Picobirnavirus: How do you find where it’s hiding?

Picobirnaviruses (PBVs) are double-stranded RNA viruses found in a wide range of hosts including humans, animals, invertebrates and birds. First discovered in 1988 from a human stool sample, PBVs were initially considered human pathogens associated with gastrointestinal illness. However, PBV has not been definitively linked to any specific disease. The nature of their pathogenicity remains unclear, raising questions as to whether PBVs are true pathogens, opportunistic pathogens or merely bystanders. The PBV genome contains extremely high levels of genetic diversity within and between sequences, as well as in the genetic codes used for translation, leading to speculation that the virus may be prokaryotic. Several methods are currently used to detect and characterise PBV genomes. In this review, we summarise the contemporary methods used to attempt host identification, highlighting the current challenges of the methods. The methods include direct culturing, PCR, next-generation metagenomics sequencing, and cloning into bacteria. Uncovering the host could elucidate PBVs' role in both human and animal health and the broader implications within various important ecosystems.