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.