Once Ominous, West Nile Wanes As Area Threat

The majority of West Nile patients do not become severely sick, experts say, and the population at risk for getting ill from the infection is small, mainly the elderly. Many who contract the virus are unaware of it, and reported cases typically involve people who contract meningitis or encephalitis.

Regional health officials warn that it is too soon to tell whether West Nile activity will remain relatively light or become more serious as the summer progresses.

"We know that the mosquitoes are there," said Aftab Hussain, a supervisor at the Arlington County Environmental Health Bureau. "We know that the virus is endemic in the area. With human cases, we've been lucky."

Maryland reported the only West Nile fatality last year, after the region went without a single human death tied to the virus in 2005, and one West Nile-related human death in Virginia in 2004.

In 2003, Maryland had eight West Nile-related human deaths, while Virginia had one and the District none. In 2002, West Nile virus was tied to 11 deaths in the region: seven in Maryland, and two each in Virginia and the District.

The overall number of West Nile cases involving people in the region has dropped. Maryland reached its peak in 2003 with 73 cases. Virginia had its high with 29 cases in 2002, and the District peaked with 34 human cases that same year. Last year, there were 18 human cases in the region, according to the CDC. West Nile in horses and mosquitoes also has dropped significantly over the past couple of years.

But the virus, first detected in the United States in 1999, has continued to spread across the country. In 2002, there were 284 human deaths tied to West Nile in the nation, the most since the outbreak. The number of human cases nationally peaked in 2003 at 9,862, more than double the 2002 total of 4,156. Last year, there were 4,269 West Nile human cases, with 177 related deaths, according to the CDC Web site.

Officials in the Washington region say they plan to continue the public education campaign. They ask residents to continue to take the traditional precautions: Wear insect repellent when outside and remove standing water from around homes.

Although "the virus seems to be stabilized," Keller said, "it is endemic in our area."

"Our mantra is always protection and prevention," she said, "because we know the virus is here."