A strain of encephalitis never before seen in the Western Hemisphere has been found in dead birds here, raising the possibility that the new strain, not St. Louis encephalitis, killed three residents and sickened 14.
The new West Nile strain is typically found in Africa and England. It has never before been documented in the United States, according to the U.S. Centers for Disease Control and Prevention.
Barbara Reynolds, a spokeswoman for the centers, said all the cases confirmed in humans so far were thought to be the St. Louis strain, but researchers were retesting for the new strain.
Two more victims of encephalitis, believed to be the St. Louis strain, were reported Friday. They included a 90-year-old woman who lives near Central Park -- the first confirmed case in Manhattan. She was in critical condition.
Spraying to combat the mosquito that carries the St. Louis virus should also work against the West Nile virus, officials said.