Isolation and characterization of Getah virus from pigs in Guangdong province of China

Abstract

Getah virus (GETV) is a mosquito‐borne virus that is widely distributed in Asian countries including China, in which the first case of equine GETV infection was reported in Guangdong province in August 2018. In this study, GETVs were detected in two classical swine fever virus‐positive samples collected from swine herds in Foshan city, Guangdong province, 2018. Infection of porcine PK‐15 cells produced rapid cytopathic effects (CPEs), including shrinking, rounding and detaching, and peak titre of 109.3 TCID50/ml occurred at 24 hr post‐infection. Electron microscopy and ultra‐thin sectioning revealed spherical GETV particles of 70 nm diameter with an isometric interior and are found to be lining the outer membrane of infected cells. Whole‐genome analysis showed that the two GETV isolates are identical to each other and cluster with Group III strains of GETV, sharing 96.1%–99.7% nucleotide sequence identity with all available reference strains. The most closely relative of the obtained GETV isolates was porcine strain HNJZ‐S2 from Henan province (99.7%), with 98.6% sequence identity shared with equine GETV strain GZ201808 first identified in Guangdong province, indicating different sources for porcine and equine GETV infections in this region. No evidence of GETV infection was found in 497 archived porcine samples collected between 1990 and 2018 in Guangdong province.

Emergence and Phylogenetic Analysis of a Getah Virus Isolated in Southern China

“…The tropical and subtropical climates of these regions provide a favorable environment for the reproduction of mosquitoes, which play a key role in the spread of GETV among different hosts (30). The existence of GETV-infected animals and mosquitoes in Hunan, Guangdong, and Yunnan provinces, which are the neighboring provinces located in the east and west of Guangxi province, has meant that they are likely to spread, and they have already been reported (23,25,27,28). In this study, we detected and isolated for the first time in Guangxi province, a GETV strain in pig sera using BHK-21 cells, proving the existence of GETV in this region of China.…”

“…Sequence comparison showed that GX201808 shares high sequence identity at the nucleotide level with the strains HuN1, SD17/09, and JL1808. Group III, represented by the first Chinese strain (M1) that was isolated in 1964 from mosquitoes, contains most GETV strains appearing in mosquitoes, pigs, horses, cattle, foxes, and other animals and has become the dominant viruses circulating among species (17,23,(26)(27)(28).…”

“…GETV infections in horses and pigs have been reported several times in Japan since the 1970's (18)(19)(20)(21), and the outbreak of GETV infections in horses were reported in 1990 in India (22). In China, GETV is widely distributed in 15 provinces ranging from the southwest to northern areas of China since it was first identified from mosquitos in Hainan province, and it has caused several outbreaks in animals in recent years (2,7,17,(23)(24)(25)(26)(27)(28). In 2017, an outbreak of GETV infection was reported in swine herds in Hunan province, China, resulting in the death of ∼200 piglets and reproductive disorders of more than 150 pregnant sows (25).…”

Sequencing of Historical Isolates, K-mer Mining and High Serological Cross-Reactivity with Ross River Virus Argue against the Presence of Getah Virus in Australia

“…GETV also represents a potential emerging burden for the pig industry, recently highlighted for China [ 20 ]. Infected piglets show depression, tremors, hind limb paralysis, diarrhea and high mortality, and infection of sows can be associated with abortion [ 21 ]. Live GETV was recently isolated as an adventitious agent contaminating a commercial live-attenuated vaccine for porcine reproductive and respiratory syndrome virus (manufactured in MARC-145 cells) [ 22 ]; perhaps a contributing factor in the increased GETV burden in pigs.…”

Monitoring Mosquito-Borne Arbovirus in Various Insect Regions in China in 2018

“…The number of cases of GETV-affected mammals has rapidly increased over the last decade. These included pigs in Henan [2011, ( Zhou et al., 2018 )], Hunan [2017, ( Yang et al., 2018 )], Anhui [2017 (available on GenBank but unpublished)], Sichuan [2018, ( Jiang et al., 2019 )], and Guangdong [2018, ( Xing et al., 2020 )], blue foxes in Shandong [2017, ( Shi et al., 2019 )], beef cattle in Jilin [2018, ( Liu et al., 2019 )], and horses in Guangdong [2018, ( Lu et al., 2019 )]. A GETV outbreak occurred on a swine farm in Hunan Province in June and July 2017 and caused many fetal mummies, stillbirths, and piglet deaths ( Yang et al., 2018 ).…”