Hello all.

Rotten corpses, feces, decomposing matter are smelly because their particles get airborne and sensed by olfaction.

Can those fouled particles carrying the smell, transport microbes as to propagate certain illnesses just by smelling ? (restricted to smell, not as splashes or mist)

Apparently not. The bad smell of decomposition is not a biohazard; it's simply unpleasant. I can attest to this personally, having seen a number of decomposing bodies and handled parts thereof, with no ill effects.

The smell is a mixture of small volatile molecules and are not very (or at all) toxic. The bacteria are sitting in and on corpses (and its liquids) and some of them might be pathogenic, but they do not swirl i the air with the volatile compounds. At least not without agitation. However, corpses do release liquids which can contain bloodborne and especially GI bacteria/viruses and if the corpse is bloated they can release gases where some may be around (probably not a lot in most cases, though). Fungi can also grow on corpses, potentially releasing spores (which again needs to be agitated to get into the air and lungs) but generally speaking if you do not get corpse juice on you, (and lick it) one should be fine.

 

 

 

Airborne bacteria and viruses pretty much stop being a problem once the victim stops breathing/coughing/sneezing them out. Nevertheless, we used to go in gloved, masked and gowned when a decomposing corpse was deposited in the isolation room. It's not what you can smell that's dangerous; it's what you don't that could be. Toxins and pathogens usually transfer via liquids, so you want to keep your hands at arm's length. Miasma didn't cause the 1850's cholera outbreaks in London: contaminated water did. 

 

Edited October 24, 20241 yr by Peterkin

2 hours ago, Externet said:

Hello all.

Rotten corpses, feces, decomposing matter are smelly because their particles get airborne and sensed by olfaction.

Can those fouled particles carrying the smell, transport microbes as to propagate certain illnesses just by smelling ? (restricted to smell, not as splashes or mist)

Your misunderstanding is to think in terms of “particles”. As @CharonY says, the smell is due to volatile molecules, not macroscopic particles. It is an evolutionary advantage for animals to be able to detect these molecules at low concentration, either to avoid contact with decomposing flesh or, in the case of flies, to be attracted to it to lay their eggs on it.

Thanks. 

I take it then like the foul smells are translated as an evolutionary warning reaction to 'not get closer' to a danger area sourcing the smell.  Not as a 'you smelled it; now you are sick'

And that the airborne smell molecules are too small to carry microbes 'on board' ?

Thinking out of the box, if evolution has taught to stay away from foul smells, is it because that 'experience' has somehow harmed before ?   Does it make sense to think that way ?  

2 minutes ago, Externet said:

Thinking out of the box, if evolution has taught to stay away from foul smells, is it because that 'experience' has somehow harmed before ?   

It's unpleasant for most of us. The early sign of spoilage in meat or dairy is a bad smell, warning us not to eat it. People who do eat spoiled food don't usually get sick, but it's a nasty experience. 

 Canines will sometimes roll in cowpats or rotting corpses to hide their own scent from potential prey. 

26 minutes ago, Externet said:

Thinking out of the box, if evolution has taught to stay away from foul smells, is it because that 'experience' has somehow harmed before ?   Does it make sense to think that way ?  

Yes, especially for hunter-gatherers who might be camping next to water - a smell of decomp would be a warning of fouled water.  Or finding a carcass - if it's gone off, they don't scavenge it.  We came to perceive sulfur compounds like hydrogen sulfide as stinky because it indicates food unfit to eat or water not potable.

Edited October 24, 20241 yr by TheVat

27 minutes ago, Externet said:

Thanks. 

I take it then like the foul smells are translated as an evolutionary warning reaction to 'not get closer' to a danger area sourcing the smell.  Not as a 'you smelled it; now you are sick'

And that the airborne smell molecules are too small to carry microbes 'on board' ?

Thinking out of the box, if evolution has taught to stay away from foul smells, is it because that 'experience' has somehow harmed before ?   Does it make sense to think that way ?  

You need to have an idea of scale here. Molecules are of the order of 0.1-1 nanometres (nm) across. Viruses are of the order of 100nm and bacteria about 10x larger than that. Viruses and bacteria are made of molecules. So fairly obviously a molecule cannot carry a virus or a bacterium.

I have not looked up the evolution of sense of smell, but given that smell is widely used in the animal kingdom to detect what is good to eat, it seems reasonable that part of that would include the identification of what to avoid because it would make the creature ill. But the way you phrase the question seems to be in terms of what an individual organism has learnt, from experience. That may be part of it but a sense of what constitutes a “bad” smell is instinctive.
 

We all agree on bad smells - and sometimes even train ourselves to override them, e.g. in the case of certain aged or fermented foods like strong French cheese or game. 

Edited October 24, 20241 yr by exchemist

46 minutes ago, Externet said:

Thinking out of the box, if evolution has taught to stay away from foul smells, is it because that 'experience' has somehow harmed before ?   Does it make sense to think that way ?  

Not universally so. As already mentioned, some animals seek out carrion. Some insects breed there, but there are also carrion eaters (crows, vultures, many predators).

25 minutes ago, exchemist said:

So fairly obviously a molecule cannot carry a virus or a bacterium.

Perhaps somewhat interestingly, the characteristic smell of cadavers is caused by bacteria (obviously), and much of the foul odour is caused by diamines, such as cadaverine and putrescine.

3 hours ago, CharonY said:

Not universally so. As already mentioned, some animals seek out carrion. Some insects breed there, but there are also carrion eaters (crows, vultures, many predators).

Perhaps somewhat interestingly, the characteristic smell of cadavers is caused by bacteria (obviously), and much of the foul odour is caused by diamines, such as cadaverine and putrescine.

