Novel viruses belonging to the family Circoviridae identified in wild American wigeon samples

Members of the family Circoviridae are known to infect several avian species, with the ability to cause severe disease outcomes in some species. Using a high-throughput sequencing-informed approach, we identified two novel lineages of circoviruses, referred to as wigfec circovirus 1 and 2, in faecal matter of American wigeons (Mareca americana) collected in Arizona, USA. Wigfec circovirus 1 was identified in eight samples and is most closely related to the other waterfowl circoviruses, sharing ~64% genome-wide sequence identity with duck circoviruses. On the other hand, wigfec circovirus 2 was identified in two samples and is most closely related to two circoviruses identified in bat samples, sharing ~71% genome-wide pairwise identity. Both novel circoviruses were recovered from samples collected at the same location two months apart. Furthermore, in one sample, both of these viruses were identified, indicating these viruses are likely common amongst these birds and/or their environment.