Abstract
Metatranscriptomics is transforming our knowledge of the virosphere by revealing the diversity and abundance of viruses. This unbiased exploration allows for a breadth of novel viruses to be unveiled. However, the viromes of invertebrate hosts are poorly understood. Mosquitoes are common disease vectors, and whilst currently do not transmit any known pathogenic diseases to humans in New Zealand, little is known about the viruses they harbour and the risk they pose to public and animal health.
Using a metatranscriptomic approach on a range of mosquitoes sampled during 2021-2022 from the Mackenzie region in the South Island of New Zealand, we aimed to uncover the diversity of viruses they carried. From RNA sequences, we searched for conserved RdRp (RNA-dependent RNA polymerase) and NSP (Non-Structural Protein) regions using sequence similarity searches against a database of known viruses. Non-viral sequences were excluded based on length, dissimilarity to viral species and significance threshold. Viral sequences identified were aligned with genetically similar viruses and phylogenetic trees were estimated to classify and confirm likely host species.
In this study, we discovered 17 invertebrate-host associated viral species, all of which were novel, spread across 10 taxonomic orders/families. Two viruses in the Partitiviridae and the Picornavirales are closely related to potentially pathogenic species for their invertebrate hosts. Other viruses included single and double stranded RNA viruses, and a single stranded DNA virus.
These findings illustrate how it is vital for research into New Zealand invertebrate hosts to expand so we can better understand the diversity of viromes within these species and the implications for interacting species and populations. Whilst no human-associated diseases were revealed, this study highlights how limited the knowledge on viromes of vector species is. Knowing the presence of a potentially pathogenic disease in a vector species is important surveillance to recognise emergent disease.