Post by Andrew Broadbent

Although avian influenza dominates the headlines, other viruses circulate in poultry and are of considerable economic impact, one of which is infectious bursal disease virus (IBDV). This year, my lab has published 4 articles on IBDV that I would like to share 🥚 🐣 🐥 🐓 🍗 👇 🦠 IBDV replicates in the cytoplasm in “virus factories” (VFs) formed through liquid-liquid phase separation (LLPS). My graduate student, Andrew Brodrick (now at NIH) et al discovered that viral protein (VP)3 is necessary for driving phase separation, but it can’t do it alone. Instead, it forms a higher order complex with the polymerase and likely viral RNA to drive the process. Moreover, VP3 contains a predicted intrinsically disordered region (IDR) that modulates VF liquidity. This sets IBDV apart from reovirus which only uses one protein to phase-separate. It also provides more information on LLPS which is of growing interest to cell biology, and indicates that the VP3 IDR might be a good target for attenuating IBDV. https://lnkd.in/e7ttgKih 🦠 IBDV is immunosuppressive, so infected birds are more susceptible to secondary infections. In work that began in the UK and finished in the US, my postdoc, Salik Nazki et al evaluated whether IBDV could influence the spillover, spread and evolution of avian influenza virus (AIV) in chickens. Using a low path H3N8 as a model, we found a significantly greater number of amino acid substitutions in the AIV population shed from chickens with prior IBDV infection, compared to no IBDV, but thankfully IBDV had a minimal effect on the amount or duration of AIV shedding, or on transmission, meaning it is unlikely to affect the ecology of AIV. This is important to know for designing control strategies in poultry. https://lnkd.in/ezJHXY2B Our colleagues in the Cardona Lab (MN) also did a similar study with low path H7 https://lnkd.in/eHBGZJjr 🦠 Given the importance of IBDV to the poultry industry, we wanted to sequence what was actually circulating in the field. A postdoc in my lab, Sofia Egana Labrin (now at Mississippi State) et al found 5 clades in Delmarva that seemed to be evolving independently of each other, and one of these clades had taken over - going from 25% prevalence in 2007 to 76% in 2023. Some of its capsid mutations also reduced neutralizing antibody binding so we think it might be able to escape vaccine induced immunity- we are testing that hypothesis now. https://lnkd.in/edGDm6-W 🦠 Finally, I wrote a review as part of the Journal of Virology “new voices in virology” collection, which talks about how IBDV (and related viruses like IPNV) evolve- this can happen by antigenic drift, recombination, and reassortment, and I highlight research gaps that we can try to plug. https://lnkd.in/ex3wUUxq Watch this space for more to come - we have another 4 manuscripts in preparation- I just need to get my act together and actually write them now!