Preface to the Second Koala Retrovirus Workshop online 25–27 May 2021. In Proceedings of the Second Koala Retrovirus Workshop, ed. D. E. Alquezar-Planas, D. P. Higgins, C. L. Singleton, and A. D. Greenwood

In 2013, the first Koala Retrovirus Workshop was held in San Diego, bringing together biology and veterinary specialists to assess discuss state of knowledge on koala retrovirus (KoRV) form professional bridges networks. Tremendous progress has been made years following Diego meeting, large part due ongoing international collaborations that were fostered study KoRV. This volume presents peer-reviewed papers from most oral presentations discussions during Second 2021. Unfortunately, COVID-19 pandemic forced workshop into an online only format. Despite this limitation, three days based highlighted current important information gaps, culminating suggested ways forward, all summarized volume.