| Sindbis virus | |
|---|---|
 | |
| CryoEM model of Sindbis virus.EMDB entryEMD-2374[1] | |
Virus classification | |
| (unranked): | Virus |
| Realm: | Riboviria |
| Kingdom: | Orthornavirae |
| Phylum: | Kitrinoviricota |
| Class: | Alsuviricetes |
| Order: | Martellivirales |
| Family: | Togaviridae |
| Genus: | Alphavirus |
| Species: | Alphavirus sindbis |
Sindbis virus (SINV) is a member of theTogaviridae family, in theAlphavirus genus. The virus was first isolated in 1952 inCairo, Egypt.[2] The virus is transmitted bymosquitoes (Culex andCuliseta). SINV is linked toPogosta disease[3] (Finland),Ockelbo disease (Sweden) andKarelian fever (Russia). In humans, the symptoms includearthralgia,rash andmalaise. Sindbis virus is widely and continuously found in insects and vertebrates in Eurasia, Africa, and Oceania. Clinical infection and disease in humans however has almost only been reported from Northern Europe (Finland, Sweden, Russian Karelia), where SINV is endemic and where large outbreaks occur intermittently. Cases are occasionally reported in Australia, China, and South Africa.[4]
SINV is anarbovirus, it isarthropod-borne, and it is maintained in nature by transmission betweenvertebrate (bird) hosts andinvertebrate (mosquito) vectors. Humans are infected with Sindbis virus when bitten by an infected mosquito.
Sindbis viruses are enveloped particles with an icosahedralcapsid, with a positive single strandedRNA genome, with an approximate size of 11.7 kb. The RNA has a5'-cap and 3'-polyadenylated tail, and therefore serves directly as messenger RNA (mRNA) in a host cell. The genome encodes four non-structural proteins, the capsid, and two envelope proteins. This is characteristic of allTogaviruses.Replication iscytoplasmic and rapid. The genomic RNA is partiallytranslated at the 5' end to produce the non-structural proteins which are then involved in genome replication and the production of new genomic RNA and a shorter sub-genomic RNA strand. This sub-genomic strand istranslated into the structural proteins. The viruses assemble at the host cell surfaces and acquire theirenvelope throughbudding.
Anon-coding RNA element has been found to be essential for Sindbis virus genome replication.[5]
Recombination has been demonstrated betweenRNAs of Sindbis virus.[6][7] The mechanism of recombination appears to be template switching (copy choice) during RNA replication.[6][7]