This may not put her mind at rest-but too see empty "egg shells" then go to google to identify without seeing what hatched out is a bit of a leap
Also what would you have done if you hadn't noticed these or not had internet access
And bear in mind that manure has been incorporated into soil for hundreds or years without as a far as I am aware no ill effects-providing you use sensible precautions like hand washing
Then what are equine worms?-do they infect humans and how from eating something that is grown in the soil will you catch these
What I am really saying is far too many assumptions with no real evidence of anything wrong or to worry about
But then I am not a scientist or doctor so make of this what you will but to me it is a bit like self-diagnosing a headache as a brain tumour because google says it is a possibility
Google is not always your friend