Is it possible to have worms in fertile eggs???

[aegg]

So I have been incubating five duck eggs for the past 18 going on 19 days and I was doing a quick candling to check on air sac development and I noticed in one of them there was a clearer spot, (not completely clear but I can see the larger veins a little bit) now some of my other eggs also have small patches like this clearer spot, but in this one I saw a little stubby worm shape and it seemed to wiggle away when I shined the light at it I've been watching the eggs pretty closely and candling ever 2-3 days and it seems to be developing fine. Anyways my questions are is it possible for worms to be in a duck egg? Could this just be the duckling moving a vein or something? If there was a worm would it kill the duck or is it possible the duck is still alive and thriving? Could this possible worm contaminate the other eggs? (I should also say that I haven't noticed this throughout any point in incubation besides today.)

 

[ChickenCanoe]

It's not impossible but the odds are about 99.99999 out of 100.
Worms don't live in the oviduct.
There also couldn't be cross contamination from one egg to another. How would it get out of one shell and into another?

 

[BelovedBirds]

It's not impossible but the odds are about 99.99999 out of 100.
Worms don't live in the oviduct.
There also couldn't be cross contamination from one egg to another. How would it get out of one shell and into another?

it has to be more possible than that, while candling my duck eggs I found long worms wiggling around inside, white/partially clear, not veins, parasites.
Trouble is I'm pretty sure two of the eggs are fertilised and now I'm worried they'll be doomed.

 

[Miss Lydia]

@Isaac 0 any thoughts?

 

[Isaac 0]

If the worm migrated to the oviduct it may have been captured inside the egg during the ovulation process. A heavy infestation could increase the incidence of this happening.
A picture/video of the egg being candled would be nice to see. Some parts of the egg such as the chalazae can resemble a worm, but I'm unsure whether this would be noticeable late into hatching.
Here are some links I found:
https://www.thepoultrysite.com/publications/egg-quality-handbook/35/roundworms-in-eggs
https://www.sciencedirect.com/science/article/pii/S0032579119492079

If the eggs are from your stock, you should consider having a fecal floating done on their stool to determine if they are carrying a load of worms. This can be accomplished by seeing your nearest vet. The test runs cheap in most areas.