Ridecamp: [RC] FW: Gene May Determine Who Gets West Nile Fever-Report

For what it's worth. They don't mention that horses have this gene, but I
wouldn't be surprised. I wonder how/if it works in combination with
vaccination. But it may well have something to do with how our Egyptian
horses...and even those imported from elsewhere...survive. Except for the
show breeders, with our rudimentary health care, it's definitely survival of
the fittest.

Maryanne Stroud Gabbani
Cairo, Egypt
maryanne@xxxxxxxxxxxxxx
www.ratbusters.net

-----Original Message-----
From: VETMED: Veterinary Medicine [mailto:VETMED@xxxxxxxxxxxxxxxxxx]On
Behalf Of Mary Brownell
Sent: August 20, 2002 6:39 AM
To: VETMED@xxxxxxxxxxxxxxxxxx
Subject: Gene May Determine Who Gets West Nile Fever-Report


Gene May Determine Who Gets West Nile Fever-Report
                     Mon Aug 19, 5:18 PM ET

                     WASHINGTON (Reuters) - Some people may be genetically
predisposed to have a deadly reaction to West Nile virus ( news - web
sites), which has killed 11 people in the United States this year, French
researchers reported on Monday.

                      The researchers said they had bred a strain of mice
that quickly developed the deadly encephalitis -- brain inflammation -- when
infected with West Nile virus. Normal "wild-type" mice do not become sick
from West
Nile.

                     The inbred mice have a genetic mutation that seems to
affect the immune system. People who contract West Nile fever may have a
similar mutation, the researchers report in this week's issue of the
Proceedings of the National Academy of Sciences ( news - web sites).

                     West Nile first appeared in the United States in 1999,
and has now spread to every state east of the Rocky Mountains. The U.S.
Centers for Disease Control and Prevention ( news - web sites) report 251
people
confirmed to have been infected with the virus.

                     But the mosquito-borne disease has been reported for
decades in Africa, the Middle East and parts of Europe.

                     Eight out of 10 people who are infected show no
symptoms at all, but 20 percent of those infected develop a fever, which can
progress to encephalitis. This can be deadly and often leaves life-long
damage
in those who survive.

                     Jean-Louis Guenet of the Institut Pasteur in Paris and
colleagues found their inbred mice had a mutation in a section of genes
coding for production of enzymes called oligoadenylate synthetases. These
are
usually involved in fighting viral infections.

                     The mutation shortened one version of the enzyme,
apparently making it less effective.

                     Charles Samuel of the University of California Santa
Barbara said the finding my explain who is susceptible not only to West
Nile, but
to various related viruses known as flaviviruses, which include St. Louis
encephalitis, also common in the United States, and yellow fever.

                     "Given the low background on immunity, West Nile virus
spread and amplified transmission has the potential to result in future
summertime epidemics," Samuel wrote in a commentary.

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