That is a good question. They are fatal, just not in First World Nations. At least, not until now. (This disease has only been seen previously in tropical 3rd world nations with poor sanitation and access to medical care.)
See these:
How many people die from Ascaris? About 60,000 people die each year from ascariasis. Of those, about 2,000 people (mostly children) die because the worms block their intestine or bile ducts (tubes that connect the liver and gallbladder to the small intestine). The infection is common in tropical or subtropical areas with poor sanitation.
https://www.msdmanuals.com/home/infections/parasitic-infections-nematodes-roundworms/ascariasis
Life-threatening complications of ascariasis in trauma patients: a review of the literature
Ascaris lumbricoides: A Startling Discovery during Screening Colonoscopy
That is a good question. I think they do. Just not in First World Nations. At least, not until now. (This disease has only been seen previously in tropical 3rd world nations with poor sanitation and access to medical care.)
See these:
How many people die from Ascaris? About 60,000 people die each year from ascariasis. Of those, about 2,000 people (mostly children) die because the worms block their intestine or bile ducts (tubes that connect the liver and gallbladder to the small intestine). The infection is common in tropical or subtropical areas with poor sanitation.
Life-threatening complications of ascariasis in trauma patients: a review of the literature
Ascaris lumbricoides: A Startling Discovery during Screening Colonoscopy