Oral Presentation 12th Australasian Virology Society Meeting 2024

Diversity of insect-specific viruses in Culex mosquitoes collected in Papua New Guinea (#47)

Nayomi S Danthanarayana 1 2 , James O'Dwyer 1 , Joelyn Goi 3 , Vittoria Stevens 1 , Martin Pal 2 4 5 , Brian P McSharry 2 6 , Marta Hernandez-Jover 6 7 , Stephan S Karl 3 8 , Justin A Roby 2 6 , Jade K Forwood 2 6 , Matthew J Neave 1 , David T Williams 1
  1. CSIRO, Australian Centre for Disease Preparedness, Geelong, VIC, Australia
  2. School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
  3. Papua New Guinea Institute of Medical Research, Goroka, Papua New Guinea
  4. Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
  5. Walter and Eliza Hall Institute of Medical Research, WEHI, Parkville, VIC, Australia
  6. Gulbali Institute, Charles Sturt University, Wagga Wagga, NSW, Australia
  7. School of Agricultural, Environmental and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
  8. Australian Institute of Tropical Health and Medicine, James Cook University, Smithfield, QLD, Australia

Insect-specific viruses (ISVs) form a diverse group that exclusively infect invertebrates and exert a significant impact on the vectorial capacity of mosquitoes. Our knowledge of ISVs through metagenomic next-generation sequencing has significantly expanded in recent years but remains incomplete. Exploring new ecological niches of important mosquito vectors is expected to offer additional insights into ISVs. This study utilized a meta-transcriptomic approach to determine ISVs in Culex mosquitoes collected from five provinces in Papua New Guinea (PNG) in 2019 and 2020. The mosquitoes were individually analysed or pooled based on their location, feeding status, and species. Next-generation sequencing was performed on 57 samples consisting of 24,706 mosquitoes to identify ISVs. A preliminary analysis has identified more than 800 known viral species. Further analysis was conducted on 145 viral species with complete or near-complete genomes. Among the subgroup, 70% of all viral species were ISVs. Prominent families of ISVs identified were Birnaviridae and Rhabdoviridae, and the top viral species detected were Hubei virga-like virus2, Cambodia Culex birnavirus, XiangYun partiti-picobirna-like virus2, and Merida virus or closely related sister species to those given. The samples contained several ISVs known to influence arbovirus transmission. Although some ISVs were recognized across different locations and mosquito species, several unique ISVs were found within each group. The highest ISV diversities were observed at a geographic level in the Western province samples and at a species level in Culex pullus mosquitoes. Given the high prevalence of ISVs belonging to the Rhabdoviridae family, phylogenetic analyses were conducted on these samples. It was observed that ISVs of the same or closely related species clustered based on geographic location. Future analysis will explore genomes of other viral families and identify unassigned or novel viruses. The findings are expected to significantly expand our understanding of the mosquito virome in Culex mosquitoes of PNG.