- Monitoring the blood supply is a very positive step in
the battle against West Nilelike Virus. Jeff, you and I both advocated
doing so as far back as Spring 2000. As the virus becomes more ingrained
in the population we will probably see a substantial number of cases found
via this method. It is also necessary to protect the fragile folks who
will receive the blood. Anything we can do to make the blood supply safer
is a positive step.
- From ProMED-mail
- Saskatchewan: West Nile Virus-Positive Blood Donor Is
First Human Case
- Saskatchewan has confirmed Canada's first domestic case
of West Nile virus in a human this year. It is also the first time a person
has contracted the virus in Saskatchewan. Provincial health officials announced
the case on Fri 25 Jul 2003, saying only that the person was from Assiniboia,
130 kilometres southwest of Regina. They did not give the person's age
or say whether the person was male or female. However, sources say the
person is a man.
- "Fortunately this person is one of the majority
who didn't get ill," said Eric Young, Saskatchewan's deputy chief
medical officer. "However, I think it just brings home the fact that
people have to take precautions, they have to take the potential for West
Nile seriously and they have to do the things they can to reduce that risk."
- On Thursday, Ontario officials announced that province's
first probable case of the 2003 season but said the person likely contracted
the disease while on a trip to the United States. "We knew it was
only a matter of time before someone in Saskatchewan became infected,"
said Dr. Ross Findlater, the province's chief medical health officer. "We
are entering a period where there are more of the mosquitoes that carry
West Nile virus."
- The virus was found in a unit of blood donated in the
province on Tuesday, the Canadian Blood Services reported in a news release.
"He was well when he donated and remains well," said Ted Alport,
medical director of Canadian Blood Services Saskatchewan. Once the blood
tested positive for the virus, it was withdrawn from inventory and the
donor, who has been notified, will not be eligible to donate blood again
for 56 days, at which time the virus will no longer be present.
- "This result shows that our West Nile virus test
is doing exactly what it was designed to do -- helping reduce the risk
that the virus will enter the blood supply," Dr. Graham Sher, chief
executive officer of Canadian Blood Services, said in the release. But
since this person had no symptoms, Dr. Donald Low, a leading expert in
infectious diseases, said he expects this is simply the first detected
case of a person contracting West Nile virus infection, not the only person
to have the disease. "If we've detected one case in a blood donor,
then we're sure that there are more cases out there that have gone unrecognized,"
said Low, a microbiologist at Mount Sinai Hospital in Toronto.
- There were 416 probable or confirmed cases of West Nile
virus in Canada in 2002, although officials acknowledge that was probably
just the tip of the iceberg. It's believed 80 percent of people who get
the virus have such mild symptoms they aren't even aware they've been infected.
Dr. Mike Drebot, head of the viral zoonosis section of Health Canada's
National Microbiology Laboratory in Winnipeg, said it is difficult to predict
what the Saskatchewan case means for the province or the rest of Canada.
"We may see cases in a number of provinces or maybe we'll see the
majority of cases in only one or 2 provinces -- it's really difficult to
say. "But the risk for cases wherever we've detected West Nile activity,
and this ranges from Alberta even to New Brunswick, is there. Although
in certain jurisdictions, the risk may be higher than in others.
- "I would hope that with all the public education
that's been done as well as mosquito abatement procedures, that we'll be
able to dampen the risk and we'll see fewer human cases than we saw last
year." Last year, 20 deaths were attributed to West Nile virus infection
in Canada: 18 in Ontario and 2 in Quebec. The 2 were the only provinces
that recorded domestically acquired cases of the disease in 2002, the first
year there were human cases in this country. 8 U.S. states have already
reported a total of 12 human cases of West Nile virus so far this year:
Alabama, Ohio, Texas, South Carolina, South Dakota, Minnesota, Colorado,
- Birds play a pivotal role in the buildup of the virus
in an area. Early in the season, mosquitoes become infected by feeding
on infected birds. The mosquitoes then transmit the virus to other birds,
building up a critical mass of virus in an area. That process is called
amplification. When sufficient amounts of virus are found in the bird and
mosquito populations of an area, mosquitoes that feed mainly on people
can also become infected, transferring the virus into the human population.
- To date, 69 dead birds have tested positive for West
Nile virus in Manitoba and another 39 in Ontario. Dead birds have also
tested positive for the virus in New Brunswick (one), Saskatchewan (17),
Quebec (8) and Alberta (3).
- ProMED-mail email@example.com
- [This circumstance mirrors the American experience (in
the states of Colorado and Florida): that the surveillance of donations
by blood banks is proving to be a sensitive indicator of the presence of
West Nile virus infection in the human population, well before the first
symptomatic cases make their appearance. In the Canadian situation, the
surveillance of blood donations has revealed the first human case of West
Nile virus infection in the province of Saskatchewan in the absence of
overt disease. - Mod.CP]
- [At the risk of a barrage of emails, the thought that
comes to mind here is: so much for sentinel chickens... sentinel chicks
may be better! - Mod.MPP]
- Patricia A. Doyle, PhD Please visit my "Emerging
Diseases" message board at: http://www.clickitnews.com/ubbthreads/postlist.php?Cat=&Board=emergingdiseases
Zhan le Devlesa tai sastimasa Go with God and in Good Health