Meeting Abstract
West Nile virus (WNV) is one of the most widespread arboviruses and a main cause of human viral encephalitis worldwide. WNV exists in a bird-mosquito transmission cycle where mammals act as dead-end hosts and passerine birds act as the primary reservoir host. The mammalian immune response to WNV has received considerable attention. However, little is known about the avian immune response to WNV. Avian taxa show variable susceptibility to WNV but what drives this variation is unknown. Thus, to study the immune response to WNV in birds, we infected captive zebra finches (Taeniopygia guttata). Zebra finches provide a useful model, as they are moderately susceptible to WNV, provide sufficient viremia to infect mosquitoes, and have a high-quality reference genome. We inoculated individuals with 104 plaque-forming units of the 1999 American Crow (Corvus brachyrhynchos) WNV isolate and sampled individuals (n=3 each) prior to infection and on Days 2 and 4 post-inoculation, corresponding to peak viremia. We performed Illumina RNAseq on spleens to provide an overview of their transcriptional response and performed differential gene expression analyses. In pairwise comparisons between Control, Day 2 and Day 4, we found a diverse repertoire of immune genes differentially expressed, including components of both the innate and adaptive immune response. Overall, we find broad parallels between the avian and the mammalian immune response to WNV, including the differential expression of five genes in the RIG-I pathway. We also uncover a number of immune genes not previously reported in the host response to WNV. Together with complementary immunological assays, we set the stage for future studies assessing variable immune responses to WNV among populations and taxa.
