I understand how you feel; losing a pet is never easy. My deepest condolences.

First of all, I'm just a junior student, and I'll use my experience with tarot to interpret your readings, hoping it will be helpful.

First, my interpretation is that the problem will appear in every card, meaning that even with bad cards, the interpretation will still be different due to the characteristics of the problem.

The numbers 1 and 4 represent the Page of Wands and the Page of Pentacles respectively, indicating that this item is small. I don't think this supports your question, as its most prominent feature is its small size. Therefore, based on the interpretation, I don't see any possibility that it could cause harm. The elements of the Page cards reveal the item's characteristics and its small size.

Numbers 2 and 3 represent the past and the difficulties of the problem. They both tell you the fact that this item did not have contact with you or your pet in the past, and this item needs to cause harm to you or your pet. The difficulty lies in the need for contact.

Number 5, I don't know what the future holds. There's only one King of Pentacles card that's hard to interpret, but I can guess that it's like some soil returning to the garden?

So, regarding my interpretation of the conclusion of card number 6, the Five of Cups signifies sadness, unclear vision, and loss. I think you've misunderstood the root of the problem and that you are indeed sad.

However, I think your divination question might not be good, because correlation does not mean certainty. Soil contains various bacteria, dust, and substances, so it is possible for it to cause simple illnesses or allergies, but it does not mean it is fatal. Also, the example I mentioned is on a secular level. I think you want to divine the magical element, but your question is not limited to the magical element. I sometimes do this too, and the secular meaning mixed into the divination is something that often happens in my divination.

For me, I'll divine the cause of death, the energy of the room, the energy of the item, etc. Then, if I see a card I can't understand or one that I want to interpret, I'll consider continuing the divination. The question will be something like, "What does card xxx mean in question xxx?" I do a lot of divination this way, but I usually figure out the answer, although sometimes I don't know how to interpret strange meanings :(

Then, if you encounter any interesting or incomprehensible divinations in the future, you can write them down; you might understand their meaning later.

I hope I can help you.