Introduction
Noroviruses (NoVs) are important
pathogens causing gastroenteritis in children and young animals.
Infection with NoV in children and young animals can cause intestinal
lesions and post-infectious diarrhea (Smiley,Chang,Hayes,Vinje, & Saif,
2002; Bridger,Hall, & Brown, 1984; Woode & Bridger, 1978). In humans,
NoV is one of the most important etiological agents of gastroenteritis;
however, little is known about NoV causing diarrhea in cattle.
NoVs are small non-enveloped, positive-sense single-stranded RNA
viruses. According to the diversity of the VP1 amino acid (aa)
sequence, NoVs are divided into seven genogroups (GI to GVII). Bovine
NoVs (BNoVs) belong to GIII and are further divided into two different
genotypes,
i.e., genotype 1 (Bo/Jena/1980/DE) and genotype 2 (Bo/newbury2/1976/UK),
which were first identified in Germany (Otto et al., 2011) and the UK
(Jung,Scheuer,Zhang,Wang, & Saif, 2014). The BNoV genome, which has a
size of 7.5–7.7 kb, contains three open reading frames (ORFs). Starting
from the 5’ end of the genome, ORF1 encodes a non-structural protein,
including an enzyme responsible for transcription, viral genome
replication, and accurate initiation of RNA synthesis by RNA-dependent
RNA polymerase (RdRp). RdRp prevents the virus from losing its genetic
information (Deval,Jin,Chuang, & Kao, 2017; Lee,Chung, & Kim, 2017).
ORF2 encodes the major capsid protein VP1 . It is involved in
receptor recognition and host specificity (Chen et al., 2004).Viral
evasion of antibody neutralization results in frequent variations in theVP1 aa sequences, which are also associated with the emergence of
new epidemic strains (Lochridge & Hardy, 2007; Lindesmith et al.,
2013). ORF3 encodes the minor capsid protein VP2 , a hypervariable
protein that may play a role in maintaining the stability of NoV
particles (Lin,Fengling,Lianzhu,Yuxiu, & Yanhua, 2014).
Previous studies have reported the detection of BNoV in many countries
including the UK (Woode & Bridger, 1978; Bridger,Hall, & Brown, 1984),
Germany (Gunther,Otto, & Heilmann, 1984), the Netherlands (van der Poel
et al., 2003; van Der Poel et al., 2000), the USA (Cho et al., 2013;
Wise et al., 2004), New Zealand (Wolf et al., 2007), South Korea (Park
et al., 2007), Norway (Jor,Myrmel, & Jonassen, 2010), France
(Kaplon,Guenau,Asdrubal,Pothier, & Ambert-Balay, 2011), Turkey
(Kaplon,Guenau,Asdrubal,Pothier, & Ambert-Balay, 2011), and Tunisia
(Hassine-Zaafrane et al., 2012). According to previous reports, BNoV was
first detected in Southern China in 2018 (Wang,Yue, & Tang, 2019), and
it was detected in central China in 2019 (Shi,Wang,Xu,Zhang, & Lan,
2019).
BNoV has become a threat to the global cattle industry, and it may bring
huge economic losses to the cattle industry in China. Although BNoV is
prevalent globally, the study of its pathogenicity, epidemiology, and
molecular biology is only in the preliminary stage. Up to now, GenBank
contained only seven complete BNoV genome sequences; two are GIII.1
strains (GenBank accession numbers: MK159169 and AJ011099) and five are
GIII.2 strains (GenBank accession numbers: JX145650, AY126474, AF097917,
MN122335.1, and EU794907). In China, only two BNoV genomes have been
completely sequenced, i.e., one from southern China and one from central
China. There are not enough data to establish the genetic relationship
and evolutionary rate of BNoVs in China. At present, the virus has not
been successfully isolated, hindering the development of an effective
vaccine. We studied the molecular profile of the virus and analyzed its
genetic variation, in order to provide a reference for the prevention
and control of viral spread in China.
We identified a BNoV strain, named Bo/CH/HB/BD/2019, from Hebei, in
northern China, and conducted phylogenetic analysis of the entire genome
and the VP1 region. BNoV may be highly prevalent in China, but
there are few epidemiological data on the prevalence of the virus. This
study lays a foundation for the further exploration of the molecular
biological characteristics of BNoV and the prevalence of BNoV in China.