APPENDIX II-BM:
WNV Decline-DeBess.
This appendix is copied from:
http://list.uvm.edu/cgi‑bin/wa?A2=ind0503A&L=SAFETY&P=12796
[2]USA (Oregon)
Date: Sat 5 Mar 2005
From: ProMED‑mail <promed@promedmail.org>
Source: Statesman Journal online, Associated Press report, Thu 3 Mar 2005
[edited]
<http://159.54.226.83/apps/pbcs.dll/article?
AID=/20050303/STATE/503030338/1042>
USA: Oregon Faces Tougher Year of West Nile Virus
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Oregon's brush with West Nile virus last summer [2004] might have been merely
a primer for what the state will face this year [2005], a health official
said. The mosquito‑borne virus, which has been detected in 8 counties,
sickened birds, horses and 5 people last year [2004]. This year, hundreds of
human cases could be diagnosed if the virus follows the pattern seen in other
states, said Emilio DeBess, a public health veterinarian and epidemiologist
with the Oregon Department of Human Services.
DeBess will convene a summit Tuesday in Portland for public health and
hospital officials from across the state to plan how to deal with a major
outbreak. The virus, which peaks during the summer when mosquitoes are most
active, entered the
the country. It killed 88 people in 2004, according to the national Centers
for Disease Control and Prevention. DeBess and other epidemiologists theorize
that the disease can enter an area in 3 stages. In the beginning stage,
infected birds fly into a state and are bitten by mosquitoes, which in turn
become infected with the virus. During the 2nd stage, the virus spreads
widely among mosquitoes [not, of course, from mosquito to mosquito but
because more of the birds they feed on are infected. ‑ Mod.JW]
The mosquitoes bite a large number of people who become infected. DeBess said
it is likely that
numbers of human infections this year. In the 3rd year and beyond, the number
of human cases typically declines rapidly because those who were previously
exposed to the virus acquire an immunity to it. Colorado, for example,
reported 14 human cases in 2002. That ballooned to 2947 in 2003 and then
dwindled to 276 in 2004.
It is impossible for the disease to transfer from an animal to a human or a
human to a human, state health officials said. Cattle, sheep, swine, cats and
dogs appear to be immune [the journalist means resistant to infection; an
animal only becomes immune if it survives infection. One dog in Nevada & one
in New Mexico tested WNV positive in 2004, one cat & 5 dogs in 2003 ‑‑ see
ref. 2004 (12) & 2003 (33) below. ‑ Mod.JW]. In humans, most people infected
with the virus exhibit no illness or only mild symptoms such as fever,
headache and body aches. DeBess said that although the number of human cases
declines in subsequent years, the amount of virus circulating among
mosquitoes still is high. "The thing to remember is that the virus circulates
between birds and mosquitoes," DeBess said. "Human beings are dead‑end hosts.
They're just innocent bystanders in this."