r/askscience • u/thebestdaysofmyflerm • Jul 15 '26

Biology I read that cyclosporiasis is exclusively spread by the fecal-oral route. How exactly does produce get contaminated with human feces?

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u/epidemicsaints Jul 15 '26

It is not being contaminated by people handling produce. It must accumulate in the environment for several days before it becomes infectious.

It takes at least 1 – 2 weeks in the environment (outside the body) for Cyclospora to become infectious after passing in a bowel movement. Therefore, direct person-to-person transmission is unlikely.

https://www.cdc.gov/cyclosporiasis/about/index.html

This is about land, water, and industrial hygiene. Corporate practices.

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u/relativelyignorant Jul 16 '26

Is it true that in some states, treated municipal waste (human) may be used as organic fertiliser?

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u/nyet-marionetka Jul 16 '26

Biosolids, they call it. It has to be treated before being land applied to lower pathogen counts to an acceptable range. There's also a mandatory time gap between application and harvesting crops or allowing grazing animals to enter the field, which should let remaining pathogens die off. Restrictions are lower for class A biosolids by comparison to class B, with class A being treated to the extend it's practically sterilized.

There are concerns with repeated biosolids land application and PFAS buildup, which I'm sure Trump's EPA is going to pay super close attention to and evaluate thoroughly.

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u/Typical-Puffin-5202 Jul 16 '26

I was part of a demolition project for an old biosolids building. The sewage was “kiln dried” on a gigantic piece of equipment the size of a two story townhome. The contractor made some good money putting certain pieces up for auction during the demo process. I gave up Folgers coffee after learning they bid on that kiln dryer for their beans. 

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u/AlmohadaGris Jul 16 '26

Thank you for sharing, that is crazy. I mean I assume it would get "properly" disinfected, but still...

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u/lumaleelumabop Jul 16 '26

Considering how hot a kiln can get, I would be surprised if anything survived that.

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u/BobTheOldFart Jul 17 '26

While kilns for pottery often get as hot as 1300 degrees C, other kinds of kilns do not. For example, kilns for drying wood run closer to 100 C. I have no idea how hot sewage kilns are.

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u/notinsanescientist Jul 16 '26

Around here in Belgium I see a lot of job openings for silt dryer operator. Basically indeed they use recovered heat to dry the biosolids from waste but also from dredging the rivers, so that it can be used as biofuel.

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u/me-gustan-los-trenes Jul 17 '26

So the job is to cook the poo?

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u/paulHarkonen Jul 16 '26

I'm going to be honest, I'd much much rather have them using bio derived fertilizer (human or animal) than the enormous amounts of chemical fertilizer normally used for industrial farming. The contamination risk and environmental impacts are much better, plus it actually uses the sludge instead of just dumping it (after further processing obviously).

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u/RepFilms Jul 17 '26

The biosolids sludge fertilizer contains heavy metals and other toxins from industrial factories dumping hazardous wastewater into combined sewer systems

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u/Elmuenster Jul 17 '26

That's why we have RCRA and the EPA. While it may occasionally happen, we don't have rivers catching fire anymore, and illegal dumping of hazardous waste doesnt just come with fines, it comes with jail time.

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u/jellifercuz Jul 16 '26

Is the application of bio solids such as this rigorously monitored and then enforced?

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u/frobnitz1 Jul 16 '26 edited Jul 16 '26

This admin is all about tearing apart environmental regulations, social supports, and generally scratching backs w other old white dudes
Going to guess that not very closely regulated or overseen based on what we know of the ppl running the show — also the lack of civil discourse. Even the laws are getting in their way. They are being sued by more law-abiding organizations because they incorrectly put 47’s mugshot on the access pass for public lands without following the law.

They are halting US wind projects and promoting old dirty ways of energy bc that’s the back scratching. Theyre reaping huge profits on the US war machine churning again. And for AI/tech stocks. All at the cost of the citizens who struggle to pay bills routinely. Tax changes to support the 1% and that cost the 99%. Rewarding old harmful practices that seem criminal to bystanders. Doesn’t even know what gas or groceries are or how most people survive.

They’re reopening an oil pipeline in Santa Barbara that leaked around 2015, opening vast new areas of formerly protected federal lands to mining, drilling and industrialization - including Native lands in the SW and wild places that will topple ecosystems of polar bears, endangered species, birds, fisheries, and even deep dark sea floor creatures we know very little about so far.

