Bats are reservoir hosts for a spectrum of infectious diseases. Some pathogens (such as Hendra, Nipah and Marburg viruses) appear to use mainly fruit bats as reservoir. We describe designed immortalization of primary fetal cells from the Egyptian fruit bat (Rousettus aegyptiacus) to facilitate isolation and characterization of pathogens associated with these mammals. Three cell lines with different properties were recovered and successful immortalization was confirmed by continuous cultivation for over 18 months. Surprisingly, the cell lines are fully permissive for a highly attenuated poxvirus, modified vaccinia Ankara (MVA). MVA is a safe and well characterized vaccine vector that cannot replicate in most mammalian cells. High permissivity of Rousettus cell lines could justify testing bats for susceptibility to MVA as a replication competent vector with low zoonotic potential to induce herd immunity in bat colonies against viruses causing rabies or haemorrhagic fevers.