Marc Johnson Profile picture
Jun 4, 2023 15 tweets 4 min read Read on X
Ohio cryptic lineage update.

We’ve made no progress identifying the individual, but we have learned a few things.
1/ Image
First, the signal is almost always present in the Columbus Southerly sewershed, but not always at Washington Court House. I assume this means the person lives in Columbus and travels to WCH, presumably for work.
2/ Image
Second, the signal is increasing with time. Washington Court House had its highest SARS-CoV-2 wastewater levels ever in May, and the most recent sequencing indicates that this is entirely the cryptic lineage.
3/ Image
Third, I’ve tried to calculate how much viral material this person is shedding. (Multiply the cryptic concentration by the total volume). I’ve done this several times and gotten pretty consistent results.
They are shedding a few trillion (10^12) genomes/day.
4/
What does this tell us? How much tissue is infected? It’s impossible to know for sure. Chronically infected cells probably don't release much, but acutely infected cells produce a lot more. I gather a typical output in the lab is around 1,000 virus per infected cell.
5/
If we assume we are getting 1,000 viral particles per infected cell, that would mean there are at least a billion infected cells. The density of monolayer epithelial cells is around 300k cells/sq cm. A billion cells would represent around 3.5 square feet of epithelial tissue!
6/
Don’t get me wrong. The intestines have a huge surface are and 3 square feet is a tiny fraction of the total.
But it’s still a massive infection, no matter how you slice it.
7/
I do not know of any persistent infections that shed this much virus without killing the patient. (Correct me if I’m wrong). The closest would probably be HCV, an infection that often ends in liver cancer.
8/
My point is that this patient is not well, even if they don’t know it, but they could probably be helped if they were identified.
9/
How do you figure out if you have a COVID GI infection. Most rapid antigen test are not explicitly for stool. However, I know of at least one that is. The instructions from that test say to mix a ‘matchhead’ worth of feces with the buffer.
10/

dyonmedical.com/en/corona-ag-a… Image
I can tell you that with very positive wastewater samples we got a positive by just sticking the swab into the wastewater before adding it to the buffer. Either way, it is essential to use the buffer provided or the test doesn’t work.
11/
If you do get a positive reading, I would suggest having someone else try with the same kind of test with their feces to be sure it isn’t a false positive. Weird shit happens.
12/
If you are the individual, let me know. There is a lab in the US that can do 'official' tests for COVID in stool, and there are doctors that I can put you in contact with that would like to try to help you.
13/
What's more, if we can figure out how these infections occur, and how to treat them, it could potentially help out a whole lot of people.
14/ Image
Two comments I should have made in my thread.

Washington Court House is a town of 15k (not an actual courthouse).

I haven't invaded anyone's privacy. Approximately 1600 people commute between Columbus and WCH. That isn't enough information to pinpoint the source.

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More from @SolidEvidence

Jul 9
I've always found this frustrating.

You or your child has a respiratory infection. It's not flu or COVID. Your doctor can only tell you, 'you have a virus'.

Could it be a little bit more specific?

We hope to help answer this question, non-invasively, and for free.
1/ Image
Contrary to my prior assumptions, many of the most common pathogens are not everywhere, all the time. They occur in discrete waves, often nationwide.

I wrote about this recently with Rhinoviruses, the most frequent cause of the common cold.

2/
As promised, we've now added a standalone readout of the rhinoviruses on our wastewater dashboard.

3/
lungfish-science.github.io/wastewater-das…Image
Read 10 tweets
Jun 29
This is cool. I was poking around at the Rhinovirus (common cold) data and realized that my perception about these viruses was completely wrong.
1/ Image
Rhinoviruses (Rhino is Greek for nose) are picornaviruses in the enterovirus genus (same as polio). Enteros can be GI or respiratory (or both), but Rhinos are usually respiratory, and are the main cause of the common cold.

2/cdc.gov/rhinoviruses/a…
There are 3 species of Rhinoviruses (A, B, and C), and over a hundred antigenically distinct serotypes.

3/en.wikipedia.org/wiki/Rhinovirus
Read 16 tweets
Jun 28
I’m thrilled to announce the update of our water surveillance dashboard.

Many improvements, and our first substantial move into ‘OneHealth’.

Read to the end to find the Easter Egg.
1/
dholab.github.io/public_viz/001…
The first big improvement is that the output is more precise, and interactive. For each data point we tell you the date, the reads mapped, the total reads in each sample, and the reads/billion for each pathogen.

The heat map color is dictated by reads/billion.

2/ Image
As before, we have a dropdown menu (now divided into categories) where you can do a city-to-city comparison of the different pathogens.

We hope to show more locations soon.
3/ Image
Read 17 tweets
Jun 12
Our latest cryptic lineage paper was accepted in PLoS Pathogens.

This paper has some nuanced implications about the origins of SARS-CoV-2.
1/
journals.plos.org/plospathogens/…
There haven’t been a ton of changes to the manuscript since I wrote a post on the preprint, so I’ll make this summary brief and focus on the things that changed.
2/
Cryptic lineages are anachronistic, evolutionarily advanced SARS-CoV-2 lineages detected from wastewater. We are pretty certain they are all from persistent infections.

We developed techniques for finding these lineages and partially reconstruction their genomes.
3/ Image
Read 11 tweets
Jun 6
This is so cool.

I’m pleased to share version 1.0 of our new dashboard for displaying data from our wastewater metagenomic project.

This is a collaborative projected between MU, U. Wisc @dho, and SecureBio; funded by Inkfish and Open Philanthropy.
1/
lungfish-science.github.io/wastewater-das…
For the last 18 months we have been getting weekly composite wastewater samples, isolating the viral fractions (the virome) and randomly sequencing everything.

We average about 1 billion reads per sample.
2/
The project started with Columbia, MO in late 2023, but we’ve expanded to include Chicago, Boston, Boise, and Riverside. We are doing other sites too (and expanding), but these are the first we are reporting.
3/ Image
Read 15 tweets
Apr 20
We are recruiting sewersheds for an expanding project. Basically, we want to learn everything that can be learned from wastewater.
Read on if you are interested.
1/ Image
This is a collaboration with SecureBio that started about 18 months.

Basically, we isolate the viral fraction from wastewater and sequence the crap out of it (~1 billion reads/sample). This is unbiased sequencing; we don’t want to miss anything.
2/
securebio.org
There are three main levels to the analysis of the wastewater virome.
The first is SecureBio’s main focus, which is novel pathogen detection with a particular focus on engineered pathogens.
3/
naobservatory.org/blog/detecting…
Read 16 tweets

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