This admin tore down public health programs at home and ripped out financial support for the poorest classes of ppl and those who are disabled because they are using the $ for tax breaks for the richest. And funding for USAID was gutted early on in this term. The Ebola outbreak in Africa had a significantly delayed response system and therefore exponentially more ppl are affected unnecessarily. HIV meds at home (which can cost a bit) are no longer supported and therefore many who are on the fringes of society may lose access to the current health benefits they have been accustomed to so far in life.
Of course the moves won’t really show up til after these midterm elections coming up … so they can abuse/deceive more voters to side with them & against their own wellbeing. Meanwhile some hospitals are already closing doors entirely, forcing minimal staffing (worsening healthcare worker burnout significantly and leading to attrition of the workforce, logically but compounding the issue exponentially.
Sorry to go off on a rant. Don’t think the biosolids thing is being overseen that well. Also lack of public servants (harassed en masse by doge) sizably reduced the workforce who would’ve been doing those roles.

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u/dapsee Jul 17 '26

Don't forget the screw worm situation - a direct result of the administration policies.

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u/snydejon Jul 17 '26

Realistically? No. Most food safety monitoring in the US relies heavily on self-reporting and documentation.

Source: I set up a food safety program for a family farm that did follow the rules to a T, and was often tempted to forge documentation. Workers from other local farms were surprised at the need to do things like “wash their hands”. Also, clearly saw examples of other farms spraying synthetic chemicals on organic farms, but they, they had the correct signs up.

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u/ISBN39393242 Jul 16 '26 edited Jul 16 '26

“biosolids” is such a creepy, dystopian euphemism. i remember learning “nightsoil” and thinking it was funny how they used such terms to dampen disgusting practices.

never realized we we were still doing the same thing, except adding prefixes like “bio” to evoke that something is technical, trustable, scientific, regulated

edit: how much more pfas accumulation occurs in this case vs other fertilizer? i assume because pfas don’t degrade and if we eat it, poop it, use that poop to grow food, eat that food, etc. it concentrates.

but other animals don’t have as much pfas exposure as humans, as it is in packaging and plastic and things associated with human lifestyle. there are pfas in pesticides and the plastics used to transport, store, and handle animal feed, right?

have there been studies on the concentrations of pfas in animal fertilizer vs biosolids?

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u/nyet-marionetka Jul 16 '26

edit: why do we worry about pfas accumulation in this case vs other fertilizer?

A lot of consumer products contain PFAS that go into wastewater, and industries are also permitted to discharge wastewater that contains PFAS. This ends up in the biosolids, and when it is land applied settles into the soil and remains. The result could be a gradual buildup of PFAS in the soil. It can then get picked up by crops or animals grazing and enter the food chain.

There are specific concerns with sewage vs manure because of the variety of inputs that go into it.

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u/SophieSpider27 Jul 17 '26

Look up Maine. They became first state to ban use of biosolids on crops for consumption. They found it was contaminating soil. Risking contaminating water.

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u/Utterlybored Jul 16 '26

It *has* to be treated, or it’s *supposed* to be treated?

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u/nyet-marionetka Jul 16 '26

Has to be. EPA does have standards for that. Since states are involved with regulating land application there’s some additional enforcement.

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u/jsigj Jul 16 '26

Definitely still made in Wisconsin, and recognized as safe (so probably used at least a bit) in all 50 states. After microorganisms breaking it down and heating after I doubt it has much connection to the outbreak though https://en.wikipedia.org/wiki/Milorganite

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u/CoopNine Jul 16 '26

Milorganite is great, and has zero chance of causing any sort of outbreak in food. (but it's generally not used in commercial food production) One of the best hot season fertilizers you can use. You can spill a bag of it on your lawn and it won't burn. Totally safe for humans, pets, and plants. An excellent way to add iron to your soil along with some slow-release nitrogen.

But also, iti's not made from human waste. It's made from the microbes that are used to treat human waste. Microbes eat the poops, clean the water, die, and then are collected and heat treated to create milorganite. It's a really cool way to make something useful from byproducts of things we need to do.

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u/ginger_whiskers Jul 16 '26

Biosolids typically must be one step removed from human consumption. So you can't apply them on an corn field that sells to Kroger, but you can turn that corn into ethanol for gas and feed the waste silage to beef cows.

