Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna (IZSLER), Via Antonio Bianchi 7/9, 25124, Brescia, Italy.
WOAH Reference Laboratory for RHD, Via Antonio Bianchi 7/9, 25124, Brescia, Italy.
Sci Rep. 2024 Nov 25;14(1):29234. doi: 10.1038/s41598-024-79670-y.
Lagoviruses are viruses of the Caliciviridae family affecting lagomorphs. Both pathogenic and non-pathogenic lagoviruses affect the European rabbit (Oryctolagus cuniculus), and they are phylogenetically distinguished. Rabbit Hemorrhagic Disease Virus (RHDV/GI.1) and Rabbit Hemorrhagic Disease Virus-2 (RHDV-2/GI.2) belong to the first group, while in the second group, several genotypes of Rabbit Calicivirus (RCV/GI.3-GI.4) are present. The first RCV strain was described in Italy in 1996, and since then, several RCV strains have been characterised in Europe and Australia. RCVs, different from the pathogenic hepatotropic RHDVs, have an enteric tropism and could be identified from the duodenum/intestine and faeces. This study aimed firstly to indirectly show through a seroepidemiological survey from 1998 to 2008 the circulation of RCVs strains in rabbit farms and then to genetically characterise RCV strains diagnosed in Italy in faecal and intestinal samples of wild and farmed rabbits collected in various regions in the following years (2000-2022). Of 262 analysed samples, 69 resulted in RT-PCR positive for lagovirus but negative for RHDV. Eleven RCV strains were characterised by complete vp60 sequencing. Phylogenetic analysis showed that the Italian RCV strains are grouped in European (RCV_E1/GI.3) and Australian (RCV_E2/GI.4) RCV clusters, with an estimated country prevalence of 26%. Based on the proposed genotype classification, considering the nucleotide differences of vp60 higher than 15%, we can hypothesise that two other genotypes, GI.5 and GI.6, might exist within the cluster of non-pathogenic viruses.
兔杯状病毒是杯状病毒科的病毒，影响兔科动物。致病性和非致病性兔杯状病毒都会影响欧洲兔（Oryctolagus cuniculus），它们在系统发育上是有区别的。兔出血症病毒（RHDV/GI.1）和兔出血症病毒-2（RHDV-2/GI.2）属于第一组，而在第二组中，存在几种兔杯状病毒（RCV/GI.3-GI.4）基因型。第一株 RCV 于 1996 年在意大利被描述，从那时起，在欧洲和澳大利亚已经有几个 RCV 株被鉴定出来。RCVs 与致病性嗜肝的 RHDVs 不同，具有肠道趋向性，可以从十二指肠/肠道和粪便中识别出来。本研究的主要目的是通过 1998 年至 2008 年的血清流行病学调查，间接显示 RCV 株在兔场的传播情况，然后对意大利在随后几年（2000-2022 年）从野生和养殖兔的粪便和肠道样本中诊断出的 RCV 株进行遗传特征分析。在分析的 262 个样本中，69 个样本通过 RT-PCR 对 lagovirus 呈阳性，但对 RHDV 呈阴性。通过对完整 vp60 进行测序，对 11 株 RCV 进行了特征分析。系统进化分析表明，意大利的 RCV 株分为欧洲（RCV_E1/GI.3）和澳大利亚（RCV_E2/GI.4）RCV 群，估计在意大利的流行率为 26%。基于所提出的基因型分类，考虑到 vp60 的核苷酸差异高于 15%，我们可以假设在非致病性病毒的聚类中可能存在另外两种基因型 GI.5 和 GI.6。
