Taxonomy of the order Mononegavirales: update 2019.

In February 2019, following the annual taxon ratification vote, the order Mononegavirales was amended by the addition of four new subfamilies and 12 new genera and the creation of 28 novel species. This article presents the updated taxonomy of the order Mononegavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV).

Taxonomy of the order Mononegavirales: second update 2018.

In October 2018, the order Mononegavirales was amended by the establishment of three new families and three new genera, abolishment of two genera, and creation of 28 novel species. This article presents the updated taxonomy of the order Mononegavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV).

Macrophages and Dendritic Cells Are the Predominant Cells Infected in Measles in Humans.

Characterization of human measles cases is essential in order to better assess the data generated in model systems of morbillivirus infection. To this end, we collected formalin-fixed tissue samples from 23 natural measles cases from different areas in the world and different phases of disease ranging from prodromal and acute measles to a persistent infection in an immunocompromised subject. We show that the vast majority of measles virus (MV)-infected cells in epithelia were intraepithelial immune cells that were, in most cases, positive for the CD11c myeloid cell marker.

Taxonomy of the order Mononegavirales: update 2018.

In 2018, the order Mononegavirales was expanded by inclusion of 1 new genus and 12 novel species. This article presents the updated taxonomy of the order Mononegavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV) and summarizes additional taxonomic proposals that may affect the order in the near future.

Taxonomy of the order Mononegavirales: update 2017.

In 2017, the order Mononegavirales was expanded by the inclusion of a total of 69 novel species. Five new rhabdovirus genera and one new nyamivirus genus were established to harbor 41 of these species, whereas the remaining new species were assigned to already established genera. Furthermore, non-Latinized binomial species names replaced all paramyxovirus and pneumovirus species names, thereby accomplishing application of binomial species names throughout the entire order.

Possibility and Challenges of Conversion of Current Virus Species Names to Linnaean Binomials.

Botanical, mycological, zoological, and prokaryotic species names follow the Linnaean format, consisting of an italicized Latinized binomen with a capitalized genus name and a lower case species epithet (e.g., Homo sapiens).

Taxonomy of the order Mononegavirales: update 2016.

In 2016, the order Mononegavirales was emended through the addition of two new families (Mymonaviridae and Sunviridae), the elevation of the paramyxoviral subfamily Pneumovirinae to family status (Pneumoviridae), the addition of five free-floating genera (Anphevirus, Arlivirus, Chengtivirus, Crustavirus, and Wastrivirus), and several other changes at the genus and species levels. This article presents the updated taxonomy of the order Mononegavirales as now accepted by the International Committee on Taxonomy of Viruses (ICTV).

Early target cells of measles virus after aerosol infection of non-human primates.

Measles virus (MV) is highly infectious, and has long been thought to enter the host by infecting epithelial cells of the respiratory tract. However, epithelial cells do not express signaling lymphocyte activation molecule (CD150), which is the high-affinity cellular receptor for wild-type MV strains. We have generated a new recombinant MV strain expressing enhanced green fluorescent protein (EGFP), based on a wild-type genotype B3 virus isolate from Khartoum, Sudan (KS).

A point mutation, E95D, in the mumps virus V protein disengages STAT3 targeting from STAT1 targeting.

Mumps virus, like other paramyxoviruses in the Rubulavirus genus, encodes a V protein that can assemble a ubiquitin ligase complex from cellular components, leading to the destruction of cellular signal transducer and activator of transcription (STAT) proteins. While many V proteins target the interferon-activated STAT1 or STAT2 protein, mumps virus V protein is unique in its ability to also target STAT3 for ubiquitin modification and proteasome-mediated degradation. Here we report that a single amino acid substitution in the mumps virus V protein, E95D, results in defective STAT3 targeting while maintaining the ability to target STAT1.

The F gene of rodent brain-adapted mumps virus is a major determinant of neurovirulence.

Prior to the introduction of live-attenuated vaccines, mumps virus (MuV) was the leading cause of virus-induced meningitis. Although vaccination has been effective at controlling the disease, the use of insufficiently attenuated strains has been associated with high rates of aseptic meningitis in vaccinees. The molecular basis of MuV attenuation is poorly understood, and no reliable molecular markers of virulence have been identified.

Measles virus M and F proteins associate with detergent-resistant membrane fractions and promote formation of virus-like particles.

Assembly and release of particles comprise a late step in virus-host cell interactions. Though it may share major biological properties with its orthologues in related viruses, trafficking and oligomerization of the matrix (M) protein of Measles virus (MV) and its relative contribution to assembly and budding of particles from particular host cells have not been addressed in more detail. Plasmid-driven expression of authentic and mutant M proteins revealed that the amino acid at position 89, an important adaptation determinant for growth of attenuated strains in Vero cells, influences the electrophoretic mobility but not the intracellular distribution of M proteins, nor their ability to oligomerize or migrate as a doublet band in SDS-PAGE.

Morbilliviruses and human disease.

Morbilliviruses are a group of viruses that belong to the family Paramyxoviridae. The most instantly recognizable member is measles virus (MV) and individuals acutely infected with the virus exhibit a wide range of clinical symptoms ranging from a characteristic mild self-limiting infection to death. Canine distemper virus (CDV) and rinderpest virus (RPV) cause a similar but distinctive pathology in dogs and cattle, respectively, and these, alongside experimental MV infection of primates, have been useful models for MV pathogenesis.

Rational attenuation of a morbillivirus by modulating the activity of the RNA-dependent RNA polymerase.

Negative-strand RNA viruses encode a single RNA-dependent RNA polymerase (RdRp) which transcribes and replicates the genome. The open reading frame encoding the RdRp from a virulent wild-type strain of rinderpest virus (RPV) was inserted into an expression plasmid. Sequences encoding enhanced green fluorescent protein (EGFP) were inserted into a variable hinge of the RdRp.

Molecular mechanisms of measles virus persistence.

As measles virus causes subacute sclerosing panencephalitis and measles inclusion body encephalitis due to its ability to establish human persistent infection, without symptoms for the time between the acute infection and the onset of clinical symptoms, it has been the paradigm for a long term persistent as opposed to chronic infection by an RNA virus. We have reviewed the mechanisms of persistence of the virus and discuss specific mutations associated with CNS infection affecting the matrix and fusion protein genes. These are placed in the context of our current understanding of the viral replication cycle.