Group IV Getah Virus in Culex Mosquitoes, Malaysia

Abstract

A new Getah virus (GETV) strain, B254, was isolated from Culex fuscocephalus mosquitoes captured at Mount Ophir, Malaysia, in 2012. Phylogenetic analyses revealed that GETV B254 is distinct from the old Malaysia GETV MM2021 strain but closely related to group IV GETV from Russia (LEIV16275Mag), China (YN12031), and Thailand (GETV/SW/Thailand/2017).

Genomic and In Vitro Phenotypic Comparisons of Epidemic and Non-Epidemic Getah Virus Strains

“…The GETV GIV B254 strain is a new virus strain recently isolated from Culex fuscocephalus in Malaysia, since the first virus isolation in 1955 [ 19 ]. It is phylogenetically distinct from the old Malaysian GETV MM2021, but similar to other GIV strains, where it shared the closest relationship with the China YN12031 strain isolated in 2012 [ 19 , 28 ]. It has been hypothesized that the GETV GIII and GIV viruses evolved from the GII Sagiyama strain.…”

“…Strain MM2021 was provided by the World Reference Center for Emerging Viruses and Arboviruses, The University of Texas Medical Branch, Galveston, TX, USA. Strain B254 was isolated from Culex fuscocephala in Peninsular Malaysia between 2011–2014 [ 19 ]. The epidemic strains, MI-110 and 14-I-605, were isolated from infected equines during the GETV outbreaks in Japan in 1978 and 2014, respectively [ 5 ].…”

“…Both epidemic strains were provided by Dr. Hiroshi Bannai and Dr. Manabu Nemoto from Equine Research Institute, Japan Racing Association, Tochigi, Japan. The MM2021 and B254 represent GI and GIV, respectively [ 18 , 19 ], while both MI-110 and 14-I-605 represent GIII GETVs [ 18 ].…”

“…Currently, the GIII lineage is the dominant lineage with the largest virus populations, comprising mainly the virus strains associated with the animal disease epidemics. The GIV lineage, however, is comprised mostly of viruses that were found in the mosquitoes, including the recent Malaysian GETV B254 (2012) discovered in our previous study [ 19 ]. Recently, one GIV strain (GETV/SW/Thailand/2017) was isolated from pig serum in Thailand in 2017, with no clinical signs reported [ 20 ].…”

Serological survey for Getah virus in domestic pigs of South Korea

“…Although Sagiyama virus (SAGV) was also isolated from the mosquito Culex tritaeniorhynchus at a similar time, SAGV is now regarded as a strain of GETV [4]. GETVs can be grouped into four evolutionary groups [5], with Group I including the prototype of GETV (MM2021); Group II including the SAGV strain; Group III, the most abundant group, being associated with several epidemic outbreaks of GETV; and Group IV being relatively restricted [6][7][8].The transmission cycle of GETV includes horses and pigs as major amplifiers and mosquitoes as the primary arthropod. Clinical indications of GETV infection in horses include fever, anorexia, edema of the hind limbs, enlargement of lymph nodes and rash [9].…”