“West Nile outbreak expected to worsen”
By Anita Manning
USA TODAY
Fri/Sat/Sun, August 16-18, 2002

This year’s record-setting outbreak of West Nile virus is likely to worsen, and as many as 1,000 people could become seriously ill in the next few weeks, a federal health official said Thursday.

Relative to other more common viral infections, such as the flu, 1,000 would be a small number of cases. But West Nile is a relatively new disease in the USA that has spiked quickly, reaching epidemic proportions.

The acknowledgment by Lyle Petersen, a West Nile virus expert at the Centers for Disease Control and Prevention, underscores the breadth and the scope of a virus that is claiming new victims every day.

Already, at least 160 people in nine states and Washington, D.C., have been infected, the “vast majority” hospitalized with brain infections, meningitis or encephalitis, Petersen said. Nine people have died of the virus so far this year. That equals last year’s total.

In previous years, West Nile outbreaks have not peaked until the last week of August or the first week in September.

“It’s safe to assume we can expect more cases, and potentially a lot more cases,” Petersen said in a routine press briefing. If the epidemic follows the pattern of previous years, he said, it could cause 1,000 serious illnesses and 100 deaths.

Earlier this month, the governors of Louisiana and Mississippi, where the bulk of the illnesses this year have occurred, declared states of emergency. Louisiana Sens. Mary Landrieu and John Breaux have requested help from the Air Force to spray pesticides to kill the mosquitoes that carry West Nile virus. The request has yet to be worked out with local agencies.

West Nile is a mosquito-borne virus that was unknown in North America until it appeared in New York City late in 1999. It has spread across the Mississippi River to 37 other states and is expected to soon reach the West Coast.

“It’s just a matter of time,” Petersen said.

Colorado health officials Thursday reported animal cases of West Nile, making it, if confirmed by the CDC, the 38th and westernmost state to be affected.

It’s unclear why Louisiana, which has reported 85 human cases this year, has been hit so hard, Petersen said, though its warm, wet climate and abundance of mosquitoes that could spread the virus are factors.

Only one in five people who are infected have symptoms, and most suffer a mild fever that goes away after three to six days, he says. One in 150 develop a serious illness. Although younger people have developed the severe form during this outbreak, the risk is greatest for people older than 50. There is no human vaccine and no anti-viral medicine to treat it.

In severe cases, doctors treat the patient’s symptoms until the patient’s immune system is able to defeat the virus. People who become infected once develop immunity. But those who develop the severe form of the disease may have long-term problems.

Mosquito-control efforts in Louisiana, where most cases have occurred, could have a “major blunting effect on this epidemic,” Petersen said, but in some states, such programs have languished.

“This is a classic case of an ignored problem that has now resurfaced,” he said. “Over the last few decades, mosquito-borne disease was not thought to be a problem anymore.”

West Nile human cases in the USA

1999 7 deaths 62 severe illnesses 2000 2 deaths 21 severe illnesses 2001 9 deaths 66 severe illnesses 2002 9 deaths 160 severe illnesses