Why is there pathogens in the first place ?
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TOPIC: Why is there pathogens in the first place ?

Why is there pathogens in the first place ? 03 Mar 2014 09:41 #7589

  • ben
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Dear all,

I felt a bit ashamed the other day, after all these years working in sanitation, I couldn’t answer properly my 12 years old niece asking me “Why is there pathogens in the first place“

This is therefore a naïve question that I’d like to bring in this forum, hoping that biologist and anthropologists will have a clear and simple answer to it.

• Why is there pathogens in our digestive system that don’t make us sick when they are inside our stomach but do make us sick if we eat them ?

The cows are eating grass where they defecated the day before, I believe most farm mammals are not really affected by eating their own feces – what explains that in the natural selection process human this very big problem remained. Before being pathogens outside are they essantial to our digestion inside ? What about our cousins the apes, are they sick too if they eat their own feces or is it a human particularity ?

Thanks a lot for sharing articles or researches on the subject.

Wishing you all a good day.

Ben

Re: Why is there pathogens in the first place ? 03 Mar 2014 09:56 #7590

  • joeturner
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Well, of course, someone with watery Diarrhea is sick. A lot of pathogens are spread by people who are ill.

The other side of it is that different people have different tolerances to the microbes. If someone gets the cold virus in a household, it doesn't necessarily mean that everyone in the household is going to catch it. The likelihood is that everyone has been exposed to it, but some have a higher tolerance than others. Someone can be a 'carrier' of a microbial infection without actually showing symptoms of it.

Hence those who are particularly susceptible are most affected by water-bourne disease - children, those with other illnesses, the old etc. Healthy adults may not be affected by the pathogens - or may get sick without it killing them.
I don't work for anyone, I am a philosopher interested to think about how we think about WASH and sanitation. All thoughts are mine alone, I am responsible for any errors.

Previously trained and worked as a Soil Scientist and worked on projects composting sewage sludge.
Last Edit: 03 Mar 2014 09:57 by joeturner.

Re: Why is there pathogens in the first place ? 03 Mar 2014 10:11 #7593

  • JKMakowka
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Three factors to consider mostly:

1. "Opportunistic pathogens" (en.wikipedia.org/wiki/Opportunistic_infection ), meaning that certain microorganism can be perfectly harmless (and even beneficial via symbiosis) in a healthy individual, but when they come in contact with a weakened one they "switch gears" and become pathogenic

2. Acquired immunity (en.wikipedia.org/wiki/Adaptive_immune_system), similar to how vaccinations work it is possible to get used to a pathogen and the immune system is keeping it in check in one individual. But once that pathogen is spread to another individual that has not acquired (partial) immunity, most often children below 5, they will become sick. This is why WASH interventions especially benefit children.

3. The general risk of spreading pathogens from a sick individual to a healthy one, irregardless of the two above factors. This is mostly an issue in public sanitation facilities and sewerage systems that mix faeces from many people.

Last but not least there are also the special cases of typhoid or salmonella (and a few other pathogens) which have evolved a special mechanism of an "silent" illness (asymptomatic carrier) in a few people who then subsequently continue to infect others without being sick themselves; see famous case of "Typhoid Mary": en.wikipedia.org/wiki/Typhoid_Mary
(the difference to opportunistic pathogens is these are not microorganisms that commonly inhabit healthy individuals).

Did this answer your question?
Krischan Makowka
Technical Adviser at the Uganda Water and Sanitation NGO Network (UWASNET)
www.uwasnet.org
Last Edit: 03 Mar 2014 10:15 by JKMakowka.

Re: Why is there pathogens in the first place ? 03 Mar 2014 10:13 #7594

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Thanks for your reply Joe,

However from what I understand even a non sick person has got potential harmfull pathogens in its feces. This is more this case that I was talking about, the spread of someone already ill via feacal route being more intuitive.

Best,

Ben

Re: Why is there pathogens in the first place ? 03 Mar 2014 10:16 #7595

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Awesome Krischan,

I'll look at your links with great interest.

Thanks again.

Re: Why is there pathogens in the first place ? 03 Mar 2014 10:32 #7596

  • JKMakowka
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Glad I could help.


