Why Viruses are More Virulent in Winter

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James Michael Howard
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Why Viruses are More Virulent in Winter

Why Bird Viruses and Human Viruses Increase Virulence in Winter

Copyright 2005, James Michael Howard, Fayetteville, Arkansas, U.S.A.

Testosterone is an immunosuppressant. Testosterone reduces both cell-mediated and humoral immunity in birds (Behvioral Ecology 2000; 11: 654-662). In the "Northern pintail duck," testosterone is lowest from July-September, increasing thereafter throughout the winter to reach maximum levels during the breeding season of April-June (Reproduction, Fertility and Development 2000; 12(4) 229 - 235).

It is my hypothesis that DHEA is necessary for immune function. A number of studies have demonstrated the effectiveness of DHEA against viral and other infectious agents. Testosterone reduces conversion of DHEAS, the background source of DHEA, to DHEA. Since DHEA may be involving in heat production, cold weather should increase use of DHEA for heat. It is known that avian viruses are increased by increased cold. Increasing levels of testosterone during winter could explain why avian viruses increase during the winter season. This could also explain why humans exhibit increased vulnerability to viruses in the winter since testosterone increases in autumn and winter in humans.

It is my hypothesis that the "secular trend," the increase in size and earlier puberty in children, is caused by an increase in the percentage of individuals of higher testosterone within the population with time. This is a periodic trend because excessive testosterone increases morbidity and mortality which eventually reduces the percentage of individuals of high testosterone within the population. I suggest we are currently in a period of increased testosterone which has allowed viruses to enter humanity, for example, the HIV.

DHEA is highest around age twenty. Periods of very low DHEA occur in the very young and the elderly; these are ages more affected by viruses.

MariaMaria
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If testosterone is the reason

If testosterone is the reason for increasing the virulence of viruses, what would be the best way to decrease such level and what are going to be the side effects?

James Michael Howard
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Take DHEA.

Take DHEA.

Jason King
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Then you would expect most

Then you would expect most women to be significantly more suceptible then all men and that bald men would be resistant?

How about: In winter, the temperature is lower, thus viruses present in water droplets (or bird poo) survive longer due to the slower evaporation. Add to this that when it's colder, people tend to spend more time indoors and thus in closer contact with other people (and if you're a poor duck/chicken farmer living in the east of Turkey you may feel that you have to bring the birds inside for the winter too. Logically you don't want the birds sleeping in your room so you put them in with the kids! QED).

An interesting fact relating to the last flu pandemic: it preferentially affected young adults (who would have had DHEA).

samm
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Parvoman has made a good

Parvoman has made a good point. Leave alone avian flu - even the more common viral diseases - incl the rhinovirus common cold - is greatly enhanced in winter because of the reasons he stated.

Children often are more susceptible to infections - because it is schooling time for the immune system too. It would be rather wrong to attribute this supposed 'deficiency' to testosterone!

Also, doesn't DHEA also act as an antioxidant? That would partially explain why some of the "nutritional supplements" actually appear to boost immunity.

James Michael Howard
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parvoman wrote:Then you would

parvoman wrote:

Then you would expect most women to be significantly more suceptible then all men and that bald men would be resistant?

How about: In winter, the temperature is lower, thus viruses present in water droplets (or bird poo) survive longer due to the slower evaporation. Add to this that when it's colder, people tend to spend more time indoors and thus in closer contact with other people (and if you're a poor duck/chicken farmer living in the east of Turkey you may feel that you have to bring the birds inside for the winter too. Logically you don't want the birds sleeping in your room so you put them in with the kids! QED).

An interesting fact relating to the last flu pandemic: it preferentially affected young adults (who would have had DHEA).

No, I would expect men to be more susceptible because they have more testosterone than women. It is my hypothesis that baldness occurs when the ratio of testosterone to DHEA is high. Baldness occurs more in men because of higher testosterone and less DHEA. So... I would suspect that bald men may be more susceptible, not less. (I do not know of a study regarding balding and infections.)

I suspect the past pandemic may have affected young adults more because testosterone is highest in young adults. Since DHEA begins to naturally decline around age 20, the high testosterone at that time may have worsened the testosterone to DHEA ratio.

James Michael Howard
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samm wrote:Parvoman has made

samm wrote:

Parvoman has made a good point. Leave alone avian flu - even the more common viral diseases - incl the rhinovirus common cold - is greatly enhanced in winter because of the reasons he stated.

Children often are more susceptible to infections - because it is schooling time for the immune system too. It would be rather wrong to attribute this supposed 'deficiency' to testosterone!

Also, doesn't DHEA also act as an antioxidant? That would partially explain why some of the "nutritional supplements" actually appear to boost immunity.

Well, thank you for the response but I do not agree with Parvoman's explanation. There are two times in the human life span when DHEA is very low: young children before age 5-6 and very old. Most infections usually hit these groups hardest. In the case of the last flu pandemic, mentioned by Parvoman, I think the ratio of testosterone to DHEA became more important than simply having low DHEA. This may have involved behavioral transmission because testosterone drives people together.

I think the effects of DHEA are much more than simply being "antioxidants."

tdaos
tdaos's picture
James Michael Howard wrote

James Michael Howard wrote:

parvoman wrote:
Then you would expect most women to be significantly more suceptible then all men and that bald men would be resistant?

How about: In winter, the temperature is lower, thus viruses present in water droplets (or bird poo) survive longer due to the slower evaporation. Add to this that when it's colder, people tend to spend more time indoors and thus in closer contact with other people (and if you're a poor duck/chicken farmer living in the east of Turkey you may feel that you have to bring the birds inside for the winter too. Logically you don't want the birds sleeping in your room so you put them in with the kids! QED).

An interesting fact relating to the last flu pandemic: it preferentially affected young adults (who would have had DHEA).

No, I would expect men to be more susceptible because they have more testosterone than women. It is my hypothesis that baldness occurs when the ratio of testosterone to DHEA is high. Baldness occurs more in men because of higher testosterone and less DHEA. So... I would suspect that bald men may be more susceptible, not less. (I do not know of a study regarding balding and infections.)

I suspect the past pandemic may have affected young adults more because testosterone is highest in young adults. Since DHEA begins to naturally decline around age 20, the high testosterone at that time may have worsened the testosterone to DHEA ratio.

Taking dhea and reducing Testosterone and cortisol.Thats seems to be the key.

But,about suplements and inmune sistem.

vitamin E rises testosterone.
Zinc rises testosterone.Vitamin A and D rises testosterone.B vitamins rises testosterone.So,i guess they can reduce Dhea levels because of this,or the elevation of testosterone they produce is compensated by a similar rise in Dhea levels??

Very interesting this theory about Testosterone-Dhea-and inmune system.Great job.