To clarify the identity of the RVFV target cells, we carried out histopathological analysis in RVFV-hRLuc-infected Ifnar1 2/2 No histological lesions were detected in the other organs. In the liver, lung and spleen, the lesions were similar to those previously reported in RVFV-infected wild-type mice [18, 19, 20, 21] . Diffuse apoptosis of lymphoid cells have been previously reported in areas with or without RVFV antigen in the thymus of infected BALB/c [21] . Accordingly, we identified the thymus as one of the major targets of RVFV by bioluminescence. However, the pancreas and reproductive organs were also luminescent although none of these organs are known as tissue targets of RVFV. Therefore, to identify cell types that support RVFV replication in these organs, we studied tissue samples by histology and immunohistochemistry with antibodies against the RVFV. In the pancreas, no histological lesions were found in the exocrine or endocrine components ( Figure 6A ). However, a multifocal inflammatory lesion was observed in the mesentery around pancreatic acini (peritonitis), characterized by necrosis of adipocytes associated with infiltration of macrophages and neutrophils ( Figure 6A-C) . Viral antigens were present only in the cytoplasm of macrophages ( Figure 6D ) and, more rarely, in neutrophils ( Figure 6E ), confirming that the virus did not target the pancreatic exocrine or endocrine cells but macrophages. Similarly, in the ovaries, viral nucleocapsid-positive macrophages were seen in the stroma ( Figure 6F ). Thus macrophages appeared as important cell targets for the replication of RVFV-hRLuc in Ifnar1-deficient mice. To examine whether macrophages are also cell targets for the replication of virulent RVFV in wild-type mice, histopathological and immunohistochemical analysis was performed in wildtype 129S2/SvPas mice (N = 3) infected i.p. with 10 4 PFU ZH548. Post-mortem analyses were carried out once mice displayed clinical signs, i.e. three to five days after the inoculation. Histopathological analysis of the pancreas and its mesentery revealed no peritonitis. However, numerous macrophages containing intracytoplasmic viral antigens were observed in the sinus of the pancreaticoduodenal lymph node (Figure 6, G and H) . These macrophages occasionally displayed a hyperbasophilic and condensed nucleus, a morphological change that is characteristic for irreversible cell injury (Figure 6 , I). Collectively, these results confirmed that macrophages are important cell targets of the RVFV in the mouse.