West Nile virus more of a threat than previously thought

May 31 2005

West Nile has traditionally only been considered a serious problem for the elderly and frail, and more of a nuisance illness for everyone else. But a surprising number of patients show the virus is more threatening than widely believed.

New research finds that even so-called mild cases of West Nile fever can impair people for weeks or months.

Colorado woman Patricia Heller, a keen skier and a competitive cyclist, when she collapsed in the street after a daylong bike ride,shrugged off the weakness as cramps.But by the following morning Heller's left leg was completely paralyzed.

Heller had contracted West Nile virus from a mosquito bite she doesn't even remember and needed months of grueling therapy in order to walk again and now almost two years later, still isn't fully recovered.

Dr. Henry Masur of the National Institutes of Health, is concerned that as the nation gears up for a seventh season of the mosquito-borne virus West Nile is fading a little bit from the public consciousness. He says there are more cases of paralysis from West Nile than there were in many years of polio.

West Nile virus was present for decades, from the tip of Africa up to Europe and throughout Asia, before it appeared in New York City in 1999 and began an inexorable march across this country. Since then, the Centers for Disease Control and Prevention (CDC) have counted more than 16,600 human cases and 654 deaths.

Although severe illness is still rare, considering that 80 percent of people infected never show symptoms, last year, about a third of the West Nile cases reported to CDC had neurologic complications like meningitis or encephalitis. Those are most common in older adults.

Other patients like Heller, come 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 suddenly quits working. Sometimes, the paralysis leads to respiratory failure.

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

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

The less serious version of the illness, West Nile fever, is proving to be harder to kick than doctors initially thought, and the CDC has largely abandoned its earlier characterization as a "mild disease."

A Chicago health department study last autumn found that West Nile fever was severe enough to keep half of sufferers out of school or work for 10 days, fatigue lasted a month, and the average time to get back to normal was an appalling 60 days.

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

As yet there is no vaccine or approved West Nile treatment. The best protection is to avoid mosquitoes, using repellent whenever you're 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.

Potential West Nile therapies are being studied, including infusions of West Nile-fighting antibodies from the blood of survivors and are poised to begin as soon as this year's first patients appear. California especially is putting doctors and residents on notice to seek out these research studies, as that state prepares foran expected large outbreak.

Dr. Patrick Joseph, a San Francisco physician and member of the National Foundation of Infectious Diseases, says if new symptoms develop at any age, do not assume that it is an innocuous, transient viral infection,and seek help so diagnostic testing can be done.

Dr. Mazen Dimachkie of the University of Texas Medical School in Houston, advises that for those who suffer paralysis, prompt physical therapy is crucial.

Therapy is what Heller credits with her ability to walk again, and she is hoping one day to be able to run again. In the meantime Heller advises everyone she meets to slap on the bug spray.