FORT COLLINS, COLORADO-- A group of public health researchers announced at a workshop held here last week that the DNA sequence of the virus that caused an epidemic of brain inflammation in and around New York City this summer conclusively shows that it is the West Nile virus--an identification that was under debate until recently. They also reported that the virus9s genome is almost identical to that of a West Nile strain found in Israel last year, suggesting that it originated in the Middle East. Many now agree it has a good chance of establishing itself and spreading in the Western Hemisphere.