Potential origins of fish toti-like viruses in invertebrates

Abstract

The virus family Totiviridae had originally been considered to include only viruses which infected fungal and protist hosts, but since 2006 a growing number of viruses found in invertebrates and fish have been shown to cluster phylogenetically within this family. These Totiviridae-like, or toti-like, viruses do not appear to belong within any existing genera of Totiviridae, and whilst a number of new genus names have been suggested, none has yet been universally accepted. Within this growing number of toti-like viruses from animal hosts, there exists emerging viral threats particularly to aquaculture, namely Infectious myonecrosis virus in whiteleg shrimp and Piscine myocarditis virus (PMCV) in Atlantic salmon (Salmo salar). PMCV in particular continues to be an issue in salmon aquaculture as a number of questions remain unanswered about how the virus is transmitted and the route of entry into host fish. Using a phylogenetic approach, this study shows how PMCV and the other fish toti-like viruses probably have deeper origins in an arthropod host. Based on this, it is hypothesized that sea lice could be acting as a vector for PMCV, as seen with other RNA viruses in Atlantic salmon aquaculture and in the toti-like Cucurbit yellows-associated virus which is spread by the greenhouse whitefly Trialeurodes vaporariorum.

Detection of known and novel virus sequences in the black solider fly and expression of host antiviral pathways

“…Another novel virus detected in this study, which we call Hermetia illucens toti-like virus 2, groups within a large clade of insect-infecting toti-like viruses, and clusters closely with toti-like viruses that infect other insects of the order Diptera (Shi et al, 2016; W. Zhang et al, 2022). Totiviruses are a family of double-stranded RNA viruses that have historically been associated with fungi, but more recently, many metatranscriptomic studies are detecting toti-like viruses in other taxa, including insects (Giovannini et al, 2022; Huang et al, 2018; Koyama et al, 2015, 2016; Shi et al, 2016; Tighe et al, 2022; P. Zhang et al, 2018). Hermetia illucens toti-like virus 2 is the second toti-like virus discovered in BSF (Pienaar et al, 2022).…”

“…ToPviruses are a family of double-stranded RNA viruses that have historically been associated with fungi, but more recently, many metatranscriptomic studies are detecPng toP-like viruses in other taxa, including insects (Giovannini et al, 2022;Huang et al, 2018;Koyama et al, 2015Koyama et al, , 2016Shi et al, 2016;Tighe et al, 2022;P. Zhang et al, 2018).…”

Do bed bugs transmit human viruses, or do humans spread bed bugs and their viruses? A worldwide survey of the bed bug RNA virosphere

“…Totiviruses are dsRNA viruses that typically infect fungi, but there is a growing number of toti-like viruses detected in arthropod and vertebrate metatranscriptomic studies ( Tighe et al, 2022 ). According to our phylogenetic analysis, Cimex toti-like virus 1 falls within a clade of arthropod and plant infecting viruses, along with a toti-like virus 1 detected in an anal swab from a bird (GenBank: QKN88741.1) ( Fig.…”

Do bed bugs transmit human viruses, or do humans transmit bed bug viruses? A worldwide survey of the bed bug RNA virosphere

“…Totiviruses are dsRNA viruses that typically infect fungi, but there is a growing number of toti-like viruses detected in arthropod and vertebrate metatranscriptomic studies (Tighe et al, 2022). According to our phylogenetic analysis, Cimex toti-like virus 1 falls within a clade of arthropod and plant infecting viruses, along with a toti-like virus 1 detected in an anal swab from a bird (GenBank: QKN88741.1) ( Figure 6 ).…”