An airway-to-brain sensory pathway mediates influenza-induced sickness 2023 Bin et al

I'm reading around this part of the article and I don't understand what is paradigm-shifting here? This is sickness behavior, what is different about this other than that they didn't know about specific neurons being involved, and possibly which molecules act on it?

If you'd have put this description to me, I would have thought this is already the paradigm, other maybe than knowing exactly the where and how. What is the current paradigm if not that? The psychosocial stuff?

 

I am seriously baffled at the discussion over the evolutionary aspect of the sickness response and the "paradox" that it's better to alleviate it.

Because this is exactly what's expected. It has an evolutionary advantage in nature, not in a controlled lab. This is exactly what is expected. This response is not to promote the organism's survival in an artificial setting, an evolutionary response acts as a pressure in a natural environment on a scale of generations.

Again just the weird expression of puzzlement at finding exactly what's expected is just alarming. Being ill in nature is a good way to get eaten. Being ill in a cage in a lab isn't. No paradox here.

 

Or maybe "sickness programme"?

 

Haven't read the paper but what's most interesting to me is that - assuming I picked this up correctly from the snippets here - is

1) that the sickness response may be made up of several parts which function independently of each other to some degree, and

2) that the sickness response may originate in the periphery.

Point 1 is interesting because to me it doesn't look like our ME symptoms quite match the typical sickness response which includes fever and lack of thirst for example. Some pwME undoubtedly experience those but many don't, and some experience the opposite, too low a body temperature and increased thirst during PEM. So to me the typical sickness response and the ME symptom picture look similar but not quite the same. But could it be that in ME only some selected parts of the standard sickness response are activated (together with plenty of other stuff going wrong at the same time)? Or even that a failure to activate the entire sickness response at the appropriate time is the problem?

Point 2 is interesting because it points to the possibility of a primary problem in the periphery, not in the brain. Only a possibility though, there's bound to be some primary brain mechanism(s) which can trigger a sickness response, too

 

yes my temp tends to drop to low end of normal 36 ish when in PEM with increased thirst, but i also get increased thirst during viral infections, its always been marked that when i am ill i get very thirsty, regardless of the infection. And i rarely lose my appetite unless i have a sickness/diarrhoea bug or a migraine - with flu etc i can still eat its just that what i want changes & obviously its difficult with a sore throat if it hurts too much to swallow.

I'm just wondering if this discovery in mice might be useful in further investigating any kind of signalling problem in ME @Jonathan Edwards

 

I suspect not in that the signalling they describe is well known. They have identified some specific airway nerves but that does not seem very relevant to ME.

I think that the study may serve to remind us that symptoms of feeling ill involve both peripheral and central signal components.

With flu, or for me in the post Covid weeks, it seems obvious that something is wrong with one's muscles or gut or nerves or joints etc. because they hurt or give other symptoms. But it is unlikely that there is anything wrong with the ability of these tissues to do their jobs other than being inhibited by danger signals.

It makes sense that these danger signals are coming all the way from the arms and legs or gut. But it is also useful to remember that the brain normally suppresses all sorts of signals from the body and that all we may need to get danger signals from the body is for the brain to turn the 'squelch button' The squelch button is what you had on VHF radios which is there to damp down signals until you can only hear the useful ones from other radios. If you turn squelch up you get lots of noise all the time.

These mechanisms are to some extent what people talk about in terms of peripheral and central sensitisation but that term has been highjacked by people who have special theories about how it works.

 

I got Covid or influenza last December. Symptoms involved sore throat, coughing, loss of appetite, no fever for 5 days. I experienced on and off leg muscle fatigue for a little over a week. I went back to baseline 3 weeks later and thought I had recovered, but when I went for my usual 50 minute brisk walk, I got up the next morning and couldn't stand on my legs for 3 weeks from severe leg muscle exhaustion. I had to eat canned food.

My M.E PEM is a completely different experience. It involves whole body fatigue (arms and legs), dehydration, shakiness, ataxia, slurred speech, cognitive impairment and chest pressure. I had none of that with sickness behaviour.

 

yes i get all those too, but they come on top of sickness behaviour, so its like SB Plus. I would never call the weakness from sickness behaviour sensation 'whole body fatigue' - whole body fatigue is a qualitatively different experience for me.

I'm not trying to say it's about severity - a milder sickness behaviour experience can be much less disabling than PEM, or indeed than severe overwhelming exhaustion, its just a different bodily sensation for me. Which is, for me, unique to having an infection of some kind. So SB experience is identical to ME/PEM, plus the other symptoms added in on top. Although to be fair, when i have had bad doses of flu befor i have experienced some cognitive dysfunction

 

@JemPD

By SB, which is an adaptive response, are you saying that you feel as though you're fighting an infection during PEM?

My delayed PEM starts when I've gone over my energy limit. It's worse if I'm dealing with an infection of course, but it's tricky to fully know whether my immune system has cleared the virus from what I experienced recently.

 

oh yes absolutely.

As i said in my earlier post, (in response to Hutan's question what people thought about ME/CFS= chronic sickness response theory) the experience is identical - which i guess isnt strictly accurate really since i also have the other symptoms we talked about. Its identical & then some other bits on top.

 

When mild I essentially dosed up on ibuprofen daily for years, which masked the severity of my symptoms and led me to write the illness off as just repeated colds/infections