Isolation and
characterization of the first porcine Getah virus strain HNJZ-S1 from an
aborted piglet in China
Running Head: the first porcine Getah virus strain in China
Feng Zhou1, Aojie Wang1, Hongtao
Chang1, Dandan Cui1, Xingang
Wang1, Lu Chen1*, Chuanqing
Wang1*
1College of
animal science and veterinary medicine, Henan Agricultural University,
Agricultural Road No. 63, Zhengzhou, Henan, China (450002)
*Address correspondence to: Chuanqing Wang, E-mail:wchuanq@163.com
Lu Chen, E-mail: chenluhau@126.com
ABSTRACT
Severity of porcine reproductive and respiratory syndrome (PRRS)
implicated co-infection with other pathogens in pig herd in China, which
normally were found Japanese encephalitis virus (JEV), pseudorabies
virus (PRV), porcine reproductive and respiratory syndrome virus
(PRRSV), porcine circovirus, porcine parvovirus and classical swine
fever virus (CSFV). Here we verified a specific fragment which was
similar to Getah virus (GETV) by RT-PCR and sequencing from aborted
fetuses in Henan province, China. Then we isolated and purified the
stain virus. We named it as HNJZ-S1. Furthermore, we characterized
HNJZ-S1 by passage and plaque titer, whole genome sequencing, Electron
microscopy and animal infection experiments with mice and piglets. The
data show that the full-length genome sequence of HNJZ-S1was 11689 bp
with homologous 97.4%–99.3% identical to the GETV sequence available
in GenBank. Phylogenetic tree analysis showed that HNJZ-S1 was closely
related to mosquito isolate 12IH26 from Japan, horse isolates
14-I-605-C1 and 14- I-605-C2, and mosquito isolate HB0234 from China.
Animal experiments showed that the isolate HNJZ-S1 caused abortion in
pregnant mice and was lethal postnatal day 3 mice and piglets. This
study provides important information on the tropism, infection,
pathogenicity, environmental microbiology and public health implications
of pig derived GETV and will also serve as a source of reliable research
materials.
Keywords: Swine, Getah virus, Abortive, Virus isolation, Pathogenicity
The mosquito borne Geta virus (GETV) belongs to the
genus Alphavirus , family Otariidae . The viral genome of
GETV is composed of positive single-stranded RNA including a 5’-cap
structure, two open reading frames (ORFs) and a 3’-poly(A) tail. The two
ORFs encodes the structural (C/capsid, E3, E2, 6K, E1) and
non-structural proteins (NSP1 to NSP4) respectively, which are flanked
by a 44 nt 26S junction region associated with transcription of an
intracellular subgenomic 26S RNA(Strauss et al., 1994). Previous
serological studies showed that this virus can infect multiple species,
including humans(Li et al., 1992; Marchette et al., 1980 ), horses,
pigs, cattle, monkeys and birds(Li et al., 2007). The symptom of
infection includes rash, fever and joint edema in horses(KAMADA et
al.,1991; KAMADA et al.,1991), reproductive disorders in pregnant sows
and tremors in piglets, deaths only occur in pigs in the fetal
stage(Yago et al., 1987; Kawamura et al., 1987).
GETV was well known that the first isolated from Culex sp.
mosquitoes in Malaysia in 1955 and is now widely distributed across Asia
(Ksiazek et al., 1981) (Morita and Igarashi, 1984)(Ksiazek et al., 1981;
Morita et al., 1984; Leake et al., 1986; Bryant et al., 2005), Europe
and Australia based on viral isolation and/or molecular epidemiological
investigations(Fukunaga et al., 2000). In 1964, GETV was first isolated
from mosquitoes on Hainan Island in China (Li et al., 1992) and was
later detected in mosquitoes in several provinces and cities (Zhai et
al., 2008). In addition, recently two high pathogenic swine GETV strains
were detected in blue foxes in China (Shi et al., 2019).
In November 2016, during attempt to detect pathogens in aborted fetuses
from a pig farm in Henan Province, we found that classical swine fever
virus (CSFV), porcine reproductive and respiratory syndrome virus
(PRRSV), Japanese encephalitis virus (JEV) and pseudorabies virus (PRV)
were negative. Interestingly, a non-specific band was amplified using
CSFV primers. The non-specific band was sequenced and analyzed by BLAST
search against the GenBank database. It turned out that the amplicon had
high homology to GETV. GETV was isolated by cell passage and plaque
purification, and was subjected to electron microscopy observation,
genome sequencing. Moreover, we determined the pathogenicity of the
strain for pregnant and neonatal mice, and the piglets.