Introduction

The virus order Mononegavirales was established in 1991 to accommodate related viruses with nonsegmented, linear, single-stranded negative-sense RNA genomes. These viruses were initially assigned to three mononegavirus families: Filoviridae, Paramyxoviridae, and Rhabdoviridae [32, 33]. The families Bornaviridae and Nyamiviridae joined the order in 1996 [34] and 2014 [1, 25], respectively, followed by the families Mymonaviridae, Pneumoviridae, and Sunviridae in 2016 [2]. The order was continuously amended in 1995 [7], 1997 [35], 2000 [36], 2005 [37], 2011 [17], and 2016 [2]. In 2016, the Study Groups of the International Committee on Taxonomy of Viruses (ICTV) responsible for the taxonomy of the order and its eight families assigned unclassified mononegaviruses to existing or novel taxa and continued efforts to streamline order nomenclature. Here we present the changes that were (re)proposed via official ICTV taxonomic proposals (TaxoProps) at http://www.ictvonline.org/ in 2016 and that were accepted by the ICTV Executive Committee. These changes are official ICTV taxonomy as of 2017.

Taxonomic changes at the order level

No changes were made at the order level.

Taxonomic changes at the family level

Bornaviridae

The family Bornaviridae remains monogeneric but was expanded in 2017 by one species (Mammalian 2 bornavirus) for the newly discovered variegated squirrel bornavirus 1 [23] (TaxoProp 2016.013aM.A.v1.Bornavirus_sp).

Filoviridae

No changes were made to this family.

Mymonaviridae

No changes were made to this family.

Nyamiviridae

The family Nyamiviridae was expanded to include a third genus (Peropuvirus) including the new species Pteromalus puparum peropuvirus for a virus recently discovered in parasitoid wasps, Pteromalus puparum negative-strand RNA virus 1 [45] (TaxoProp 2016.015a-dM.A.v1.Peropuvirus).

Paramyxoviridae

The non-Latinized binomial species name format [40] was applied throughout the family Paramyxoviridae (TaxoProp 2016.011aM.A.v2.Paramyxoviridae_spren). In addition, the genus Avulavirus was expanded by one novel species, Avian avulavirus 13, for avian paramyxovirus 13 discovered in geese [19, 24, 47] (TaxoProp 2016.001a,bM.A.v2.Avulavirus_spren). The genus Rubulavirus was expanded by 10 species to accommodate two long-known viruses (e.g., Menangle virus, Tioman virus) and eight newly discovered bat viruses (bat mumps virus, Achimota viruses 1 and 2, Sosuga virus, Teviot virus, Tuhoko viruses 1–3) [3, 5, 11, 12, 16, 26] (TaxoProp 2015.016aM.A.v3.Rubulavirus_10sp). Finally, the previous species name Newcastle disease virus was changed to Avian avulavirus 1 to reflect the fact that “Newcastle disease virus” is but one strain of the member virus of this species, avian paramyxovirus 1 (APMV-1) [46] (TaxoProp 2016.001a,bM.A.v2.Avulavirus_spren).

Pneumoviridae

The non-Latinized binomial species name format [40] was applied throughout the family Pneumoviridae (TaxoProp 2016.012aM.A.v1.Pneumoviridae_spren).

Rhabdoviridae

The most extensive changes were introduced into the family Rhabdoviridae. The new genus Almendravirus was created to include five new species (TaxoProp 2016.002a-dM.A.v3.Almendravirus) to accommodate mosquito viruses discovered from 2009–2013 (Arboretum virus, Balsa virus, Coot Bay virus, Puerto Almendras virus, and Rio Chico virus) [13, 43, 44]. The new genus Curiovirus, including four new species, was created for unclassified dipteran viruses known since the 1970s–80s (Curionopolis virus, Iriri virus, Itacaiunas virus, Rochambeau virus) (TaxoProp 2016.003a-dM.A.v3.Curiovirus) [14, 15, 44]. Twelve mostly dipteran viruses (Hart Park virus, Gray Lodge virus, Joinjakaka virus, Kamese virus, La Joya virus, Landjia virus, Manitoba virus, Marco virus, Mosqueiro virus, Mossuril virus, Ord River virus, and Parry Creek virus), isolated in the 1950s to late 1970s, were classified into twelve new species in the new genus Hapavirus. The previously free-floating rhabdovirus species Flanders virus, Ngaingan virus, and Wongabel virus were moved into the genus Hapavirus and renamed accordingly (Flanders hapavirus, Ngaingan hapavirus, and Wongabel hapavirus, respectively) [4, 21, 44] (TaxoProp 2016.005a-gM.A.v4.Hapavirus). The largest newly created rhabdovirus genus is Ledantevirus. This genus includes 14 new species for Barur virus, Fikirini virus, Fukuoka virus, Kern Canyon virus, Keuraliba virus, Kolente virus, Kumasi rhabdovirus, Le Dantec virus, Mount Elgon bat virus, Nkolbisson virus, Nishimuro virus, Oita virus, Wǔhàn louse fly virus 5, and Yǒngjiā tick virus 2, which were isolated from or detected in arthropods and/or mammals [6, 10, 18, 28, 38, 44] (TaxoProp 2016.006a-dM.A.v2.Ledantevirus). Finally, the novel genus Sripuvirus was created to include five new species for sandfly and lizard viruses (Almpiwar virus, Chaco virus, Niakha virus, Sena Madureira virus, and Sripur virus) [29, 41, 44] (TaxoProp 2016.007a-dM.A.v5.Sripuvirus).

The existing genus Cytorhabdovirus was expanded by inclusion of the novel species Colocasia bobone disease-associated cytorhabdovirus for a plant virus first described in 1973 in the taro plant (Colocasia esculenta)] [22] (TaxoProp 2016.017aM.A.v1.Cytorhabdovirus_sp). The genus Ephemerovirus was enlarged by three species to accommodate the long-known bovid viruses Kimberley and Koolpinyah, and the mosquito-borne Malakal and Yata viruses [8, 9] (TaxoProp 2016.004aM.A.v2.Ephemerovirus_3sp). The recently described, possibly human, Bas-Congo virus and Ekpoma viruses 1 and 2, and the biting midge-borne Sweetwater Branch virus were classified into four new species of the genus Tibrovirus [20, 27, 39, 44] (TaxoProp 2016.008aM.A.v3.Tibrovirus_4sp). Klamath virus, discovered in 1962 in a vole, was assigned to a novel species in the genus Tupavirus [44] (TaxoProp 2016.009aM.A.v2.Tupavirus_sp), and seven new species were added to the genus Vesiculovirus for American bat vesiculovirus (isolated from bats in 2008) and Jurona virus, Malpais Spring virus, Morreton virus, Perinet virus, Radi virus, and Yug Bogdanovac virus (isolated from mosquitoes or sandflies in 1962–1986) [22, 30, 31, 42, 44] (TaxoProp 016.010aM.A.v3.Vesiculovirus_7sp).

Finally, the existing species names Oncorhynchus 1 novirhabdovirus (formerly Infectious hematopoietic necrosis virus) and Oncorhynchus 2 novirhabdovirus (formerly Viral hemorrhagic septicemia virus) were changed to Salmonid novirhabdovirus and Piscine novirhabdovirus, respectively, to be more reflective of the host spectrum of their members. (2016.018aM.A.v1.Novirhabdovirus_spren).

Sunviridae

In 2017, no changes were made to this family.

Summary

A summary of the current, ICTV-accepted taxonomy of the order Mononegavirales is presented in Table 1.

Table 1 ICTV-accepted taxonomy of the order Mononegavirales as of 2017