High rate of viral evolution in the capsid protein of porcine parvovirus

Abstract

In recent years, it has been shown that some parvoviruses exhibit high substitution rates, close to those of RNA viruses. In order to monitor and determine new mutations in porcine parvovirus (PPV), recent PPV field isolates from Austria, Brazil, Germany and Switzerland were sequenced and analysed. These samples, together with sequences retrieved from GenBank, were included in three datasets, consisting of the complete NS1 and VP1 genes and a partial VP1 gene. For each dataset, the nucleotide substitution rate and the molecular clock were determined. Analysis of the PPV field isolates revealed that a recently described amino acid substitution, S436T, appeared to be common in the VP2 protein in the Austrian, Brazilian and German virus populations. Furthermore, new amino acid substitutions were identified, located mainly in the viral capsid loops. By inferring the evolutionary dynamics of the PPV sequences, nucleotide substitution rates of approximately 10 "5 substitutions per site per year for the non-structural protein gene and 10substitutions per site per year for the capsid protein gene (for both viral protein datasets) were found. The latter rate is similar to those commonly found in RNA viruses. An association of the phylogenetic tree with the molecular clock analysis revealed that the mutations on which the divergence for both capsid proteins was based occurred in the past 30 years. Based on these findings, it was concluded that PPV variants are continuously evolving and that vaccines, which are based mainly on strains isolated about 30 years ago, should perhaps be updated.

Health Assessment of Wild Lowland Tapir (Tapirus Terrestris) Populations in the Atlantic Forest and Pantanal Biomes, Brazil (1996–2012)

“…Porcine parvovirus infection is highly prevalent in domestic pigs (Sus scrofa) in Brazil and is considered to be the main cause of reproductive problems in herds (Streck et al 2011). Domestic pigs were introduced to the Pantanal 200 years ago and became feral during the Paraguay War.…”

An inactivated whole-virus porcine parvovirus vaccine protects pigs against disease but does not prevent virus shedding even after homologous virus challenge

“…If the fetuses are infected after day 70 of gestation, they usually develop antibodies against PPV and eliminate the virus (Zeeuw et al, 2007;Truyen & Streck, 2012). In recent years, studies have shown that PPV is much more diverse than previously thought (Zimmermann et al 2006;Streck et al, 2011). Several PPV strains of different virulence are known.…”

“…Based on phylogenetic analyses of the VP1/VP2 protein genes, PPV can be defined into at least seven clusters (Zimmermann et al, 2006;Streck et al, 2011Streck et al, , 2013a. Recently, a population dynamic analysis showed that, despite the high evolutionary rate, only a few PPV strains (similar to strain 27a) have been predominant in Europe in recent years (Streck et al, 2013b).…”

Classic Nuclear Localization Signals and a Novel Nuclear Localization Motif Are Required for Nuclear Transport of Porcine Parvovirus Capsid Proteins

“…This results in the constant presence of PPV in herds, enabling the occurrence of mutated field strains. This virus has a single-stranded DNA (ssDNA) genome, known to have a high mutation rate (8). Monitoring the emergence of new strains and understanding cell-virus interactions are therefore important to gain a better knowledge of the life cycle of this pathogen.…”