MIAMI - The West Nile virus that first appeared in North America when it struck New York two years ago has reached as far south as Florida, federal and state health officials say.
The virus was discovered this month in a dead crow in the Florida Panhandle in what health officials saw as a troubling development in the migratory pattern of the virus. Its appearance in Florida does not fit the state-by-state migration pattern of the virus, according to the Centers for Disease Control and Prevention in Atlanta.
On Friday, the state Department of Health said preliminary tests of three additional crows found in northern Florida showed evidence of West Nile virus. So experts at the centers say the virus, carried in birds and mosquitoes, has spread south faster than expected or has reached Florida by another route.
"The finding in Florida is the first time we have identified the virus in a noncontiguous area," said Dr. David Ostroff, the coordinator for the West Nile virus at the centers, "and the first time its spread has been identified during the time of year that is not the tail-end of when birds are migrating. In June and July in northern Florida there is not much bird migration going on."
Five other states that previously reported positive tests for West Nile virus have discovered new cases this year, the centers said. They are New York, New Jersey, Connecticut, Maryland and Rhode Island.
With the addition of Florida, a total of 12 states and the nation's capital have confirmed cases of the virus since it was discovered in this country in New York in 1999, the centers said.
The other states are New Hampshire, North Carolina, South Carolina, Pennsylvania, Delaware and Virginia. Last year, the virus spread nearly county-by-county from one state to the next, down the East Coast, Ostroff said.
Experts say it is too early in the mosquito season to estimate how far the virus will spread this year or how many people are likely to become infected. But as more states have reported the West Nile virus, health and agriculture agencies have been able to sketch a map of where it would very likely spread down the Eastern Seaboard.
"We had positive findings not only throughout the state of New York in all but one county but as far to the northeast as New Hampshire and as far south as South Carolina," Ostroff said, "and we had positive findings in all those contiguous states. When you look to see what happened in 2000, the virus expanded its geographic range considerably from the year before."
Florida health officials say they have been bracing for the arrival of the virus, given its southern movement, and have stepped up efforts to control its spread and to tell people about its potential dangers. "We fully expected the virus to spread from the New York epicenter outward," said Dr. Steven Wiersma, an epidemiologist with the Florida State Department of Health.
Wiersma said officials had particularly tried to reduce the potential impact of the virus on the state's elderly residents, the group most vulnerable to becoming ill if infected with the virus.
The virus, which is native to West Africa, mostly infects birds and mosquitoes but can also be contracted by animals and people through mosquito bites. Most people who get it do not become ill or experience only mild flulike symptoms. But it can cause encephalitis and it can be fatal, particularly for the elderly and people with weak immune systems. In New York, the virus has killed nine people and made 83 others ill.
Florida and many other states began developing preventive plans soon after the virus spread beyond New York.