Proposal for a unified classification system and nomenclature of lagoviruses.

Lagoviruses belong to the Caliciviridae family. They were first recognized as highly pathogenic viruses of the European rabbit (Oryctolagus cuniculus) and European brown hare (Lepus europaeus) that emerged in the 1970-1980s, namely, rabbit haemorrhagic disease virus (RHDV) and European brown hare syndrome virus (EBHSV), according to the host species from which they had been first detected. However, the diversity of lagoviruses has recently expanded to include new related viruses with varying pathogenicity, geographic distribution and host ranges. Together with the frequent recombination observed amongst circulating viruses, there is a clear need to establish precise guidelines for classifying and naming lagovirus strains. Therefore, here we propose a new nomenclature based on phylogenetic relationships. In this new nomenclature, a single species of lagovirus would be recognized and called Lagovirus europaeus. The species would be divided into two genogroups that correspond to RHDV- and EBHSV-related viruses, respectively. Genogroups could be subdivided into genotypes, which could themselves be subdivided into phylogenetically well-supported variants. Based on available sequences, pairwise distance cutoffs have been defined, but with the accumulation of new sequences these cutoffs may need to be revised. We propose that an international working group could coordinate the nomenclature of lagoviruses and any proposals for revision.

Neofunctionalization of the Sec1 α1,2fucosyltransferase paralogue in leporids contributes to glycan polymorphism and resistance to rabbit hemorrhagic disease virus.

RHDV (rabbit hemorrhagic disease virus), a virulent calicivirus, causes high mortalities in European rabbit populations (Oryctolagus cuniculus). It uses α1,2fucosylated glycans, histo-blood group antigens (HBGAs), as attachment factors, with their absence or low expression generating resistance to the disease. Synthesis of these glycans requires an α1,2fucosyltransferase. In mammals, there are three closely located α1,2fucosyltransferase genes rSec1, rFut2 and rFut1 that arose through two rounds of duplications. In most mammalian species, Sec1 has clearly become a pseudogene. Yet, in leporids, it does not suffer gross alterations, although we previously observed that rabbit Sec1 variants present either low or no activity. Still, a low activity rSec1 allele correlated with survival to an RHDV outbreak. We now confirm the association between the α1,2fucosyltransferase loci and survival. In addition, we show that rabbits express homogenous rFut1 and rFut2 levels in the small intestine. Comparison of rFut1 and rFut2 activity showed that type 2 A, B and H antigens recognized by RHDV strains were mainly synthesized by rFut1, and all rFut1 variants detected in wild animals were equally active. Interestingly, rSec1 RNA levels were highly variable between individuals and high expression was associated with low binding of RHDV strains to the mucosa. Co-transfection of rFut1 and rSec1 caused a decrease in rFut1-generated RHDV binding sites, indicating that in rabbits, the catalytically inactive rSec1 protein acts as a dominant-negative of rFut1. Consistent with neofunctionalization of Sec1 in leporids, gene conversion analysis showed extensive homogenization between Sec1 and Fut2 in leporids, at variance with its limited degree in other mammals. Gene conversion additionally involving Fut1 was also observed at the C-terminus. Thus, in leporids, unlike in most other mammals where it became extinct, Sec1 evolved a new function with a dominant-negative effect on rFut1, contributing to fucosylated glycan diversity, and allowing herd protection from pathogens such as RHDV.

Metastasis of malignant tumors to the oral cavity: Systematic review of case reports and case series.

OBJECTIVE: To summarize published information regarding malignant tumors with metastasis to the oral cavity. MATERIALS AND METHODS: This was a systematic review with meta-analysis. An electronic search of Pubmed, Scopus, and Google Scholar databases from inceptions to February 2022 were performed. Only case reports or case series with histopathological results demonstrating metastasis to the oral cavity were included. The main outcomes included demographics, primary site, metastatic site, clinical manifestations, and patient survival. The quality of primary articles was assessed using the Joanna Briggs Institute - University of Adelaide scorecards for case reports and case series. Descriptive analysis and a Kaplan-Meier survival curve were performed. RESULTS: 273 articles were selected (50 case series and 223 case reports), for a total of 950 cases. The mean age was 57.11 years. Males were more affected (57.5%). The most common primary sites in women and men was breast (29.8%), and lung (24.8%), respectively. In ∼1/3 of the cases, oral metastasis preceded tumor dissemination. Jawbones were more affected (56.7%) than soft tissues (37.9%), with the mandible being the most affected site (45.5%), followed by the gingiva (19.9%). The most common clinical manifestation was a mass or nodule. Most radiographic evidence was radiolucency of the jaw (60.6%). 3-year and 5-year survival rates were 14.2 and 10.7%. In the majority of cases, the primary tumor was the first to be diagnosed, while in 30.4%, metastasis was the first sign of the disseminated disease. This can be implied that the oral metastasis should be included in the differential diagnosis list of the oral diseases. CONCLUSION: Clinicians should be aware of the possibility of, albeit uncommon, oral metastases. Because the extracted data in this review was relatively generalized, the investigators cannot develop the diagnostic clues of oral metastasis, which require further investigations.

Adenovirus emergence in a red squirrel (Sciurus vulgaris) in Iberian Peninsula.

Adenoviruses (AdV) are pathogens capable of infecting animals and humans leading to a wide spectrum of diseases. They have a widespread geographical dissemination and infect several species, including red squirrels (Sciurus vulgaris). In the Iberian Peninsula, there are no reports of infection of red squirrels by AdV. In this study, we report for the first time the detection of squirrel AdV in a red squirrel trapped in central Portugal. The phylogenetic analysis showed that the sequences obtained for the hexon and the penton base genes were similar to the Korean squirrel AdV strain and strongly divergent from the strains present in red squirrels in Europe. These findings indicate the emergence of a new strain circulating in Europe and raise concerns regarding the conservation of the red squirrel.