Thread: How does heat suppress viruses?

Apparently one strategy our bodies employ in fighting infection is simply raising the temperature a degree or two. I fail to understand how that could work against viruses - which i think are tough simple little machines, compared to our more subtle & fragile cells. How could one or two degrees make any difference?

There isn't really a good answer to that, fever in animal studies seems to be better than no fever, but too much fever is bad. Why fever seems to help is up for debate. It may inhibit proliferation of some bacteria, but the more likely reason is that it speeds up the reactions of the immune system and allows our immune system to function more efficiently.

It may inhibit proliferation of some bacteria, but the more likely reason is that it speeds up the reactions of the immune system and allows our immune system to function more efficiently.

so the as the temperature increases is it because the "kinetic energy" of the molecules speed up, therefore showing fastening reactions on the cellular level?

I do not know the answer.

Conjecture: Maybe it does not affect the virus directly but makes our immune response more potent/reactive/etc

I personally think that when I get cold because of cold temeratures I'm much more likely to get sick, and it seams to me that the cold itself does not contain/transmit bacterias/virus but has a negative effect on my immune system and any bacteria or virus that was already there got activated or exploited the opportunity. Although I have to admit that when the symptom of the illness occurs my body is back to normal temperature but maybe the damage is already done and the war is on.

It may inhibit proliferation of some bacteria, but the more likely reason is that it speeds up the reactions of the immune system and allows our immune system to function more efficiently.

Maybe it also makes the virus more vulnerable to the immune system.

Interestingly in my aquarium hobby boosting the temperature of the aquarium when infected with a pest called "ich" exsposes larger numbers of the pest .. which normaly are enclosed in protected stages .. to exposure from chemical treatments by speeding up the life cycle of the pest.

MB ...

Increased temperature denatures proteins, such as the proteins which form the shell of a viral particle. Result can be a loss of function or even a loss of solubility. So for pathogens that have proteins with a limited optimal temperature range, pushing up the temperature is going to mess with their cell binding functions and replicative functions and so forth. It'll also mess with our own proteins somewhat, but a balance can be struck. It won't work for all pathogens, but it will help for some. It's also possible, as some suggest here, that some immune reactions will be enhanced by the increased temperature. Perhaps some antibodies or some complement subunits have optimum temperatures above body temp, though that would be news to me.

Hi new to the forum, not a scientist, but hope to be participating in conversations, so excuse what might seem to be inane questions.

Biologista, you mentioned that increased temperature will mess with our proteins, but a balance can be struck. How is that balance finally struck? What stops all our proteins from being messed with?

Roth J. Fever in acute illness: beneficial or harmful? Wien Klin Wochenschr. 2002 Feb 15;114(3):82-8.

Fever may represent a leukocyte-based amplification mechanism to affect host challenge: enhanced motility of leukocytes, enhanced lymphocyte response to mitogens, increased production of interferon, enhanced immune response to viral antigens.

I didn't make it up

Edit: Since I'm at home and have access to my books.

Janeway's Immunobiology 7th ed. 2008 says fevers are "believed to help in eliminating infections" by "decreased viral and bacterial replication, increased antigen processing, [and] increased specific immune response". That's pretty much all the information on fevers in this 800 page immunology text book...

I don't think the effect of the increase of a few degrees on the denaturing of pathogen's proteins is all that clear, it must have some effect though.

Pong you mentioned how our cells are more fragile. Seeing as some viruses cannot survive outside of cells for long could the raising in temperature perhaps be just another way to try and destroy viruses by destroying the cells that contain them(perhaps some increased weakness when contaminated). Obviously there are problems with that theory but is it perhaps a possibility?

Originally Posted by i_feel_tiredsleepy

I don't think the effect of the increase of a few degrees on the denaturing of pathogen's proteins is all that clear, it must have some effect though.

Actually, denaturing is probably an inaccurate term in this case- that tends to require temperatures far higher than we can survive. But certainly we can generate temperatures that would alter protein conformation and thus activity.

I don't disagree, I'm sure the temperature change is sufficient to render the protein function suboptimal, it probably isn't enough to render most proteins completely nonfunctional. I think it might also have more to do with the decreased half-life expected of most proteins in higher temperatures, the cells have to work harder to replace proteins, this would contribute to suboptimal bacterial growth but wouldn't cause too much damage to our cells.

I would imagine viruses have a harder time with it, because they have no mechanisms to replace proteins or adapt to higher temperatures.

Wow thanks, people. I cant' say I've digested all of the above, but I see that there's no easy answer here. Whether or not to combat a high temperature in children (i.e. with aspirin) is an ongoing debate amongst parents.

Something I've been wondering: could temperature itself be a signal?

Originally Posted by Pong

Wow thanks, people. I cant' say I've digested all of the above, but I see that there's no easy answer here. Whether or not to combat a high temperature in children (i.e. with aspirin) is an ongoing debate amongst parents.

Something I've been wondering: could temperature itself be a signal?

You mean to the immune response? Interesting question. I don't know but it's certainly plausible.

I give my kids medicine to lower their fever. Never aspirin by the way. Doctors orders

Being a plant person :wink: ... I have not read about this subject in some time .. just giving my two cents.

Though I think in general fever is more then anything a signal that something is wrong and the body is responding. I wouldn't let fevers climb in my kids.

MB ...

Originally Posted by TheBiologista

You mean to the immune response? Interesting question. I don't know but it's certainly plausible.

It would seem to me that the fever is induced by certain cytokines (my memory of which escapes me I was never very good at remembering them all), that the immune response isn't activated by the fever. Although, some sort of feedback loop may be possible, or maybe certain aspects of the immune response are activated by the fever.

High fevers are not good though, and superantigens created by some bacteria that induce dangerously high fevers that often cause death. In most cases I think the fever response seems to be helpful, but like anything biological it isn't perfect.

Originally Posted by i_feel_tiredsleepy

Originally Posted by TheBiologista

You mean to the immune response? Interesting question. I don't know but it's certainly plausible.

It would seem to me that the fever is induced by certain cytokines (my memory of which escapes me I was never very good at remembering them all), that the immune response isn't activated by the fever.

I know that, but complex feedback is very common in immune responses.