Hepadnaviruses have been identified in several animal species. The hepadnavirus prototype, human hepatitis B virus (HBV), is a major public health problem associated with chronic liver diseases and hepatocellular carcinoma. Recently, a novel hepadnavirus, similar to HBV, was identified in domestic cats. Since several pathogens can be shared between cats and dogs, we hypothesized that dogs could also harbor hepadnaviruses and we tested a collection of canine sera with multiple molecular strategies. Overall, hepadnavirus DNA was identified in 6.3% (40/635) of canine serum samples, although the viral load in positive sera was low (geometric mean of 2.70 × 10²genome copies per mL, range min 1.36 × 10²—max 4.03 × 10⁴genome copies per mL). On genome sequencing, the canine hepadnaviruses revealed high nucleotide identity (about 98%) and similar organization to the domestic cat hepadnavirus. Altered hepatic markers were found in hepadnavirus-positive dogs, although the role of hepadnavirus in canine health remains to be elucidated.

Norovirus (NoV) causes serious gastrointestinal disease worldwide and is regarded as an important foodborne pathogen. Due the difficulties of in vitro cultivation for human NoV, alternative caliciviruses (i.e., feline calicivirus, FCV, or murine NoV) have long been used as surrogates for in vitro assessment of the efficacy of antivirals. Essential oils (EOs) are natural compounds that have displayed antimicrobial and antioxidant properties.

Kobuviruses (KoVs) are a group of small, non-enveloped RNA viruses classified in the genus Kobuvirus within the Picornaviridae family, comprising Aichivirus species A to F. KoVs have been identified in humans and several mammals, including domestic ungulates. This study investigated the presence of KoVs in a collection of bovine stool samples (n = 38) obtained from animals with enteritis or without clinical signs. By RT-PCR screening, KoV RNA was detected in 10/38 animals (26.3%). Six of the ten positive animals had enteric signs. On sequence analysis of the amplicons, eight strains were related to species Aichivirus B, commonly identified in cattle. In contrast, two strains (ITA/2019/572-1 and ITA/2020/bovine/30-2), displayed the highest nt identity (up to 97.1%) to cattle, yak, and goat Aichivirus D strains. On whole genome analysis, strains ITA/2019/572-1 and ITA/2020/30-2 showed 88.9% nt identity to each other and 87.8–90.3% nt to the bovine kobuvirus strain CHN/2021/ON730709 identified in China. Interestingly these three Aichivirus D strains showed a recombinant makeup, clustering with D1 genotype in the capsid region and with D2 genotype in the non-structural genes. These findings suggest that Aichivirus D KoVs are common components of livestock virome. Understanding the genetic diversity of KoVs in animals will be useful to improve the diagnostics and gather epidemiological data.

Capozza P, et al. J Vet Sci. 2021 Sep;22:e84. https://doi.org/10.4142/jvs.2021.22.e84

Massive sequencing techniques have allowed us to develop straightforward approaches for the whole genome sequencing of viruses, including influenza viruses, generating information that is useful for improving the levels and dimensions of data analysis, even for archival samples. Using the Nanopore platform, we determined the whole genome sequence of an H3N8 equine influenza virus, identified from a 2005 outbreak in Apulia, Italy, whose origin had remained epidemiologically unexplained. The virus was tightly related (>99% at the nucleotide level) in all the genome segments to viruses identified in Poland in 2005–2008 and it was seemingly introduced locally with horse trading for the meat industry. In the phylogenetic analysis based on the eight genome segments, strain ITA/2005/horse/Bari was found to cluster with sub-lineage Florida 2 in the HA and M genes, whilst in the other genes it clustered with strains of the Eurasian lineage, revealing a multi-reassortant nature.