In the set you presented. The only people who have increased risk of ALS are those that play sports on grass fields. Maybe that's the key? Grass.
https://www.cbsnews.com/newyork/news/ticks-lyme-disease-cdc-...
Lots of anecdotal evidence of ALS developing after tick bites, or more concretely infection with Borrelia Burgdorferi.
Probably a genetic component, and other enviromental factors are also involved, but the only dramatic reversals of MND I have seen documented (or heard about) have been either with IV antibiotics [1][3], or years of Mercury chelation [2]
[1] https://invisibledisabilities.org/award-recipients/2011award...
[3] https://pubmed.ncbi.nlm.nih.gov/17212618/
[2] https://www.researchgate.net/publication/317849075_Healing_o...
In the recent book "Chronic" by Dr. Stephen Philips, he's frustrated since he can only treat successfully (outcome similar to Dr. Martz), with antibiotics, about 15% of his ALS-like patients. Considering how uniformly fatal ALS diagnosis is otherwise, even considering how skewed of a sample he might get (patients that already know they are Lyme positive or suspect it), still find it astonishing.
https://storelli.com/blogs/the-storelli-blog/soccer-concussi....
https://journals.lww.com/cjsportsmed/Abstract/2001/10000/Con...
From the first link, here is the ranking of concussion rate:
1. Rugby (4.18/1,000 AE) 2. Ice hockey (1.20/1,000 AE) 3. American football (0.53/1,000 AE) 4. Lacrosse (0.24/1,000 AE) 5. Soccer (0.23/1,000 AE) 6. Wrestling (0.17/1,000 AE) 7. Basketball (0.13/1,000 AE) 8. Softball & field hockey (0.10/1,000 AE) 9. Baseball (0.016/1,000 AE) 10. Cheerleading (0.07/1,000 AE) 11. Volleyball (0.03/1,000 AE)
> Athletic Exposure (AE) is defined as one athlete participating in one game or practice.
Possibly infection when being looked at for a head injury, but I assume they take decent precautions.
Another user proposed grass was the commonality between those sports, in that case grass/dirt entering the eyes?
For forest/streams, possibly water/dirt entering the eyes?
Doesn't really narrow much down though, avoid all dirt, grass, and water.
I think the Borrelia Burgdorfferi hypothesis would fit better, with Lyme disease numbers climbing in recent decades.
Football players also have a 4x increased risk: https://tulsaworld.com/lifestyles/ask-the-doctor-pro-footbal...
But basketball players don’t - go figure.
Stephen Hawkins spent ca 1000h on boats during his college years (interesting since you mentioned that streams might bear some trigger)