[Distribution of Borna disease virus in naturally infected animals with clinical disease]. / Die Verteilung des Bornavirus in natürlich infizierten Tieren mit klinischer Erkrankung.

Borna disease (BD) is a naturally occurring enzootic encephalomyelitis of horses and sheep. The aetiological agent, Borna disease virus (BDV) is an unclassified, neurotropic, negative stranded RNA virus. The study aimed at providing further information on BD of naturally infected animals. Samples obtained from 20 animals (18 horses, 1 donkey, 1 sheep) were investigated by a series of virological and molecular biological tests. The highly sensitive reverse transcription-polymerase chain reaction (RT-PCR) method was used to analyze the tissue distribution of BDV-specific RNA. BDV-specific RNA was detected in bulbus olfactorius, nucleus caudatus, hippocampus and cerebral cortex of all infected animals. BDV-RNA was also present in the spinal cord, eye, nasal mucosa, parotide gland, lung, heart, liver, kidney, bladder and ovaries. In addition, BV-specific RNA was also detected in conjunctival fluid, nasal secretions and saliva of two infected animals. By Western Blot assays the highest amounts of BDV antigens were demonstrated in bulbus olfactorius, nucleus caudatus, hippocampus and cerebral cortex.

Sequence analyses of the p24 gene of Borna disease virus in naturally infected horse, donkey and sheep.

By reverse transcriptase/PCR amplification and subsequent sequence determination of the p24 gene, the relatedness of Borna disease virus (BDV) in various naturally infected animal species was determined. These results are indicative of a common ancestral virus pool and a remarkably low species barrier of BDV. Comparison of 11 sequences to that of tissue culture adapted virus revealed that the homology among all isolates was at least 96.2% at the nucleotide level, and 97% at the amino acid level. Viral sequences from sheep, donkey and horse were found to be not more distantly related to each other than sequences from different infected horses. Tissue-specific virus variants were detected in one horse: the sequences established from infected cerebrum and kidney showed 10 mutations, whereas sequences obtained from parotid gland contained 20 mutations in comparison to the nucleotide sequence of MDCK cell adapted BDV.