Filovirus infection induces an anti-inflammatory state in Rousettus bats

The filoviruses Ebola (EBOV) and Marburg (MARV) cause severe disease in humans. In contrast, the Egyptian rousette bat (Rousettus aegyptiacus), a natural reservoir of MARV, exhibits a subclinical phenotype with limited MARV replication and nearly undetectable EBOV replication. Rousettus cell lines support replication of filoviruses, however. To understand the bat-filovirus interaction, transcriptomes of tissues from EBOV- and MARV-infected R. aegyptiacus bats were analyzed. While viral transcripts were only detected in liver, a systemic response was observed involving other tissues as well. By focusing on evolutionarily divergent (from human homologues) protein-coding genes, we identified novel transcriptional pathways that suggest infected bats exhibit impaired coagulation, vasodilation, aberrant iron regulation, and impaired complement system leading to muted antibody responses. Furthermore, a robust T-cell response and an anti-inflammatory state driven by M2 macrophages were identified. These processes likely control infection and limit pathology. All data can be freely explored and downloaded through our tools (http://katahdin.girihlet.com/shiny/bat/).