''Getah virus'' is a mosquito-borne

arbovirus Arbovirus is an informal name for any virus that is transmitted by arthropod vectors. The term ''arbovirus'' is a portmanteau word (''ar''thropod-''bo''rne ''virus''). ''Tibovirus'' (''ti''ck-''bo''rne ''virus'') is sometimes used to more spe ...

in the ''

Alphavirus ''Alphavirus'' is a genus of RNA viruses, the sole genus in the ''Togaviridae'' family. Alphaviruses belong to group IV of the Baltimore classification of viruses, with a positive-sense, single-stranded RNA genome. There are 32 alphaviruses, ...

'' genus. The virus was first isolated in Malaysia in 1955 from the ''Culex gelidus'' mosquito. It has been known to infect pigs but more commonly affects horses. The virus was isolated near rubber plantations; the word ''Getah'' means rubber in Malay. The first outbreak among racehorses occurred in Japan September–November 1978. Getah virus is widely distributed in South-east Asian countries and while previous studies have indicated the presence of Getah virus in Northern Australia these have recently been brought into question.

Genome

Getah virus has a positive-sense single stranded RNA genome. According to

Baltimore Classification Baltimore classification is a system used to classify viruses based on their manner of messenger RNA (mRNA) synthesis. By organizing viruses based on their manner of mRNA production, it is possible to study viruses that behave similarly as a di ...

System, this virus is in Group IV. The virus appears to have evolved about 1872 (95% range: 1773 - 1942) and has diverged into four lineages.Li YY, Liu H, Fu SH, Li XL, Guo XF, Li MH, Feng Y, Chen WX3, Wang LH, Lei WW, Gao XY, Lv Z, He Y, Wang HY, Zhou HN, Wang GQ, Liang GD (2017) From discovery to spread: The evolution and phylogeny of Getah virus. Infect Genet Evol 55:48-55

Transmission & infection

The virus is transmitted by mosquitoes, specifically those in the ''

Aedes ''Aedes'' is a genus of mosquitoes originally found in tropical and subtropical zones, but now found on all continents except perhaps Antarctica. Some species have been spread by human activity: ''Aedes albopictus'', a particularly invasive spe ...

'' and ''

Culex ''Culex'' is a genus of mosquitoes, several species of which serve as vectors of one or more important diseases of birds, humans, and other animals. The diseases they vector include arbovirus infections such as West Nile virus, Japanese encep ...

'' genera. It is also transmitted between horses through aerosols or direct nasal contact, though this seems unlikely since a large portion of virus particles are necessary for transmission and are found in lower numbers in nasal secretions. In horses, the virus causes fever, rash, edema of the hind legs, and swelling of the lymph nodes. In inoculated horses, the symptoms manifested themselves beginning 2–4 days post infection. In pigs, the virus causes miscarriage; symptoms occurred 1–3 days after experimental infection. Though the virus does not produce illness in humans, neutralizing antibodies have been identified within humans.

Treatment

There is an inactivated-virus vaccine for horses. Once the horse is infected, supportive therapy is the only treatment available. Horses usually make a full recovery after 1 to 2 weeks. No Getah virus deaths have been reported in horses in clinical settings, and deaths only occur in pigs in the fetal stage.

References

{{Taxonbar, from=Q18976352 Alphaviruses