Mesocricetus auratus) resembling hantavirus infection in natural rodent hosts

Abstract

The mechanism of hantavirus persistent infection in natural hosts is poorly understood due to a lack of laboratory animal models. Herein, we report that Syrian hamsters (Mesocricetus auratus) infected with Puumala virus (PUUV) at 4weeks old show persistent infection without clinical symptoms for more than 2months. IgG and IgM antibodies against the viral nucleocapsid protein and neutralizing antibody were first detectable at 14days postinoculation (dpi) and maintained through 70dpi. Viral RNA was first detected from 3dpi in lungs and blood clots, and was detected in all tissues tested at 7dpi. The viral RNA persisted for at least 70days in the lungs, kidney, spleen, heart, and brain. The highest level of RNA copies was observed at 14dpi in the lungs. Slight inflammatory reactions were observed in the lungs, adrenal glands, and brain. Immunohistochemical analysis revealed that PUUV antigen persisted until 56dpi in the kidneys and adrenal glands. Infected hamsters showed no body weight loss or clinical signs. These results indicate that PUUV infection in hamsters is quite similar to the hantavirus infection of natural host rodents.