Identification and genomic characterization of a novel porcine parvovirus (PPV6) in china

Abstract

BackgroundParvoviruses are classified into two subfamilies based on their host range: the Parvovirinae, which infect vertebrates, and the Densovirinae, which mainly infect insects and other arthropods. In recent years, a number of novel parvoviruses belonging to the subfamily Parvovirinae have been identified from various animal species and humans, including human parvovirus 4 (PARV4), porcine hokovirus, ovine partetravirus, porcine parvovirus 4 (PPV4), and porcine parvovirus 5 (PPV5).MethodsUsing sequence-independent single primer amplification (SISPA), a novel parvovirus within the subfamily Parvovirinae that was distinct from any known parvoviruses was identified and five full-length genome sequences were determined and analyzed.ResultsA novel porcine parvovirus, provisionally named PPV6, was initially identified from aborted pig fetuses in China. Retrospective studies revealed the prevalence of PPV6 in aborted pig fetuses and piglets(50% and 75%, respectively) was apparently higher than that in finishing pigs and sows (15.6% and 3.8% respectively). Furthermore, the prevalence of PPV6 in finishing pig was similar in affected and unaffected farms (i.e. 16.7% vs. 13.6%-21.7%). This finding indicates that animal age, perhaps due to increased innate immune resistance, strongly influences the level of PPV6 viremia. Complete genome sequencing and multiple alignments have shown that the nearly full-length genome sequences were approximately 6,100 nucleotides in length and shared 20.5%–42.6% DNA sequence identity with other members of the Parvovirinae subfamily. Phylogenetic analysis showed that PPV6 was significantly distinct from other known parvoviruses and was most closely related to PPV4.ConclusionOur findings and review of published parvovirus sequences suggested that a novel porcine parvovirus is currently circulating in China and might be classified into the novel genus Copiparvovirus within the subfamily Parvovirinae. However, the clinical manifestations of PPV6 are still unknown in that the prevalence of PPV6 was similar between healthy pigs and sick pigs in a retrospective epidemiological study. The identification of PPV6 within the subfamily Parvovirinae provides further insight into the viral and genetic diversity of parvoviruses.

Increasing diversity of swine parvoviruses and their epidemiology in African pigs

“…More recent ones are yet to be assigned into species and genus under the subfamily. These include PPVs 5, 6 and 7 (Xiao et al, 2013a;Ni et al, 2014;Schirtzinger et al, 2015;Palinski et al, 2016;Xing et al, 2018).…”

“…Protoparvovirus) in the classification, while porcine parvovirus 2 (PPV2) and porcine parvovirus 3 (PPV3) were categorized together with human parvovirus 4 (PARV4) in the genus Tetraparvovirus due to their relatively close genomic homologies. The porcine parvovirus 4 (PPV4) belongs to the genus Copiparvovirus alongside with bovine parvovirus 2 (Cotmore et al, 2014), and the genus have been proposed to contain the novel PPVs 5 and 6 as they have constantly clustered within the group in phylogenetic analyses (Xiao et al, 2013b;Ni et al, 2014;Schirtzinger et al, 2015). In addition, eigth pig viruses and virus variants are presently grouped under the genus Bocaparvovirus to make four distinct genera of swine parvoviruses in the published classification (Cotmore et al, 2014).…”

“…Since about five decades ago that PPV1 was first detected in Germany (Mayr et al, 1968), many more porcine parvoviruses other than those in bocavirus group have been detected in swine population with the recent advancement in the use of molecular techniques in pathogen discovery and epidemiology (Table 1) (Ni et al, 2014). Generally, the new development has brought about a continuing increase in the number of new parvoviruses grouped under the subfamily Parvovirinae including those that have been found in other animal species such as Ovine hokovirus (O-PARV4) and also a group of novel porcine bocaviruses Tse et al, 2011;Huang et al, 2014).…”

“…In the following year, Ni et al (2014) for the first time identified another novel pig parvovirus, tentatively named as PPV6, from aborted swine foetuses which showed negative results for other swine's reproductive failure pathogens in pigs in China. Subsequently, the virus has been detected through a high throughput sequencing of PRRSV positive serum samples from swine in the USA and Mexico, with a very high similarity to the PPV6 discovered in China (Schirtzinger et al, 2015).…”

Identification of three PPV1 VP2 protein-specific B cell linear epitopes using monoclonal antibodies against baculovirus-expressed recombinant VP2 protein

“…novel porcine parvoviruses (PPVs) have been identified in swine herds, including porcine parvovirus type 2 (PPV2), PPV3, PPV4, PPV5, and PPV6, and their prevalence and potential roles in clinical diseases have been investigated to some extent (Cheung et al 2010;Hijikata et al 2001;Ni et al 2014;Sun et al 2015;Wang et al 2010). However, because the isolation of PPV2-6 is limited, their pathogenicity has not yet been clarified.…”