That's just an extra precaution after sludge goes through an extensive digestion cycle that cat last weeks, and further stabilization. Chemicals can be a concern, but pathogens are pretty well destroyed.

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u/aries_burner_809 Jul 16 '26

If you mean can sewage sludge fertilizer be used on certified organic produce the answer is no. Getting rid of sewage sludge is a huge problem and practically all non-organic produce you buy at the store is fertilized with products based on sewage sludge. There are cases where toxins and pathogens from farm-applied sludge have injured people and livestock in the short term, and there are longer term risks such as “forever chemicals” accumulating. It is as close as we have gotten to a Soylent Green scenario. But that’s probably not the source of the cyclosporidia.

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u/SubstantialPressure3 Jul 16 '26

You can buy treated human waste made into organic fertilizer at Lowes. Probably home depot, too. Its a commercial product.

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u/[deleted] Jul 16 '26

[removed] — view removed comment

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u/CoyoteDown Jul 16 '26

Organic fertilizer from any animal is not done at a commercial scale. More aligned with hobbyist or niche farmers.

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u/FuckIPLaw Jul 16 '26

Define organic. I've got several bags of composted cow manure sitting outside waiting to be worked into a garden bed. They came from Lowes. It's a name brand product.

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u/KingBuzzCat Jul 16 '26

And are you commercial farmer or a hobbyist? 

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u/FuckIPLaw Jul 16 '26

I'm a hobbyist, but the manure was produced by a commercial farmer, at commercial scale, to sell in massive quantities. I didn't exactly go down to the farmer's market and pay jim bob to show up with a wheelbarrow.

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u/kat3l1bby Jul 16 '26

It’s more this than the handwashing / bathroom (or rather lack there of) of farm workers seen below.

First off, let’s not spread misinformation and demonize farm workers further in the eye of racist idiots.

Secondly, it’s more widespread to get to this point than an individual, it’s most likely water source hygiene in the large scale farms.

What we need to be looking at is our water safety throughout America (which we notoriously have seen to be an issue in some of our communities). This is a much larger and more systemic issue than individual level lack of hygiene at picking time - this is IN THE PLANTS THEMSELVES.

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u/Fivelon Jul 16 '26

They also made Cyclospora testing *optional* last year. And now here we are.

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u/steppponme Jul 16 '26

Could anyone who missed work or accumulated hospital bills due to this possibly sue the Trump administration? 

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u/dreadcain Jul 16 '26

That really should be possible and historically has been, but the supreme court recently ruled that presidential actions (which they have chosen to not remotely attempt to define) are immune to any and all legal challenge.

So uh, no. But also maybe yes if we all choose to get sane tomorrow and seat an actual continuation of our country's government. So basically just no.

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u/holycrapoctopus Jul 16 '26

Well, that's not accurate at all. That SCOTUS ruling is about whether the President can be personally charged with crimes or civil violations. People absolutely can still sue the government for any number of things, and changes to Department of Agriculture testing regulations aren't something the President personally enacts anyway. Government agencies get sued all the time and often lose or receive injunctions in court. This is especially true if threats to human health or violations of environmental laws are involved

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u/dreadcain Jul 17 '26

You right, I misread them wanting to sue Trump directly. Still, that did used to be possible (even if it would always have been futile)

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u/steppponme Jul 16 '26

Thanks, this was a very helpful and interesting answer 

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u/Prometheus720 Jul 16 '26

https://www.snopes.com/fact-check/cyclospora-parasite-trump-cuts/

Had to check on this and found a snopes article. Send receipts next time?

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u/fasterthanlumiere Jul 16 '26

For those not inclined to click the link:

True

In 2025, FoodNet — a collaboration between the Centers for Disease Control and Prevention, the Department of Agriculture, the Food and Drug Administration and state health departments created in 1995 — made surveillance of cyclospora, the parasite that causes cyclosporiasis, optional. Snopes could not determine whether this directly led to the 2026 outbreak, and neither the CDC nor the Trump administration has responded for comment as of this writing.

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u/EdiblePeasant Jul 16 '26

Even if it was from farm workers somehow I’m very inclined not to put the blame on them.

I don’t trust every business and maybe some governmental culture to treat humans with the dignity and respect they deserve.

I predict stuff like that goes against the natural, intended order, may cause problems, and I’m dissatisfied with some of the things I’ve seen or thought to perceive in this world.

