Hei,
I think you could check several possibilities:
- can anyone throw / put some kind of "treaty" (filled with whatever a sick person has on hands which means Do you or your dog have "enemies"), than it will be impossible to trace the poison in her blood now
- has it been one of the first really hot days? If so it might as well have been a sunstroke
- if you walk her out in the morning may she have eaten something unseen/ unrecognised - like a bait?
- has she eaten gras or herbs that morning - perhaps next to a field (my experience is that in the more rural parts peasants do not care what kind of pesticide/rodenticide they use as long as it helps) - which might have been contaminated?
- have you/your family lately started to protect yourselves against gnats, biting houseflies, zecce...? There are repellenti con Dietiltoluamide which human beings use... a dog licking this might take in too much of this poisening substance.
Three years ago it has been some kind of fashion sports in a regione next to your place - right up the Majella and next to the national park - to display poisened baits next to dog owners places...
Hoping that you will find out that your dog has not been poisened intentionally and perhaps you will find some evidence that she knows what went wrong - and now will avoid it....Our dogs are quite special concerning this ability.
ti auguro una bella serata
have a nice evening
koboldine