Published Date: 2002-09-06 23:50:00
Subject: PRO/AH/EDR> West Nile virus, human - USA (CA): suspected
Archive Number: 20020906.5247
WEST NILE VIRUS, HUMAN - USA (CALIFORNIA): SUSPECTED
A ProMED-mail post
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International Society for Infectious Diseases
Date: 6 Sep 2002
From: ProMED-mail <firstname.lastname@example.org>
Source: AP Online 6 Sep 2002 13:59 EDT
California may have first West Nile case
WASHINGTON (AP): Doctors were treating a young woman in California with
symptoms consistent with West Nile [virus infection] in what could mark the
first human case of the virus in the western United States, health
officials said on Friday.
The unidentified Los Angeles County woman has aseptic meningitis, a
condition sometimes associated with West Nile [virus infection], said Lea
Brooks, a spokeswoman for the California Department of Health Services.
Preliminary tests showed possible exposure to the virus; confirmatory tests
were expected later in the day, she said.
Another official said the woman's case is important because she had not
traveled outside the area, suggesting that West Nile [virus infection],
which first appeared in New York, may have completed its journey across the
Nationally, the number of confirmed West Nile cases this year hit 854 on
Thursday, with 43 dead, the Centers for Disease Control and Prevention
(CDC) reported. Many others are infected but may never show symptoms, so
there could be 110 000 to 150 000 people who have been infected in the US,
most of whom will never suffer its effects or know they have the virus, CDC
epidemiologist Dr Anthony A Marfin said.
These numbers are likely to keep growing in the coming weeks as the West
Nile [virus infection] season peaks, but cases should drop off as the
weather gets colder and disease-carrying mosquitoes disappear, officials
said. In the past few years, West Nile has disappeared by December, but the
disease has spread much farther this year and cases could appear well into
Also on Friday, health officials were working to trace blood donated to
[two cases with] West Nile [virus infection], trying to determine if the
virus can be transmitted through blood. With no blood screening test
available, experts worry that the virus could travel through the blood
supply undetected. Still, they say, any risk is minimal and is far
outweighed by the medical need for blood.
CDC investigators were focusing on two West Nile victims who may have
contracted the disease through blood transfusions: a Georgia woman who
received blood from 63 people as doctors unsuccessfully tried to save her
from a car accident, and a Mississippi woman who received blood from 18
people during an obstetrical procedure.
The Georgia woman died, and her organs were donated to four people, all of
whom were infected with the disease. That convinced health authorities that
the virus can be spread through transplants, but they remained uncertain
whether it also could be transmitted through blood donations.
The Mississippi woman became sick with West Nile encephalitis soon after
her surgery, and is now recuperating at home. The investigation into her
case was launched Thursday after it was discovered by state
epidemiologists. They were reviewing a sample of infected patients to see
what they may have in common and looking for patients who might have
received a significant amount of blood before becoming infected.
Health officials cautioned that both women may have been infected by
mosquito bites, as other West Nile victims were. The Mississippi woman, in
particular, lives in an area with many cases of the disease and she
reported having been bitten by mosquitoes many times.
Even if one of the people who gave her blood turns out to have West Nile,
the woman still could have been infected by a mosquito, officials said.
"It's very hard to sort that out," Marfin said.
As a precaution, remaining blood from donors who gave to either woman was
pulled from the shelves. CDC investigators were collecting samples from
each donor to check for traces of the virus. Other patients who received
blood products, including red cells, plasma and platelets, from these
donors were also being checked for West Nile.
CDC officials cautioned that many people are infected with West Nile, so
some of them are likely to have received blood as well. That alone does not
prove that the virus is carried by blood, said Dr Lyle Petersen, deputy
director of CDC's vectorborne disease division. "There is absolutely no
proof at this point that West Nile virus transmitted by blood transfusions
has occurred," Petersen said. "This still remains a theoretical possibility."
Federal officials have urged blood banks to pay particular attention to
would-be donors, screening out anyone who is sick and may have West Nile.
But many people infected [are not] sick, and no blood screening test [is]
available. So even if the disease does prove to be bloodborne, there is
little more that can be done.
The same goes for donated organs. Officials emphasized that the risk of
forgoing a lifesaving organ is vastly greater than the risk of contracting
West Nile from a transplant.
For each person who becomes severely ill, experts believe there are an
additional 30 infected people who get mildly sick and 120 to 150 others who
do not show any symptoms. It is possible those healthy but infected people
could carry the virus to others.
In the most severe cases, West Nile causes a potentially fatal brain
inflammation. Others get a flu-like illness, with fever, headache and
muscle pains that lasts two or three days.
[byline: Laura Meckler]