- NEW ORLEANS -- West Nile
virus appears to cause a higher rate of serious nervous system problems
than researchers had thought, including Parkinson's-like movement disorders
and temporary limb paralysis, a government neurologist reported Sunday.
- Researchers had previously assumed that fewer than 1
percent of people bitten by infected mosquitoes develop severe central
nervous system illnesses - a tiny tip of the West Nile iceberg, according
to Dr. James Sejvar of the Centers for Disease Control and Prevention.
- But a small West Nile study that started in August in
St. Tammany Parish, north of New Orleans, suggests "the tip of that
iceberg may be bigger than we thought," Sejvar said at the Fourth
National Conference on West Nile Virus in the United States.
- About 360 people, mostly federal, state and county public
health workers, are attending the three-day meeting.
- West Nile swept across the United States last summer,
sickening about 4,000 people and killing 263. The virus was detected in
Colorado in mid-August, and the state finished the year with 13 non-fatal
human cases. The Colorado case count is expected to rise in 2003.
- In the St. Tammany Parish study, CDC researchers worked
with local physicians to find 42 people with fever of unknown origin or
symptoms of encephalitis or meningitis, the two diseases most often associated
with severe West Nile illness.
- Sixteen of the 42 tested positive for West Nile and are
being tracked in a study that will last at least a year, Sejvar said.
- Fifteen of the 16 displayed tremors - sometimes severe
enough to interfere with eating and grooming - during their illness. Ten
patients experienced an involuntary jerking or twitching of the muscles.
- In many cases, the tremors and twitching persisted more
than five days, Sejvar said.Eleven of the 16 showed Parkinson's-like symptoms,
including "cogwheel rigidity," which combines rigid muscles with
tremors, balance problems, and slowed body movements.
- Three of the 16 displayed temporary paralysis in a limb
or on one side of the body.
- "What appears to be going on is that the virus is
affecting regions of the brain that direct and control motion," Sejvar
said. The Louisiana study marks the first time many of these movement disorders
have been tied to West Nile illness, he said.
- Lyle Petersen, deputy director of the CDC lab in Fort
Collins, called the findings "very important."
- "They tell us something about the pathology of the
disease and they give us some clue about what the long-term consequences
of having West Nile virus infection might be."None of the 16 patients
died. But in telephone interviews five to six months after their illness,
most reported they were still experiencing persistent headaches, memory
problems, fatigue and an inability to concentrate.
- A much larger follow-up study is needed to flesh out
the details of the findings uncovered in the St. Tammany pilot project,