Isolation of Non-Host Nucleic Acids From Viliuisk Encephalomyelitis



Irina Alexeeva*

and Robert G. Rohwer. Baltimore Research and Education

Foundation, Inc., Veterans Affairs Medical Center, Baltimore, MD

Viliuisk encephalomyelitis (VE)

is a unique progressive neurological disorder resulting in death

several months to over 6 years after disease onset. Originally

confined to an isolated Yakut population inhabiting the Viliui

river valley in Eastern Siberia, VE has recently spread to Yakut

communities in previously disease free regions of the Sakha

Republic. Clinical, epidemiological and neuropathological studies

indicate a communicable disease, but preliminary investigations

have failed to demonstrate a causative agent. Two molecular

methods were used in an attempt to detect and identify VE agent.

Representational difference analysis (RDA) is a powerful method

for finding the differences between two complex genomes by means

of subtractive hybridization using PCR to recover the subtracted

species. Using RDA to compare DNA isolated from VE patients and

healthy individuals, we isolated several non-host DNA fragments

which have not revealed significant homology to any known human

genes. PCR amplification of small subunit ribosomal (16S) RNA

genes can be used to detect and identify microbes. Generic

primers were used to amplify 16S rDNA from VE infected brain

tissue and the resulting products were cloned and sequenced

revealing presence of bacterial DNA in the specimens. Both

methods have proved to be sensitive enough to detect the presence

of the unique foreign nucleic acid fragments in these complex

genomic DNA preparations. Further screening will be required to

establish whether or not these sequences belong to the etiology

agent of viliuisk encephalomyelitis.