Regarding common cold
In Sweden common colds are a major problem in our daycare centers. However
the last couple of years have seen a development of outdoor daycare
centers, which spend most of their daily activities regardless the weather,
outdoors. This has resulted in a drastic decrease in upper respiratory
tract infections in this centers and possibly supporting the indoor,
crowding theory
sincerely
Anders Cervin
-----Ursprungligt meddelande-----
Fr}n: Ron Eccles [SMTP:[log in to unmask]]
Skickat: den 14 oktober 1998 11:08
Till: [log in to unmask]
[mne: Re: Cold and common colds
In response to the question about chilling and colds by Ron Halweil- all
the experiments have not
been able to show any increased susceptibility to infection or any increase
in symptom severity-
however just because this relationship has not bee shown in the lab does
not mean it does not occur
in the field !!!
Some of the original experiments were reported by-
Douglas R G J, Lindgren K M, Couch R B (1968) Exposure to cold environment
and rhinovirus common
cold. Failiure to demonstrate effect. New England Medical Journal 279:
742-747.
Dowling H F, Jackson G G, I.G. S, Inouye T (1958) Transmission of the
common cold to volunters
under controlled conditions. II. The effect of chilling of the subject upon
susceptibility. American
Journal of Hygiene 66: 59-65.
Andrewes C H (1950) Adventures among viruses. III. The puzzle of the common
cold. New England
Medical Journal 242: 235-240.
Some of my own ideas about cold and colds are given below-
Common colds are much more common during the cold, wet, dark days of winter
and this
seasonality has been explained by some effect of the weather on the common
cold viruses and how
they are spread.
It is generally believed that the viruses spread more easily during winter
because we tend to
spend more time indoors in poorly ventilated rooms. Another factor could
be that sunlight kills
viruses and that there is far less sunlight during the short dark days of
winter. However, in
recent years these explanations of the seasonality of common colds have
been modified as
scientists have realised that changes in the weather affect mankind as well
as the common cold
viruses. Another explanation for the increased incidence of common colds
during winter may be
that due to changes in our immune system we are more susceptible to
infection. The cold wet
weather and lack of sunlight certainly makes many of us feel 'under the
weather' or depressed and
these psychological changes can affect our immune system.
Scientists have known for some time that our mood influences our immune
system and that when
we are stressed or depressed our susceptibility to infection is increased.
Perhaps the seasonal
nature of common colds is due to the effects of weather on our bodies
rather than influences on
the spread of viruses. If this was the case then one way of avoiding colds
would be to migrate
South with the Swallows at the end of the summer and enjoy the summers in
both the Northern and
Southern halves of the world. This would be a rather expensive but
certainly very enjoyable way of
avoiding common colds.
Best wishes
Ron Eccles
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Professor Ronald Eccles
Director, Common Cold Centre
Cardiff University
Cardiff CF1 3US
Wales, United Kingdom
voice 44-1222-874099
fax 44-1222-874093
WEB URL http://www.cf.ac.uk/uwcc/biosi/associates/cold/home.html
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