The family Arenaviridae was established in 1976 to accommodate predominantly murid viruses with bisegmented, ambisense single-stranded RNA genomes that form enveloped particles with a “sandy” appearance [7]. Until recently, the family was monogeneric, including the single genus Arenavirus, with a steadily increasing number of species. The taxonomy of the family was substantially amended and emended [22] following the discovery of several distinct arenaviruses in alethinophidian snakes [4, 10, 24]. In particular, the genus Arenavirus was renamed Mammarenavirus, and a second genus, Reptarenavirus, was established in 2014 for several of the newly discovered snake viruses. A non-Linnean binomial species nomenclature was adopted for the entire family Arenaviridae [22] (ICTV TaxoProps [taxonomic proposals] 2014.011a-dV and 2014.012aV). Since then, the genus Mammarenavirus has been extended by 8 species for novel murid viruses discovered in Africa and Asia [3, 8, 11, 15, 21, 25] (TaxoProps 2014.013aV.A.v3.Mammarenavirus_2sp, 2015.001aM, 2016.014aM and 2016.019aM.A.v2.Mammarenavirus_sp).

The order Bunyavirales was established in 2017 to accommodate related viruses with segmented, linear, single-stranded, negative-sense or ambisense RNA genomes distributed among nine families (TaxoProp 2016.030a-vM). In particular, the then existing family Bunyaviridae was elevated to the rank of order. The three established bunyaviral genera Hantavirus, Nairovirus, and Tospovirus were renamed Orthohantavirus, Orthonairovirus, and Orthotospovirus and included in the newly established families Hantaviridae, Nairoviridae, and Tospoviridae, respectively (TaxoProp 2016.030a-vM). The genus Orthonairovirus was expanded by five species [13] (TaxoProp 2016.026a,bM). The family Peribunyaviridae was created to include the established bunyaviral genus Orthobunyavirus and a new genus, Herbevirus, for bunyaviruses discovered in invertebrates [14, 17] (TaxoProps 2016.024a-dM and 2016.030a-vM). The family Phenuiviridae was created to accommodate the established bunyaviral genus Phlebovirus, the previously “free-floating” plant virus genus Tenuivirus, and two new genera, Goukovirus and Phasivirus, for novel invertebrate bunyaviruses [16] (TaxoProps 2016.022a-dM and 2016.027a-dM). Three new families, Feraviridae, Jonviridae, and Phasmaviridae, were established for newly discovered invertebrate bunyaviruses [2, 14, 18] (TaxoProps 2016.021a-dM, 2016.025a-dM and 2016.028a-dM). In addition, the family Fimoviridae was created to accommodate the previously “free-floating” plant virus genus Emaravirus, which was expanded by three species for newly discovered plant viruses [5, 6, 26] (TaxoProps 2016.016aP, 2016.017aP, 2016.018aP, and 2016.030a-vM). Finally, a non-Linnean binomial species nomenclature was adopted for the entire family (TaxoProps 2016.020aM, 2016.023a-cM, 2016.026a,bM, 2016.029aM.A.v2.Tenuivirus_spren, and 2016.030a-vM).

After the establishment of the order Bunyavirales, the ICTV Study Groups responsible for the taxonomy of Arenaviridae and Bunyavirales assigned unclassified viruses to existing or novel taxa and continued streamlining order nomenclature in collaboration with other virus experts. Here we present the changes to both taxa that were proposed via official TaxoProps at in 2017 and that were accepted by the ICTV Executive Committee. These changes are official ICTV taxonomy as of March 2018.

