Time to stock up on bug spray: West Nile virus can sting hard

WASHINGTON – Patricia Heller was an avid skier and bicyclist – so when she collapsed in the street after a bike ride, she shrugged it off.

By the next morning, Heller’s left leg was paralyzed. It was West Nile virus, from a mosquito bite the Colorado woman doesn’t remember. She would need months of therapy to walk again and today, almost two years later, isn’t fully recovered.

West Nile was long considered a serious problem only for the elderly and frail, and more of a nuisance illness for everyone else. Now a surprising number of patients shows the virus is more threatening than believed – and new research finds that even so-called mild cases of West Nile fever can impair people for weeks or months.

Seventh season

It’s sobering news as the nation gears up for a seventh season of the mosquito-borne virus.

West Nile virus struck abroad for decades, from the tip of Africa up to Europe and throughout Asia, before it appeared in New York City in 1999 and began a march across this country. Since then, the Centers for Disease Control and Prevention has counted more than 16,600 human cases and 654 deaths. Severe illness still is rare, considering that 80 percent of people infected never show symptoms.

But last year, about a third of West Nile cases reported to CDC had neurological complications like meningitis or encephalitis. Those are most common in older adults.

Then there are patients like Heller, who came down with West Nile’s most perplexing complication: polio-like paralysis or severe muscle weakness that often strikes healthy people in their 30s, 40s and 50s. They may show no other symptoms before a limb quits working. Sometimes, the paralysis leads to respiratory failure.

There are no good counts of this West Nile complication, and some doctors believe it’s frequently mistaken for a stroke or other paralyzing ailment.

In a study to be published in July, CDC’s Dr. Jim Sejvar estimates 10 percent of people who develop the most severe West Nile may have some degree of the polio-like complication, and many don’t recover muscle function.

Even the less serious form of illness, West Nile fever, is turning out to be harder to kick than doctors initially described – so much so that the CDC has largely abandoned its earlier characterization as a “mild disease.”

A study by Chicago’s health department last fall found West Nile fever was bad enough to keep half of sufferers out of school or work for 10 days, fatigue lasted a month and the median time to get back to normal was 60 days.

More virulent strain

In much of the world, West Nile is a fairly mild illness. But the form working its way through the United States appears similar to a more virulent Israeli strain, something not initially apparent to health workers.

There is no vaccine or approved West Nile treatment. The best protection is to avoid mosquitoes, using repellent when outdoors and not letting puddles collect in flower pots, wading pools or other spots where mosquitoes can breed.

Anyone with symptoms of serious illness should see a doctor right away: high fever, severe headache, confusion or difficulty thinking, stiff neck, severe muscle weakness, or tremors.

Studies of potential West Nile therapies – including infusions of West Nile-fighting antibodies from the blood of survivors – are poised to begin as soon as this year’s first patients appear.

Doctors on notice

California especially is putting doctors and residents on notice to review the studies as that state braces for what it expects to be a large outbreak.

“If new symptoms develop at any age, don’t assume that it is an innocuous, transient viral infection,” says Dr. Patrick Joseph, a San Francisco physician and member of the National Foundation of Infectious Diseases. “Seek help so diagnostic testing can be done.”

For those who suffer paralysis, prompt physical therapy is crucial, too, advises Dr. Mazen Dimachkie of the University of Texas Medical School in Houston. That therapy is what Heller credits with her ability to walk again, and she’s keeping it up in hopes of one day also being able to run again. Meanwhile, she advises everyone she meets to slather on the bug spray.