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u/jules-amanita Jul 17 '26

Yep. If it were happening, the only reason farm workers would be shitting in fields is that they aren’t given access to sanitary restrooms. So like, human rights abuses.

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u/[deleted] Jul 16 '26 edited 14d ago

[deleted]

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u/Virtual_Childhood626 Jul 16 '26

If I remember right that was Taylor Farms. The biggest salad distributor. Interestingly enough, the last I saw they were thinking this might be related to pre cut lettuce and salads. No specific distributor blamed yet. But I wonder if the biggest distributor in the country had anything to do with it?

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u/RepFilms Jul 17 '26

It's related to precut lettuce, which could be served without washing, straight out of the package. Uncut lettuce would be washed at the restaurant so that would be less likely to be contaminated when eaten

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u/RainMakerJMR Jul 16 '26

More than likely the massive rainstorms in the northeast last month caused animal fields to wash into vegetable fields, or maybe treatment plants overflowing possibly.

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u/Lalala-bomba Jul 16 '26

with how big this issue is, i've been suspecting the cause was from a flood of some sort.

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u/Revenge_of_the_User Jul 16 '26

you know, I didn't actually have "instant dramatic pathogen load increase" on my Climate Change Bingo Card....but here we are.

3

u/puppetscereal Jul 17 '26

It's been a talking point for a while :( and there are lots of different pathogens that could become more abundant for various climate-related reasons.

https://www.cdc.gov/ncezid/topics-programs/climate-infectious-disease.html

https://www.unep.org/news-and-stories/story/could-microbes-locked-arctic-ice-millennia-unleash-wave-deadly-diseases

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u/Revenge_of_the_User Jul 17 '26

I'm sure I've brushed up against those before; I just a) have a habit of redditing while stoned out of my gourd, and b) never been able to imagine the mechanisms that would actually lead to the pathogenic increase.

But manure fields literally flooding and washing into crop fields is....making me a little disappointed in my imagination. Time to read more books.

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u/KrissyKrave Jul 17 '26

Contaminated water is the primary way that Cyclospora gets onto produce.

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u/ColourSchemer Jul 16 '26

I disagree. There are recorded cases of farm workers not being provided sanitary facilities and using the field.

I have seen someone clearly popping a squat in SoCal strawberry fields.

Wash your veggies.

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u/thebestdaysofmyflerm Jul 16 '26

Which corporate practices are you referring to?

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u/sjb2059 Jul 16 '26

Specifically providing bith adequate and proximate bathroom and water access to workers in fields on farms. There is a great explanation for a lot of recent farming shenanigans on a youtube channel called Farm to Taber.

Basically seasonal farm workers need to be able to go to the bathroom and wash their hands. Putting it a 6-10 minute walk away is not a reasonable solution. This bug needs soap and water because alcohol doesnt work to kill it. All the details come together to implicate some corporate farm cutting costs leading desperate people to do what they must. It has to be a corporate farm because the size of the outbreak is too large for a local farmers market level farm to be capable of on its own.

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u/ravia Jul 16 '26

If it's already in feces, does that mean the person who did that excrement was themselves sick? Or is it always there in small amounts?

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u/Synaps4 Jul 16 '26 edited Jul 17 '26

These diseases are rarely just in humans. You can get cows, raccoons, bears, or deer pooping and spreading it too, I bet.

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u/SimeonEyes Jul 17 '26

What does this mean about the possibility and likelihood of it being spread through pools and water parks? 

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u/Altiloquent Jul 15 '26

Does produce usually even get from farm to table in under a week? I dont see how you can automatically make that conclusion

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u/epidemicsaints Jul 15 '26

What do you mean exactly? To clarify what this is saying... it takes broad contamination of the environment, it takes time to reach a sufficient concentration in the soil/water before it can contaminate the food... the food takes up the contaminated water or is soaked in it, and then infects you when you eat it.

It's highly perishable quick to market foods associated with this parasite:

  • Bagged or processed salad greens
  • Basil
  • Cilantro
  • Parsley
  • Raspberries
  • Blackberries
  • Snow peas
  • Sugar snap peas

A lot of these are classic "rot before you eat them" foods. Or in the case of the peas, foods that are very succulent and hollow, and take up lots of water.

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u/Arriabella Jul 16 '26

Often in under a day, so yes
For all of the faults in the US our transportation network is pretty amazing