# High Prevalence of a Novel Circovirus in the European Hedgehog (Erinaceus europaeus), a Common Species in Decline

## TL;DR

A new circovirus was found in European hedgehogs, but its link to a deadly disease remains unclear.

## Contribution

Discovery of the first circovirus in the mammalian order Eulipotyphla, with high prevalence in European hedgehogs.

## Key findings

- A novel circovirus was identified in European hedgehogs using metagenomic sequencing.
- The circovirus was detected in 61% of hedgehog liver samples, but no significant association with HDD was found.
- The virus is phylogenetically related to circoviruses found in dogs.

## Abstract

Hedgehog (Erinaceus europaeus) declines in western Europe have been associated with the emergence of Hedgehog diphtheric disease (HDD), with a probable multifactorial, yet unidentified etiology. We used metagenomic sequencing of cell-free DNA (cfDNA) in hedgehog blood to identify possible causes of HDD. We detected a novel circovirus species in the European hedgehog, providing the first record of a circovirus within the mammalian order Eulipotyphla. The novel circovirus genome exhibits the characteristic circovirus structure, including a functional replicase (REP) and capsid (CAP) gene. Phylogenetic analysis placed all four detected genomes in a monophyletic clade, most closely related to sequences isolated from dogs. Subsequent PCR-based screening of 188 hedgehog liver samples demonstrated a high prevalence (61%) of this circovirus in hedgehogs brought to wildlife rescue centers, however, without any significant association with HDD. Since circoviruses are well known to interfere with host immunity across mammalian and avian taxa, the high level of circovirus detection in hedgehogs warrants further research into the role of this novel virus in hedgehog health.