Buggy Creek Virus (Togaviridae:Alphavirus) Upregulates Expression of Pattern Recognition Receptors and Interferons in House Sparrows (Passer domesticus)

Abstract

Birds serve as reservoirs for at least 10 arthropod-borne viruses, yet specific immune responses of birds to arboviral infections are relatively unknown. Here, adult House Sparrows were inoculated with an arboviral alphavirus, Buggy Creek virus (BCRV), or saline, and euthanized between 1 and 3 days postinoculation. Virological dynamics and gene expression dynamics were investigated. Birds did not develop viremia postinoculation, but cytopathic virus was found in the skeletal muscle and spleen of birds 1 and 3 days postinoculation (DPI). Viral RNA was detected in the blood of BCRV-infected birds 1 and 2 DPI, in oral swabs 1-3 DPI, and in brain, heart, skeletal muscle, and spleen 1-3 DPI. Multiple genes were significantly upregulated following BCRV infection, including pattern recognition receptors (TLR7, TLR15, RIG-1), type I interferon (IFN-a), and type II interferon (IFN-c). This is the first study to report avian immunological gene expression profiles following an arboviral infection.

Transcriptional response to West Nile virus infection in the zebra finch (Taeniopygia guttata)

“…This results in a corresponding over-representation of genes in the interferon signalling and regulation GO categories (table 2; electronic supplementary material, table S4). While no studies have investigated the role of the RLR following WNV infection in birds, this pathway appears important for avian influenza clearance in ducks [43][44][45], Buggy Creek virus clearance in house sparrows [48], and probably for the broad avian antiviral immune response, including WNV. Interestingly, chickens (Gallus gallus), which are often used as sentinels for WNV, have lost the gene encoding the DDx58 RLR during their evolution [43] yet do not develop disease post WNV infection [22].…”