- Four people who have donated blood to the Bonfils Center
in the past 15 days have tested positive for West Nile virus, the mosquito-borne
disease that killed 284 Americans last year.
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- A new test implemented July 1 spotted the anomalies,
Jessica Maitland, vice president for communications at Bonfils Blood Center,
said Tuesday, emphasizing that the blood was quarantined and not given
to any patients.
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- Two cases were reported on Friday and two on Monday,
and none of the donors reported feeling any of West Nile's flulike symptoms.
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- Since July 1, the blood from every donor has been tested
for West Nile, along with several other potentially dangerous diseases,
such as hepatitis.
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- "We're trying to confirm that there are no false
positives," a process that could take two weeks, said Maitland.
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- All four donors whose blood tested positive are cooperating,
letting doctors draw blood to see if their systems, in fact, have developed
antibodies to the virus.
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- Last year, 14 Coloradans tested positive for West Nile,
but there were no deaths.
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- The head of communicable diseases for the state health
department says that until the tests are confirmed, he'll maintain "a
healthy skepticism" that all four donors actually have the virus.
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- Having four positives in just a few days in a state where
just four horses and no chickens have tested positive seems unusual, said
Dr. Ken Gershman of the Colorado Department of Public Health and Environment.
He said the federal government rushed approval of the tests and that it's
not unusual for a new test to show many false positives.
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- Still, he said, "There is reason to believe there
might be one or four asymptomatic infections that are a harbinger"
of a busy West Nile season in August and September.
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- Despite the surprising news, Maitland and Gershman agree
that the blood supply here and across the nation is safe.
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- Bonfils is one of 22 large blood centers around the nation
to implement new screening tests. The one Bonfils uses is a nucleic acid
test developed by Chiron of Emeryville, Calif.
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- Bonfils now includes specific symptoms for West Nile
on the screening checklist for donors waiting their turn to give blood,
Maitland said. The goal of blood centers is to discard any blood that has
the slightest chance of infection, so the new tests are useful for them,
Gershman said.
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- For public health, the results are less useful until
their accuracy can be confirmed.
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- If the results are confirmed, they could rewrite the
assumptions about how many people are infected but remain without symptoms.
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- Those assumptions are that most people won't get bitten
by a mosquito carrying the virus, and that of those who do, most will be
asymptomatic. It is also believed that of those who have symptoms, most
will recover, and that of those with serious symptoms, most will avoid
death or the swelling of the brain called encephalitis.
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- But with West Nile virus still in its infancy in the
U.S., it's still just a guess what "most" means.
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- So far this month, Bonfils has collected 7,459 units
of blood. If the four recent Colorado donors do, in fact, have West Nile
virus, that extrapolates to 2,400 people statewide who might have the virus
but don't know it because they don't feel sick.
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- The health department hopes to retest the blood, using
a different test, as soon as possible, but needs Bonfils' cooperation,
Gershman said. Bonfils' plan was to confirm the tests with a private firm.
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- Gershman hopes that when a key official returns to the
office today at Bonfils, the samples can get to the state health department
without further delay. Nationwide, four human cases - three in Texas and
one in South Carolina - have been confirmed, Dr. Julie Gerberding, director
of the Centers for Disease Control and Prevention, said Tuesday.
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- That's the same number as this time last year, but more
worrisome is that cases have been found in animals in 32 states so far,
compared with 20 states last July, she said.
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- "We need to be prepared," Gerberding said.
"It's too soon to predict the shape of the epidemic, but the signs
all indicate there is reason to anticipate a problem."
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- The best defense is for people to protect themselves
by wearing long-sleeve clothing outside in the mornings and evenings; using
insect repellent; and emptying water from flower pots, tires and the like
in back yards.
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- Gerberding said human clinical trials for West Nile vaccines
could start as early as September.
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- West Nile infection usually starts with a fever, a very
serious headache, muscle aches and fatigue.
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- Bonfils has seen its typical post-Fourth of July drop
in donations, but because of generous giving in the spring and early summer
isn't facing the critical shortage other centers are, Maitland said.
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- http://rockymountainnews.com/drmn/local/article/0,1299,DRMN_15_2112583,00.html
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