P.S.:
ben wrote:

The cows are eating grass where they defecated the day before, I believe most farm mammals are not really affected by eating their own feces


Having grown up on a farm, I can tell you that this is most definitely not the case. Cows and other farm animals have certain "open defecation" spaces where they go to relieve themselves and where they don't eat (or have even evolved feces that they can avoid eating like sheep and goats).

However in industrial farms where animals are either kept indoors ("no-grazing") or where manure is systematically spread on range-lands to promote grass growth, the spread of illnesses is a serious issue as the cows can not avoid coming in contact with their own feces. This is the reason why farm animals are given so much antibiotics these days (official as "growth stimulators" but in reality all it does is counteract the in-hygienic crammed conditions of industrial livestock rearing, proven by the point that the more hygienic a farm is the less effect antibiotics have on stimulating growth).
Krischan Makowka
Technical Adviser at the Uganda Water and Sanitation NGO Network (UWASNET)
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Re: Why is there pathogens in the first place ? 05 Mar 2014 04:46 #7636

  • canaday
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Hi Ben,

I think a basic response to your niece could be "There are diseases and parasites that reproduce at our expense, if we let them. They have evolved to have lots of babies and they do not care if this makes us sick. They eat our food and they even eat part of us. We can catch these from sick people's feces. Healthy people's feces cannot get us sick (except for the healthy carriers and opportunisitic pathogens mentioned by Krischan), but, we never know exactly how healthy other people are, so all human feces are disgusting to us and we need to treat them cautiously to keep them out of everyone's environment (for example, via UDDTs)."

I suggest that the concept you mention of "even a non-sick person has got potentially harmful pathogens in his or her feces" is a manifestation of Fecophobia (the irrational fear of feces), given that the above-mentioned cases of healthy carriers and opportunistic pathogens are pretty rare.

(How are things going for you in France? Please tell us more about the case where you want to extract fertilizer from the urine in public toilets.)

Best wishes,
Chris Canaday
Conservation Biologist and EcoSan Promoter
Omaere Ethnobotanical Park
Puyo, Pastaza, Ecuador, South America
inodoroseco.blogspot.com
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Re: Why is there pathogens in the first place ? 05 Mar 2014 09:38 #7641

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Another point is that faeces are quite a nice media to incubate microbes, so even faeces from healthy people can cause nasty pathogens which just happen to be around in the air and the soil to multiply.

I agree with Chris and Krischan, although I'm not sure even if you only had access to your own faeces and you knew beyond doubt that you were not carrying anything that you could ever be completely confident that it did not include pathogens.
I don't work for anyone, I am a philosopher interested to think about how we think about WASH and sanitation. All thoughts are mine alone, I am responsible for any errors.

Previously trained and worked as a Soil Scientist and worked on projects composting sewage sludge.

Re: Why is there pathogens in the first place ? 09 Mar 2014 18:05 #7698

  • KeithBell
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Ben, what a brilliant question by your 12 year old niece. I think it would help for her to understand a bit about our physiology and the major differences between the small and large intestines. Many "pathogens" aren't necessarily virulent unless they overgrow in the wrong location, usually the small intestine. We need to keep most of our flora in the large intestine where they belong with a balance of many types of microbes.

Small intestinal microbial overgrowth is the malady of our time and it's an environmental health issue of the highest order related to poor sanitation because it affects everything in body from hormonal imbalance including fertility issues to brain and mental health issues.

When microbes are introduced orally, they reach the small intestine first (after the stomach, if they survive stomach acid). Even inhaled through air they reach the small intestine via lungs which is why air pollution is now associated with diabetes. That's right, there are even inhalable microorganisms.

The small intestine is meant to be relatively sterile compared to the large intestine. Though the small intestine is still teeming with life, it has to be the right mix of microbes to avoid malabsorption syndrome associated with poor general health, mental and physical.

The same dynamic applies to chemical pollution such as mercury which causes microbial imbalance when sensitive microbes are killed allowing opportunistic overgrowth of other, more tolerant microbes such as fungi and gram-negative bacteria. It's all about balance. Viruses and helminths (worms) also cause gut flora imbalances.

