Canine parvovirus (CPV) phylogeny is associated with disease severity

Giovanni Franzo,Mattia Cecchinato,Marco Caldin,Martí Cortey,Tommaso Furlanello,Sira Casagrande,Michele Drigo,Matteo Legnardi,Claudia Maria Tucciarone

doi:10.1038/s41598-019-47773-6

Giovanni Franzo, Mattia Cecchinato + Show 7 more

Open Access

https://doi.org/10.1038/s41598-019-47773-6

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Abstract

After its first identification in 1978, canine parvovirus (CPV) has been recognized all around the world as a major threat for canine population health. This ssDNA virus is characterized by a high substitution rate and several genetic and phenotypic variants emerged over time. Overall, the definition of 3 main antigenic variants was established based on specific amino acid markers located in a precise capsid position. However, the detection of several minor variants and incongruence observed between the antigenic classification and phylogeny have posed doubts on the reliability of this scheme. At the same time, CPV heterogeneity has favored the hypothesis of a differential virulence among variants, although no robust and consistent demonstration has been provided yet. The present study rejects the antigenic variant concept and attempts to evaluate the association between CPV strain phylogeny, reconstructed using the whole information contained in the VP2 coding gene, and several clinical and hemato-biochemical parameters, assessed from 34 CPV infected dogs at admission. By using different statistical approaches, the results of the present study show an association between viral phylogeny and host parameters ascribable to immune system, coagulation profile, acute phase response and, more generally, to the overall picture of the animal response. Particularly, a strong and significant phylogenetic signal was proven for neutrophil count and WBC. Therefore, despite the limited sample size, a relation between viral phylogeny and disease severity has been observed for the first time, suggesting that CPV virulence is an inherited trait. The likely existence of clades with different virulence highlights once more the relevance of intensive epidemiological monitoring and research on CPV evolution to better understand the virulence determinants, their epidemiology and develop adequate countermeasures.

Highlights

Carnivore protoparvovirus 1 is a species within the genus Protoparvovirus in the family Parvoviridae that includes several viruses of remarkable epidemiological relevance for wild and domestic carnivores[1]
Half of the animals were properly vaccinated against canine parvovirus (CPV), while the remaining did not complete the standard vaccination protocol or were not vaccinated at all
Forms of inheritance from common ancestors, and phylogenetic clustering, can be expected. Such association has been speculated for CPV too, and a different virulence among antigenic variants has been hypothesized[19]

Summary

Introduction

Carnivore protoparvovirus 1 is a species within the genus Protoparvovirus in the family Parvoviridae that includes several viruses of remarkable epidemiological relevance for wild and domestic carnivores[1]. Likely due to the new host adaptation of a feline parvovirus-like of wild carnivores[5], CPV rapidly spread worldwide in the dog population[6,7], causing severe disease outbreaks and high mortality[8]. Since CPV totally relies on the host cell machinery, viral replication requires actively proliferating cells. This feature largely explains the viral cell tropism and pathogenesis. Www.nature.com/scientificreports endotoxemia, systemic inflammation, coagulation disorders and septic shock are commonly present in CPV infected animals and contribute significantly to the disease severity and lethality[11,12,13]. Up to date and except for anecdotal reports, no study has consistently demonstrated an association between antigenic variants and pathogenicity/virulence[5,19,20,21]

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