Ha! Don't talk to me about amines. I once had to take my French mother in law's fridge, at the holiday house in Brittany,  to the déchetterie after it had failed 6 months previously......... with several packs of her coquilles St. Jacques in the freezer compartment. They had turned into a sort of black sludge. The only way I could cope with cleaning it out without throwing up was to think as hard as possible about amine chemistry. You never know when - or how - your degree will come in handy! 

You can also put Vaseline in your nostrils and try to breathe through your mouth. Unfortunately, you can't escape it altogether, but you can learn to cope. I used to have to boil badly putrified skulls (to clean the bones for ID) and slice femurs of drowning victims to look for diatoms. Sometimes the remains would come in big plastic bags and maggots would jump out when you opened one. Obviously not my favourite part of the job.  

14 hours ago, Externet said:

Thinking out of the box, if evolution has taught to stay away from foul smells, is it because that 'experience' has somehow harmed before ?   Does it make sense to think that way ?  

If an organism had an adverse sensory response to an olfactory stimulus and persisted long enough  to reproduce, versus one of the same species that was attracted to it and died, the former prevails evolutionarily. The converse can be true as well for another olfactory stimulus scenario, where a smell attraction aids reproductive potential. The genetic subtype that is harmed reproductively by a stimulus they are attracted to tends to die out, leaving the individuals who avoid it to prevail genetically. That's selection.

Edited October 25, 20241 yr by StringJunky

On 10/24/2024 at 1:22 PM, Peterkin said:

You can also put Vaseline in your nostrils and try to breathe through your mouth.

(spotted this thread; not old enough to be "necro posting" but maybe necro in another sense...)

I briefly worked in a stink environment and one of the recommended methods was rubbing Vicks Vaporub (camphor, eucalyptus, menthol, cedarleaf oil, etc) under the nose. Intense but effective.

On 10/24/2024 at 12:53 PM, exchemist said:

fridge, at the holiday house in Brittany,  to the déchetterie after it had failed 6 months previously......... with several packs of her coquilles St. Jacques in the freezer compartment. They had turned into a sort of black sludge.

And they're not all that great even fresh. 😁

3 hours ago, TheVat said:

(spotted this thread; not old enough to be "necro posting" but maybe necro in another sense...)

I briefly worked in a stink environment and one of the recommended methods was rubbing Vicks Vaporub (camphor, eucalyptus, menthol, cedarleaf oil, etc) under the nose. Intense but effective.

And they're not all that great even fresh. 😁

Oh I like them. The scallop is the traditional symbol of St James the Greater in Christian iconography, hence the French name. The statue of Sint Jacobus de Meerdere in the parish church inThe Hague had a scallop, I remember.

During my apprenticeship in the paper industry I lost several colleagues to hydrogen sulphide poisoning. It's detectable by smell in the non-lethal ppb level, but not so at the lethal ppm levels they were exposed to. I guess that Darwinism survival only works when the chance of survival is non-zero.

3 hours ago, exchemist said:

Oh I like them. The scallop is the traditional symbol of St James the Greater in Christian iconography, hence the French name. The statue of Sint Jacobus de Meerdere in the parish church inThe Hague had a scallop, I remember.

My dislike of shellfish was somewhat culturally acquired and should be viewed as the culinary bigotry it is. Growing up, our family lived in a largely Jewish community for three years, where shellfish violated kashrut, and so were to be avoided. I tried them (scallops) on an outing in Boston, found them rubbery, and let my mind harden against them. What can I say, it was early teen years and I wanted to fit in with my circle of anti-bivalve pals. When we moved back to the goyische depths of Nebraska, I did slide back into an occasional clam chowder but to this day have never mixed milk and meat in a meal (also proscribed in kashrut law). My friend's uncle once showed me a concentration camp number tattooed on his arm - when you're twelve and someone shows you that you tend to listen to their advice.

Wildly OT, though I could bring it back sort of to topic with Jewish burial law, which requires the body in the ground in 24 hours, partly to avoid the decomp odors which arise when embalming is proscribed. The casket must also be untreated wood with no metal.

1 hour ago, TheVat said:

Wildly OT, though I could bring it back sort of to topic with Jewish burial law, which requires the body in the ground in 24 hours, partly to avoid the decomp odors which arise when embalming is proscribed.

It's a question of dignity. Egyptian aristocrats could lie around in public for weeks without losing esteem. For Jews, it was a matter of hours. You have to cope with the prejudices of your forefathers - in this case, the importance of leaving the body intact for burial vs keeping some bits in jars in the same room. It's something children internalize at their mother's knee and can never question.

Like thinking a certain tattoo turns someone into a mentor. Lots of ignorant, unprincipled and silly people were caught in that evil net, along with the wise, kind and noble. You have to look past the label.

(Oysters and scallops are horrible. That Levite priest probably tasted some and decided that if he found them horrible, they were horrible for all God's adopted children.)

Everything in the process of organic disintegration exudes chemical vapors that we find offensive. The vapour doesn't kill us, but the decomposing matter very well might. Being offended by the smell warns us off potentially harmful food. These warning signals, so important to wolves and lemurs, are the price we pay for evolution. Part of the price.

Edited May 29May 29 by Peterkin

The OP sounds like the idea of "bad air" causing diseases, called miasma. The particles responsible were Miasmata.

This theory was superceded by the germ theory.

A few of you guys mentioned handling cadavers.

A mention to Ignaz Semmelweis found that hand washing by physicians and later apparatus cleansing, decreased mortality in hospitals.

https://www.nationalgeographic.com/history/article/handwashing-once-controversial-medical-advice