This balance of microorganisms is also necessary for vaccination to be effective as they are key to immune response. Poor sanitation is the reason vaccination campaigns fail. But also, there are no studies about collateral damage to flora balance by vaccination which I believe is the mechanism behind vaccine injury.

Re: Why is there pathogens in the first place ? 09 Mar 2014 18:32 #7700

  • JKMakowka
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KeithBell wrote:
Even inhaled through air they reach the small intestine via lungs which is why air pollution is now associated with diabetes. That's right, there are even inhalable microorganisms.


Sure, plenty... with Tuberculosis (TB) probably the one that causes the most problems world wide.
But I am unaware of a direct path for microorganisms from the lungs to the small intestine (apart from general systemic, i.e. blood or lyme infections that might originate from the lungs). Do you have a source describing such an infection pathway of the small intestine?
Krischan Makowka
Technical Adviser at the Uganda Water and Sanitation NGO Network (UWASNET)
www.uwasnet.org
Last Edit: 09 Mar 2014 18:33 by JKMakowka.

Re: Why is there pathogens in the first place ? 09 Mar 2014 19:47 #7701

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Great question, JK. I believe lung-to-gut transmission is "general systemic," as you describe; not a direct path. But gut-to-lung route is small intestine to liver to lungs which is why I believe TB of intestinal origin is largely overlooked by TB experts believing it's all about airborne transmission. They don't believe TB is a sanitation issue.

Recent study about inhalable microbes suggests one reason China leads the world in diabetes:
pubs.acs.org/doi/full/10.1021/es4048472
www.dailymail.co.uk/news/article-2540955...iananmen-Square.html

Air pollution linked with diabetes:
www.sciencedaily.com/releases/2010/09/100929105654.htm
www.loe.org/shows/segments.html?programI...0002&segmentID=5

Earth surrounded by microbes in the upper atmosphere, likely feeding on particulate pollution as prebiotic:
www.popsci.com/science/article/2013-06/bacteria-33000-feet
(not long ago, sugar was discovered in space, suggesting extraterrestrial microbial life.)
Last Edit: 09 Mar 2014 19:50 by KeithBell.

Re: Why is there pathogens in the first place ? 12 Mar 2014 08:47 #7750

  • F H Mughal
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Dear Ben,

While the question of your 12 years old niece has been taken care of by the colleagues, I have packed small information for your niece. The information is from various sources (WHO, UNICEF, and WB):

2.6 billion people or nearly half of humanity lives without access to adequate sanitation.

700,000 children die every year from diarrhoea.

Diarrhoea is the second biggest killer of children under five years.

60 million children are born into homes without sanitation.

Lack of access to clean water and sanitation kills children at a rate equivalent of a jumbo jet crashing every four hours.

780 million people lack access to an improved water source; approximately one in nine people.

The water and sanitation crisis claims more lives through disease than any war claims through guns.

An American taking a five-minute shower uses more water than the average person in a developing country slum uses for an entire day.

More people have a mobile phone than a toilet.

1.1 billion still practice open defecation.

Of the 60 million people added to the world's towns and cities every year, most move to informal settlements (i.e. slums) with no sanitation facilities.

Half of the hospital beds in the world are occupied by patients suffering from diseases associated with lack of access to safe drinking water, inadequate sanitation and poor hygiene.

Every 21 seconds, a child dies from diarrhea.

An estimated 200 million hours are spent each day globally collecting water.

About 4 billion cases of diarrhoea per year cause 1.8 million deaths, over 90 per cent of them (1.6 million) among children under five. Repeated episodes of diarrhoeal disease makes children more vulnerable to other diseases and malnutrition.

Without sanitation facilities to safely contain and dispose of human faeces, which are the primary source of diarrhoeal pathogens, the health of a community, especially its children who are most vulnerable to disease, is put at risk. It is estimated that globally more than 200 million tons of human waste and untold millions of tons of wastewater are discharged, uncontained and untreated, into watercourses every year.

One gram of faeces can contain:
10,000,000 viruses
1,000,000 bacteria
1,000 parasite cysts
100 parasite eggs

443 million school days are lost each year due to water-related illness.

F H Mughal
F H Mughal (Mr.)
Karachi, Pakistan
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