WASHINGTON (AP) _ A mild virus related to dangerous West Nile protected mice from the deadly disease when used as a vaccine, a team of Australian researchers reports.
West Nile virus has been spreading rapidly since it was first reported in the United States in 1999. It causes flu-like symptoms and encephalitis and has resulted in numerous deaths. There is no current cure.
The researchers, led by Roy Hall of the University of Queensland, studied a relatively harmless virus called Kunjin that has similar genetic sequences to the West Nile virus. Kunjin produces only mild, nonfatal disease.
Hall and colleagues injected mice with varying amounts of Kunjin DNA, modified to reduce the strength of the virus.
When tested after 19 days the mouse blood produced antibodies to both Kunjin and West Nile, the team reported in this week's online edition of Proceedings of the National Academy of Science.
They then gave the immunized mice a lethal dose of West Nile virus, and the animals that had received even a small dose of Kunjin were protected from illness.
While more testing is needed, the researchers suggested Kunjin may provide a source for development of a vaccine for both humans and horses.