Family Arenaviridae

Taxonomic changes at the family rank

In 2018, the family was extended by addition of a novel genus, Hartmanivirus, for Haartman Institute snake virus (HISV) isolated from a captive boa constrictor in Finland [9, 10] (TaxoProp The genus Mammarenavirus was extended by addition of two novel species for Ryukyo virus (RYKV) and souris virus (SOUV) discovered in mice in China and Cameroon, respectively (TaxoProps 2017.002M.A.v2.Mammarenavirus_sp and 2017.003M.A.v1.Mammarenavirus_sp). Five mammarenavirus species were renamed due to the ICTV decision to disallow diacritic marks in taxon names (TaxoProp 2017.001G.A.v2.43spren): Amaparí mammarenavirus, Junín mammarenavirus, Paraná mammarenavirus, Pichindé mammarenavirus, and Sabiá mammarenavirus were renamed Serra do Navio mammarenavirus, Argentinian mammarenavirus, Paraguayan mammarenavirus, Cali mammarenavirus, and Brazilian mammarenavirus, respectively, whereas the member virus names remained unchanged (TaxoProp 2017.001G.A.v2.43spren). Finally, the three reptarenavirus species names Alethinophid 1 reptarenavirus, Alethinophid 2 reptarenavirus, and Alethinophid 3 reptarenavirus were renamed Golden reptarenavirus, California reptarenavirus, and Rotterdam reptarenavirus. Two new reptarenavirus species were created for tavallinen suomalainen mies virus 2 (TSMV-2) and University of Giessen viruses 1–3 (UGV-1–3) discovered in captive boa constrictors; several newly sequenced reptarenaviruses were assigned to existing species [9] (TaxoProp 2017.015M.A.v1.Reptarenavirus_2sp3ren).

Order Bunyavirales

Taxonomic changes at the order rank

In 2018, no changes were made at the order rank.

Taxonomic changes at the family rank


In 2018, no changes were made at the family rank.


In 2018, no changes were made at the family rank.


In 2018, no changes were made at the family rank.


In 2018, no changes were made at the family rank.


The family Nairoviridae was expanded in 2018 by addition of two new species for the long-known but previously unsequenced Artashat virus (ARTSV) and Chim virus (CHIMV), both originally isolated from ticks. In addition, the species Burana orthonairovirus was renamed Tamdy orthonairovirus to better reflect the discovery history of species members, and several newly sequenced nairoviruses were classified into existing species [1] (TaxoProp 2017.008M.A.v1.Orthonairovirus_2sp1ren).


The family Peribunyaviridae was expanded in 2018 by addition of a novel species for Wolkberg virus (WBV) discovered in wingless bat flies (Eucampsipoda africana) in South Africa [12] (TaxoProp 2017.007M.A.v1.Orthobunyavirus_sp).


In 2018, no changes were made at the family rank.


In 2018, no changes were made at the family rank.


In 2018, no changes were made at the family rank.


The taxonomy of viruses of the family Arenaviridae and the order Mononegavirales remains in flux, and additional important changes are likely forthcoming. Indeed, in 2017, two additional taxonomic proposals that would affect the family Arenaviridae and the order Mononegavirales were debated during the most recent ICTV EC meeting in Singapore. TaxoProp 2017.006M.U.v2.Negarnaviricota proposes the

  • establishment of a phylum for negative-sense RNA viruses that is subdivided into two subphyla; and

  • establishment of a class including the order Bunyavirales, to be assigned to one of the subphyla.

TaxoProp 2017.012M.U.v2.Bunyavirales_rev proposes

  • dissolution of the families Feraviridae, Jonviridae, and Tospoviridae and absorption of their genera into remaining families;

  • the creation of three new bunyaviral families for novel invertebrate viruses [19, 20, 23];

  • the inclusion of the family Arenaviridae in the order; and

  • the creation of 19 new bunyaviral genera. These genera are planned to accommodate novel, mostly invertebrate, viruses [14, 23], but some of them are deemed necessary for reclassification of certain hantaviruses and phleboviruses.

These two proposals failed to find unanimous approval at a final ICTV EC vote in fall of 2017 and were deferred to the 2018 ICTV EC meeting, at which a simple majority vote would suffice for approval of the original proposals.


Summaries of the current, ICTV-accepted taxonomies of the family Arenaviridae and the order Bunyavirales are presented in Tables 1 and 2, respectively. These tables also include corrections and updates in virus name or abbreviation spelling.

Table 1 ICTV-accepted taxonomy of the family Arenaviridae as of 2018. Listed are all arenaviruses that have been classified into species
Table 2 ICTV-accepted taxonomy of the order Bunyavirales as of 2018. Listed are all bunyaviruses that have been classified into species