Arenaviridae

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Arenaviridae
Lassa virus virions TEM 8699 lores.jpg

Lassa virus budding

Systematics
Classification : Viruses
Area : Riboviria
Empire : Orthornavirae
Phylum : Negarnaviricota
Subphylum : Polyploviricotina
Class : Ellioviricetes
Order : Bunyavirales
Family : Arenaviridae
Taxonomic characteristics
Genome : (+/-) ss RNA segmented
Baltimore : Group 5
Symmetry : helical / circular
Cover : available
Scientific name
Arenaviridae
Left
NCBI  Taxonomy: 11617
ViralZone ( ExPASy , SIB): 501
ICTVdB Virus Code : 00.003

The family Arenaviridae or arena viruses originally included only one class arenavirus of enveloped viruses single with a segmented ambisense - RNA as genome . The Arenaviridae include pathogens causing hemorrhagic fever , encephalitis and meningoencephalitis in humans, which are transmitted to humans by animals (predominantly rodents ) as a natural reservoir . The human diseases of the Arenaviridae belong to the zoonoses . The new genus Reptarenavirus includes newly isolated viruses in reptiles ( boas and pythons ) that may be associated with an often fatal infection.

The family's name is derived from the Latin arenosus 'sandy' or arena 'sand' to describe the sandy ribosomal structure inside the virions . The original name arenovirus has been dropped because of the risk of confusion with adenovirus .

As the first member of the Arenaviridae family , the lymphocytic choriomeningitis virus (LCMV ) was isolated and described during an encephalitis epidemic in St. Louis (USA) in 1933 .

morphology

Schematic structure of an arena virus

The virions (virus particles) of the Arenaviridae have a round to irregular shape and are 50 to 300 nm (mostly between 110 and 130 nm) in diameter , depending on the species and preparation of the test material  . 8–10 nm long, club-shaped glycoprotein spikes are embedded in the virus envelope . The individual spikes consist of a tetramer of the viral envelope protein. The two capsids for packaging the two RNA segments (ribonucleocapsids) are closed in a ring and have helical symmetry ; their length varies between 450 and 1300 nm. One molecule of the viral RNA polymerase (L protein) is attached to each of them.

Morphologically very unusual is the presence of a varying number of cellular ribosomes within the virion, which give the virus particles their “sandy” appearance. A number of different cellular RNAs (including ribosomal RNA) as well as replicative forms of viral RNA, such as various viral mRNAs (bound to the ribosomes) and complete complementary strands of the virus genome can also be found in purified virus preparations . These non-genomic RNAs are all located outside the capsids in varying amounts.

The viral genome consists of two molecules of single-stranded RNA with mixed (i.e., ambisense, +/-) polarity . They are called L ( large ) and S ( small ) and are about 7.5 and 3.5 kb in size, respectively  . Although the capsids are closed in a ring, the RNA strands are linear and therefore not circular. A 19 to 30 base sequence at the 3 'end of the RNA is present on both strands and is also conserved within the virus family.

Biological properties

The human pathogenic Arenaviridae (with the exception of the species Tacaribe virus ) have various rodents ( Rodentia ) as a natural reservoir. The LCMV is found in mice , the African arenaviruses mainly in multi-teat mice ( Mastomys ) and African soft rats ( Praomys ). The New World Arenaviruses have several species of New world (subfamily Sigmodontinae ) to the host, including the rice rats ( Oryzomys ), Stachel oryzomys ( Neacomys ), Andean Swamprat ( Neotomys ), Vesper mice ( Calomys ) and cotton rats ( Sigmodon ). Unlike the other arenaviruses, the tacaribe virus has fruit bats ( Artibeus spp. ) As its host. The Arenaviridae cause a chronic infection with viraemia and viruria in their hosts, but mostly without symptoms of the disease; this is due to a slow or non-existent defense by the host's immune system, which has adapted over time. In humans, as a non-adapted host , however, serious, often fatal diseases occur.

In the genus Reptarenavirus arenaviruses are summarized in snakes.

Systematics and occurrence

All species of Falimie Arenaviridae were previously placed in the genus Arenavirus . However, in 2014 this was divided into the genera Mammarenavirus with hosts under the Mammalia and Reptarenavirus with hosts under the snakes.

  • Family Arenaviridae
  • LCMV / Lassa Complex (Old World Arena Viruses)
Further suggestions that have not yet been confirmed by ICTV as of 2017 are:
  • Tacaribe Complex: (New World Arenaviruses)
Further suggestions that have not yet been confirmed by ICTV as of 2017 are:
  • CAS virus (California Academy of Science Virus, CASV)
Unclassified reptarena viruses according to NCBI (selection as of October 2019):
  • Hair Man Institute snake virus
Further proposals, the confirmation of which by ICTV, status March 2019, are still missing (according to NCBI, status October 2019):
  • Species Dante Muikkunen virus 1
  • Species Hair Man Institute snake virus 2
  • Species Old schoolhouse virus 1
  • Species Old schoolhouse virus 2
  • Species Veterinary Pathology Zurich virus 1
  • Species Veterinary Pathology Zurich virus 2

literature

  • PJ Southern: Arenaviridae: the viruses and their replication. in: David M. Knipe, Peter M. Howley et al. (eds.): Fields' Virology, 3rd Edition, Philadelphia 1996
  • CM Fauquet, MA Mayo et al .: Eighth Report of the International Committee on Taxonomy of Viruses , London, San Diego, 2004

Web links

Individual evidence

  1. ↑ ICTV Master Species List 2018b v1 MSL # 34, Feb. 2019
  2. ↑ a b ICTV: ICTV Taxonomy history: Akabane orthobunyavirus , EC 51, Berlin, Germany, July 2019; Email ratification March 2020 (MSL # 35)
  3. ↑ ICTV proposals 2014.011a-dV et al. , Mark D. Stenglein et al.
  4. ↑ ICTV proposals 2014.012aV et al. , Michael J. Buchmeier et al.
  5. ↑ a b c Sheli R. Radoshitzky et al .: Past, present, and future of arenavirus taxonomy (PDF) , in: Arch Virol., Springer-Verlag Vienna, May 3, 2015, doi: 10.1007 / s00705-015-2418 -y
  6. ↑ SIB: Mammarenavirus , on: ViralZone
  7. ^ NCBI: unclassified Old World arenaviruses
  8. ↑ NCBI: unclassified Reptarenavirus
  9. ^ NCBI: unclassified Hartmanivirus