From:
Sukie Crandall
Date: 2007-10-19 16:11:16 UTC
Subject: [ferrethealth] Influenza survival and transmission
To: ferret-l@LISTSERV.FERRETMAILINGLIST.ORG, ferrethealth@yahoogroups.com
Granted, this is someone who doesn't know how to interact w ferrets,=20
but the reasons behind influenza (which ferrets and humans get) being=20
more common in winter may be better understood now according to the=20
Live Science article:
1. Colder and drier conditions help the virus survive better between=20
hosts
2. Those conditions also move away water at the virus, allowing the=20
virus to remain airborne longer
3. Drier conditions reduce the mucus barrier which otherwise could=20
help stop infection.
4. Less mucus also means an inability to expel the virus before it=20
can take hold.
http://www.livescience.com/health/071018-flu-season.html
The study is in PLoS (Public Library of Science, a freely available=20
source) Pathogens and the full article may be found here:
http://pathogens.plosjournals.org/perlserv/?request=3Dget-
document&doi=3D10.1371/journal.ppat.0030151
Abstract:
BEGIN QUOTE
Influenza Virus Transmission Is Dependent on Relative Humidity and=20
Temperature
Anice C. Lowen1*, Samira Mubareka1, John Steel1, Peter Palese1,2*
1 Department of Microbiology, Mount Sinai School of Medicine, New=20
York, New York, United States of America, 2 Department of Medicine,=20
Mount Sinai School of Medicine, New York, New York, United States of=20
America
Using the guinea pig as a model host, we show that aerosol spread of=20
influenza virus is dependent upon both ambient relative humidity and=20
temperature. Twenty experiments performed at relative humidities from=20
20% to 80% and 5 =B0C, 20 =B0C, or 30 =B0C indicated that both cold and dry=
=20
conditions favor transmission. The relationship between transmission=20
via aerosols and relative humidity at 20 =B0C is similar to that=20
previously reported for the stability of influenza viruses (except at=20
high relative humidity, 80%), implying that the effects of humidity=20
act largely at the level of the virus particle. For infected guinea=20
pigs housed at 5 =B0C, the duration of peak shedding was approximately=20
40 h longer than that of animals housed at 20 =B0C; this increased=20
shedding likely accounts for the enhanced transmission seen at 5 =B0C.=20
To investigate the mechanism permitting prolonged viral growth,=20
expression levels in the upper respiratory tract of several innate=20
immune mediators were determined. Innate responses proved to be=20
comparable between animals housed at 5 =B0C and 20 =B0C, suggesting that =
cold temperature (5 =B0C) does not impair the innate immune response in =
this system. Although the seasonal epidemiology of influenza is well=20
characterized, the underlying reasons for predominant wintertime=20
spread are not clear. We provide direct, experimental evidence to=20
support the role of weather conditions in the dynamics of influenza=20
and thereby address a long-standing question fundamental to the=20
understanding of influenza epidemiology and evolution.
END QUOTE
Alternatively, a person can go to
http://www.plos.org/
select and click on the pathogen journal from the menu on the=20
reader's right
then if it is not coming up on the first page select "more". There=20
are rotating first pages. At least one contains a direct link but=20
another is on coral.
Sukie (not a vet)
Recommended ferret health links:
http://pets.groups.yahoo.com/group/ferrethealth/
http://ferrethealth.org/archive/
http://www.afip.org/ferrets/index.html
http://www.miamiferret.org/fhc/
http://www.ferretcongress.org/
http://www.trifl.org/index.shtml
http://homepage.mac.com/sukie/sukiesferretlinks.html
[Non-text portions of this message have been removed]
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