Ancient and current association of the Trichinella complex with negative-sense and double-stranded RNA viruses

The earliest records of Trichinellosis might be found in bibles that recommend against pork consumption due to the spread of a disease that resembles what is now identified as Trichinellosis. Parasitic nematodes (round worms) of the genus Trichinella form a complex of at least 13 species with a broad geographic range. Herein, through data mining of transcriptomic data, and re-sequencing of the transcriptome of representative isolates, we demonstrate the presence of viruses within 10 recognized Trichinella species. We provide genome sequences of 4 viral species of negative sense RNA viruses that belong the Family Lispiviridae, Order Mononegavirales and of 8 novel viruses of double-stranded RNA viruses that belong to a novel sub-order within the order Ghabrivirales. The integration of viral genome fragments within encapsulated Trichinella genomes demonstrate that these parasite-virus associations are ancient. Overall, viruses show co-diversification with their parasitic hosts. Yet the phylogenetic position of viruses revealed past host jump from an ancestral encapsulated Trichinella species to the ancestral T. pseudospiralis, and challenges previous dogma on the phylogeny and biogeography of Trichinella species in North America.