A surveillance of human, porcine and bovine rotaviruses was carried out in Slovenia in 2004 and 2005. Stool samples were collected from a total of 406 pigs (373 from asymptomatic animals), 132 cattle (126 from asymptomatic animals) and 241 humans (all with diarrhoea), tested for group A rotaviruses using RT-PCR and analysed by sequencing. The aims of the study were to determine the incidence of asymptomatic rotavirus infection in animals, to look for evidence of zoonotic transmission and to detect reassortment among rotaviruses. The rates of asymptomatic shedding of rotaviruses in pigs and cattle were 18.0 % (67/373) and 4.0 % (5/126), respectively. Evidence for zoonotic transmission was detected in one human rotavirus strain, SI-MB6, with the G3P[6] genotype combination, as the nucleotide and predicted amino acid sequences of the VP6, VP7, VP8* and NSP4 genes of strain SI-MB6 and of porcine strains showed high nucleotide and amino acid sequence identity. Two porcine rotavirus strains carried VP7 of probable human origin, suggesting an interspecies reassortment event in the past.

A rotavirus surveillance study was undertaken in Slovenia from December 2005 to March 2006. Stool samples from 114 children hospitalized with acute viral gastroenteritis were collected from two main Slovenian hospitals. These confirmed rotavirus-positive samples were selected for a rotavirus G and P genotype prevalence study. Six untypable strains of genotype G were further analyzed with sequencing of the VP7, VP8*, and NSP4 genes. The findings of the study were that the G1 genotype was the most prevalent, found in 72 samples (63.2%), followed by G9 in 26 samples (22.8%), G4 in 10 samples (8.8%), and G3 in 2 samples (1.7%). All G genotypes were combined with the P[8] genotype specificity. After sequence analysis, one G8 and two G12 genotypes were also characterized. In a VP7-based phylogenetic analysis, the G8P[8] strain (SI-885/06) was more closely related to the Cody I801 bovine strain than to other human strains. Both G12 strains (SI-264/06 and SI-403/06) were shown to belong to the Se585 G12 cluster. In the VP8* phylogenetic tree, all analyzed strains except one, belonged to the P[8] lineage II and shared high identity in amino acid sequence. All characterized strains were clustered into the NSP4 genotype B. The molecular characterization of this G8 strain supports the theory of interspecies transmission of rotaviruses and animal-human genome reassortment. This is the first report on rotavirus G12 detection in Slovenia.

SUMMARYThis study evaluated the time course distribution of rabbit haemorrhagic disease virus (RHDV) structural protein VP60 in tissues from experimentally infected rabbits from three different age groups. Viral VP60 antigen could not be detected in tissue samples from animals under four weeks, and only a few hepatocytes (0·01 to 0·2 per cent) were stained in the 6-week-old animals. A 6-week-old rabbit euthanised at 72 hpi showed VP60-labelling in hepatocytes and macrophages close to areas of inflammation. Viral VP60 antigen was detected as early as 12 hpi in a few hepatocytes (0·03 per cent) from adult animals. Within this age group, the extent of hepatocyte labelling considerably increased at 18 (3·0 per cent), 24 (25·5 per cent), 36 (50 per cent) and 48 (60 per cent) hpi. Extrahepatic viral VP60 antigen was also detected at 36 and 48 hpi in spleen macrophages and lymphocytes from adult rabbits. These findings support the hypothesis that the hepatocyte is the only cell type in the liver able to support RHDV replication almost immediately after viral infection.

Rotaviral RNA was detected in the stool sample of an asymptomatic fattening pig at a Slovenian pig farm. To characterize the rotavirus, RT-PCR was used, employing primers specific for the VP7, VP4 and NSP4 genes. Specific products were purified and the sequencing reaction was performed for the molecular analysis of amplified genes. Nucleotide and amino acid sequences of the VP7 gene were found highly identical (85.3-88.1% and 90.7-91.6%) to G1 genotype strains. Phylogenetic and molecular analyses of the VP7 antigen regions revealed the sample to be from a new lineage of G1 genotype. In the molecular analysis of the VP4 gene, only 70.9% nucleotide (76.2% amino acid) identity was found with the most related rotavirus VP4 gene from GenBank. Following this, the NSP4 gene was also analyzed. After the phylogenetic analysis, it clustered with the NSP4 B genotype, but also seemed to represent a new lineage of this genotype. This new rotavirus strain, named P21-5, differed greatly from all rotaviruses characterized so far in all three genes analyzed. The virulence of this strain is not clear yet and has to be investigated.

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