Dear Xelda, I am very sorry for the pain and heartbreak you have gone through.
There have been a couple of errors in this thread, and there are a number of people wanting more information, so I will post a few facts and thoughts below. Please be aware that whilst the medical facts are correct, the opinions expressed are my own.
As soon as you said that there were worms in the mouth I was suspecting lungworms, but I wanted to await the necropsy results without seeing the worms myself.
Lungworms generally refers to Rhabdias spp. in snakes and Entomelas spp. in lizards. They have direct life cycles and eggs or larvae may be ingested in fecally contaminated food or water, or hatched larvae can gain access to the host by percutaneous (through unbroken skin) penetration.
Strongyloides (or Strongyles) are intestinal parasites that are very similar in appearance to the lungworm, but they exert their effects primarily through the gastrointestinal (GI) tract. Strongyloides also has a direct life cycle and eggs or larvae may also be ingested in fecally contaminated food or water, or hatched larvae can gain access to the host through intact skin. Diarrhoea and GI dysfunction are the most common symptoms, often in the presence of a mucus-laden stool. The infective larvae do migrate through the lungs, and, in rare cases, respiratory distress is noted.
The eggs of both parasites are very similar. Both can be diagnosed from fresh fecal samples. For those that have never prepared a sample to take to the vets for examination - I collect samples in clingwrap, and wrap them so that the fecal matter is not exposed to any air, hence preventing it from drying out. I then place that in a plastic bag which I also seal for hygienic reasons. Samples can be refrigerated overnight, but should never be frozen. The fresher the sample the better. My personal belief is that all reptiles should undergo fecal examinations initially and yearly as part of a regular check-up. Since I am fortunate to be able to perform my own fecal examinations and hence no cost is involved, I do fecals on all my reptiles twice a year.
Anyway, back to the lungworms - clinical signs are mild unless the infestation is heavy then the snake may present with signs of infection including lethargy, regurgitation, respiratory disease characterized by irregular breathing patterns, gaping, wheezing and production of excessive mucus, which contains the worms and their embryonated eggs. Unsanitary cage conditions are said to enhance a continuous infection. Diagnosis can also be made from looking at the mucus. Heavy loads can also lead to further problems.
Treatment of most worms can be performed with fenbendazole (Panacur) however, I have seen Oxfendazole recommended for these, and treatment is often disappointing. Ivermectin is another option.
It was suggested that round worms or tongue worms may be the problem in this case. Whilst it has already been shown that they are not present here, it would be also very unlikely to see them in oral mucus.
Neither lungworms or roundworms can be transmitted to humans and so zoonotic potential is not an issue. (Tongue worms are another matter entirely.)
With regards to treating with panacur - it is a very safe drug and treats most worms very effectively with no side effects to the reptile. If some of a collection needs treating then it is quite probable that the whole collection does, and so it may be best to just treat all animals. Remember that just because a fecal comes up clean doesn't guarantee that the animal has no worms, it could just be that no eggs were being shed at that time. Once treatment is commenced, the cage must be kept spotless under full quarantine conditions to prevent re-infection. I use three successive fecals as a sign of having eliminated the infection.
My advice to all parties involved here would be to get fecal examinations done on all your animals. Note that if you have lots of animals and can't afford to get that many fecals done - just mix up the poop from a few animals and pay for one examination. Even though you don't know which one produced the infected poop, if one needs treating that they probably all need treating anyway.